]> This ontology is developed specifically to compare problem-solving between biology and technology, using biological cases. The cases are taken from a large literature database which has concentrated, over the years, on physical and mechanical effects, plus a few specific topic areas such as phenolic tanning and arthropod cuticle. There is no good reason for limiting the ontology to this range of topics - invitation to you to enlarge it! Plants and animals are equally represented in that botanical cases have been actively sought. The main comparisons have been achieved via the Inventive Principles of TRIZ, since this seems to be the most reliable and accessible assemblage of design variables. The method is to establish in each case what Function is to be amplified, and what Function might therefore be sacrificed or downgraded. This helps to identify the precise method used to resolve the conflict so defined. I have made it a bit easier to decide what Functions are to be chosen by listing them separately in a class called Problem. I've done the same for the Inventive Principles, giving a big list of Functions. The biological principles are then derived by consideration of the biological functions affected, and expressed as Inventive Principles (IPs). The biological IPs are then used as a key to explore the conflict matrix to see whether they occur in that particular grouping in technology. If so, the pair of Functions so defined is compared with that established at the start, and a judgement made as to whether each pair (if not identical) is describing the same conflict, or which might be the better. In some instances this second pairing has been accepted in preference to the original. Having made this choice, the IPs defined by the conflicting pair of Functions - which have been derived from technology - are then examined and compared with the biological IPs. The degree of overlap or similarity is roughly quantified. The IPs (and the Features) have also been grouped according to whether they are most closely related to changes in substance, structure, energy, space, time or information. This blurring of the IPs is basically sampling differences at a different level of differentiation, and leads to useful differentiation between biological and technical IPs for resolving the same problems. There are some problems which I haven't managed to overcome (surprise!). The main one is that the individual case studies (in the class "SynthesisOf" are equivalent to the thesis-antithesis pair which represents the problem being solved. This is at the heart of the ontology, and so cannot be changed (I've tried and a lot of the usefulness seems to go). With this equivalence, the solution to a particular type of problem, in terms of the manipulations required to effect that solution, is universal covering all organisms. That's the power of the method. But at the same time, then links up very diverse organisms, so that a search for Tetrapods which contain a certain tissue will inevitably come up with insects since there's every chance that the same problem is being solved in the two groups of animals. This is a strength . . . and a weakness!! DON'T FORGET TO RUN THE REASONER, USING FACT++ ---------------------------------- Illustrations of the formulation of DL queries (you can cut-and-paste the queries direct into the DL tab). --------------------------------- To extract solutions of a problem, use: (FeatureToImprove some F_19) and (FeatureThatSuffers some F_28) substituting your own Feature indices (see the annotations to the list of Features for what each number indicates). You can also use a more general term taken from the list Substance, Structure, Energy, Space, Time, Information to see how these Features might be dealt with in Biology and Technology. This also compares different ways in which biology and technology approach the same type of problem. ---------------------------------------- To extract biological solutions which use Energy-based Principles, use: hasBiologicalSolution some IP_Energy (similarly for the other 5 terms - see above) ----------------------------------------------------- To compare biological and technology (i.e. TRIZ) solutions, use: (hasBiologicalSolution some IP_Information) and (hasTrizSolution some IP_Energy) -------------------------------------------------------- Checking the database of TRIZ solutions (often called the TRIZ Contradiction Matrix). Woven bone (part of an article by John Currey) seems to use the Inventive Principles 11, 35, and 27 (my estimate). The following DLQuery turns up three possible entries from the Matrix: hasTrizSolution some (IP_11 and IP_35 and IP_27) These represent the solutions to three different contradictions or conflicts defined from engineering patents. Look at the Features of the Conflicts (click on the F_ numbers) and see which (if any) might apply. You can then see whether biology is using design principles we also use, or whether there is something here which we haven't yet explored. "FeatureToImprove" represents the advantage which is being sought, or the challenge which is being imposed on the system "FeatureThatSuffers" represents the aspect which might reduce in performance as a result of the required or imposed change. For instance a stronger bridge might have to be heavier. 'Weight of stationary object' then appears as the antithesis, as it is the usual downside of making something stronger. This is a sub-function of an Inventive Principle. Listed under 'Functions'. A great help when deciding which Inventive Principle to use. The TRIZ solution and the biological solution are taken from the list of Inventive Principles, and are the changes which, if implemented, might achieve the advantage requested by the thesis without the disadvantage represented by the antithesis. The TRIZ solution and the biological solution are taken from the list of Inventive Principles, and are the changes which, if implemented, might achieve the advantage requested by the thesis without the disadvantage represented by the antithesis. values are given in GPa Values are given in MPa Common in most animals Functions work better when separated, but need to be integrated to form a system Lunch box with special compartments for hot and cold solid foods and for liquids Habitat is divided into independent patches Internal organs are bounded by membranes which separate them physically and metabolically. Especially true of arthropods. Lose a twig or leaf by erecting an isolation layer Take heat from the environment Absorb gas, liquid, heat, etc. Acquire bits of material from the surroundings; stick bits on to an object, making it larger Pre-empt an event Be able to accommodate change and so avoid problems Add material which won't change any chemical characteristics Add material of any sort Ad a material which interacts with the surface to become a part of it Use or generate a force for flying Join particles or objects together 10 2 Frogs, toads, salamanders, newts, caecilians Increase or magnify This section contains all the tools needed to describe and analyse in TRIZ. Actually, only the TRIZ conflict matrix is used at present. 0 Even-toed ungulates Put together from a range of separate parts, which may be similar or different Behaviour which elicits a response different in kind or magnitude Movement which is exaggerated to one side or the other Feedback through the ears using sound Lose a leg or tail by breaking the skeleton at some point. Usually done by muscle contracting across a plane of weakness Destroy or reduce symmetry, in any mode Go to sleep A colony or nest (Hymenoptera, salps, coral, cnidaria) or swarm or school (fish) or population or community (different degrees of cohesion) breaks up into individual organisms Seeds in a pod; asexual reproduction; binary fission; 6 6 12 This section contains all the aspects of biology - morphology, chemistry, etc - which characterise the mechanisms which resolve the conflicts resolved in the Data section. Molecules of different chemistry can bond due to same spacing of bonding sites. E.g. chitin to beta-protein F_18 Thin-walled shell deforms out of the plane Misdirection - any sense (sound, light, shape, movement . . . ) Store intercepted energy - light, strain, etc. Material with holes in it 140 130 Amphioxus Positive feedback for amplification; negative feedback for control Reflect, absorb or diffract light at different wavelengths Change reflection/diffraction, etc characteristics at elevated temperature Become capable of greater or lesser degrees of mobility Change length, width, height, etc Become stiffer or more compliant, as a material or a structure Do it faster or slower Change spacing between elements so that interference effects are modulated Turn the lights off; use black pigment Change intensity, colour or angle of illumination Look at things in more detail Sensing in liquid medium 200 150 Hydrozoa (Hydra, siphonophores) Scyphozoa (jellyfish) Cubozoa (Boz jellies) Anthozoa (sea anemones, corals, sea pens) 2 30 The rate of senescence in maternal performance increases with early-life fecundity in red deer Nussey, D. H., L. E. Kruuk, A. Donald, M. Fowlie and T. H. Clutton-Brock Rates of senescence in maternal breeding performance in a natural population of red deer (Cervus elaphus) used a mixed model framework to control for between-individual variation. Senescence began at 9 years of age in two maternal performance traits. In both traits, females that produced more offspring in early life had faster rates of senescence. This tradeoff is evident alongside significant effects of individual quality on late life breeding performance. These results present rare evidence in support of the disposable soma and antagonistic pleiotropy theories of senescence from a wild vertebrate population and highlight the utility of mixed models for testing theories of ageing. 2006 Positive: reproduce earlier and more often F_39 Negative: Grow older quicker F_15 Ecology Letters 9: 1342-50. Rolff, J. and M. T. Siva-Jothy Copulation corrupts immunity: a mechanism for a cost of mating in insects Positive: Reproduction needs reduced immunological defence for better compatibility F_16 Negative: This leaves the individual more susceptible to disease F_30 In Tenebrio molitor mating reduces a major humoral immune effector-system (phenoloxidase) in both sexes, mediated by juvenile hormone. Because both juvenile hormone and phenoloxidase have highly conserved functions across all insects, the mechanism is similarly likely to be highly conserved. The positive physiological function of mating-induced juvenile hormone secretion is gamete and accessory gland production: we propose that its negative effects on immune function are the consequence of physiological antagonism. Therefore, we have identified a physiological tradeoff between mating and immunity. Our results suggest that increasing mating success can result in increasing periods of immune suppression, which in turn implies that reproductively successful individuals may be more vulnerable to infection by, and the negative fitness effects of, pathogens. 2002 Proceedings of the National Academy Of Sciences of the United States of America 99: 9916-8. Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 142: 65-73. Romero, L. M., D. Strochlic and J. C. Wingfield New feathers may be more important to the survival of a bird than the ability of corticosterone to respond maximally to a stressor. Corticosterone is seasonally modulated in many passerines, with plasma concentrations lowest during the prebasic molt when all feathers are replaced. The birds reduce corticosterone during molt and avoid its degradative effects on proteins and its inhibition of protein synthesis, since it could slow protein deposition during feather production and result in a longer period of degraded flight. Empty or corticosterone-filled silastic implants were inserted into captive European starlings (Sturnus vulgaris) and white-crowned sparrows (Zonotrichia leucophrys) undergoing induced (feather replacement after plucking) and natural molts. Corticosterone-implanted birds showed a significantly decreased rate of feather growth compared to control animals. Basal corticosterone concentrations of induced molt and non-molting birds were compared but no difference was noted. 2005 Corticosterone inhibits feather growth: potential mechanism explaining seasonal down regulation of corticosterone during molt Positive: Reduction of corticosteroid allows feathers to grow more quickly F_39 Negative: Reduction of corticosteroid increases exposure to stress F_35 Proceedings of the National Academy Of Sciences of the United States of America 96: 5826-31. 1999 Rome, L. C., C. Cook, D. A. Syme, M. A. Connaughton, M. Ashley-Ross, A. Klimov, B. Tikunov and Y. E. Goldman Trading force for speed: why superfast crossbridge kinetics leads to superlow forces Superfast muscles power high-frequency motions such as sound production and visual tracking. As a class, these muscles also generate low forces. Swimbladder fibers have evolved a 10-fold faster crossbridge detachment rate than fast-twitch locomotory fibers, but the crossbridge attachment rate has remained unchanged. These kinetics result in very few crossbridges being attached during contraction of superfast fibers (only approximately 1/6 of that in locomotory fibers) and thus low force. This imbalance between attachment and detachment rates is likely to be a general mechanism that imposes a tradeoff of force for speed in all superfast fibers. Positive: Muscle contracts quickly F_09 Negative: Not enough time for crossbridges to form, so force is less F_10 in a potential field, limit position changes such as raising & lowering a heavy object as few times as possible over as short a distance as possible. Don't stop! Go from waxy to absorbent Change from a straight line to a helix, either as an object or as a pathway Become active Stop moving in a line and move in an arc or spin 2009 Mach, K. J. Mechanical and biological consequences of repetitive loading: crack initiation and fatigue failure in the red macroalga Mazzaella Journal of Experimental Biology 212: 961-976. Individual waves are not forceful enough to account for observed rates of breakage; fatigue may be more important. The smaller male gametophytes endured more loading cycles before breakage than tetrasporophytes, which in turn lasted longer than the larger female gametophytes; likewise, Mazzaella splendens withstood more loading cycles at a given repeated stress than M. flaccida. Crack formation frequently occurred in association with endophytes and female gametophyte reproductive structures, suggesting a cost of endophyte infection and a tradeoff between reproduction and mechanical survival. crocodiles, gavials, caimans, and alligators: 23 species Comb jellies This is the database section of the ontology, containing examples of biological systems which are analysed as TRIZ objects in order to compare biology with the engineering which native TRIZ describes 10 These examples are typical of descriptive biology and so are concerned with morphology and physiology, behaviour, evolution etc. There is not necessarily any indication of function, although of course function is implicit. They are therefore the base-line of biology and a large part of their description is contained within the "Biology" section of the ontology. Journal of Insect Physiology, 58: 1582-1588. Pupae of the cotton bollworm, Helicoverpa armigera from a northern population enter diapause in response to short daylengths (D strain) while moths from a southern population exhibit no diapause under the same conditions (N strain). Crosses and backcrosses to D strain showed a clear long-day response, similar to that of the D strain, suggesting that the photoperiodic response controlling diapause in this moth is heritable. The incidence of diapause in F1 N strain was significantly higher than those in F1 D strain, indicating that the male parent plays a more important role in the determination of diapause. The N strain also showed a short-day photoperiodic response at the lower temperature indicating that the N strain can still enter a photoperiodically induced diapause, depending on the rearing temperature. Inheritance of diapause does not fit an additive hypothesis and the capacity for diapause is transmitted genetically in the manner of incomplete dominance with non-diapause characteristic partially dominant over the diapausing. Diapause duration in hybrid pupae was also influenced by their inheritance from both parents. Diapause duration in hybrid pupae was intermediate between those of their parents. Both induction and duration of diapause are under the control of polygene. 2012 Chen, C, Q.-W. Xia, Y.-S. Chen, H.-J. Xiao and F.-S. Xue Inheritance of photoperiodic control of pupal diapause in the cotton bollworm, Helicoverpa armigera (Hübner). The characin fish, Astyanax mexicanus, has sighted surface and numerous blind cave populations. The cave populations are largely independent in their origins. A clearly defined change in ecological conditions, from surface to cave, is correlated with a dramatic reduction in sleep in three independently derived cave populations. The alleles for reduced sleep in two of the cave populations are dominant to the surface alleles. Only a small number of loci with dominant effects are involved. Sleep is an evolutionarily labile phenotype, highly responsive to changes in ecological conditions. To our knowledge, this is the first example of a single species with a convergence on sleep loss exhibited by several independently evolved populations correlated with population-specific ecologies Current Biology, 21: 671-676. Evolutionary convergence on sleep loss in cavefish populations. Duboué, E. R., A. C. Keene and R. L. Borowsky 2011 Teng, B., S. Dao, Z. R. Donaldson and G. F. Grether New communal roosting tradition established through experimental translocation in a Neotropical harvestman Animal Behaviour, 84: 1183-1190. 2012 A species of harvestman (Prionostemma sp.) that forages solitarily at night has formed roosting aggregations in spiny palms by dawn in the same sites for over a decade, and yet the aggregation sites do not appear to differ from unused sites in tree characteristics or microclimate. By moving harvestmen to new location release sites attracted harvestmen at much higher rates than did matched control sites. Most individuals that came to release sites were new recruits, and one site continued to attract several harvestmen for at least 7 days. Among sites used by the harvestmen, the size of the aggregations was strongly predicted by microclimate and spiny palm characteristics. Together these findings support the hypothesis that attraction to conspecific cues is the primary mechanism responsible for the long-term stability of aggregation sites, while also suggesting that site characteristics play a previously unrecognized role. Understanding how site traditions develop may have direct applications in conservation. Journal of Morphology, 272: 34-49 2011 We provide a detailed description of the ultrastructure of deer hair fibers. Guard hairs and underhairs from the winter coat of red deer (Cervus elaphus), and antler velvet hairs from the same species were examined. All fibers displayed the typical keratin fiber morphology of overlapping cuticle cells surrounding a core of cortex cells, and often a centrally-located medulla, but there were considerable differences in the diameter, cuticle thickness, and scale pattern, and in the relative amounts of cortex and medulla along individual fibers, and between the different types of fiber. In addition, closer examination of cortex cells using transmission electron microscopy revealed considerable differences in the arrangement of intermediate filaments in the different fiber types. Fine underhairs appeared similar to fine wool fibers from sheep because intermediate filament arrangements were very similar to those found in wool orthocortex cells and paracortex cells. In addition, a similar bilateral distribution of these cell types was evident. However, in the antler velvet hairs and the guard hairs, intermediate filament arrangements were more variable and complex, and showed similarities to those in heterotype cortex cells described for human hair. Morphology and Ultrastructure of Antler Velvet Hair and Body Hair From Red Deer (Cervus elaphus) Woods JL, D. P. Harland, J. A. Vernon, G. L. Krsinic and R. J. Walls Tuberous electrosensory systems are found in two orders of weakly electrogenic fishes, the Gymnotiformes of South America and the Mormyriformes of Africa. At the periphery, electrosensory neurons use combinations of rate and/or timing to broadly encode information. This information is subjected to complex filtering at the next stage of processing, a hindbrain structure known as the electrosensory lateral line lobe (ELL). Neurons in the ELL receive massive descending feedback that can dramatically alter their encoding properties. Neurons in the ELL, in turn, transmit electrosensory information to the midbrain where complex features, such as moving objects and certain social signals, are extracted. Fortune E. S. and M. J. Chacron 2011 Physiology of Tuberous Electrosensory Systems Encyclopedia of Fish Physiology 366-374 Journal of Structural Biology, 174: 512-526. Seidl, B, K. Huemer, F. Neues, S. Hild, M. Epple and A. Ziegler Ultrastructure and mineral distribution in the tergite cuticle of the beach isopod Tylos europaeus Arcangeli, 1938. The surface of the tergites of Tylos europaeus bears epicuticular scales, sensilla and micro-tubercles. A distal layer of the exocuticle is characterised by a low density of organic fibres and the presence of magnesium-calcite. Surprisingly, the mineral forms regions containing polyhedral structures alternating with smooth areas. Between sub-domains within the distal exocuticle calcite varies in its crystallographic orientation. Proximal layers of the exocuticle and the endocuticle are devoid of calcite and the mineral occurs in the form of . Using thin sections of mineralised cuticle we describe for the first time that amorphous calcium carbonate forms tubes around single protein-chitin fibrils. 2011 2012 Molecular characterization and gene expression of juvenile hormone binding protein in the bamboo borer, Omphisa fuscidentalis. Journal of Insect Physiology, 58: 1493-1501. OfJHBP transcription in the fat body was moderately high during 3rd, 4th and 5th instars, then rapidly increased, reaching a peak during early diapause. The expression remained high in mid-diapause, then decreased in late-diapause until the pupal stage. Both juvenile hormone analog (JHA), methoprene, 20-hydroxyecdysone (20E) exhibited a similar stimulatory pattern in OfJHBP expression in diapausing larvae. OfJHBP mRNA levels gradually increased and showed a peak of gene expression on the penultimate, then declined to low levels in the pupal stage. For in vitro gene expression, both of JHA and 20E induced OfJHBP mRNA expression in fat body. Fat body maintenance in vitro with JHA induced OfJHBP mRNA expression to high levels within the first 30 min whereas 20E induced gene expression at 120 min. To study the synergistic effect of these two hormones, fat body was incubated in vitro with JHA or 20E or a combination of both hormone for 30 min. Induction of OfJHBP expression by JHA and 20E was significantly greater than that of either hormone alone. Ritdachyeng,E., M. Manaboon, S. S. Tobe and T. Singtripop Co-Variation of Chemical and Mechanical Defenses in Lima Bean (Phaseolus lunatus L.) Plants usually express multiple chemical and mechanical defenses simultaneously. The interplay of these defenses is still poorly understood, as predictions range from negative associations such as allocation tradeoffs to positive correlations forming synergistic defense syndromes. Surprisingly, little empirical evidence exists on the co-variation of multiple plant defenses. We analyzed different genotypes of lima bean (Phaseolus lunatus L.) for the expression of two direct chemical defenses [cyanogenic potential (constitutive), polyphenolase (inducible)], two indirect chemical defenses [volatiles and extrafloral nectar (both inducible)] and a constitutive mechanical defense (hook-shaped trichomes). While the occurrence of trichomes was positively correlated with cyanogenesis, these traits showed a tradeoff with polyphenol oxidase activity, release of volatiles, and secretion of nectar. Hook-shaped trichomes were abundantly present in four of 14 genotypes investigated, and were found only in one monophyletic group of an AFLP-based tree, thus indicating a single evolutionary origin within the species. Our findings show that different lima bean genotypes express either one of two defense systems: 1) high constitutive defense via cyanogenesis and trichomes or 2) high inducible defense via volatiles, nectar, and polyphenolase activity. Journal of Chemical Ecology 39: 413-7. 2013 Ballhorn, D. J., A. L. Godschalx and S. Kautz Many animals and plants survive harsh conditions (heat, cold) by dehydrating. Done properly, this preserves the tissues and membranes Plant, cell & environment 36: 405-18. Pineda-Garcia, F., H. Paz and F. C. Meinzer Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding 2013 Late-successional species resist drought through two mechanisms: high resistance of xylem to embolism, or reliance on high stem water storage capacity. High sapwood water reserves delay the effects of soil drying by transiently decoupling plant and soil water status. Resistance to soil drought results from the interplay between variations in the vulnerability of xylem to embolism, reliance on water reserves in the sapwood and reduction in leaf area, leading to a tradeoff of avoidance of soil drought against tolerance. Positive: A larger brain makes you more intelligent Negative: A larger brain requires more energy to grow American Journal of Physical Anthropology 143: 579-90. Encephalization, expensive tissues, and energetics: An examination of the relative costs of brain size in strepsirrhines Barrickman N. L. and M. J. Lin The evolution of encephalization requires that energetic challenges be met. Several hypotheses, such as the maternal energy and expensive tissue hypotheses, have been proposed to explain how some species are able to provide adequate energetic resources for large brains. The former incorporates maternal investment strategies, such as extended life history and elevated resting metabolic rate, which contribute to the growth of a large brain. The latter incorporates the reduction of gut size, which increases available energy for the maintenance of adult brain size. This study examines a sample of strepsirrhines, testing the hypothesis that encephalized species utilize some combination of the above-mentioned strategies. Infants and juveniles from three species at the Duke Lemur Center (DLC) were measured periodically to arrive at head and body growth trajectories. These data were used to determine the energetic tradeoff among the offspring. The examination of gestation length, weaning age, intestinal size and resting metabolic rate was used to assess adult brain maintenance and maternal energetic contribution. The results reveal that Daubentonia, the most encephalized and thus human-like of the lemurs, does not experience an energetic trade-off between brain and body during ontogeny, but does exhibit a trade-off between extensive brain growth and possibly reduced intestinal growth. Also, maternal energy is utilized. Encephalized lemurs, such as Daubentonia, have higher resting metabolic rate, while encephalized lorisiforms have a longer period of gestation. These results demonstrate that there are several strategies for meeting the energetic demands of encephalization, and they can be manifested differentially across taxa. 2010 Moving object can easily change position in space, either on its own, or as a result of external forces. Vehicles and objects designed to be portable are the basic members of this class. Weight of moving object: The force that the body exerts on its support or suspension. Stationary object does not change position in space, either on its own, or as a result of external forces. Consider the conditions under which the object is being used. Weight of stationary object The mass of the object, in a gravitational field. The force that the body exerts on its support or suspension, or on the surface on which it rests. Moving object can easily change position in space, either on its own, or as a result of external forces. Vehicles and objects designed to be portable are the basic members of this class. Length of moving object. Any one linear dimension, not necessarily the longest, is considered a length. Stationary object does not change position in space, either on its own, or as a result of external forces. Consider the conditions under which the object is being used. Moving object can easily change position in space, either on its own, or as a result of external forces. Vehicles and objects designed to be portable are the basic members of this class. A geometrical characteristic described by the part of a plane enclosed by a line. The part of a surface occupied by the object. OR the square measure of the surface, either internal or external, of an object. Stationary object does not change position in space, either on its own, or as a result of external forces. Consider the conditions under which the object is being used. A geometrical characteristic described by the part of a plane enclosed by a line. The part of a surface occupied by the object. OR the square measure of the surface, either internal or external, of an object. Moving object can easily change position in space, either on its own, or as a result of external forces. Vehicles and objects designed to be portable are the basic members of this class. The cubic measure of space occupied by the object. Length x width x height for a rectangular object, height x area for a cylinder, etc. Stationary object does not change position in space, either on its own, or as a result of external forces. Consider the conditions under which the object is being used. The cubic measure of space occupied by the object. Length x width x height for a rectangular object, height x area for a cylinder, etc. The velocity of an object; the rate of a process or action in time Force measures the interaction between systems. In Newtonian physics, force = mass X acceleration. In TRIZ, force is any interaction that is intended to change an object's condition. Force per unit area. Also, tension. The external contours, appearance of a system. The wholeness or integrity of the system; the relationship of the system's constituent elements. Wear, chemical decomposition, and disassembly are all decreases in stability. Increasing entropy is decreasing stability. The extent to which the object is able to resist changing in response to force. Moving object can easily change position in space, either on its own, or as a result of external forces. Vehicles and objects designed to be portable are the basic members of this class. The time that the object can perform the action. Service life. Mean time between failure is a measure of the duration of action. Also, durability. Stationary object does not change position in space, either on its own, or as a result of external forces. Consider the conditions under which the object is being used. The time that the object can perform the action. Service life. Mean time between failure is a measure of the duration of action. Also, durability. The thermal condition of the object or system. Loosely includes other thermal parameters, such as heat capacity, that affect the rate of change of temperature. Light flux per unit area, also any other illumination characteristics of the system such as brightness, light quality, etc. Moving object can easily change position in space, either on its own, or as a result of external forces. Vehicles and objects designed to be portable are the basic members of this class. The measure of the object's capacity for doing work. In classical mechanics, Energy is the product of force times distance. This includes the use of energy provided by the super-system (such as electrical energy or heat.) Energy required to do a particular job. Stationary object does not change position in space, either on its own, or as a result of external forces. Consider the conditions under which the object is being used. The measure of the object's capacity for doing work. In classical mechanics, Energy is the product of force times distance. This includes the use of energy provided by the super-system (such as electrical energy or heat.) Energy required to do a particular job. The time rate at which work is performed. The rate of use of energy. Use of energy that does not contribute to the job being done. See 19. Reducing the loss of energy sometimes requires different techniques from improving the use of energy, which is why this is a separate category. Partial or complete, permanent or temporary, loss of some of a system's materials, substances, parts, or subsystems. Partial or complete, permanent or temporary, loss of data or access to data in or by a system. Frequently includes sensory data such as aroma, texture, etc. Time is the duration of an activity. Improving the loss of time means reducing the time taken for the activity. "Cycle time reduction" is a common term. The number or amount of a system's materials, substances, parts or subsystems which might be changed fully or partially, permanently or temporarily. A system's ability to perform its intended functions in predictable ways and conditions. The closeness of the measured value to the actual value of a property of a system. Reducing the error in a measurement increases the accuracy of the measurement. The extent to which the actual characteristics of the system or object match the specified or required characteristics. Susceptibility of a system to externally generated (harmful) effects. A harmful effect is one that reduces the efficiency or quality of the functioning of the object or system. These harmful effects are generated by the object or system, as part of its operation. The degree of facility, comfort or effortlessness in manufacturing or fabricating the object/system. Simplicity: The process is NOT easy if it requires a large number of people, large number of steps in the operation, needs special tools, etc. "Hard" processes have low yield and "easy" process have high yield; they are easy to do right. Quality characteristics such as convenience, comfort, simplicity, and time to repair faults, failures, or defects in a system. The extent to which a system/object positively responds to external changes. Also, a system that can be used in multiple ways for a variety of circumstances. The number and diversity of elements and element interrelationships within a system. The user may be an element of the system that increases the complexity. The difficulty of mastering the system is a measure of its complexity. Measuring or monitoring systems that are complex, costly, require much time and labour to set up and use, or that have complex relationships between components or components that interfere with each other all demonstrate "difficulty of detecting and measuring." Increasing cost of measuring to a satisfactory error is also a sign of increased difficulty of measuring. The extent to which a system or object performs its functions without human interface. The lowest level of automation is the use of a manually operated tool. For intermediate levels, humans program the tool, observe its operation, and interrupt or re-program as needed. For the highest level, the machine senses the operation needed, programs itself, and monitors its own operations. Could imply self-assembly and emergent mechanisms in natural systems. Could also be the implementation of a mechanism as a direct consequence of the morphology. The number of functions or operations performed by a system per unit time. The time for a unit function or operation. The output per unit time, or the cost per unit output. Biological growth? Individual 'sub-features' are listed under 'Problems' which is the preferred check list Current biology : CB 18: 1520-4. Positive: Bees survive by taking extra time to identify predators (more difficult if predator is camoflaged) Negative: Less time for foraging 2008 Ings, T. C. and L. Chittka Speed-accuracy tradeoffs and false alarms in bee responses to cryptic predators Is predator-avoidance learning and memory disrupted by cryptic coloration of predators, such as crab spiders? We exposed foraging bumblebees to controlled predation risk from robotic crab spiders that were cryptic or highly contrasting. Bees slow their inspection flights after learning that there is a risk from cryptic spiders. The adjustment of inspection effort results in accurate predator detection, leveling out predation risk at the expense of foraging time. Overnight-retention tests reveal no decline in performance, but bees that had experienced cryptic predators are more prone to rejection of foraging opportunities on safe flowers than those that had experienced conspicuous predators. Therefore, bees in the cryptic-spider treatment made a functional decision to trade off reduced foraging efficiency via increased inspection times and false-alarm rates against higher potential fitness loss from being injured or eaten. Many organisms reproduce at high rates producing less “well designed” individuals which can grow more quickly, reproduce younger, and utilise a more ephemeral habitat Predator pressure can force organisms to reproduce younger Romero, C., B. M. Bolker and C. E. Edwards The New phytologist 182: 261-71. Stem responses to damage: the evolutionary ecology of Quercus species in contrasting fire regimes 2009 The ability of tree stems to recover from damage is critical for survival and may explain species distributions across disturbance regimes. Two primary responses to stem damage, decay compartmentalization and wound closure, act in concert to limit decay and pathogen spread. A previous study demonstrated a tradeoff between wound responses that varied with anatomical traits, but its wide taxonomic range made it hard to analyze responses in an evolutionary context. Here, we tested the stem wound responses of 13 species of Quercus inhabiting three habitats across a gradient of fire intensity. We also quantified anatomical and structural traits and phylogenetic position, in order to assess the relative contributions of ecological adaptation and phylogenetic history in determining traits. Xylem anatomical traits were phylogenetically constrained, while phloem traits and damage responses varied with habitat. Across habitats, hammock and sandhill species closed bark wounds effectively, whereas scrub species limited the spread of xylem decay. There was a tradeoff between wound closure and decay compartmentalization within the white+live oaks. The fact that some wound response traits are phylogenetically constrained while others respond to ecological pressures suggests that damage responses integrate mechanisms operating at several levels within plants. PLoS genetics 8: e1003102. We challenged populations of an RNA virus, bacteriophage Phi6, to evolve in a novel temperature environment where heat shock imposed extreme virus mortality. A single amino acid substitution in the viral lysin protein P5 (V207F) favored improved stability, and hence survival of challenged viruses, despite a concomitant tradeoff that decreased viral reproduction. This mutation increased the thermostability of P5. Crystal structures of wild-type, mutant, and ligand-bound P5 reveal the molecular basis of this thermostabilization -- the Phe207 side chain fills a hydrophobic cavity that is unoccupied in the wild-type -- and identify P5 as a lytic transglycosylase. The mutation did not reduce the enzymatic activity of P5, suggesting that the reproduction tradeoff stems from other factors such as inefficient capsid assembly or disassembly. 2012 Selective pressure causes an RNA virus to trade reproductive fitness for increased structural and thermal stability of a viral enzyme Dessau, M., D. Goldhill, R. L. McBride, P. E. Turner and Y. Modis Responses of floodplain forest species to spatially condensed gradients: a test of the flood-shade tolerance tradeoff hypothesis 2006 Battaglia L. L. and R. R. Sharitz Oecologia 147: 108-18. We test the tradeoff hypothesis in an old-growth bottomland hardwood forest by (1) comparing shade and moisture profiles of woody juveniles versus random points and (2) using individual-based sampling of woody juveniles to model probability of occurrence in response to distance-to-water table and canopy openness gradients. We found that juveniles of all species combined occupied a similar range of distance-to-water table compared to measurements taken at random points, but average canopy openness above seedlings was significantly higher than at random points. On average, shade-tolerant species, with the exception of Acer rubrum, were found in shaded areas that were also drier, whereas less shade-tolerant taxa, plus A. rubrum, were found in wetter, more open areas, suggesting a tradeoff between flood and shade tolerance. Predictive models of species occurrence, which incorporate the availability of canopy and microtopographic conditions, indicated that three taxa (Fraxinus pennsylvanica, Quercus spp., and Ulmus americana) had patterns consistent with a flood-shade tolerance tradeoff. In contrast, Asimina triloba, Celtis laevigata, and Liquidambar styraciflua had positive responses when the joint stresses of flooding and shade were diminished. A. rubrum appeared to be the most tolerant to both stresses. The acquisition of function is often associated with destabilizing mutations, giving rise to the stability-function tradeoff hypothesis. To test whether function is also accommodated at the expense of foldability, fibroblast growth factor-1 (FGF-1) was subjected to a comprehensive phi-value analysis at each of the 11 turn regions. FGF-1, a beta-trefoil fold, represents an excellent model system with which to evaluate the influence of function on foldability: because of its threefold symmetric structure, analysis of FGF-1 allows for direct comparisons between symmetry-related regions of the protein that are associated with function to those that are not; thus, a structural basis for regions of foldability can potentially be identified. The resulting phi-value distribution of FGF-1 is highly polarized, with the majority of positions described as either folded-like or denatured-like in the folding transition state. Regions important for folding are shown to be asymmetrically distributed within the protein architecture; furthermore, regions associated with function (i.e., heparin-binding affinity and receptor-binding affinity) are localized to regions of the protein that fold after barrier crossing (late in the folding pathway). These results provide experimental support for the foldability-function tradeoff hypothesis in the evolution of FGF-1. Notably, the results identify the potential for folding redundancy in symmetric protein architecture with important implications for protein evolution and design. Longo, L., J. Lee and M. Blaber Protein science : a publication of the Protein Society 21: 1911-20. 2012 Experimental support for the foldability-function tradeoff hypothesis: segregation of the folding nucleus and functional regions in fibroblast growth factor-1 Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology 197: 351-9. The peripheral auditory system performs a spectral decomposition of sound that should result in a tradeoff between frequency and temporal resolution. Temporal resolution was greater in house sparrows (Passer domesticus) than Carolina chickadees (Poecile carolinensis) and white-breasted nuthatches (Sitta carolinensis), as predicted based on previous observations of broader auditory filters (lower frequency resolution) in house sparrows. Furthermore, within chickadees, individuals with broader auditory filters had greater temporal resolution. In contrast to predictions however, temporal resolution was similar between chickadees and nuthatches despite broader auditory filters in chickadees. These results and the results of a model simulation exploring the effect of broadened auditory filter bandwidth on temporal resolution in the auditory periphery strongly suggest that frequency resolution constrains temporal resolution in songbirds. Species differences in temporal resolution may reflect adaptations for efficient processing of species-specific vocalizations, while individual differences within species may reflect experience-based developmental plasticity or hormonal effects. Songbirds tradeoff auditory frequency resolution and temporal resolution 2011 Henry, K. S., M. D. Gall, G. M. Bidelman and J. R. Lucas Positive: If frequency resolution is high . . . Negative: . . . then temporal resolution tends to be low 2012 Sequence-function-stability relationships in proteins from datasets of functionally annotated variants: the case of TEM beta-lactamases Abriata, L. A., M. L. Salverda and P. E. Tomatis FEBS Letters 586: 3330-5. ß-lactamase in bacteria breaks down antibiotics; TEM is a gene. A list of TEM lactamase variants with different substrate and inhibition profiles was compiled and analyzed. Trends show that loops are the main evolvable regions (i.e. least destabilising) in these enzymes, gradually accumulating mutations which generate increasingly complex functions. Many mutations present in evolved enzymes are also found in simpler variants, probably originating functional promiscuity. Following a function-stability tradeoff, the increase in functional complexity driven by accumulation of mutations fosters the incorporation of other stability-restoring substitutions, although our analysis suggests they might not be as "global" as generally accepted and seem instead specific to different networks of protein sites. The members of this class are all descriptions of a function, and could therefore be included in the class "Synthesis" except that I'm not sure what the problem was that was being solved. However, they can be described, at least in part, by Inventive Principles. Little is known about the extent to which solitary individuals differ in their social behaviour from group-living ones within the same species. Using the socially flexible African striped mouse, we tested through a series of dyadic encounters in a neutral arena whether group-living mice that later became solitary differed from their philopatric conspecifics. We compared philopatric and solitary mice both before and after dispersal. We predicted striped mice that became solitary would be more aggressive, less amicable and more investigative than individuals that remained group living, and would change their social behaviour after changing from group to solitary living in the same direction (becoming more aggressive, etc.). Dyadic encounters were conducted on 42 group-living individuals and 13 individuals that were first group living and later became solitary. Striped mice that became solitary showed higher levels of aggression and social investigation than their conspecifics that remained group living, differences that were already present before individuals dispersed. Dispersing striped mice showed a negative correlation between amicability and aggression towards opposite-sex individuals, which could be linked to sexual motivation. A second behavioural syndrome in the form of a positive correlation between aggression and social investigation towards same-sex individuals might have indicated that dispersing striped mice were ready to defend their own territory. Our study provides evidence that within the same population and at the same time, individuals that disperse and become solitary differ behaviourally from their group-living conspecifics even before dispersal, and further change their behaviour after dispersal in an evolutionarily adaptive way. 2012 Schoepf I. and C. Schradin Differences in social behaviour between group-living and solitary African striped mice, Rhabdomys pumilio Animal Behaviour, 84: 1159-1167. Construction and nanomechanical properties of the exoskeleton of the barnacle, Amphibalanus reticulatus. Journal of Structural Biology, 176: 360-369. 2011 The parietal shell of Amphibalanus reticulatus is constructed of six compartments yielding a truncated cone geometry, which is neatly fixed onto the basal shell that attaches the organism to the substrate surface. The connections among the different compartments happen through sutured edges and also have chemical interlocking to make the junctions impermeable. Also, the shell parts are furnished with hollow channels reducing the overall mass of the construction. The structure and functions of different parts of the exoskeleton are identified and outlined. Finally, the mechanical properties such as modulus, hardness and fracture toughness of the exoskeleton obtained by indentation techniques are discussed. Raman S. and R. Kumar Total small RNAs (sRNAs) in Apis mellifera foragers and dancers were extracted and analyzed. 12.62% of the unique sRNAs (the number of sequence types) was shared between foragers and dancers, but their expression accounted for 92.92% of the total sRNAs (the number of all sequence reads). Out of 58 miRNAs, 54 were present in both foragers and dancers and most of them were down-regulated in dancers. 86 and 104 novel miRNAs were detected in foragers and dancers, respectively. Furthermore, two known miRNAs have lower expressions in dancers; their target genes were associated with kinase, neural function, synaptotagmin and energy. Thus miRNAs are substantially different between the foraging and dancing stages, and suggest that miRNAs might regulating dancing in honey bees. Li, L., F. Liu, W. Li, Z. Li, J. Pan, L. Yan, S. Zhang, Z. Y. Huang and S. Su Journal of Insect Physiology, 58: 1438-1443. 2012 Differences in microRNAs and their expressions between foraging and dancing honey bees, Apis mellifera L. 2011 Structural characterization and mechanical behavior of a bivalve shell (Saxidomus purpuratus) The structure and mechanical behavior of Saxidomus purpuratus bivalve shell were investigated. XRD results show that the only form of calcium carbonate present in the shell is aragonite. The inner and middle layers have a cross-lamellar structure, while the outer layer has porosity and does not have tiles, but instead has blocky regions. The hardness of middle and inner layer are close in both plane view and cross section, but the hardness of outer layer is significantly less, especially in the plane view. The compressive strengths with loading along the three orientations were established and significant differences were found. The Weibull strength at 50% of the probability of failure varies between 59 and 148 MPa and is dependent on the loading orientation and in condition of shell (dry vs. hydrated). These differences are interpreted in terms of the anisotropic structure and coarser structure of the external layer. Yang,W., N. Kashani, X.-W. Li, G.-P. Zhang and M. A. Meyers Materials Science and Engineering: C, 31: 724-729. Journal of Insect Physiology, 58: 1525-1533. To reduce water loss, D. kikkawai is more melanised and D. leontia has more cuticular lipid. D. kikkawai can acclimatise and reduce water loss but D. leontia cannot. 2012 Divergent strategy for adaptation to drought stress in two sibling species of montium species subgroup: Drosophila kikkawai and Drosophila leontia. Ramniwas S. and B. Kajla Drosophila leontia (warm adapted) has been considered as a sister species of D. kikkawai (sub-cosmopolitan) with a very similar morphology. Cuticular lipid mass is positively correlated with desiccation resistance and negatively correlated with cuticular water loss in D. leontia. Greater melanization, reduced water loss and better dehydration tolerance confer greater desiccation resistance on D. kikkawai while the reduced rate of water loss is the only possible mechanism to enhance desiccation tolerance in D. leontia. The use of organic solvents has supported water proofing role of cuticular lipids in D. leontia but not in D. kikkawai. Thus melanization and cuticular lipids may represent alternative strategies for coping with dehydration stress in melanic versus non-melanic drosophilids. In both these species, carbohydrates were utilized under desiccation stress but a higher level of stored carbohydrates was evident in D. kikkawai. Further, we found increase desiccation resistance in D. kikkawai through acclimation while D. leontia lacks such a response. Thus, species specific divergence in water balance related traits in these species are consistent with their adaptations to wet and dry habitats. Salminen,T. S., L. Vesala and A. Hoikkala Journal of Insect Physiology, 58: 1541-1547. In two northern Drosophila montana populations with different patterns of voltinism: (1) when maintained before eclosion in short day conditions, representing early autumn, the flies develop faster and are lighter than when maintained in long day conditions, representing early summer (2) photoperiodic time measurement is apparently reset after eclosion, adjusting the development of flies according to post eclosion conditions (3) the sensitive period for diapause induction is after eclosion (4) there is no direct connection between egg-to-adult development time of females and their reproductive state at adulthood, which suggests that these traits can be determined by photoperiodic cues through different time measurement systems. Independence of photoperiodic regulation of life-history traits before and after eclosion enables D. montana to respond quickly to changing photoperiods and match life-history traits according to season Photoperiodic regulation of life-history traits before and after eclosion: Egg-to-adult development time, juvenile body mass and reproductive diapause in Drosophila montana. 2012 Ravens utilize a large set of calls and show individually distinctive call repertoires. Moreover, they show advanced social tactics during foraging, suggesting that they are capable of dealing with individual conspecifics. When confronted with food that is difficult to access, ravens produce "haa" yells that attract other ravens and, thus, have been hypothesized to serve as "functionally referential signals". We found that food calls show individual call characteristics in fundamental frequency and intensity providing ravens with the opportunity to respond according to these individually distinct features. Furthermore, ravens discriminated between unfamiliar ravens, indicating that they can discern individual differences. Raven food calls are individually distinct and that the birds may be capable of differentiating between food-calling individuals. 2012 Who wants food? Individual characteristics in raven yells Animal Behaviour 84: 1123-1130. Boeckle, M., G. Szipl and T. Bugnyar The ability of insects to adhere to surfaces is facilitated by the use of adhesive organs found on the terminal leg segments. These adhesive pads are inherently "tacky" and are expected to be subject to contamination by particles, leading to loss of function. Here, we investigated the self-cleaning of ants and beetles by comparing the abilities of both hairy and smooth pad forms to self-clean on both high and low energy surfaces after being fouled with microspheres of two sizes and surface energies. We focused on the time taken to regain adhesive potential in unrestrained Hymenopterans (Polyrhachis dives and Myrmica scabrinodis) and Coccinellids (Harmonia axyridis and Adalia bipunctata) fouled with microspheres. We found that the reattainment of adhesion is influenced by particle type and size in Hymenopterans, with an interaction between the surface energy of the contaminating particle and substrate. In Coccinellids, reattainment of adhesion was only influenced by particle size and substrate properties. The adhesive organs of Coccinellids appear to possess superior self-cleaning abilities compared with those of Hymenopterans, although Hymenopterans exhibit better adhesion to both surface types. The Journal of Experimental Biology, 215: 279-286. Orchard, M. J., M. Kohonen and S. Humphries 2012 The influence of surface energy on the self-cleaning of insect adhesive devices Physalin B inhibits Trypanosoma cruzi infection in the gut of Rhodnius prolixus by affecting the immune system and microbiota Castro, D. P., C. S. Moraes, M. S. Gonzalez, I. M. Ribeiro, T. C. B. Tomassini, P. c. Azambuja and E. S. Garcia Journal of Insect Physiology, 58: 1620-1625 2012 Physalin B is a natural secosteroid, extracted from Physalis angulata, which is an immune-modulator in Rhodnius prolixus. R. prolixus was infected with Trypanosoma cruzi and treated with physalin B which significantly decreased the number of T. cruzi in the gut. A concentration of physalin B 1000 times greater was required to produce the same effect in vitro. All infected insects treated with physalin B had more bacteria in the gut than the non-treated controls infected with T. cruzi. Infected insects treated with physalin B topically and by contact had lower antibacterial activity in the gut. Those dosed orally with physalin B produced higher levels of nitrite and nitrate in the gut. Physalin B decreases transmission of T. cruzi by indirectly inhibiting parasite development in the vector R. prolixus by means either of increasing the bacterial burden or increasing the concentration of nitrite and nitrate. These functions are a mixture of biological, engineering and general design. Some are quite specific (e.g. "autotomise") and others are very general (e.g. "add material"). However, they have all been derived by trial and error as the ones which seem to make the most general sense and/or occur with reasonable frequency. None of them refers to more than one Inventive Principle (where they are also listed) so they form a basis for choosing the Principles and distinguishing between them. If you want to hunt for a particular one and it doesn't occur in the alphabetical order of the list, go to the search box at the top right of the Protege screen and enter the search term (or the first few letters) preceded by an asterisk. Once you've decided on a Function, if it doesn't quite fit go to the IP number under which it is also filed. There you will find other functions from this list which are similar in effect. Skunk Bombardier beetle 1990 Grazing in a turbulent environment: energy dissipation, encounter rates, and efficacy of feeding currents in Centropages hamatus The creation of feeding currents by calanoid copepods increases encounter rates of copepods with their food and provides and advantage in dilute nutritional environments. Small-scale turbulence has also been hypothesized to increase the encounter rate between planktonic predators and their food. Centropages hamatus was exposed to turbulent and nonturbulent environments at two prey concentrations to quantify the influence of turbulence on feeding current efficacy. Turbulent energy dissipation rates used in the experiment were in the range of 0.05-0.15 cm2. sec-3. In the nonturbulent environments, feeding currents increased the encounter rates of C. hamatus 3-5 times that of control encounter areas. In turbulent environments, encounter rates were not increased by feeding currents, yet C. hamatus continued to create feeding currents. Energetic calculations indicate a tradeoff in the value of turbulence to a copepod feeding on phytoplankton. While turbulence is probably beneficial at low food concentrations, it may be deleterious at high food concentrations. Proceedings of the National Academy Of Sciences of the United States of America 87: 1653-7. Marrase, C., J. H. Costello, T. Granata and J. R. Strickler Oecologia 149: 194-202. The growth-mortality tradeoff: evidence from anuran larvae and consequences for species distributions Schiesari, L., S. D. Peacor and E. E. Werner 2006 A tradeoff affecting the ability to grow under high versus low resource levels has been commonly hypothesized to influence species distributions across resource gradients in a wide variety of taxa. This influence is dependent on individual growth being proportional to traits that affect demographic processes such as mortality. However, data on how individual growth scales with demographic performance are rare. We conducted a mesocosm experiment, and re-analyzed data from a similarly designed field experiment, to examine the relationship between growth and mortality in two tadpole species that segregate across a resource gradient. Overall, environmental conditions leading to faster growth also lead to lower mortality rates. However, species differed in this relationship. Leopard frogs achieved faster growth than wood frogs, but their absolute mortality was greater and increased steeply as growth decreased. Conversely, absolute mortality of wood frogs was lower and less strongly dependent on growth. These interspecific differences suggest a second tradeoff, that between maximizing growth rates or minimizing mortality, with potentially important demographic consequences. Leopard frogs grow faster than wood frogs in productive ponds, but are excluded from unproductive ponds dominated by wood frogs due to accelerating mortality rates with declining realized growth. A review of the literature suggests that in diverse taxa, including plants, microcrustaceans and drosophilids, patterns in mortality are consistent with this tradeoff indicating that the mechanism we demonstrate could be a link between individual performance and demographic rates influencing species distributions in other systems. Many organisms have adapted to fire so it opens up the habitat and provides a sudden influx of nutrients as the burnt material dissolves into the soil, thus effectively reducing competition from other organisms. Many plants in hot and dry environments produce aromatics which accelerate and support fire 6 1 1 1 4 5 5 2012 H. Padmanabha, F. Correa, M. Legros, H. F. Nijhout, C. Lord and L. P. Lounibos In Aedes aegypti, three life history traits that are critical to urban population dynamics and control are: size, developmental rate and mortality due to starvation. Our model of reserve dependent growth (RDG), which considers a potential tradeoff between the accumulation of reserves and structural biomass, predicted reduced size at higher temperatures, but increased reserves relative to size, are supported by the available evidence in Aedes spp. Temperature-size patterns in mosquitoes are driven by a net benefit of finishing the growing stage with proportionally greater reserves relative to structure at higher temperatures. By relating basic energy flows to three fundamental life history traits, we provide a mechanistic framework for development of A. aegypti to which ecological complexity can be added. Ultimately, this could provide a framework for developing and field testing hypotheses on how processes such as climate variation, density dependent regulation, human behavior or control strategies may influence population dynamics of A. aegypti and associated disease risk. Journal of Insect Physiology 58: 1597-1608. An eco-physiological model of the impact of temperature on Aedes aegypti life history traits 2013 Hummingbird flight muscle is estimated to have among the highest mass-specific power output among vertebrates, based on aerodynamic models. However, little is known about fundamental contractile properties of their remarkable flight muscles. We hypothesized that hummingbird pectoralis fibers generate relatively low force when activated in a tradeoff for high shortening speeds associated with the characteristic high wing beat frequencies that are required for sustained hovering. Our objective was to measure maximal force-generating ability (maximal force/cross-sectional area, Po/CSA) in single, skinned fibers from the pectoralis and supracoracoideus muscles, which power the wing downstroke and upstroke, respectively, in hummingbirds (Calypte anna) and in another similarly-sized species, zebra finch (Taeniopygia guttata), which also has a very high wingbeat frequency during flight but does not perform a sustained hover. Mean Po/CSA in hummingbird pectoralis fibers was very low - 1.6, 6.1 and 12.2 kN/m2, at 10, 15 and 20oC, respectively. Po/CSA in finch pectoralis fibers was also very low (for both species, ~5% of the reported Po/CSA of chicken pectoralis fast fibers at 15oC). Force generated at 20oC/force generated at 10oC ('Q10-force' value) was very high for hummingbird and finch pectoralis fibers (mean = 15.3 and 11.5, respectively), compared to rat slow and fast fibers (1.8 and 1.9, respectively). Po/CSA in hummingbird leg fibers was much higher than in pectoralis fibers, at each temperature, and the mean Q10-force was much lower. Thus, hummingbird and finch pectoralis fibers have an extremely low force-generating ability, compared to other bird and mammalian limb fibers, and an extremely high temperature-dependence of force generation. The extrapolated maximum force-generating ability of hummingbird pectoralis fibers in vivo (~48 kN/m2) is, however, substantially higher than the estimated requirements for hovering flight of C. anna. The unusually low Po/CSA of hummingbird and zebra finch pectoralis fibers may reflect a constraint imposed by a need for extremely high contraction frequencies, especially during hummingbird hovering. The Journal of Experimental Biology (MS.) Reiser, P. J., K. C. Welch, R. K. Suarez and D. L. Altshuler Very low force-generating ability and unusually high temperature-dependency in hummingbird flight muscle fibers Dead plant parts can move because they expand by different amounts when they absorb water Hydraulic efficiency compromises compression strength perpendicular to the grain in Norway spruce trunkwood 2011 The aim of this study was to investigate bending stiffness and compression strength perpendicular to the grain of Norway spruce (Picea abies (L.) Karst.) trunkwood with different anatomical and hydraulic properties. Hydraulically less safe mature sapwood had bigger hydraulic lumen diameters and higher specific hydraulic conductivities than hydraulically safer juvenile wood. Bending stiffness (MOE) was higher, whereas radial compression strength lower in mature than in juvenile wood. A density-based tradeoff between MOE and hydraulic efficiency was apparent in mature wood only. Across cambial age, bending stiffness did not compromise hydraulic efficiency due to variation in latewood percent and because of the structural demands of the tree top (e.g. high flexibility). Radial compression strength compromised, however, hydraulic efficiency because it was extremely dependent on the characteristics of the "weakest" wood part, the highly conductive earlywood. An increase in conduit wall reinforcement of earlywood tracheids would be too costly for the tree. Increasing radial compression strength by modification of microfibril angles or ray cell number could result in a decrease of MOE, which would negatively affect the trunk's capability to support the crown. We propose that radial compression strength could be an easily assessable and highly predictive parameter for the resistance against implosion or vulnerability to cavitation across conifer species, which should be topic of further studies. Rosner, S. and B. Karlsson Trees 25: 289-299. 2008 We tested the effects of growth characteristics and basic density on hydraulic and mechanical properties of mature Norway spruce (Picea abies (L.) Karst.) wood from six 24-year-old clones, grown on two sites in southern Sweden differing in water availability. Hydraulic parameters assessed were specific hydraulic conductivity at full saturation (ks100) and vulnerability to cavitation (Psi50), mechanical parameters included bending strength (sigma b), modulus of elasticity (MOE), compression strength (sigma a) and Young's modulus (E). Basic density, diameter at breast height, tree height, and hydraulic and mechanical parameters varied considerably among clones. Clonal means of hydraulic and mechanical properties were strongly related to basic density and to growth parameters across sites, especially to diameter at breast height. Compared with stem wood of slower growing clones, stem wood of rapidly growing clones had significantly lower basic density, lower sigma b, MOE, sigma a and E, was more vulnerable to cavitation, but had higher ks100. Basic density was negatively correlated to Psi50 and ks100. We therefore found a tradeoff between Psi50 and ks100. Clones with high basic density had significantly lower hydraulic vulnerability, but also lower hydraulic conductivity at full saturation and thus less rapid growth than clones with low basic density. This tradeoff involved a negative relationship between Psi50 and sigma b as well as MOE, and between ks100 and sigma b, MOE and sigma a. Basic density and Psi50 showed no site-specific differences, but tree height, diameter at breast height, ks100 and mechanical strength and stiffness were significantly lower at the drier site. Basic density had no influence on the site-dependent differences in hydraulic and mechanical properties, but was strongly negatively related to diameter at breast height. Selecting for growth may thus lead not only to a reduction in mechanical strength and stiffness but also to a reduction in hydraulic safety. Rosner, S., A. Klein, U. Muller and B. Karlsson Tree Physiology 28: 1179-88. Tradeoffs between hydraulic and mechanical stress responses of mature Norway spruce trunk wood Hydraulic efficiency and safety of branch xylem increases with height in Sequoia sempervirens (D. Don) crowns The hydraulic limitation hypothesis suggests that water supply to leaves becomes increasingly difficult with increasing height of the tree. We conjectured that the vertical hydrostatic gradient which gravity generates on the water column in tall trees would cause increased resistance to embolism and implosion and a decrease in hydraulic conductivity. Measurements of resistance of branch xylem to embolism did indeed show an increase in 'safety' with height. However, the expected decrease in conductivity was not observed. Instead, hydraulic conductivity of branches increased slightly, while leaf-specific hydraulic conductivity increased dramatically, with height. The latter could be largely explained by strong vertical gradients in specific leaf area. The increase in conductivity with height corresponded to a decrease in xylem wall thickness, an increase in percentage of earlywood and slight increase in conduit diameter. These changes are probably adaptive responses to the increased transport requirements of leaves growing in the upper canopy where evaporative demand is greater. The lack of a safety-efficiency tradeoff may be explained by opposing height trends in the pit aperture and conduit diameter of tracheids and the major and semi-independent roles these play in determining xylem safety and efficiency, respectively. Burgess, S. S., J. Pittermann and T. E. Dawson Plant, cell & environment 29: 229-39. 2006 1 1 1 1 2 Segmentation - divide an object into independent parts, make an object easy to dismantle or increase fragmentation. Division of an “object” is seen in insect colonies, when groups of ants, bees or wasps act as a coherent unit when they defend the nest or swarm. Many animals are simply segmented and most plants are modular (leaves, flowers, stem, root). Modern genetics shows that the underlying instructions are very similar, so that an insect’s antenna can be persuaded to develop as a leg. Ease of dismantling is seen in autotomy and abscission mechanisms, in which parts of plants and animals can be made to fall off in a controlled manner. Examples are autumnal leaf fall and loss of limbs or tail by many animals when challenged. It is a general rule when designing a structure that compressive and tensile elements should be minimised and kept separate, and that either one (usually the compressive element) if reduced to zero will allow the least amount of the other element (tensile) to be used. This is seen in animals and plants with hydrostatic skeletons (which accounts for all non-woody plants). This can only be done with pre-stress (see Principle 9). Extraction - extract, isolate or remove an interfering or necessary part or property from an object. A beetle's wing is opened by the action of muscles at the base of the wing, in contrast to the bird or bat which has instrinsic muscles. Many animals or plants develop particular features at the expense of others. Flowers are a relatively late development in the evolution of plants, but are obviously successful in allowing the plant have a specialised organ for reproduction. Similarly the pupal stage in many insects provides a separation between larva and winged adult, allowing a complete change in the morphology. Local quality (“Qualities” are the properties of the object or system.) Change a system or object's structure from uniform to non-uniform; change an external environment (or external influence) from uniform to nonuniform. Make each part of an object or system function in conditions most suitable for its operation. Make each part of an object fulfill a different and useful function. This is probably where evolution belongs, since the basic expansion of an evolutionary series relies on the development of small adaptations within an overall structure or bauplan. Each internal organ in an animal has its own micro-environment, often surrounding itself with a membrane to emphasise this separation. Any organism has to be multifunctional, even a single cell, and so is very heterogeneous. There is much to be learned here regarding the optimisation between the various functions and the optimisations involved in spatial separation and functional integration. Invertebrates tend to allow more autonomy to their internal organs which possibly makes them more robust. Asymmetry - change the shape of an object from symmetrical to asymmetrical or increase its asymmetry. Very few biological objects are symmetrical at all levels and so may be difficult to model and analyse. The asymmetry is usually a direct response to the usage or history of the object, and so represents an immediately adaptive and efficient response to function. Symmetry probably occurs in engineering only for ease of fabrication and calculation. Consolidation - approximate or merge identical or similar objects or functions, assemble identical or similar parts to perform parallel operations. Bring closer together (or merge) identical or similar objects; assemble identical or similar parts to perform parallel operations. Make operations contiguous or parallel; bring them together in time. In many animals (for instance insects and snails) the nervous system is primitively divided in numbers of local units (ganglia) which tend to fuse in the more evolved members of the groups. This presumably allows faster central signal processing. This concept also applies to growth, in that tissues can be considered as the consolidation of a number of similar cells. The assembly of tissues into organs and of organs into individuals comes into the same category. Hierarchy is therefore divided between this Principle and Principle 7, 'Nesting'. Also related to another TRIZ concept - Mono-Bi-Poly - where items are integrated to make multifunctional objects. Universality - make a part or object perform multiple functions; eliminate the need for other parts. The number of parts and operations is decreased, and useful features and functions retained. The outer covering of the insect is waterproof, the skeleton, a food store, a signalling system (sound and vision), and a sensing material. Wood supports the tree and transports nutrient from the leaves and water to them. Nesting - nest objects sequentially inside another or make one part pass through a cavity in the other. The female aphid reproduces parthenogentically (i.e. without need of sperm). The “nesting” allows unborn aphids to have their offspring developing inside them, even several generations further on. The aphid can then reproduce extremely quickly when it finds itself on a good food supply, and ensures that all the individuals are genetically the same, which under these conditions ensures that they are all best adapted for that particular food source. This general principle can also be exemplified by deployable structures in insects, where many of them are made by the retraction of one segment or part inside another. Examples are stings, egg-laying tubes, tubular mouthparts. Anti-weight - merge a heavy object with one that provides lift or use aerodynamic, hydrodynamic, buoyant and other forces. Commonly used in locomotion (flight, swimming). Many organisms are planktonic, floating in water but going up and down on a daily cycle. They do this either by active swimming or by changing their bouyancy. Many flying animals use upward currents of air (thermals, updrafts) in a similar fashion. Bouyancy can be passive (density control) or active (relying on hydro- or aero-dynamics). Prior counteraction - prestress the material in tension to allow the structure to take compressive forces, or provide protection before the challenge. In fracture mechanics there are many toughening mechanisms which are 'hidden' within the material and not expressed until the structure starts to fail. Examples are microcracks, sacrifical layers, etc. The cellulose in all non-woody plants is prestressed in tension which allows the amount of solid material in the structure to be minimised (see Principle 1). The provision of protection against the physical environment is a general property of living things - extreme examples are penguin feathers (against cold) and thick bark in eucalyptus trees which can peel off (protection against dust pollution and fire). Prior action - prepare the environment or the organism for the next action. Preliminarily perforated packaging is easy to open. Organisms in temperate climates are linked to the seasons, so that (for instance) mating occurs at a suitable time for the offspring to be born when there is the most food around. In the shorter term hormones prepare us for various actions (an example is adrenalin). Jet lag is an expression of this phenomenon, in that we are physiologically prepared for sleeping in addition to responding to changes in external light conditions. Prior cushioning - Prepare emergency means beforehand to compensate for the relatively low reliability of an object. Our nervous system as a pattern analyser can extrapolate present observations to predict the probability of events. Organisms also have various degrees of redundancy and safety factors built in to their design to allow for failure rates in use. The failure rate is closely related to the reproductive rate of the organism - an organism which reproduces at a higher rate can afford greater loss of individuals. Equipotentiality - in a potential field, limit position changes such as raising and lowering a heavy object as few times as possible over as short a distance as possible. This comes into the general area of energy conservation, Examples are strain energy storage in locomotion, which is reduced by reducing inertia. That is why a running athlete folds his / her legs as far as possible on the recovery stroke, reducing the effective length of the leg. Functional reversal - swap actions, for instance instead of cooling an object, heat a neighbouring one, make movable parts fixed and fixed parts movable, or invert the object. Examples would be the eversible gut of a star fish which wraps itself around the prey item, thus eliminating “swallowing”; the exodigestion of food by flies and other insects, which spread enzymes over the food and suck up the partially digested material. Spheroidality - use curves instead of straight lines, use rollers, balls, spirals, domes; use rotary motion and centrifugal forces. There are relatively few straight lines in nature because physics and engineering are more complex than we usually admit. Although there is only one rotating joint in nature (at the base of the flagellum, the “hair” which pushes bacteria along) there are many examples of spirals and domes, probably because they are relatively simple shapes to define (by internal pressure or by having a growing edge which is slightly asymmetrical) and can produce structures which will take forces without generating shear through the thickness of the shell. Dynamics - Relax stresses or strains so that shapes or parts find optimal operating conditions and are movable or adaptive rather than rigid or inflexible. A lamp has been made more controllable introducing hinges. The penalty has been an increasing number of parts. The solution has been further improved by transition to elastic components. The single elastic component has many micro-level parts, very many very small hinges. Here the segmentation principle (1) helps the system to get more dynamic. Generally, if the improvement by one principle causes new difficulties, involve a different principle to solve the new problem. Stiff and immovable structures are often replaced by more dynamic ones: wings that change form and other dynamic structures. The cells which comprise organisms, or the structures they produce, accept only low loads from the environment and bend out of the way of high loads, or readjust in the presence of (detected) high loads. The nervous system is necessary for detection; the muscular system is necessary for the readjustment in the short term, or growth in the long term. Partial or excessive action - a problem may be simplified if it is under- or over- performed. While manufacturing an electrical conductor with channels, a ceramic plate is covered entirely and the conducting layer removed from between the channels. Control mechanisms in animals tend (as might be expected) to be optimally damped, but at several levels. Peripherally (by basic inertial design and the actuation system) and centrally (by the nervous system). Excessive action is seen in various reproductive strategies which require large amounts of gametes or seeds to be distributed; partial action is involved in the preparations of lines of fracture for abscission and dehiscence. Another dimension - use an extra dimension of space or deployment. Biological organisms make maximal use of the space available. Their limitation is usually mechanical rather than conceptual. Thus the more primitive organisms tend to align themselves with environmental surfaces because they lack the stiffness or stability to move away from them. Mosses grow on the ground or as low mounds; only in higher plants has a stem of sufficient stiffness been developed for the plant to raise itself off the substrate. Mechanical vibration - vibrate; increase frequency; use resonant frequency. There are many examples of oscillators in nature, presumably because once the conditions for a resonant frequency have been established it is not too difficult to maintain those conditions. In animals there are Central Pattern Generators which control functions such as chewing, the heart beat and locomotion. These are delay loops with feedback. Resonant frequencies are also very common in the mechanical parts of a locomotory system (leg-as-pendulum) and communication (vocalisations, insect noises). Periodic action - use periodic or pulsating actions or change the periodic magnitude or frequency; use pauses between impulses for something different. Many insects communicate using modulation of a frequency rather than changing the basic frequency - presumably this is energy-efficient. The bombardier beetle produces a pulsed stream of hot phenols and peroxide which it can squirt at its predator at high velocity. Continuity of useful action - work continuously and eliminate idle or intermittent actions or work. Many natural systems have down-time (sleep) built in to them either for reconstitution or because the daily cycle presents times when the environment is not optimal (too hot, too cold, too dark, too light). In a constant environment (beyond the Polar circles) sleep tends to be absent or continuous depending on season. So perhaps this is a general principle which is not much observed or understood. More highly evolved organisms tend to function at constant temperature. Skipping - do things at high speed. This can keep an organism out of trouble. In surgery, the longer the patient is anesthetized, the higher the risk of failure and complications. Open-heart surgery that once took 8 hours or more is now done in less than one hour, using combinations of new tools and methods. The basilisk lizard can run across water if it pushes its feet down fast enough (unfortunately this effect is limited by scaling). It implies high rates of energy dissipation (=high power) which is not usual in biology. Arguably this therefore applies to ballistics mechanisms which involve elastic strain energy storage, such as the jumping of small animals and the distribution of seeds. Convert harm into benefit - use harmful factors to achieve a positive effect; eliminate two harmful factors by addition; amplify a harmful factor so that it is no longer harmful. Each time the system survives an attack, information is generated that makes the system better protected from the next attack: surviving an illness generates antibodies that protect the victim from the next attack. Many organisms respond to minor damage by increasing their growth rate; plants being eaten by insects frequently grow more quickly. Many organisms have adapted to fire so it opens up the habitat and provides a sudden influx of nutrients as the burnt material dissolves into the soil, thus effectively reducing competition from other organisms. Many plants in hot and dry environments produce aromatics which accelerate and support fire. Feedback - feedback to improve a process or action; modulate feedback for further improvement. Feedback is a primary learning mechanism and therefore highly adaptive. All organisms have feedback built in, since the chemical reactions which maintain them can occur under only relatively controlled conditions. Feedback can be chemical (e.g. cellular metabolism), neural (cf. fine-tuning optical or aural response), neuromuscular (co-ordinated movements) etc. Nature is replete with feedback mechanisms since they can greatly improve the performance of a wide variety of functions which are not mechanically perfect or optimised. A particularly good example is the use of feedback in frequency analysis in the middle ear. There is also much feedback in the control of density of populations. Mediator - use an intermediary carrier or process or merge one object temporarily with another. A definition of parasitism, where one animal or plant lives inside another for a greater or lesser part of its life-cycle, or of the use of tools. An enzyme. Any molecule which binds some other molecule, such as an adhesive or water-binding space-filler. Self-service - dual use or recycling. Self-treatment and self-test. Patients can perform some medical tests on themselves, like the measurement of blood pressure, or blood sugar, or testing for fertility previously done only by medical personnel. In some cases, the patient also adjusts his/her treatment or behavior based on the test results. Flying locusts breathe by opening the front and back breathing pores (spiracles) allowing the air to run through the tracheae which may also cool the flight muscles. Many insects use the haemolymph (“blood”) to take heat away from the flight muscles in the thorax and radiate it from the abdomen. Copying - use simpler cheaper copies. Replace an object, or process with optical (visible, infrared or ultraviolet) copies. “Copying” (reproduction) is one of the main features of a living organism. Mimicry in animals can be in the form of camouflage (copying aspects of the physical or plant environment) or warning colouration (bright colours which imitate poisonous or dangerous animals - prevalent amongst insects) (Fuji and Novales 1969). Some plants mimic the physical environment (e.g. stoneplants - Lithops). And of course the nervous system keeps a continually updated virtual copy of the environment in store. Designed obsolescence - Replace a cheap object with many cheap objects. Many organisms reproduce at high rates producing less “well designed” individuals which can grow more quickly, reproduce younger, and utilise a more ephemeral habitat. Some protective mechanisms associated with dehiscence or shedding (e.g. protective bark) come under this heading. Mechanics substitution - replace a mechanical effect with a sensory (optical, acoustic, taste or smell) effect. Transition to better controllable interactions is often associated with transition to the micro-level or segmentation. Many organisms mark their territory - e.g. wolves urinating at strategic markers around the perimeter (smell) and the spring song of birds stakes their claim both to land and mates (sound). Pneumatics and hydraulics - use gas and liquid instead of solid. One way to change to the micro-level. Since gas and liquid are metabolically cheap they are commonly used for skeletal functions (where water can take compressive pressure), flotation devices (teleost fish, Nautilus, Sepia, etc.) and locomotion (“jetting” squid). Flexible shells and thin films - use flexible shells and thin films instead of 3D structures; use them to isolate the object from the external environment. Many materials have two components that must be kept separate until shortly before use. They can be packaged away within membranous organelles or within separate cells. Hydraulics is also used - turgor pressure makes the cell stiff. Weight is reduced without loss of stiffness. Non-woody plants are confined within a stiff epidermis which takes out most of the tensile forces within the structure. Porous materials - make an object porous; use the pores to introduce a useful substance or function. Wood is made of tubes with spirally wound fibres. These tubes transmit liquid when young and provide a tough light material when dead. Hedgehog spines and porcupine quills are cellular and very light and stiff. Cellular materials are a basic structural feature of biological systems. Colour changes - change the colour or transparency of an object or its external environment. Squid and cuttlefish can express complex behaviours (agonism, emotion?) by controlling colour cells in their skin. They, and many fish, can change colour to blend in with the background. They can also control their reflectivity. Homogeneity - make an object and its support or container of the same material. Many nests are made from the surrounding material - bird’s nests (twigs, branches), solitary bees’ and termites’ nests (mud). The materials from which an organism is made are very inhomogeneous in texture, but basically only lipids, proteins and polysaccharides with added ceramic. Discarding and recovering - discard (dissolve, digest) or modify / recycle / repair obsolescent parts. All cells contain an enzyme (lysozyme) for their dissolution and recycling - it is carefully packaged away! The tail and gills of the tadpole are autolysed when it is transformed into the frog; the exoskeleton of an insect can be partly dissolved for food; teeth of rabbits and rats grow continuously and are worn away during nibbling to keep a sharp edge. The porous chorion of an insect egg is made by deposition and selective dissolution. Parameter changes - change state, concentration, consistency, compliance, temperature. Considering individual molecules absorbed from the surroundings, and the way they work in the body (e.g. with enzymes) this is a pervasive aspect of biology (as of technology). Oxygen is transported attached to haemoglobin, which greatly increases its “solubility”; many animals and plants can survive being dried or frozen which enables them to live in marginal habitats; stiffness of plants can be changed by internal pressure in cells, allowing movement. Echinoderms change the stiffness of their collagenous tissue. Most poikilothermic (“cold-blooded”) animals and many plants can control their temperature within wide limits. Phase transitions - changes in volume, loss or absorption of heat, etc. The most important type of phase change is from random polymeric to liquid crystal. This underlies many structures in nature such as silk and many collagen structures. Hydrophobic molecules (e.g. spectrins in the cell membrane) change their hydration state with changes in temperature. Thermal expansion - use thermal expansion (or contraction) of materials. Temperature is rarely a variable in biology, but water content is. Mathematically, turgor mechanisms can be identical to bi (or poly!) metallic strips. Plants can grow through concrete using only the expansion of their cells as water is attracted in to them up an osmotic gradient; dead plant parts can move because they expand by different amounts when they absorb water. Strong oxidants - increase redox potential by stages. A dangerous ploy for natural systems, but some specialists (e.g. the bombardier beetle) can cope with hot hydrogen peroxide! Otherwise this is a good description of many enzyme systems. And oxygen was probably poisonous to archaeobiology. Inert atmosphere - replace a normal environment or object with an inert one. A similar move would be to add a protective coating, as happens when your skin goes brown in the sun - the melanin absorbs the UV radiation. Composite materials The use of nothing (air or vacuum) as one of the elements of a composite—nothing is an available resource in all situations! Examples include honeycomb and sponge. Very few biological materials are not composite and there are many different types. Individual 'sub-principles' are listed under 'Functions' which is the preferred check list A tradeoff between immunocompetence and sexual ornamentation in domestic fowl Proceedings of the National Academy Of Sciences of the United States of America 96: 4478-81. Positive: High testosterone makes males look gaudy and sexy, suggesting strength F_19 Negative: But high testosterone also downgrades their immune defences F_31 Verhulst, S., S. J. Dieleman and H. K. Parmentier Females often select their mates on the basis of the size or intensity of sexual ornaments, and it is thought that such traits are reliable indicators of male quality because the costliness of these traits prevents cheating. The immunocompetence handicap hypothesis is a recently proposed mechanistic explanation of these costs and states that males carry ornaments at the expense of their resistance to disease and parasites. The tradeoff between immunocompetence and sexual ornamentation was hypothesized to arise as a consequence of the dual effect of androgens on ornamentation (+) and immune function (-). To test this hypothesis, we compared comb size between male domestic chickens Gallus domesticus of lines divergently selected for antibody responses to sheep erythrocytes (three lines: selected for low response or high response and a control line). The importance of comb size in inter- and intrasexual selection is well established, and comb size is strongly dependent on testosterone level. Comb size was larger in the males of the low line than in the high line, and comb size of control males was intermediate, indicating a tradeoff between ornamentation and immunocompetence. Testosterone (T) levels varied in a similar fashion (TLow > TControl > THigh), suggesting that this hormone could mediate the tradeoff between ornamentation and immunocompetence. These results support the idea that a tradeoff with immune function may constrain the expression of secondary sexual ornaments. 1999 F_30 Changing turgor causes plant organs to move Echinoderms can change the stiffness of their skin Linking individuals with ecosystems: experimentally identifying the relevant organizational scale for predicting trophic abundances Ovadia, O. and O. J. Schmitz Body size is an important determinant of vulnerability to predation and thus should influence the way individuals tradeoff time spent foraging against time spent avoiding contact with predators. Such tradeoffs can then influence the degree of damage herbivores inflict on their plant resources. We assigned field-caught grasshoppers to three distinct body size treatment groups (small, normal, and large) and crossed them with two spider predator treatments (spider present and absent) in a fully replicated design. We found size-dependent differences in survival and development of the grasshoppers. Moreover, predators caused grasshoppers to inflict greater damage to herbs and less damage to grasses relative to treatments without predators. However, there were no size-dependent differences in net damage level on grasses and herbs in either predator or no predator treatments owing to size-dependent compensation in effort by the grasshoppers foraging. In this ecosystem the foraging-predation risk tradeoff displayed by typical or average-sized herbivore is a sufficient amount of individual-level detail needed to explain ecosystem patterns. Proceedings of the National Academy Of Sciences of the United States of America 99: 12927-31. 2002 The Biomechanics of Chewing and Plant Fracture: Mechanisms and Implications Herbivores that chew on the leaves of flowering plants have had to evolve mechanisms to propagate fractures through structures that are chemically and physically heterogeneous. Associations exist between mandibular morphology and associated musculature and the nature of the plant diet, with species that feed on grasses sharing a suite of characteristics that differ from the features found in dicot-feeders. This pattern is evident in two major groups of chewing insects, larval Lepidoptera and Acrididae, and reflects differences in the mechanical properties of leaves, mostly driven by the pattern of leaf venation. To what extent cell walls provide a physical barrier to the extraction of nutrients by acridids and lepidopterans has been the subject of debate. The degree to which a leaf is fragmented influences the rate and amount of nutrients assimilated from the cytoplasm of a plant cell. The mechanisms that influence the fractionation of leaf material by acridids and lepidopterans are complex. Mandible morphology and associated musculature determine first, if fractures can be initiated, second, the maximum size of the bites taken, and third, the degree of chewing. On a single food type, large meals are eaten faster and less time is spent chewing than in smaller meals. The physical characteristics of the food also modify chewing behaviour. I argue that a full understanding of insect nutrition requires consideration of the mechanics of food processing. Similarly, an understanding of the mechanics of mandibles must take account of the ultimate function of feeding behaviour; the acquisition of nutrients. F. J. Clissold 2007 The devil in the details of life-history evolution: instability and reversal of genetic correlations during selection on Drosophila development The evolutionary relationships between three major components of Darwinian fitness, development rate, growth rate and preadult survival, were estimated using a comparison of 55 distinct populations of Drosophila melanogaster variously selected for age-specific fertility, environmental-stress tolerance and accelerated development. Development rate displayed a strong net negative evolutionary correlation with weight at eclosion across all selection treatments, consistent with the existence of a size-versus-time tradeoff between these characters. However, within the data set, the magnitude of the evolutionary correlation depended upon the particular selection treatments contrasted. A previously proposed tradeoff between preadult viability and growth rate was apparent only under weak selection for juvenile fitness components. Direct selection for rapid development led to sharp reductions in both growth rates and viability. These data add to the mounting results from experimental evolution that illustrate the sensitivity of evolutionary correlations to (i) genotype-by-environment (G x E) interaction, (ii) complex functional-trait interactions, and (iii) character definition. Instability, disappearance and reversal of patterns of genetic covariation often occur over short evolutionary time frames and as the direct product of selection, rather than some stochastic process. We suggest that the functional architecture of fitness is a rapidly evolving matrix with reticulate properties, a matrix that we understand only poorly. Journal of genetics 82: 133-45. Chippindale, A. K., A. L. Ngo and M. R. Rose 2003 High seedling relative growth rate and specific leaf area are traits of invasive species: phylogenetically independent contrasts of woody angiosperms In seedling growth analyses, invasive woody species were compared with less-invasive woody species commonly cultivated in California using 12 phylogenetically independent contrasts. Invasive species were hypothesized to have higher seedling relative growth rates (RGRs) and specific leaf areas (SLAs) than did related less-invasive species. In phylogenetically independent contrasts conducted among taxa within families, high seedling RGRs and SLAs have significant positive associations with invasiveness of woody plants. For contrasts containing species invasive in mediterranean regions, invasive species had significantly larger root biomass allocation than did less-invasive species. Optimization of fast seedling growth (high RGR) associated with opportunistic resource acquisition (high SLA) and increased root allocation to survive summer drought may be critical for the success of plant invaders in regions with mediterranean climates. 2007 American Journal of Botany 94: 526-532. E. Grotkopp and M. Rejmánek 2004 Oecologia 138: 39-47. Larval cannibalism, time constraints, and adult fitness in caddisflies that inhabit temporary wetlands The fitness of non-feeding adult insects depends on energy accumulated during the larval stage. Larvae of the caddisfly Asynarchus nigriculus primarily feed on plant detritus, but supplement their diet with animal material obtained through cannibalism. Habitat drying constrains development in many populations of this species, and we hypothesized that cannibalism should accelerate development to facilitate timely metamorphosis. We manipulated larval diets in a field experiment by supplementing detritus with animal material, and in a laboratory experiment by varying animal material and detritus quality (conditioned vs unconditioned). We measured the effects of dietary manipulation on larval and pupal growth and development, the timing of metamorphosis, and adult fitness correlates. The results of the laboratory experiment suggest that this species can metamorphose with a detritus-only diet, but development is extremely protracted. In the field experiment, individuals with animal material in their diet had higher larval survival, shorter larval and pupal development times, and earlier emergence dates (7-10 days), than those without a supplement. This delay in emergence should have important effects on survival in natural populations where the difference between desiccation and successful emergence can be only a few days. Dietary supplementation also affected adult body mass (30-40% increase), female fecundity (30% more eggs), and proportional allocation to different adult body parts. Our results are consistent with recent growth-development models that predict coupled (earlier emergence and larger adults) rather than tradeoff responses (earlier emergence and smaller adults) to pre-threshold manipulation of larval diets. Many detritivorous aquatic insects supplement their diets with animal material, and our data provide evidence that this supplementation can have strong effects on fitness. This type of dietary supplementation should be especially important for taxa that do not feed as adults, and in temporary habitats that impose time constraints on larval development. Wissinger, S., J. Steinmetz, J. S. Alexander and W. Brown Decoupled leaf and stem economics in rain forest trees 2010 Cross-species analyses of plant functional traits have shed light on factors contributing to differences in performance and distribution, but to date most studies have focused on either leaves or stems. We extend these tissue-specific analyses of functional strategy towards a whole-plant approach by integrating data on functional traits for 13 448 leaves and wood tissues from 4672 trees representing 668 species of Neotropical trees. Strong correlations amongst traits previously defined as the leaf economics spectrum reflect a tradeoff between investments in productive leaves with rapid turnover vs. costly physical leaf structure with a long revenue stream. A second axis of variation, the 'stem economics spectrum', defines a similar tradeoff at the stem level: dense wood vs. high wood water content and thick bark. Most importantly, these two axes are orthogonal, suggesting that tradeoffs operate independently at the leaf and at the stem levels. By simplifying the multivariate ecological strategies of tropical trees into positions along these two spectra, our results provide a basis to improve global vegetation models predicting responses of tropical forests to global change. Ecology Letters 13: 1338-47. C. Baraloto, C. E. Timothy Paine, L. Poorter, J. Beauchene, D. Bonal, A. M. Domenach, B. Herault, S. Patino, J. C. Roggy and J. Chave 2012 Greig, E. I., B. N. Taft and S. Pruett-Jones Proceedings. Biological sciences / The Royal Society 279: 3154-60. Sons learn songs from their social fathers in a cooperatively breeding bird Song learning is hypothesized to allow social adaptation to a local song neighbourhood. Maintaining social associations is particularly important in cooperative breeders, yet vocal learning in such species has only been assessed in systems where social association was correlated with relatedness. Thus, benefits of vocal learning as a means of maintaining social associations could not be disentangled from benefits of kin recognition. We assessed genetic and cultural contributions to song in a species where social association was not strongly correlated with kinship: the cooperatively breeding, reproductively promiscuous splendid fairy-wren (Malurus splendens). We found that song characters of socially associated father-son pairs were more strongly correlated (and thus songs were more similar) than songs of father-son pairs with a genetic, but no social, association (i.e. cuckolding fathers). Song transmission was, therefore, vertical and cultural, with minimal signatures of kinship. Additionally, song characters were not correlated with several phenotypic indicators of male quality, supporting the idea that there may be a tradeoff between accurate copying of tutors and quality signalling via maximizing song performance, particularly when social and genetic relationships are decoupled. Our results lend support to the hypothesis that song learning facilitates the maintenance of social associations by permitting unrelated individuals to acquire similar signal phenotypes. Proceedings. Biological sciences / The Royal Society 273: 1811-4. Leg regeneration stunts wing growth and hinders flight performance in a stick insect (Sipyloidea sipylus) Major morphological structures are sometimes produced not once, but twice. For example, stick insects routinely shed legs to escape a predator or tangled moult, and these legs are subsequently re-grown. Here, I show that in Sipyloidea sipylus, re-growth of a leg during development causes adults to have disproportionately smaller wings and increases wing loading. These morphological consequences of leg regeneration led to significant reductions in several biologically relevant measures of individual flight performance. This previously unrecognized tradeoff between legs and wings reveals the integrated nature of phasmid phenotypes, and I propose how this tradeoff may have shaped phasmid evolution. 2006 Maginnis, T. L. Annals of Botany 82: 195-202. T. Hirose and F. A. Bazzaz Trade-off Between Light- and Nitrogen-use Efficiency in Canopy Photosynthesis 1998 Canopy photosynthesis (CP) is proportional to light-use efficiency (LUE) and the number of photons (P) absorbed by the canopy (CP=LUE x P). It is also proportional to nitrogen-use efficiency (NUE) and the amount of total leaf nitrogen (LN) (CP=NUE x LN). We applied these concepts to monospecific and mixed (1:1) stands of annuals (Abutilon theophrasti and Ambrosia artemisiifolia) at two stages, established in an ambient or elevated CO2 atmosphere. In both CO2 concentrations, daily CP gave strong linear regressions with zero intercepts both against P and against LN. Doubling CO2 increased LUE by 20-80% and NUE by 20-100%. LUE tended to be higher in Ambrosia than in Abutilon, and also higher in the later stage of canopy development than in the younger stage. Interference by Abutilon increased the LUE of Ambrosia. On the other hand, NUE tended to be higher in Abutilon than in Ambrosia, and to be higher in younger than in later stages. Interference by Abutilon decreased the NUE of Ambrosia. Thus, there are trade-offs between LUE and NUE, which result from differences in leaf nitrogen per unit leaf area and from differences in leaf area development in the canopy. LUE increased with increasing leaf nitrogen concentration, while NUE increased with increasing light availability in the canopy. READ THE PAPER Current life history theory suggests that the allocation of energetic resources between competing physiological needs should be dictated by an individual's longevity and pace of life. One key physiological pathway likely to contribute to the partitioning of resources is the vertebrate stress response. By increasing circulating glucocorticoids the stress response can exert a suite of physiological effects, such as altering immune function. We investigated the effects of stress physiology on individual immunity, reproduction and oxidative stress, across an urban landscape. We sampled populations in and around St. George, Utah, examining corticosterone in response to restraint stress, two innate immune measures, reproductive output, and the presence of both reactive oxygen metabolites and antioxidant binding capacity, in populations of common side-blotched lizards (Uta stansburiana) experiencing variable levels of environmental stress. Additionally, using capture-mark-recapture techniques, we examined the relationships between these physiological parameters and population-level differences. Our results reveal elevated physiological stress corresponds with suppressed immunity and increased oxidative stress. Interestingly, urban populations experiencing the most physiological stress also exhibited greater reproductive output and decreased survival relative to rural populations experiencing less physiological stress, demonstrating a tradeoff between reproduction and life maintenance processes. Our results suggest that environmental stress may augment life history strategy in this fast-paced species, and that shifts in life history strategy can in turn affect the population at large. Finally, the urban environment poses definite challenges for organisms, and while it appears that side-blotched lizards are adjusting physiologically, it is unknown what fitness costs these physiological adjustments accrue. PLoS One 7: e49895. 2012 Lucas, L. D. and S. S. French Stress-induced tradeoffs in a free-living lizard across a variable landscape: consequences for individuals and populations 2011 The Journal of Experimental Biology 214: 2073-9. Kuo, C. Y., G. B. Gillis and D. J. Irschick Loading effects on jump performance in green anole lizards, Anolis carolinensis Locomotor performance is a crucial determinant of organismal fitness but is often impaired in certain circumstances, such as increased mass (loading) resulting from feeding or gravidity. Although the effects of loading have been studied extensively for striding locomotion, its effects on jumping are poorly understood. Jumping is a mode of locomotion that is widely used across animal taxa. It demands large amounts of power over a short time interval and, consequently, may be affected by loading to a greater extent than other modes of locomotion. We placed artificial loads equal to 30% body mass on individuals of the species Anolis carolinensis to simulate the mass gain following the consumption of a large meal. We investigated the effects of loading on jump performance (maximum jump distance and accuracy), kinematics and power output. Loading caused a significant 18% decline in maximum jump distance and a significant 10% decline in takeoff speed. In other words, the presence of the load caused the lizards to take shorter and slower jumps, whereas takeoff angle and takeoff duration were not affected. By contrast, jump accuracy was unaffected by loading, although accuracy declined when lizards jumped to farther perches. Finally, mass-specific power output did not increase significantly when lizards jumped with loads, suggesting that the ability to produce mechanical power may be a key limiting factor for maximum jump performance. Our results suggest that mass gain after a large meal can pose a significant locomotor challenge and also imply a tradeoff between fulfilling energy requirement and moving efficiently in the environment. Mechanisms of ageing and development 133: 637-46. 2012 Chamseddin, K. H., S. Q. Khan, M. L. Nguyen, M. Antosh, S. N. Morris, S. Kolli, N. Neretti, S. L. Helfand and J. H. Bauer takeout-dependent longevity is associated with altered Juvenile Hormone signaling In order to understand the molecular mechanisms of longevity regulation, we recently performed a screen designed to enrich for genes common to several longevity interventions. Using this approach, we identified the Drosophila melanogaster gene takeout. takeout is upregulated in a variety of long-lived flies, and extends life span when overexpressed. Here, we investigate the mechanisms of takeout-dependent longevity. takeout overexpression specifically in the fat body is sufficient to increase fly longevity and is additive to the longevity effects of Dietary Restriction. takeout long-lived flies do not show phenotypes often associated with increased longevity, such as enhanced stress resistance or major metabolic abnormalities. However, males exhibit greatly diminished courtship behavior, leading to a reduction in fertility. Interestingly, takeout contains a binding domain for Juvenile Hormone, a fly hormone that plays a role in the regulation of developmental transitions. Importantly, the longevity and courtship phenotypes of takeout overexpressing flies are reversed by treatment with the Juvenile Hormone analog methoprene. These data suggest that takeout is a key player in the tradeoff-switch between fertility and longevity. takeout may control fertility via modulation of courtship behavior. This regulation may occur through Juvenile Hormone binding to takeout and a subsequent reduction in Juvenile Hormone signaling activity. Experimental gerontology 34: 173-84. Extended longevity lines of Drosophila melanogaster: abundance of yolk protein gene mRNA in fat body and ovary Carlson, K. A. and L. G. Harshman Lines of Drosophila melanogaster selected for late-life female reproduction typically exhibit correlated responses of reduced early fecundity and increased longevity. This relationship suggests a tradeoff between reproductive effort and somatic maintenance, which in turn, underlies some evolutionary theories of senescence. The mechanistic basis of the apparent tradeoff between increased longevity and reduced early-age fecundity has remained obscure. The present manuscript addresses the issues of whether the reduced early-age fecundity in selected lines corresponds to reduced yolk-protein mRNA production, and whether long-lived flies exhibit somatic maintenance in terms of relatively reduced yolk-protein mRNA production in the fat body. Yolk protein is one of the most abundant proteins used for female reproduction. By comparing a set of lines selected for late life reproduction with the corresponding control lines, we show that that yolk-protein gene mRNA relative abundance during the first four days posteclosion did not correspond to reduced early-life fecundity in the selected lines. In D. melanogaster, yolk protein is produced in the fat body and ovarian follicle cells. On the fourth day posteclosion, relatively more yolk-protein gene mRNA was present in the fat body. On day 1 posteclosion, supplemental yeast did not alter relative yolk-protein gene mRNA abundance. However, on day 4 posteclosion, supplemental yeast stimulated yolk-protein gene mRNA production in the fat body, which suggests an underlying mechanism for the nutrition-based phenotypic plasticity of fecundity previously documented in these lines. On medium without supplemental yeast, the relatively low abundance of fat body yolk-protein gene mRNA in the selected lines on day 4 posteclosion corresponds to a prediction derived from the disposable soma theory. 1999 A line of weakness Comparative analyses of evolutionary rates reveal different pathways to encephalization in bats, carnivorans, and primates 2012 Proceedings of the National Academy Of Sciences of the United States of America 109: 18006-11. Smaers, J. B., D. K. Dechmann, A. Goswami, C. Soligo and K. Safi Variation in relative brain size is commonly interpreted as the result of selection on neuronal capacity. However, this approach ignores that relative brain size is also linked to another highly adaptive variable: body size. Considering that one-way tradeoff mechanisms are unlikely to provide satisfactory evolutionary explanations, we introduce an analytical framework that describes and quantifies all possible evolutionary scenarios between two traits. To investigate the effects of body mass changes on the interpretation of relative brain size evolution, we analyze three mammalian orders that are expected to be subject to different selective pressures on body size due to differences in locomotor adaptation: bats (powered flight), primates (primarily arboreal), and carnivorans (primarily terrestrial). We quantify rates of brain and body mass changes along individual branches of phylogenetic trees using an adaptive peak model of evolution. We find that the magnitude and variance of the level of integration of brain and body mass rates, and the subsequent relative influence of either brain or body size evolution on the brain-body relationship, differ significantly between orders and subgroups within orders. Importantly, we find that variation in brain-body relationships was driven primarily by variability in body mass. Our approach allows a more detailed interpretation of correlated trait evolution and variation in the underlying evolutionary pathways. Results demonstrate that a principal focus on interpreting relative brain size evolution as selection on neuronal capacity confounds the effects of body mass changes, thereby hiding important aspects that may contribute to explaining animal diversity. Journal of Insect Physiology 53: 923-932. 2007 R. A. Raguso, T. Ojeda-Avila, S. Desai, M. A. Jurkiewicz and H. Arthur Woods The influence of larval diet on adult feeding behaviour in the tobacco hornworm moth, Manduca sexta Lab-reared sphingid and noctuid moths appear to feed less than wild moths, and often are starved to enhance responsiveness in feeding assays. Larval diet affected adult eclosion time, size and fat content, the latter of which was inversely proportional to moth approaches to the floral array in a flight cage. In contrast, behaviours refractory to feeding (sitting, escaping) were associated with sex and barometric pressure, but not with diet or fat content. Frequency of floral approaches and probing was not associated with any variable. However, moths reared on Œ≤-carotene-supplemented diet were 2-3 times more likely to feed, and significantly less likely to sit or show "escape" behaviour than were moths from most other treatments. Our results suggest that decreased visual sensitivity, rather than increased fat content, accounts for reduced adult feeding by lab-reared M. sexta. Pouched animals: kangaroo, possum, bandicoot, koala, wombat . . . 2012 Insights into plant size-density relationships from models and agricultural crops Deng, J., W. Zuo, Z. Wang, Z. Fan, M. Ji, G. Wang, J. Ran, C. Zhao, J. Liu, K. J. Niklas, S. T. Hammond and J. H. Brown Proceedings of the National Academy Of Sciences of the United States of America 109: 8600-5. There is general agreement that competition for resources results in a tradeoff between plant mass, M, and density, but the mathematical form of the resulting thinning relationship and the mechanisms that generate it are debated. Here, we evaluate two complementary models, one based on the space-filling properties of canopy geometry and the other on the metabolic basis of resource use. For densely packed stands, both models predict that density scales as M(-3/4), energy use as M(0), and total biomass as M(1/4). Compilation and analysis of data from 183 populations of herbaceous crop species, 473 stands of managed tree plantations, and 13 populations of bamboo gave four major results: (i) At low initial planting densities, crops grew at similar rates, did not come into contact, and attained similar mature sizes; (ii) at higher initial densities, crops grew until neighboring plants came into contact, growth ceased as a result of competition for limited resources, and a tradeoff between density and size resulted in critical density scaling as M(-0.78), total resource use as M(-0.02), and total biomass as M(0.22); (iii) these scaling exponents are very close to the predicted values of M(-3/4), M(0), and M(1/4), respectively, and significantly different from the exponents suggested by some earlier studies; and (iv) our data extend previously documented scaling relationships for trees in natural forests to small herbaceous annual crops. These results provide a quantitative, predictive framework with important implications for the basic and applied plant sciences. Environmental-stress-mediated geographic variation in reproductive parameters has been little studied in natural vertebrate populations outside the context of climatic variation. Based on life-history theory, an increase in the degree of environmental stress experienced by a population should lead to (1) a shift in reproductive allocation from fecundity to offspring quality, (2) stronger trade-offs between reproductive parameters, and (3) changes in the relationship between female phenotype and maternal investment. To test these predictions, we investigated geographic variation in maternal investment of moor frogs (Rana arvalis) in relation to breeding site acidity (pH 4-8). We found that mean egg size increased and clutch size and total reproductive output (TRO) decreased with increasing acidity among 19 Swedish moor frog populations. Tests for variation and co-variation in maternal investment and female size and age in 233 females from a subset of four acid origin (AO) and four neutral origin (NO) populations revealed that clutch size and TRO increased with female size in both acid and neutral environments. However, in AO populations, egg size also increased with female size, and clutch size and TRO with female age, whereas in NO populations, egg size increased with female age. The strength of the egg-size-clutch-size tradeoff tended to be stronger in AO than in NO females as expected if the former experience stronger environmental constraints. All in all, these results suggest that environmental acidification selects for investment in larger eggs at a cost to fecundity, imposes negative effects on reproductive output, and alters the relationship between female phenotype and maternal investment. 2008 Geographic variation in maternal investment: acidity affects egg size and fecundity in Rana arvalis Ecology 89: 2553-62. Rasanen, K., F. Soderman, A. Laurila and J. Merila The first number in the pair is the FeatureThatSuffers; the second number is the FeatureToImprove. In the TRIZ Matrix that's the horizontal and vertical axes respectively. Journal of Insect Physiology 57: 688-693. Metabolic scaling in insects supports the predictions of the WBE model A. J. Riveros and B. J. Enquist 2011 The average scaling exponent between body size and metabolic rate (BS/MR) of 3/4 is broadly observed across animal and plant taxa. Insects, however, have recently been proposed to express a numerically different scaling exponent and thus application of the WBE network model to insects has been rejected. We show that reported deviation is largely due to the effect of a single insect family (Termitidae). We conclude that the BS/MR relationship in insects broadly supports the core predictions of the WBE model. We suggest that the deviation observed within the termites warrants further investigation and may be due to either difficulty in accurately measuring termite metabolism and/or particularities of their life history. Future work on allometric scaling should assess the nature of variation around the central tendencies in scaling exponents in order to test if this variation is consistent with core assumptions and predictions of the WBE model that stem by relaxing its secondary optimizing assumptions that lead to the 3/4 exponent. Dominguez-Cuevas, P., J. E. Gonzalez-Pastor, S. Marques, J. L. Ramos and V. de Lorenzo The Journal of biological chemistry 281: 11981-91. 2006 Transcriptional tradeoff between metabolic and stress-response programs in Pseudomonas putida KT2440 cells exposed to toluene When Pseudomonas putida KT2440 cells encounter toluene in the growth medium, they perceive it simultaneously as a potential nutrient to be metabolized, as a membrane-damaging toxic drug to be extruded, and as a macromolecule-disrupting agent from which to protect proteins. Each of these inputs requires a dedicated transcriptional response that involves a large number of genes. We used DNA array technology to decipher the interplay between these responses in P. putida KT2440 subjected to a short challenge (15 min) with toluene. We then compared the results with those in cells exposed to o-xylene (a non-biodegradable toluene counterpart) and 3-methylbenzoate (a specific substrate of the lower TOL pathway of the P. putida pWW0 plasmid). The resulting expression profiles suggest that the bulk of the available transcriptional machinery is reassigned to endure general stress, whereas only a small share of the available machinery is redirected to the degradation of the aromatic compounds. Specifically, both toluene and o-xylene induce the TOL pathways and a dedicated but not always productive metabolic program. Similarly, 3-methylbenzoate induces the expression not only of the lower meta pathway but also of the non-productive and potentially deleterious genes for the metabolism of (nonsubstituted) benzoate. In addition, toluene (and to a lesser extent o-xylene) inhibit motility functions as an unequivocal response to aromatic toxicity. We argue that toluene is sensed by P. putida KT2440 as a stressor rather than as a nutrient and that the inhibition by the aromatic compounds of many functions we tested is the tradeoff for activating stress tolerance genes at a minimal cost in terms of energy. Annals of Botany 78: 197-202. We wanted to ask whether the rhythmic pattern of shoot elongation should be taken into account for the micropropagation of Citrus aurantium L. and whether in vitroculture altered the rhythmic properties. It has been established in the present work that (1) where and when the axillary buds are excised with respect to the elongation cycle are of importance to optimize micropropagation and (2) the infradian rhythmic growth pattern of micropropagated plants is maintained with a period of 45.8d not significantly different from that of plants derived from seeds (42.4d). THIS NEEDS REVIEWING Rhythmic Growth and Optimization of Micropropagation: The Effect of Excision Time and Position of Axillary Buds on in vitro Culture of Citrus aurantium L 1996 A. A. El-Morsy and B. Millet The ability of microscopic larvae to control their fate and replenish populations in dynamic marine environments has been a long-running topic of debate of central importance to understanding the ecology and evolution of life in the sea and managing resources in a changing global environment. After decades of research documenting behaviors that keep larvae close to natal populations, it is becoming apparent that larval behaviors in a broader spectrum of species promote long-distance migrations to offshore nursery grounds. Larvae must exert considerable control over their movements. We now show that larval emigration from estuaries is favored even over minimizing visibility to predators. An endogenous tidal vertical migration that would expedite seaward migration of Uca pugilator larvae was maintained experimentally across two tidal regimes. The periodicity of the rhythm doubled to match the local tidal regime, but larvae ascended to the surface during the daytime rather than at night. This process would conserve larval emigration but increase the visibility to predators across part of the species range. The periodicity of tidal vertical migration by Sesarma cinereum larvae failed to double and was inappropriately timed relative to both environmental cycles in the absence of a diel cycle. The timing system regulating tidally timed behaviors in these two species of crabs evidently differed. Phenotypic plasticity can conserve larval transport of both species when tidal and diel cycles are present. It may be widespread in the sea where diverse habitats are encountered across extensive species ranges. 2008 Morgan, S. G. and J. R. Anastasia Proceedings of the National Academy Of Sciences of the United States of America 105: 222-7. Behavioral tradeoff in estuarine larvae favors seaward migration over minimizing visibility to predators BACKGROUND: Mutations that impair mitochondrial functioning are associated with a variety of metabolic and age-related disorders. A barrier to rigorous tests of the role of mitochondrial dysfunction in aging processes has been the lack of model systems with relevant, naturally occurring mitochondrial genetic variation. Toward the goal of developing such a model system, we studied natural variation in life history, metabolic, and aging phenotypes as it relates to levels of a naturally-occurring heteroplasmic mitochondrial ND5 deletion recently discovered to segregate among wild populations of the soil nematode, Caenorhabditis briggsae. The normal product of ND5 is a central component of the mitochondrial electron transport chain and integral to cellular energy metabolism. RESULTS: We quantified significant variation among C. briggsae isolates for all phenotypes measured, only some of which was statistically associated with isolate-specific ND5 deletion frequency. We found that fecundity-related traits and pharyngeal pumping rate were strongly inversely related to ND5 deletion level and that C. briggsae isolates with high ND5 deletion levels experienced a tradeoff between early fecundity and lifespan. Conversely, oxidative stress resistance was only weakly associated with ND5 deletion level while ATP content was unrelated to deletion level. Finally, mean levels of reactive oxygen species measured in vivo showed a significant non-linear relationship with ND5 deletion level, a pattern that may be driven by among-isolate variation in antioxidant or other compensatory mechanisms. CONCLUSIONS: Our findings suggest that the ND5 deletion may adversely affect fitness and mitochondrial functioning while promoting aging in natural populations, and help to further establish this species as a useful model for explicit tests of hypotheses in aging biology and mitochondrial genetics. 2011 Estes, S., A. L. Coleman-Hulbert, K. A. Hicks, G. de Haan, S. R. Martha, J. B. Knapp, S. W. Smith, K. C. Stein and D. R. Denver Natural variation in life history and aging phenotypes is associated with mitochondrial DNA deletion frequency in Caenorhabditis briggsae Duck-billed platypus, echidna Oecologia 157: 69-82. Fitness consequences of host use in the field: temporal variation in performance and a life history tradeoff in the moth Rothschildia lebeau (Saturniidae) Agosta S. J. 2008 Host plants are prickly ash, Mexican ash, willow, peach, citrus and acacia. That fitness varies as a function of using different hosts is a basic premise of theory addressing the ecology and evolution of oviposition behavior and host selection. Few data exist demonstrating: (1) the effects of different hosts on fitness in the field, and (2) how these effects vary spatially or temporally. Cohorts of caterpillars were followed from hatching to adulthood to test the hypotheses that: (1) hosts have significant effects on herbivore performance in nature, and (2) host "quality" for performance varies predictably (i.e., the rank order is consistent) across herbivore generations. In total, the fates of >2,000 caterpillars were followed on 238 individual host trees. Host species had significant effects on most, but not all, measured components of caterpillar performance in the field. Variation among generations was mainly quantitative rather than qualitative, with few changes in the rank order of hosts in their effects on performance. There was also a strong seasonal effect on performance such that caterpillar growth and survival were higher in the early wet season compared to the late wet season. Using estimates derived from these data, correlations among larval growth rate, larval survival, total development time, and final adult size were examined at the level of host plant species. Across generations, larval survival was consistently poor, development time was long, but final adult size attained was large on the host Spondias mombin. The converse was true for the host Exostema mexicanum. Relative performance on the host Casearia nitida was variable between the other two hosts. Overall, the data suggest that host use involves a predictable tradeoff between larval survival and final adult size, but argue that which is the "better" host from the female perspective will depend on the fitness consequences of producing a few, relatively large offspring versus producing more, relatively small offspring. Perform, or be able to perform, several functions at the same time The performance of skeletal muscle is determined by the length trajectory during movement and the pattern of stimulation. Important features of the length trajectory include its amplitude, frequency, starting length and shape (velocity profile). Many of these parameters interact. For example, changing the velocity profile during shortening may change the optimum values of the other parameters. The length trajectory that maximizes performance depends on the task to be performed. During cyclical work, muscles benefit from using asymmetric cycles with longer shortening than lengthening phases. Modifying this shortening may further increase power by augmenting force output and speeding deactivation. In contrast, when accelerating an inertial load, as in jumping, the predicted ‘optimal’ velocity profile has two peak values, one early and one late in shortening. During level running at constant speed, muscles perform tasks other than producing work and power. Producing force to support the body weight is performed with nearly isometric contractions in some of the limb muscles of vertebrates. Muscles also play a key role in producing stability during running, and the intrinsic properties of the musculoskeletal system may be particularly important in stabilizing rapid running. Recently, muscles in running invertebrates and vertebrates have been described that routinely absorb large amounts of work during running. These muscles are hypothesized to play a key role in stability. 1999 Journal of Experimental Biology 202: 3377-3385. How muscles deal with real-world loads: the influence of length trajectory on muscle performance R. L. Marsh Lampreys Hagfish 2006 J. C. Jones and B. P. Oldroyd Nest Thermoregulation in Social Insects Most social insect species are able to regulate the temperature within their nests. In this review, we examine the variety of mechanisms that social insect species have evolved to regulate temperature. We divide these mechanisms into two broad categories: active and passive. Passive temperature regulation includes such mechanisms as nest site selection to optimize internal nest temperature, nest structures that permit passive heating or cooling, or simple behaviour such as brood translocation to regions within a nest where temperatures are most favourable. Active temperature regulation refers to behaviour where individuals modify nest temperature by physical activity like wing fanning or evaporative cooling. Although there is enormous variation in the thermoregulatory mechanisms, there are also many similarities. All thermoregulatory mechanisms are self-organized and arise from simple rules followed by each individual worker. Darcy-Hall, T. L. Relative strengths of benthic algal nutrient and grazer limitation along a lake productivity gradient 2006 The relative effects of nutrients and herbivores on primary producers are rarely compared across ecosystems that vary in potential primary productivity. Furthermore, proposed mechanisms to explain such patterns remain understudied. Here, I examine the strength of nutrient and grazer (herbivore) limitation (i.e., the extent to which producers' growth is limited by insufficient nutrient supply or herbivory) of benthic algae across 13 southwest Michigan lakes that vary widely in productivity (i.e., resource supply). I compare the observed patterns of algal limitation and species composition to those predicted by two simple models: one that includes multiple species and species' traits (the food-web model) and one that includes no variation in species or traits (the food-chain model). Species in the food-web model are assumed to display a tradeoff between resource competitive ability and resistance to herbivory (the "keystone predator" tradeoff). Among these lakes, benthic algal nutrient limitation was positive (x=0.083 day-1) and declined significantly along a lake N:P gradient. In contrast, grazer limitation was negative (x=-0.019 day-1) and was not significantly related to any of the measured lake productivity variables. Negative grazer limitation indicated that the removal of grazers caused unexpected declines in algal biomass, which were potentially due to indirect, positive effects (e.g., nutrient recycling) of grazers. Nutrient limitation was significantly stronger than grazer limitation across lakes, which was more consistent with the food-web versus food-chain model. Changes in algal composition were also broadly consistent with predictions of the food-web model in that vulnerable, superior nutrient competitors dominated in low productivity lakes and more grazer-resistant species were observed in high productivity lakes. In general, these results point to the importance of examining limiting factors across systems and the consideration of key species' traits when predicting and interpreting patterns. Oecologia 148: 660-71. Many animals are planktonic, floating in water but going up and down on a daily cycle. They do this by active swimming Sensing in gaseous medium 2006 Walking humans spontaneously select different speed, frequency and step length combinations, depending on which of these three parameters is specified. This behavior can be explained by constrained optimization of cost of transport (metabolic cost/distance) where cost of transport is seen as the main component of an underlying objective function that is minimized within the limitations of specified constraints. It is then of interest to ask whether or not such results are specific to walking only, or indicate a more general feature of locomotion control. The current study examines running gait selection within the framework of constrained optimization by comparing self-selected running gaits to the gaits predicted by constrained optimization of a cost surface constructed from cost data available in the literature. Normalizing speed and frequency values in the behavioral data by preferred speed and frequency reduced inter-subject variability and made group behavioral trends more visible. Although actual behavior did not coincide exactly with running cost optimization, self-selected gait and predictions from the general human cost surface did agree to within the 95% confidence interval and the region of minimal cost+0.005 ml O2 kg-1 m-1. This was similar to the level of agreement between actual and predicted behavior observed in walking. Thus, there seems to be substantial evidence to suggest that (i) selection of gait parameters in running can largely be predicted using constrained optimization, and (ii) general cost surfaces can be constructed using metabolic data from one group that will largely predict the behavior of other groups. A. K. Gutmann, B. Jacobi, M. T. Butcher and J. E. A. Bertram Constrained optimization in human running Journal of Experimental Biology 209: 622-632. 2000 Optimum take-off techniques and muscle design for long jump Journal of Experimental Biology 203: 741-750. A. Seyfarth, R. Blickhan and J. L. Van Leeuwen A two-segment model was used to investigate the action of knee extensor muscles during long jumps. A more realistic representation of the muscle and tendon properties than implemented previously was necessary to demonstrate the advantages of eccentric force enhancement and non-linear tendon properties. During the take-off phase of the long jump, highly stretched leg extensor muscles are able to generate the required vertical momentum. Thereby, serially arranged elastic structures may increase the duration of muscle lengthening and dissipative operation, resulting in an enhanced force generation of the muscle-tendon complex. To obtain maximum performance, athletes run at maximum speed and have a net loss in mechanical energy during the take-off phase. The positive work done by the concentrically operating muscle is clearly less than the work done by the surrounding system on the muscle during the eccentric phase. Jumping performance was insensitive to changes in tendon compliance and muscle speed, but was greatly influenced by muscle strength and eccentric force enhancement. In agreement with a variety of experimental jumping performances, the optimal jumping technique (angle of attack) was insensitive to the approach speed and to muscle properties (muscle mass, the ratio of muscle fibre to tendon cross-sectional area, relative length of fibres and tendon). The muscle properties also restrict the predicted range of the angle of the velocity vector at take-off. Journal of Experimental Biology 210: 3255-3265. Mechanical power and efficiency of level walking with different stride rates Walking humans prefer to use the stride rate that results in the lowest rate of metabolic energy expenditure. Mechanical power requirements have been suggested to underlie the metabolic response, but mechanical power is consistently reported to be minimal at stride rates 20-30% lower than preferred. This may be due to limitations in how total mechanical power has been computed, as well as a failure to account for the efficiency with which muscular work is done. We investigated how mechanical power and efficiency depend on stride rate in walking, with both quantities computed from the work done by the hip, knee and ankle joint moments. Our hypotheses were that mechanical power and efficiency are both optimized at the preferred stride rate, which would explain why metabolic energy expenditure is minimized at this rate. Contrary to our hypotheses, mechanical power curves exhibited plateaus that spanned stride rates lower than preferred (predicted optima: 11-12% below preferred), while net mechanical efficiency exhibited a plateau that spanned stride rates higher than preferred (predicted optimum: 8% above preferred). As expected, preferred stride rate (54.3 strides/min) was not different from the stride rate that minimized net metabolic energy expenditure (predicted optimum: 0.2% above preferred). Given that mechanical power and mechanical efficiency exhibited plateaus on opposite sides of the preferred stride rate, the preferred rate in walking likely represents a compromise between these two factors. This may also explain the relative flatness of the curve for metabolic rate in the vicinity of the preferred stride rate. 2007 B. R. Umberger and P. E. Martin Insect eggs exert rapid control over an oxygen-water tradeoff Proceedings. Biological sciences / The Royal Society 273: 831-4. 2006 In terrestrial environments, the exchange of respiratory gases exacts a water cost: obtaining oxygen or carbon dioxide requires losing water. Insect eggs should be especially sensitive to this tradeoff-because they are unable to forage for water, have high surface area-to-volume ratios, and experience large temperature-driven changes in oxygen demand. Previous work from our laboratory, on eggs of a common hawk-moth, Manduca sexta, has shown that, during development, metabolic rate and water loss rates rise in parallel. These correlative data suggest that eggshell conductance increases to accommodate increasing metabolic demand. Here, we test this idea experimentally by subjecting eggs of M. sexta to 15, 21 (normoxia) and 35% oxygen for 24h, while measuring rates of metabolism (as carbon dioxide emission) and water loss. Hypoxia depressed egg metabolic rates, but led to pronounced, rapid increases in water loss. By contrast, hyperoxia had no significant effect on metabolism or water loss. These data demonstrate that insect eggs actively participate in balancing oxygen gain and water loss, and that they use tissue oxygen status, or some correlate of it, as a cue for increasing eggshell conductance. Rapid control over conductance may allow eggs to conserve water during an initial period of low metabolic demand, thereby deferring water costs of respiratory gas exchange until late in development. Zrubek, B. and H. A. Woods The unique properties of tree building in Arecaceae strongly constrain their architectural lability. Potentially compensating for this limitation, the extensive diversification of leaf anatomical structure within palms involves many characters whose alternate states may confer disparate mechanical or physiological capabilities. In the context of a recent global palm phylogeny, we analyzed the evolution of 10 such lamina anatomical characters and leaf morphology of 161 genera, conducting parsimony and maximum likelihood ancestral state reconstructions, as well as tests of correlated evolution. Laminar morphology evolves independently from anatomy. Although many characters do optimize as synapomorphic for major clades, anatomical evolution is highly homoplasious. Nevertheless, it is not random: analyses indicate the recurrent evolution of different cohorts of correlated character states. Notable are two surface layer (epidermis and hypodermis) types: (1) a parallel-laminated type of rectangular epidermal cells with sinuous anticlinal walls, with fibers present in the hypodermis and (2) a cross-laminated type of hexagonal cells in both layers. Correlated with the cross-laminated type is a remarkable decrease in the volume fraction of fibers, accompanied by changes in the architecture and sheath cell type of the transverse veins. We discuss these and other major patterns of anatomical evolution in relation to their biomechanical and ecophysiological significance. 2009 Evolution of lamina anatomy in the palm family (Arecaceae) American Journal of Botany 96: 1462-1486. J. W. Horn, J. B. Fisher, P. B. Tomlinson, C. E. Lewis and K. Laubengayer Trends in parasitology 25: 564-72. Lafferty, K. D. and A. M. Kuris Parasitic castration: the evolution and ecology of body snatchers 2009 Castration is a response to the tradeoff between consumption and longevity faced by parasites. Common parasitic castrators include larval trematodes in snails, and isopod and barnacle parasites of crustaceans. The infected host (with its many unique properties) is the extended phenotype of the parasitic castrator. Because an individual parasitic castrator can usurp all the reproductive energy from a host, and that energy is limited, intra- and interspecific competition among castrators is generally intense. These parasites can be abundant and can substantially depress host density. Host populations subject to high rates of parasitic castration appear to respond by maturing more rapidly. Awaiting analysis Un-even-toed ungulates The nature and cause of the division of organisms in superkingdoms is not fully understood. Assuming that environment shapes physiology, here we construct a novel theoretical framework that helps identify general patterns of organism persistence. This framework is based on Jacob von Uexkull's organism-centric view of the environment and James G. Miller's view of organisms as matter-energy-information processing molecular machines. Three concepts describe an organism's environmental niche: scope, umwelt, and gap. Scope denotes the entirety of environmental events and conditions to which the organism is exposed during its lifetime. Umwelt encompasses an organism's perception of these events. The gap is the organism's blind spot, the scope that is not covered by umwelt. These concepts bring organisms of different complexity to a common ecological denominator. Ecological and physiological data suggest organisms persist using three strategies: flexibility, robustness, and economy. All organisms use umwelt information to flexibly adapt to environmental change. They implement robustness against environmental perturbations within the gap generally through redundancy and reliability of internal constituents. Both flexibility and robustness improve survival. However, they also incur metabolic matter-energy processing costs, which otherwise could have been used for growth and reproduction. Lineages evolve unique tradeoff solutions among strategies in the space of what we call "a persistence triangle." Protein domain architecture and other evidence support the preferential use of flexibility and robustness properties. Archaea and Bacteria gravitate toward the triangle's economy vertex, with Archaea biased toward robustness. Eukarya trade economy for survivability. Protista occupy a saddle manifold separating akaryotes from multicellular organisms. Plants and the more flexible Fungi share an economic stratum, and Metazoa are locked in a positive feedback loop toward flexibility. Yafremava, L. S., M. Wielgos, S. Thomas, A. Nasir, M. Wang, J. E. Mittenthal and G. Caetano-Anolles Frontiers in genetics 4: 16. 2013 A general framework of persistence strategies for biological systems helps explain domains of life H. St√ºtzel and H. Kage 2000 A simple model of photosynthesis is described which is dependent on leaf area, organic nitrogen content and distribution within the canopy as well as on the light and temperature environments. The model is parameterized using a cauliflower crop as an example. The optimized protein-N profile within the canopy is calculated with respect to daily growth rate. By comparison with measured protein-N contents, the amount of super-optimal N-uptake, i.e. the N-uptake which does not increase productivity, is assessed for two different nitrogen and light treatments. The amount of super-optimal N accumulated in cauliflower depends on N-supply and can exceed 80 kg N ha‚àí1.C. Alt, Annals of Botany 85: 779-787. Optimal Nitrogen Content and Photosynthesis in Cauliflower (Brassica oleracea L. botrytis). Scaling up from a Leaf to the Whole Plant Bella S. D. and C. Palmer Rate effects on timing, key velocity, and finger kinematics in piano performance We examined the effect of rate on finger kinematics in goal-directed actions of pianists. In addition, we evaluated whether movement kinematics can be treated as an indicator of personal identity. Pianists' finger movements were recorded with a motion capture system while they performed melodies from memory at different rates. Pianists' peak finger heights above the keys preceding keystrokes increased as tempo increased, and were attained about one tone before keypress. These rate effects were not simply due to a strategy to increase key velocity (associated with tone intensity) of the corresponding keystroke. Greater finger heights may compensate via greater tactile feedback for a speed-accuracy tradeoff that underlies the tendency toward larger temporal variability at faster tempi. This would allow pianists to maintain high temporal accuracy when playing at fast rates. In addition, finger velocity and accelerations as pianists' fingers approached keys were sufficiently unique to allow pianists' identification with a neural-network classifier. Classification success was higher in pianists with more extensive musical training. Pianists' movement "signatures" may reflect unique goal-directed movement kinematic patterns, leading to individualistic sound. PLoS One 6: e20518. 2011 Presence/absence polymorphism for alternative pathogenicity islands in Pseudomonas viridiflava, a pathogen of Arabidopsis H. Araki, D. Tian, E. M. Goss, K. Jakob, S. S. Halldorsdottir, M. Kreitman and J. Bergelson The contribution of arms race dynamics to plant-pathogen coevolution has been called into question by the presence of balanced polymorphisms in resistance genes of Arabidopsis thaliana, but less is known about the pathogen side of the interaction. Here we investigate structural polymorphism in pathogenicity islands (PAIs) in Pseudomonas viridiflava, a prevalent bacterial pathogen of A. thaliana. PAIs encode the type III secretion system along with its effectors and are essential for pathogen recognition in plants. P. viridiflava harbors two structurally distinct and highly diverged PAI paralogs (T- and S-PAI) that are integrated in different chromosome locations in the P. viridiflava genome. Both PAIs are segregating as presence/absence polymorphisms such that only one PAI ([T-PAI, nablaS-PAI] and [nablaT-PAI, S-PAI]) is present in any individual cell. A worldwide population survey identified no isolate with neither or both PAI. T-PAI and S-PAI genotypes exhibit virulence differences and a host-specificity tradeoff. Orthologs of each PAI can be found in conserved syntenic locations in other Pseudomonas species, indicating vertical phylogenetic transmission in this genus. Molecular evolutionary analysis of PAI sequences also argues against "recent" horizontal transfer. Spikes in nucleotide divergence in flanking regions of PAI and nabla-PAI alleles suggest that the dual PAI polymorphism has been maintained in this species under some form of balancing selection. Virulence differences and host specificities are hypothesized to be responsible for the maintenance of the dual PAI system in this bacterial pathogen. Proceedings of the National Academy Of Sciences of the United States of America 103: 5887-92. 2006 2007 Plants activate distinct defense responses depending on the lifestyle of the attacker encountered. In these responses, salicylic acid (SA) and jasmonic acid (JA) play important signaling roles. SA induces defense against biotrophic pathogens that feed and reproduce on live host cells, whereas JA activates defense against necrotrophic pathogens that kill host cells for nutrition and reproduction. Cross-talk between these defense signaling pathways has been shown to optimize the response against a single attacker. However, its role in defense against multiple pathogens with distinct lifestyles is unknown. Here we show that infection with biotrophic Pseudomonas syringae, which induces SA-mediated defense, rendered plants more susceptible to the necrotrophic pathogen Alternaria brassicicola by suppression of the JA signaling pathway. This process was partly dependent on the cross-talk modulator NPR1. Surprisingly, this tradeoff was restricted to tissues adjacent to the site of initial infection; A. brassicicola infection in systemic tissue was not affected. Even more surprisingly, tradeoff occurred only with the virulent Pseudomonas strain. Avirulent strains that induced programmed cell death (PCD), an effective plant-resistance mechanism against biotrophs, did not cause suppression of JA-dependent defense. This result might be advantageous to the plant by preventing necrotrophic pathogen growth in tissues undergoing PCD. Our findings show that plants tightly control cross-talk between SA- and JA-dependent defenses in a previously unrecognized spatial and pathogen type-specific fashion. This process allows them to prevent unfavorable signal interactions and maximize their ability to concomitantly fend off multiple pathogens. Spoel, S. H., J. S. Johnson and X. Dong Regulation of tradeoffs between plant defenses against pathogens with different lifestyles Proceedings of the National Academy Of Sciences of the United States of America 104: 18842-7. 2009 This analysis goes beyond many phylogenies in exploring how phylogenetic structure imposed by morphology, ecology, and geography reveals useful evolutionary data. A comprehensive range of such diversity is evaluated within tribe Indigofereae and outgroups from sister tribes. A combined data set of 321 taxa (over one-third of the tribe) by 80 morphological characters, 833 aligned nuclear ribosomal ITS/5.8S sites, and an indel data set of 33 characters was subjected to parsimony analysis. Notable results include the Madagascan dry forest Disynstemon resolved as sister to tribe Indigofereae, and all species of the large genus Indigofera comprise just four main clades, each diagnosable by morphological synapomorphies and ecological and geographical predilections. These results suggest niche conservation (ecology) and dispersal limitation (geography) are important processes rendering signature shapes to the Indigofereae phylogeny in different biomes. Clades confined to temperate and succulent-rich biomes are more dispersal limited and have more geographical phylogenetic structure than those inhabiting tropical grass-rich vegetation. The African arid corridor, particularly the Namib center of endemism, harbors many of the oldest Indigofera lineages. A rates analysis of nucleotide substitutions confirms that the ages of the oldest crown clades are mostly younger than 16 Ma, implicating dispersal in explaining the worldwide distribution of the tribe. American Journal of Botany 96: 816-852. Phylogeny of the tribe Indigofereae (Leguminosae - Papilionoideae): Geographically structured more in succulent-rich and temperate settings than in grass-rich environments B. D. Schrire, M. Lavin, N. P. Barker and F. l. Forest This is the membrane surrounding the cell, and so defines it The plasmodium of Physarum polycephalum is a large single cell capable of optimal spanning of food sources and avoidance of harmful stimuli. When propagating on a substrate with distributed sources of food the plasmodium simulates a general-purpose storage modification machine, approximates varieties of proximity graphs and imitates calculation of shortest path and plane tessellation. The plasmodium's behaviour is determined by the space-time distribution of attracting and repelling sources, and immediately guided by the waves of excitation travelling inside the plasmodium. A harmless colored substance can be ingested by the plasmodium and distributed inside the protoplasm. By controlling the plasmodium's propagation over an uncolored substrate we can `fill' specified areas of the substrate with the color transported by the plasmodium. The plasmodium of P. polycephalum excels in adaptive transportation, mixing and transformation of colored food particles. We uncover a range of operations implementable by the plasmodium over color set, and design methods to control mixing and transportation of colors. Manipulating substances with Physarum polycephalum 2010 A. Adamatzky Materials Science and Engineering: C 30: 1211-1220. Natural polymorphism affecting learning and memory in Drosophila Knowing which genes contribute to natural variation in learning and memory would help us understand how differences in these cognitive traits evolve among populations and species. We show that a natural polymorphism at the foraging (for) locus, which encodes a cGMP-dependent protein kinase (PKG), affects associative olfactory learning in Drosophila melanogaster. In an assay that tests the ability to associate an odor with mechanical shock, flies homozygous for one natural allelic variant of this gene (forR) showed better short-term but poorer long-term memory than flies homozygous for another natural allele (fors). The fors allele is characterized by reduced PKG activity. We showed that forR-like levels of both short-term learning and long-term memory can be induced in fors flies by selectively increasing the level of PKG in the mushroom bodies, which are centers of olfactory learning in the fly brain. Thus, the natural polymorphism at for may mediate an evolutionary tradeoff between short- and long-term memory. The respective strengths of learning performance of the two genotypes seem coadapted with their effects on foraging behavior: forR flies move more between food patches and so could particularly benefit from fast learning, whereas fors flies are more sedentary, which should favor good long-term memory. Proceedings of the National Academy Of Sciences of the United States of America 104: 13051-5. 2007 Mery, F., A. T. Belay, A. K. So, M. B. Sokolowski and T. J. Kawecki Many organisms respond to minor damage by increasing their growth rate; plants being eaten by insects frequently grow more quickly We investigate human error dynamics in sequential two-alternative choice tasks. When subjects repeatedly discriminate between two stimuli, their error rates and reaction times (RTs) systematically depend on prior sequences of stimuli. We analyze these sequential effects on RTs, separating error and correct responses, and identify a sequential RT tradeoff: a sequence of stimuli which yields a relatively fast RT on error trials will produce a relatively slow RT on correct trials and vice versa. We reanalyze previous data and acquire and analyze new data in a choice task with stimulus sequences generated by a first-order Markov process having unequal probabilities of repetitions and alternations. We then show that relationships among these stimulus sequences and the corresponding RTs for correct trials, error trials, and averaged over all trials are significantly influenced by the probability of alternations; these relationships have not been captured by previous models. Finally, we show that simple, sequential updates to the initial condition and thresholds of a pure drift diffusion model can account for the trends in RT for correct and error trials. Our results suggest that error-based parameter adjustments are critical to modeling sequential effects. Can post-error dynamics explain sequential reaction time patterns? Frontiers in psychology 3: 213. 2012 Goldfarb, S., K. Wong-Lin, M. Schwemmer, N. E. Leonard and P. Holmes 2008 Kittle, A. M., J. M. Fryxell, G. E. Desy and J. Hamr Resource selection is a fundamental ecological process impacting population dynamics and ecosystem structure. Understanding which factors drive selection is vital for effective species- and landscape-level management. We used resource selection probability functions (RSPFs) to study the influence of two forms of wolf (Canis lupus) predation risk, snow conditions and habitat variables on white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus) and moose (Alces alces) resource selection in central Ontario's mixed forest French River-Burwash ecosystem. Direct predation risk was defined as the frequency of a predator's occurrence across the landscape and indirect predation risk as landscape features associated with a higher risk of predation. Models were developed for two winters, each at two spatial scales, using a combination of GIS-derived and ground-measured data. Ungulate presence was determined from snow track transects in 64 16- and 128 1-km(2) resource units, and direct predation risk from GPS radio collar locations of four adjacent wolf packs. Ungulates did not select resources based on the avoidance of areas of direct predation risk at any scale, and instead exhibited selection patterns that tradeoff predation risk minimization with forage and/or mobility requirements. Elk did not avoid indirect predation risk, while both deer and moose exhibited inconsistent responses to this risk. Direct predation risk was more important to models than indirect predation risk but overall, abiotic topographical factors were most influential. These results indicate that wolf predation risk does not limit ungulate habitat use at the scales investigated and that responses to spatial sources of predation risk are complex, incorporating a variety of anti-predator behaviours. Moose resource selection was influenced less by snow conditions than cover type, particularly selection for dense forest, whereas deer showed the opposite pattern. Temporal and spatial scale influenced resource selection by all ungulate species, underlining the importance of incorporating scale into resource selection studies. The scale-dependent impact of wolf predation risk on resource selection by three sympatric ungulates Oecologia 157: 163-75. Hollen, L. I., M. B. Bell and A. N. Radford Many foraging animals face a fundamental tradeoff between predation and starvation. In a range of social species, this tradeoff has probably driven the evolution of sentinel behavior, where individuals adopt prominent positions to watch for predators while groupmates forage. Although there has been much debate about whether acting as a sentinel is a selfish or cooperative behavior, far less attention has focused on why sentinels often produce quiet vocalizations (hereafter known as "sentinel calls") to announce their presence. We use observational and experimental data to provide the first evidence that group members gain an increase in foraging success by responding to these vocal cues given by sentinels. Foraging pied babblers (Turdoides bicolor) spread out more, use more exposed patches, look up less often, and spend less time vigilant in response to sentinel calling. Crucially, we demonstrate that these behavioral alterations lead to an increase in biomass intake by foragers, which is likely to enhance survival. We argue that this benefit may be the reason for sentinel calling, making it a truly cooperative behavior. Cooperative sentinel calling? Foragers gain increased biomass intake 2008 Current biology : CB 18: 576-9. This is a more detailed breakdown of the F_xx classes. Each one is indexed to the appropriate F_xx. Bacteria 2011 Hofmann, R. W. and M. Z. Jahufer An outdoor study was conducted to examine relationships between plant productivity and stress-protective phenolic plant metabolites. Twenty-two populations of the pasture legume white clover were grown for 4(1/2) months during spring and summer in Palmerston North, New Zealand. The major phenolic compounds identified and quantified by HPLC analysis were glycosides of the flavonoids quercetin and kaempferol. Multivariate analysis revealed a trade-off between flavonoid accumulation and plant productivity attributes. White clover populations with high biomass production, large leaves and thick tap roots showed low levels of quercetin glycoside accumulation and low quercetin:kaempferol ratios, while the opposite was true for less productive populations. The latter included stress-resistant ecotypes from Turkey and China, and the analysis also identified highly significant positive relationships of quercetin glycoside accumulation with plant morphology (root:shoot ratio). Importantly, a high degree of genetic variation was detected for most of the measured traits. These findings suggest merit for considering flavonoids such as quercetin as potential selection criteria in the genetic improvement of white clover and other crops. PLoS One 6: e18949. Tradeoff between biomass and flavonoid accumulation in white clover reflects contrasting plant strategies The bombardier beetle produces a pulsed stream of hot phenols and peroxide which it can squirt at its predator at high velocity Quality prevails over identity in the sexually selected vocalisations of an ageing mammal BACKGROUND: Male sexually selected vocalisations generally contain both individuality and quality cues that are crucial in intra- as well as inter-sexual communication. As individuality is a fixed feature whereas male phenotypic quality changes with age, individuality and quality cues may be subjected to different selection pressures over time. Individuality (for example, morphology of the vocal apparatus) and quality (for example, body size and dominance status) can both affect the vocal production mechanism, inducing the same components of vocalisations to convey both kinds of information. In this case, do quality-related changes to the acoustic structure of calls induce a modification of vocal cues to identity from year to year? We investigated this question in fallow deer (Dama dama), in which some acoustic parameters of vocalisations (groans) code for both individuality and quality. RESULTS: We carried out a longitudinal analysis of groan individuality, examining the effects of age and dominance rank on the acoustic structure of groans of the same males recorded during consecutive years. We found both age- and rank-related changes to groans; the minimum values of the highest formant frequencies and the fundamental frequency increased with the age of males and they decreased when males became more dominant. Both age- and rank-related acoustic parameters contributed to individuality. Male quality changed with age, inducing a change in quality-related parameters and thus, a modification of vocal cues to male individuality between years. CONCLUSIONS: The encoding of individuality and quality information in the same components of vocalisations induces a tradeoff between these two kinds of signals over time. Fallow deer vocalisations are honest signals of quality that are not fixed over time but are modified dynamically according to male quality. As they are more reliable cues to quality than to individuality, they may not be used by conspecifics to recognize a given male from one year to another, but potentially used by both sexes to assess male quality during each breeding season. Briefer, E., E. Vannoni and A. G. McElligott BMC Biology 8: 35. 2010 Integrative and Comparative Biology 51: 733-50. Determining how species' geographic ranges are governed by current climates and how they will respond to rapid climatic change poses a major biological challenge. Geographic ranges are often spatially fragmented and composed of genetically differentiated populations that are locally adapted to different thermal regimes. Tradeoffs between different aspects of thermal performance, such as between tolerance to high temperature and tolerance to low temperature or between maximal performance and breadth of performance, suggest that the performance of a given population will be a subset of that of the species. Therefore, species-level projections of distribution might overestimate the species' ability to persist at any given location. However, current approaches to modeling distributions often do not consider variation among populations. Here, we estimated genetically-based differences in thermal performance curves for growth among 12 populations of the scarlet monkeyflower, Mimulus cardinalis, a perennial herb of western North America. We inferred the maximum relative growth rate (RGR(max)), temperature optimum (T(opt)), and temperature breadth (T(breadth)) for each population. We used these data to test for tradeoffs in thermal performance, generate mechanistic population-level projections of distribution under current and future climates, and examine how variation in aspects of thermal performance influences forecasts of range shifts. Populations differed significantly in RGR(max) and had variable, but overlapping, estimates of T(opt) and T(breadth). T(opt) declined with latitude and increased with temperature of origin, consistent with tradeoffs between performances at low temperatures versus those at high temperatures. Further, T(breadth) was negatively related to RGR(max), as expected for a specialist-generalist tradeoff. Parameters of the thermal performance curve influenced properties of projected distributions. For both current and future climates, T(opt) was negatively related to latitudinal position, while T(breadth) was positively related to projected range size. The magnitude and direction of range shifts also varied with T(opt) and T(breadth), but sometimes in unexpected ways. For example, the fraction of habitat remaining suitable increased with T(opt) but decreased with T(breadth). Northern limits of all populations were projected to shift north, but the magnitude of shift decreased with T(opt) and increased with T(breadth). Median latitude was projected to shift north for populations with high T(breadth) and low T(opt), but south for populations with low T(breadth) and high T(opt). Distributions inferred by integrating population-level projections did not differ from a species-level projection that ignored variation among populations. However, the species-level approach masked the potential array of divergent responses by populations that might lead to genotypic sorting within the species' range. Thermal performance tradeoffs among populations within the species' range had important, but sometimes counterintuitive, effects on projected responses to climatic change. Angert, A. L., S. N. Sheth and J. R. Paul 2011 Incorporating population-level variation in thermal performance into predictions of geographic range shifts Changing turgor causes plant organs to move Sharp edges can restore themselves - e.g. mandibles of herbivorous insects, teeth of insectivores, etc. Many natural systems have down-time (sleep) built in to them either for reconstitution or because the daily cycle presents times when the environment is not optimal (too hot, too cold, too dark, too light) Negligible Senescence during Reproductive Dormancy in Drosophila melanogaster The American Naturalist 158: 248-58. Tatar, M., S. A. Chien and N. K. Priest 2001 Some endemic Drosophila overwinter in a state of adult reproductive diapause where egg maturation is arrested in previtellogenic stages. When maintained at cool temperatures, adult Drosophila melanogaster enter reproductive dormancy, that is, diapause or diapause-like quiescence. The ability to survive for extended periods is a typical feature of diapause syndromes. In adults this somatic persistence may involve reduced or slowed senescence. Here we assess whether reproductively dormant D. melanogaster age at slow rates. Adults were exposed to dormancy-inducing conditions for 3, 6, or 9 wk. After this period, demographic parameters were measured under normal conditions and compared to the demography of newly eclosed cohorts. The age-specific mortality rates of postdormancy adults were essentially identical to the mortality rates of newly eclosed, young flies. Postdormancy reproduction, in contrast, declined with the duration of the treatment; somatic survival during dormancy may tradeoff with later reproduction. Adults in reproductive dormancy were highly resistant to heat and to oxidative stress. Suppressed synthesis of juvenile hormone is known to regulate reproductive diapause of many insects. Treatment of dormant D. melanogaster with a juvenile hormone analog restored vitellogenesis, suppressed stress resistance, and increased demographic senescence. We conclude that D. melanogaster age at slow rates as part of their reproductive dormancy syndrome; the data do not agree with an alternative hypothesis based on heat-dependent "rate of living." We suggest that low temperature reduces neuroendocrine function, which in turn slows senescence as a function of altered stress response, nutrient reallocation, and metabolism. 2013 Campbell, S. A. and A. Kessler Understanding the factors that shape macroevolutionary patterns in functional traits is a central goal of evolutionary biology. Alternative strategies of sexual reproduction (inbreeding vs. outcrossing) have divergent effects on population genetic structure and could thereby broadly influence trait evolution. However, the broader evolutionary consequences of mating system transitions remain poorly understood, with the exception of traits related to reproduction itself (e.g., pollination). Across a phylogeny of 56 wild species of Solanaceae (nightshades), we show here that the repeated, unidirectional transition from ancestral self-incompatibility (obligate outcrossing) to self-compatibility (increased inbreeding) leads to the evolution of an inducible (vs. constitutive) strategy of plant resistance to herbivores. We demonstrate that inducible and constitutive defense strategies represent evolutionary alternatives and that the magnitude of the resulting macroevolutionary tradeoff is dependent on the mating system. Loss of self-incompatibility is also associated with the evolution of increased specificity in induced plant resistance. We conclude that the evolution of sexual reproductive variation may have profound effects on plant-herbivore interactions, suggesting a new hypothesis for the evolution of two primary strategies of plant defense. Proceedings of the National Academy Of Sciences of the United States of America 110: 3973-8. Plant mating system transitions drive the macroevolution of defense strategies 2006 Life history theory predicts tradeoffs among reproductive traits, but the physiological mechanisms underlying such tradeoffs remain unclear. Here we examine reproductive tradeoffs and their association with yolk steroids in an oviparous lizard. Female leopard geckos lay two eggs in a clutch, produce multiple clutches in a breeding season, and reproduce for several years. We detected a significant tradeoff between egg size and the number of clutches laid by females during their first two breeding seasons. Total reproductive effort was strongly condition-dependent in the first season, but much less so in the second season. Although these and other tradeoffs were unmistakable, they were not associated with levels of androstenedione, oestradiol, or testosterone in egg yolk. Female condition and egg size, however, were inversely related to dihydrotestosterone (DHT) levels in egg yolk. Finally, steroid levels in egg yolk were not directly related to steroid levels in the maternal circulation when follicles were developing, indicating that steroid transfer to eggs is regulated. These findings suggest that maternal allocation of DHT could mitigate tradeoffs that lead to poor offspring quality (i.e. poor female condition) and small offspring size (i.e. small egg size). Journal of evolutionary biology 19: 1819-29. Rhen, T., D. Crews, A. Fivizzani and P. Elf Reproductive tradeoffs and yolk steroids in female leopard geckos, Eublepharis macularius Changes in herbivory and resource availability during a plant's development should promote ontogenetic shifts in resistance and tolerance, if the costs and benefits of these basic strategies also change as plants develop. We proposed and tested a general model to detect the expression of ontogenetic tradeoffs for these two alternative anti-herbivory strategies in Raphanus sativus. We found that ontogenetic trajectories occur in both resistance and tolerance but in opposite directions. The juvenile stage was more resistant but less tolerant than the reproductive stage. The ontogenetic switch from resistance to tolerance was consistent with the greater vulnerability of young plants to leaf damage and with the costs of resistance and tolerance found at each stage. We posit that the ontogenetic perspective presented here will be helpful in resolving the current debate on the existence and detection of a general resistance-tolerance tradeoff 2007 Ontogenetic switches from plant resistance to tolerance: minimizing costs with age? Ecology Letters 10: 177-87. K. Boege, R. Dirzo, D. Siemens and P. Brown 1999 Desiccation resistance in interspecific Drosophila crosses. Genetic interactions and trait correlations We used crosses between two closely related Drosophila species, Drosophila serrata and D. birchii, to examine the genetic basis of desiccation resistance and correlations between resistance, physiological traits, and life-history traits. D. serrata is more resistant to desiccation than D. birchii, and this may help to explain the broader geographical range of the former species. A comparison of F2's from reciprocal crosses indicated higher resistance levels when F2's originated from D. birchii mothers compared to D. serrata mothers. However, backcrosses had a resistance level similar to that of the parental species, suggesting an interaction between X-linked effects in D. serrata that reduce resistance and autosomal effects that increase resistance. Reciprocal differences persisted in hybrid lines set up from the different reciprocal crosses and tested at later generations. Increased desiccation resistance was associated with an increased body size in two sets of hybrid lines and in half-sib groups set up from the F4's after crossing the two species, but size associations were inconsistent in the F2's. None of the crosses provided evidence for a positive association between desiccation resistance and glycogen levels, or evidence for a tradeoff between desiccation resistance and early fecundity. However, fecundity was positively correlated with body size at both the genetic and phenotypic levels. This study illustrates how interspecific crosses may provide information on genetic interactions between traits following adaptive divergence, as well as on the genetic basis of the traits. Genetics 151: 1493-502. Hercus, M. J. and A. A. Hoffmann Gonzalez-Bellido, P. T., T. J. Wardill and M. Juusola Compound eyes and retinal information processing in miniature dipteran species match their specific ecological demands 2011 Proceedings of the National Academy Of Sciences of the United States of America 108: 4224-9. The compound eye of insects imposes a tradeoff between resolution and sensitivity, which should exacerbate with diminishing eye size. Tiny lenses are thought to deliver poor acuity because of diffraction; nevertheless, miniature insects have visual systems that allow a myriad of lifestyles. Here, we investigate whether size constraints result in an archetypal eye design shared between miniature dipterans by comparing the visual performance of the fruit fly Drosophila and the killer fly Coenosia. These closely related species have neural superposition eyes and similar body lengths (3 to 4 mm), but Coenosia is a diurnal aerial predator, whereas slow-flying Drosophila is most active at dawn and dusk. Using in vivo intracellular recordings and EM, we report unique adaptations in the form and function of their photoreceptors that are reflective of their distinct lifestyles. We find that although these species have similar lenses and optical properties, Coenosia photoreceptors have three- to fourfold higher spatial resolution and rate of information transfer than Drosophila. The higher performance in Coenosia mostly results from dramatically diminished light sensors, or rhabdomeres, which reduce pixel size and optical cross-talk between photoreceptors and incorporate accelerated phototransduction reactions. Furthermore, we identify local specializations in the Coenosia eye, consistent with an acute zone and its predatory lifestyle. These results demonstrate how the flexible architecture of miniature compound eyes can evolve to match information processing with ecological demands. Optimal resting-growth strategies of microbial populations in fluctuating environments Bacteria spend most of their lifetime in non-growing states which allow them to survive extended periods of stress and starvation. When environments improve, they must quickly resume growth to maximize their share of limited nutrients. Cells with higher stress resistance often survive longer stress durations at the cost of needing more time to resume growth, a strong disadvantage in competitive environments. Here we analyze the basis of optimal strategies that microorganisms can use to cope with this tradeoff. We explicitly show that the prototypical inverse relation between stress resistance and growth rate can explain much of the different types of behavior observed in stressed microbial populations. Using analytical mathematical methods, we determine the environmental parameters that decide whether cells should remain vegetative upon stress exposure, downregulate their metabolism to an intermediate optimum level, or become dormant. We find that cell-cell variability, or intercellular noise, is consistently beneficial in the presence of extreme environmental fluctuations, and that it provides an efficient population-level mechanism for adaption in a deteriorating environment. Our results reveal key novel aspects of responsive phenotype switching and its role as an adaptive strategy in changing environments. Geisel, N., J. M. Vilar and J. M. Rubi PLoS One 6: e18622. 2011 Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 154: 376-82. Large body size is thought to produce a digestive advantage through different scaling effects of gut capacity and food intake, with supposedly longer digesta retention times in larger animals. However, empirical tests of this framework have remained equivocal, which we hypothesize is because previous comparative studies have not included digesta particle size. Larger particles require more time for digestion, and if digesta particle size increases with body mass, it could explain the lack of digestive advantage in larger herbivores. We combine data on body mass, food intake, digesta retention and digestibility with data on faecal particle size (as a proxy for digesta particle size) in 21 mammalian herbivore species. Multiple regression shows that fibre digestibility is independent of body mass but dependent on digesta retention and particle size; the resulting equation indicates that retention time and particle size can compensate for each other. Similarly, digestible food intake is independent of body mass, but dependent on food intake, digesta retention, and particle size. For mammalian herbivores, increasing digesta retention and decreasing digesta particle size are viable strategies to enhance digestive performance and energy intake. Because the strategy of increased digesta retention is usually linked to reduced food intake, the high selective pressure to evolve a more efficient dentition or a physiological particle separation mechanism that facilitates repeated mastication of digesta (rumination) becomes understandable. Evidence for a tradeoff between retention time and chewing efficiency in large mammalian herbivores Clauss, M., C. Nunn, J. Fritz and J. Hummel 2009 Moreno, J. E., Y. Tao, J. Chory and C. L. Ballare Proceedings of the National Academy Of Sciences of the United States of America 106: 4935-40. Ecological modulation of plant defense via phytochrome control of jasmonate sensitivity For plants, the tradeoff between resource investment in defense and increased growth to out-compete neighbors creates an allocation dilemma. How plants resolve this dilemma, at the mechanistic level, is unclear. We found that Arabidopsis plants produced an attenuated defense phenotype under conditions of crowding and when exposed to far-red (FR) radiation, a light signal that plants use to detect the proximity of neighbors via the photoreceptor phytochrome. This phenotype was detectable through standard bioassays that measured the growth of Spodoptera frugiperda caterpillars. Two possible explanations for the effect of FR are: (i) a simple by-product of the diversion of resources to competition, and (ii) a specific effect of phytochrome on defense signaling. The first possibility was ruled out by the fact that the auxin-deficient sav3 mutant, which fails to induce growth responses to FR, still responded to FR with an attenuated defense phenotype. In support of the second hypothesis, we found that phytochrome inactivation by FR caused a strong reduction of plant sensitivity to jasmonates, which are key regulators of plant immunity. The effects of FR on jasmonate sensitivity were restricted to certain elements of the pathway. Supporting the idea that the FR effects on jasmonate signaling are functionally significant, we found that FR failed to increase tissue quality in jar1, a mutant impaired in jasmonate response. We conclude that the plant modulates its investment in defense as a function of the perceived risk of competition, and that this modulation is effected by phytochrome via selective desensitization to jasmonates. 2009 1993 S. K. Gleeson A model is explored which describes the joint optimization of tissue nitrogen and root-shoot allocation in response to variation in nitrogen availability in the environment. The model plant is composed of root and shoot biomass and tissue nitrogen, and relative growth rate is the parameter maximized. A 'source' (uptake limited) model of joint tissue nitrogen and root-shoot allocation is reviewed (Hilbert, 1990) that optimally balances the uptake of carbon and nitrogen. Modifications including root respiratory costs and fixed root tissue nitrogen are explored. Then the role of tissue nitrogen in regulating 'sink' strength is combined with the balanced source model, and modified by assuming separate tissue nitrogen involved in source vs. sink. Generally, the results indicate that as available nitrogen increases, optimal root allocation declines and tissue nitrogen increases. These results appear to be robust for more complicated versions of the model provided that various internal nitrogen compartments 'compete' for the same nitrogen. Optimization of Tissue Nitrogen and Root-Shoot Allocation Annals of Botany 71: 23-31. Kellermeier, F., F. Chardon and A. Amtmann Natural variation of Arabidopsis root architecture reveals complementing adaptive strategies to potassium starvation 2013 Plant Physiology 161: 1421-32. Root architecture is a highly plastic and environmentally responsive trait that enables plants to counteract nutrient scarcities with different foraging strategies. In potassium (K) deficiency (low K), seedlings of the Arabidopsis (Arabidopsis thaliana) reference accession Columbia (Col-0) show a strong reduction of lateral root elongation. To date, it is not clear whether this is a direct consequence of the lack of K as an osmoticum or a triggered response to maintain the growth of other organs under limiting conditions. In this study, we made use of natural variation within Arabidopsis to look for novel root architectural responses to low K. A comprehensive set of 14 differentially responding root parameters were quantified in K-starved and K-replete plants. We identified a phenotypic gradient that links two extreme strategies of morphological adaptation to low K arising from a major tradeoff between main root (MR) and lateral root elongation. Accessions adopting strategy I (e.g. Col-0) maintained MR growth but compromised lateral root elongation, whereas strategy II genotypes (e.g. Catania-1) arrested MR elongation in favor of lateral branching. K resupply and histochemical staining resolved the temporal and spatial patterns of these responses. Quantitative trait locus analysis of K-dependent root architectures within a Col-0 x Catania-1 recombinant inbred line population identified several loci each of which determined a particular subset of root architectural parameters. Our results indicate the existence of genomic hubs in the coordinated control of root growth in stress conditions and provide resources to facilitate the identification of the underlying genes. Nitrogen assimilation of pea plants (Pisum sativum cv. Meteor) was studied in growth cabinets tinder a range of water, salt, and aeration regimes in the rooting medium. Treatments were imposed in the period 14-30 d after germination using seedlings already nodulated in an optimum root environment. Highest nitrogen fixation in water culture required a strength of culture solution one fifth of that optimal for fixation in sand culture. Fixation in water culture of optimum strength was significantly improved by continuous bubble aeration or by lowering the level of culture solution below the main zone of nodulation. However, if supra-optimal concentrations of solution were used, fixation was markedly inhibited by lowering the solution level, this being associated with an accumulation of high levels of salts on exposed root and nodule surfaces.In -N (minus nitrogen) sand culture continuous waterlogging reduced nitrogen content to 40 per cent of that of non-stressed plants. In nitrate-fed plants waterlogging effects were less severe. Waterlogging decreased nodule tissue production and decreased the specific activity of nitrogenase, as assayed by acetylene reduction. These effects were most marked three or more cm below the sand surface. Watering on alternate days with free drainage at all times yielded maximum fixation in -N sand culture. Regimes increasing the extent of waterlogging or drying out in comparison with this optimum produced increasingly great decreases in nitrogen fixation. For equivalent reductions in total fixation, percentage N in dry matter was consistently lower in waterlogged than in droughted plants suggesting that excess water had the more specific effect on symbiotic activity. Both forms of stress affected particularly the transport of nitrogen from root to shoot. Effects of water, aeration, and salt regime on nitrogen fixation in a nodulated legume - definition of an optimum root environment 1975 F. R. Minchin and J. S. Pate Journal of Experimental Botany 26: 60-69. The role of root system architecture and root hairs in promoting anchorage against uprooting forces in Allium cepa and root mutants of Arabidopsis thaliana P. H. J. Bailey, J. D. Currey and A. H. Fitter 2002 The role played by lateral roots and root hairs in promoting plant anchorage, and specifically resist¬ance to vertical uprooting forces has been deter¬mined experimentally. Two species were studied, Allium cepa (onion) which has a particularly simple root system and two mutants of Arabidopsis thaliana, one without root hairs (rhd 2-1) and another with reduced lateral root branching (axr 4-2). Maximum strength of individual onion roots within a plant increased with age. In uprooting tests on onion seedlings, resistance to uprooting could be resolved into individual roots breaking. Peak pulling resistance was due to a combination of size and the extent to which the uprooting resistance of individual roots was additive. In similar uprooting tests on A. thaliana, the mutant axr 4-2, with very restricted lateral devel¬opment, showed a 14% reduction in peak pulling resistance when compared with the wild-type plants of similar shoot dry weight. The uprooting force trace ofaxr 4-2 was different to that of the wild type, and the main axis was a more significant contributor to anchorage than in the wild type. By contrast, the root hair-deficient mutant rhd 2-1 showed no difference in peak pulling resistance compared with the wild type, suggesting that root hairs do not normally play a role in uprooting resistance. The results show that lateral roots play an important role in anchorage, and that co-operation between roots may be the most significant factor. Journal of Experimental Botany 53: 333-340. Journal of Agricultural and Food Chemistry 56: 3772-6. 2008 Kim, H. J., J. M. Fonseca, J. H. Choi, C. Kubota and D. Y. Kwon The influence of salinity stress on the growth, appearance, and nutritional compounds, especially phenolic compounds and carotenoids, of romaine lettuce (Lactuca sativa L.), a low salt tolerant plant, was studied. The dry weight, height, and color of the lettuce plants were significantly changed by long-term irrigation (15 days) with higher NaCl concentration (i.e., >100 mM). However, no significant differences were observed in the growth and appearance among the control, all short-term treatments (2 days; 50, 100, 500, and 1000 mM), and long-term irrigation with low salt concentration. Moreover, in romaine lettuce treated with long-term irrigation with 5 mM NaCl, the total carotenoid content increased without color change, and the contents of major carotenoids in romaine lettuce, lutein and beta-carotene, increased 37 and 80%, respectively. No differences were observed in lutein and beta-carotene contents in short-term-treated lettuce. The phenolic content of the romaine lettuce declined with short-term salt irrigation, whereas there were no significant differences among treatments exposed to long-term irrigation. This research indicates that long-term irrigation with relatively low salt concentration, rather than short-term irrigation with high salt concentration, can increase carotenoid content in romaine lettuce without causing a tradeoff in yield or visual quality. Salt in irrigation water affects the nutritional and visual properties of romaine lettuce (Lactuca sativa L.) Porter, M. M., E. Novitskaya, A. B. Castro-Cesena, M. A. Meyers and J. McKittrick Highly deformable bones: Unusual deformation mechanisms of seahorse armor The seahorse tail is composed of subdermal bony plates arranged in articulating ring-like segments that overlap giving controlled ventral bending and twisting. The bony plates are highly deformable which slide past one another and buckle when compressed. This complex plate and segment motion, along with the unique hardness distribution and structural hierarchy of each plate, provide seahorses with flexible joints while shielding them from impact and crushing. Acta Biomaterialia 2013 The Journal of Experimental Biology 213: 2184-2193. Snout allometry in seahorses: insights on optimisation of pivot feeding performance during ontogeny As juvenile life-history stages are subjected to strong selection, these stages often show levels of performance approaching those of adults, or show a disproportionately rapid increase of performance with age. Although testing performance capacity in aquatic suction feeders is often problematic, in pivot feeders such as seahorses models have been proposed to estimate whether snout length is optimal to minimise the time needed to reach the prey. Here, we investigate whether the same model can also explain the snout lengths in an ontogenetic series of seahorses, explore how pivot feeding kinematics change during ontogeny, and test whether juveniles show disproportionate levels of performance. Our analysis shows that the dimensions of the snout change during ontogeny from short and broad to long and narrow. Model calculations show that the snout lengths of newborn and juvenile seahorses are nearly optimal for minimising prey reach time. However, in juveniles the centre of head rotation in the earth-bound frame of reference is located near the posterior end of the head, whereas in adults it is shifted forward and is located approximately above the eye. Modelling shows that this forward shift in the centre of rotation has the advantage of decreasing the moment of inertia and the torque required to rotate the head, but has the disadvantage of slightly increasing the time needed to reach the prey. Thus, the snout lengths of juvenile seahorses appear to be close to optimal, suggesting that they reach levels of performance close to adult levels, which illustrates the pervasive nature of selection on performance in juveniles. G. Roos, S. Van Wassenbergh, A. Herrel, D. Adriaens and P. Aerts 2010 Molecular bioSystems 2013 Song, H., Z. Yuan and T. Zhou Delay-managed tradeoff in the molecular dynamics of the segmentation clock The molecular segmentation clock is a complex regulatory network that governs the periodic somite segmentation in vertebrate embryos. Underlying the rhythm of the segmentation clock is a single-cell level pace-making circuit, where inevitable molecular noise and time delay impose normal operating constraints to the pace-making. However, how the molecular mechanisms of the core circuit of the segmentation clock coordinate the operating constraints and maintain the rhythmic nature of the developmental process remains poorly understood. To address this question, we construct two biologically-motivated mathematical models with multiple clock protein transcription binding sites, with differential or rate-limited decay rates for protein monomers and dimers. We demonstrate that the rate-limited decay significantly enlarges the parameter space of noise-induced and delay-induced oscillations. Interestingly, focusing on the stochastic characters of noise-induced and delay-induced oscillations in terms of phase coherence and phase averaged amplitude noise in the polar coordinate, we find that there is a delay-managed tradeoff between phase coherence and phase averaged amplitude noise. In particular, the model with both multiple binding sites and rate-limited decay can show regular tunability as the delay increases. Our results indicate that transcriptional and post-translational mechanisms constrain the combined effects of noise and delay on the molecular dynamics of the segmentation clock. Genetics 160: 595-608. 2002 Hey, J. and R. M. Kliman Interactions between natural selection, recombination and gene density in the genes of Drosophila In Drosophila, as in many organisms, natural selection leads to high levels of codon bias in genes that are highly expressed. Thus codon bias is an indicator of the intensity of one kind of selection that is experienced by genes and can be used to assess the impact of other genomic factors on natural selection. Among 13,000 genes in the Drosophila genome, codon bias has a slight positive, and strongly significant, association with recombination--as expected if recombination allows natural selection to act more efficiently when multiple linked sites segregate functional variation. The same reasoning leads to the expectation that the efficiency of selection, and thus average codon bias, should decline with gene density. However, this prediction is not confirmed. Levels of codon bias and gene expression are highest for those genes in an intermediate range of gene density, a pattern that may be the result of a tradeoff between the advantages for gene expression of close gene spacing and disadvantages arising from regulatory conflicts among tightly packed genes. These factors appear to overlay the more subtle effect of linkage among selected sites that gives rise to the association between recombination rate and codon bias. Numerous studies have documented evolution by natural selection in natural populations, but few are genuine selection experiments that are designed and then executed in nature. We will focus on these few cases to illustrate what can be learned from field selection experiments alone or field and laboratory selection experiments together that cannot be learned from laboratory experiments alone. Both types of study allow us to evaluate cause and effect relationships because a planned experiment can be accompanied by a more direct evaluation of the factors that cause evolution. A unique benefit of field experiments is that they give us the opportunity to measure the rate and magnitude of selection in nature. We have found that this rate is far greater than one might imagine based on observations of the fossil record. A combination of field and laboratory selection experiments has revealed the importance of population size and structure in shaping the genetics of adaptation. For example, laboratory selection experiments on insecticide resistance tend to attain resistance though polygenic inheritance. The evolution of insecticide resistance in nature often eventually yields to single genes of large effect that are rare but, once they arise, represent a higher fitness solution to resistance and spread among populations. Finally, field studies enable us to test evolutionary theory in a context in which all of the tradeoffs associated with a trait are realized; in the laboratory, organisms may be shielded from the fitness tradeoffs associated with the evolution of a trait. For example, we have compared the patterns of senescence in guppies from high and low mortality rate environments in the laboratory and in the field. In the laboratory, guppies from high predation environments had delayed senescence relative to those from low predation environments. In the field the apparent relationship is the opposite. One hypothesis for this difference is that a tradeoff associated with the evolution of the high predation life history is a decrease in the investment in the immune system. Such a sacrifice would be evident in nature where there is exposure to disease and parasites but less so in the laboratory, which is relatively disease and parasite free. Reznick, D. N. and C. K. Ghalambor 2005 Integrative and Comparative Biology 45: 456-62. Selection in nature: experimental manipulations of natural populations Sensory Systems and Flight Stability: What do Insects Measure and Why? 2007 In the absence of much passive stability, flying insects rely upon active stabilisation, necessitating the provision of rich sensory feedback across a range of modalities. Here we consider from a sensory perspective what quantities flying insects measure, in order to ask from a mechanical perspective why they should want to do so. We consider each of the sensory modalities separately and uncover three general principles. Firstly, we find that insects have evolved to measure changes in kinematic state, rather than absolute state. For example, although the antennae may be loosely thought of as airspeed sensors, we show that they are configured as a sophisticated adaptive sensing system which is much more appropriate for measuring changes in airspeed than absolute airspeed. Secondly, we find that insect sensory systems are tuned to sense self-motion components in specific directions. For example, certain visual interneurons of flies operate as matched filters that are tuned to detect the optic flow fields induced specifically by rotation about one particular axis. Thirdly, we find that insects commonly combine sensory input from across modalities to form composite, multi-modal quantities which they use as feedback to the control system. For example, certain individually identified descending interneurons combine input from the compound eyes, ocelli, antennae, and cephalic wind-sensitive hairs into one composite signal which is then used in flight control. We infer from these three general organisational principles that insects are configured to sense excitation of their natural modes of motion. This natural-mode sensing hypothesis: (1) explains why insects should want to sense changes in state rather than absolute state; (2) predicts what specific directions of motion they should sense, and (3) specifies how sensory input from different modalities should be combined. G. K. Taylor and H. G. Krapp Seed hairs; insulation by feathers or hairs; spines and quils for protection; Compressive and tensile elements in a structure should be minimised and kept separate, and that either one (usually the compressive element) if reduced to zero will allow the least amount of the other element (tensile) to be used. This is seen in animals and plants with hydrostatic skeletons (which accounts for all non-woody plants). Maxwell's Lemma. Sack, C. and D. L. Stern 2007 Insect dispersal dimorphisms, in which both flight-capable and flightless individuals occur in the same species, are thought to reflect a balance between the benefits and costs of dispersal. Fitness costs and benefits associated with wing dimorphism were investigated in the male pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). In one-on-one mating competitions in small arenas between winged and wingless males, the winged aphids obtained most of the matings with virgin females. In contrast, during competition experiments in larger cages with multiple individuals of each morph, the winged males no longer had a clear mating advantage over wingless males. In the absence of competition, wingless males had marginally higher lifetime reproductive success than winged males, probably because mating winged males tended to die faster than wingless males. In the absence of females, winged males survived longer than wingless males and this difference disappeared under starvation conditions. Mating males of both morphs died significantly faster than males without access to females. There does not appear to be a direct tradeoff of dispersal ability with life history characteristics in pea aphid males, suggesting that the advantages of producing winged males may result from outbreeding. Sex and death in the male pea aphid, Acyrthosiphon pisum: The life-history effects of a wing dimorphism Journal of insect science 7: 1-9. Plant sex and the evolution of plant defenses against herbivores Johnson, M. T., S. D. Smith and M. D. Rausher Despite the importance of plant-herbivore interactions to the ecology and evolution of terrestrial ecosystems, the evolutionary factors contributing to variation in plant defenses against herbivores remain unresolved. We used a comparative phylogenetic approach to examine a previously untested hypothesis (Recombination-Mating System Hypothesis) that posits that reduced sexual reproduction limits adaptive evolution of plant defenses against arthropod herbivores. To test this hypothesis we focused on the evening primrose family (Onagraceae), which includes both sexual and functionally asexual species. Ancestral state reconstructions on a 5-gene phylogeny of the family revealed between 18 and 21 independent transitions between sexual and asexual reproduction. Based on these analyses, we examined susceptibility to herbivores on 32 plant species representing 15 independent transitions. Generalist caterpillars consumed 32% more leaf tissue, gained 13% greater mass, and experienced 21% higher survival on functionally asexual than on sexual plant species. Survival of a generalist feeding mite was 19% higher on asexual species. In a field experiment, generalist herbivores consumed 64% more leaf tissue on asexual species. By contrast, a specialist beetle fed more on sexual than asexual species, suggesting that a tradeoff exists between the evolution of defense to generalist and specialist herbivores. Measures of putative plant defense traits indicate that both secondary compounds and physical leaf characteristics may mediate this tradeoff. These results support the Recombination-Mating System Hypothesis and suggest that variation in sexual reproduction among plant species may play an important, yet overlooked, role in shaping the macroevolution of plant defenses against arthropod herbivores. 2009 Proceedings of the National Academy Of Sciences of the United States of America 106: 18079-84. Increased sexual activity reduces male immune function in Drosophila melanogaster 2001 McKean, K. A. and L. Nunney Despite the benefits of resistance, susceptibility to infectious disease is commonplace. Although specific susceptibility may be considered an inevitable consequence of the co-evolutionary arms race between parasite and host, a more general constraint may arise from the cost of an immune response. This "cost" hypothesis predicts a tradeoff between immune defense and other components of fitness. In particular, a tradeoff between immunity and sexually selected male behavior has been proposed. Here we provide experimental support for the direct phenotypic tradeoff between sexual activity and immunity by studying the antibacterial immune response in Drosophila melanogaster. Males exposed to more females showed a reduced ability to clear a bacterial infection, an effect that we experimentally link to changes in sexual activity. Our results suggest immunosuppression is an important cost of reproduction and that immune function and levels of disease susceptibility will be influenced by sexual selection. Proceedings of the National Academy Of Sciences of the United States of America 98: 7904-9. Physiological genomics 25: 393-404. 2006 Bauer, M, J. D. Katzenberger, A. C. Hamm, M. Bonaus, I. Zinke, J. Jaekel and M. J. Pankratz The reallocation of metabolic resources is important for survival during periods of limited nutrient intake. This has an influence on diverse physiological processes, including reproduction, repair, and aging. One important aspect of resource allocation is the difference between males and females in response to nutrient stress. We identified several groups of genes that are regulated in a sex-biased manner under complete or protein starvation. These range from expected differences in genes involved in reproductive physiology to those involved in amino acid utilization, sensory perception, immune response, and growth control. A striking difference was observed in purine and the tightly interconnected folate metabolism upon protein starvation. From these results, we conclude that the purine and folate metabolic pathway is a major point of transcriptional regulation during resource allocation and may have relevance for understanding the physiological basis for the observed tradeoff between reproduction and longevity. Purine and folate metabolism as a potential target of sex-specific nutrient allocation in Drosophila and its implication for lifespan-reproduction tradeoff We investigated susceptibility to photoinhibition in leaves acclimated to different light regimes in intermediately shade-tolerant Japanese oak (Quercus mongolica Fisch. ex Turcz. var. crispula (Blume) Ohashi) and shade-tolerant Japanese maple (Acer mono Maxim. var. glabrum (Lev. et Van't.) Hara), to elucidate adaptability to gap formation in leaves differing in shade acclimation. We hypothesized that there is a tradeoff between shade adaptation and capacity to mitigate photoinhibition associated with leaf morphology. We simultaneously measured chlorophyll fluorescence and gas exchange in seedlings that had been grown in full sunlight (open), 10% of full sun (moderate shade) and 5% of full sun (deep shade). Shade-tolerant A. mono adapted to deep shade through changes in leaf morphology, lowering its leaf mass per area (LMA), but Q. mongolica showed little change in LMA between moderate and deep shade. Photochemical quenching (qP) did not differ between species in full sunlight and moderate shade; however, in deep shade, qP of Q. mongolica was higher than that of A. mono, suggesting that Q. mongolica grown in deep shade is less susceptible to photoinhibition at gap formation. This is consistent with the finding that chronic photoinhibition 3 days after the transfer to full sunlight, indicated by the decrease in maximum photochemical efficiency, Fv/Fm, at predawn, was less in deep-shade-grown Q. mongolica than in deep shade-grown A. mono. In deep shade, the electron transport rate (ETR) of Q. mongolica was higher than that of A. mono, whereas thermal energy dissipation through photosystem II antennae, indicated by non-photochemical quenching, was lower in Q. mongolica than in A. mono. In deep shade, the greater ETR capacity in Q. mongolica in association with higher LMA and higher leaf N content could contribute to maintaining high qP and mitigating photoinhibition. These results indicate that, by maintaining a high electron transport capacity even in deep shade, the gap-dependent and intermediate-shade-tolerant Q. mongolica trades improved shade adaptation for higher growth potential when a gap event occurs. Tree Physiology 26: 441-8. Tradeoff between shade adaptation and mitigation of photoinhibition in leaves of Quercus mongolica and Acer mono acclimated to deep shade 2006 Kitao, M., T. T. Lei, T. Koike, H. Tobita and Y. Maruyama Shapes of krill swarms and fish schools emerge as aggregation members avoid predators and access oxygen Brierley, A. S. and M. J. Cox Shoal size and packing density varied greatly, but surface area:volume ratios (roughnesses) were distributed narrowly about approximately 3.3 m(-1). Shoals of clupeid fish (e.g., sardine, anchovy) from geographically and oceanographically diverse locations have very similar roughnesses. This common emergent shape property suggests common driving forces across diverse ecosystems. Group behavior can be complex, but a simple tradeoff--that we model--in which individual fish and krill juggle only their access to oxygen-replete water and exposure to predation can explain the observed shoal shape. Decreasing oxygen availability in a warming world ocean may impact shoal structure: because structure affects catchability by predators and fishers, understanding the response will be necessary for ecological and commercial reasons. Positive: Individual animals in a group are less likely to be predated F_07 Negative: They have to go to the surface of the group to get oxygen and are exposed to predation F_23 Current biology : CB 20: 1758-62. 2010 The variability of bird beak morphology reflects diverse foraging strategies. One such feeding mechanism in shorebirds involves surface tension–induced transport of prey in millimetric droplets: By repeatedly opening and closing its beak in a tweezering motion, the bird moves the drop from the tip of its beak to its mouth in a stepwise ratcheting fashion. We have analyzed the subtle physical mechanism responsible for drop transport and demonstrated experimentally that the beak geometry and the dynamics of tweezering may be tuned to optimize transport efficiency. We also highlight the critical dependence of the capillary ratchet on the beak's wetting properties, thus making clear the vulnerability of capillary feeders to surface pollutants. Surface Tension Transport of Prey by Feeding Shorebirds: The Capillary Ratchet Science 320: 931-934. 2008 M. Prakash, D. Quéré and J. W. M. Bush 2011 Proceedings of the National Academy Of Sciences of the United States of America 108: 5325-30. Spermatozoa are amongst the most variable cells, and three factors are thought to account for this variation in design: fertilization mode, phylogeny, and postcopulatory sexual selection. In addition, it has long been assumed that a tradeoff exists between sperm size and number, and although postcopulatory sexual selection affects both traits, empirical evidence for a tradeoff has so far been elusive. Our recent theoretical model predicts that the nature of a direct tradeoff between sperm size and number varies with sperm competition mechanism and sperm competition risk. We test these predictions using a comparative approach in two very different taxa with different sperm competition mechanisms: passerine birds (mechanism: simple raffle) and Drosophila fruit flies (sperm displacement). We show that in both groups, males increase their total ejaculate investment with increasing sperm competition risk, but whereas passerine birds allocate disproportionately to sperm number, drosophilids allocate disproportionately to sperm size. This striking difference between the two groups can be at least partly explained by sperm competition mechanisms depending on sperm size relative to the size of the female reproductive tract: in large animals (passerines), sperm numbers are advantageous in sperm competition owing to dilution inside the female tract, whereas in small animals (drosophilids), large sperm are advantageous for physical competition (sperm displacement). Our study provides two important results. First, we provide convincing evidence for the existence of a sperm size-number tradeoff. Second, we show that by considering both sperm competition mechanism and dilution, can we account for variation in sperm size between different taxa. Immler, S., S. Pitnick, G. A. Parker, K. L. Durrant, S. Lupold, S. Calhim and T. R. Birkhead Resolving variation in the reproductive tradeoff between sperm size and number Rosell, J. A., M. E. Olson, R. Aguirre-Hernandez and F. J. Sanchez-Sesma Organismal size and shape inseparably interact with tissue biomechanical properties. It is therefore essential to understand how size, shape, and biomechanics interact in ontogeny to produce morphological diversity. We estimated within species branch length-diameter allometries and reconstructed the rates of ontogenetic change along the stem in mechanical properties across the simaruba clade in the tropical tree genus Bursera, measuring 376 segments from 97 branches in nine species in neotropical dry to rain forest. In general, species with stiffer materials had longer, thinner branches, which became stiffer more quickly in ontogeny than their counterparts with more flexible materials. We found a trend from short stature and flexible tissues to tall statures and stiff tissues across an environmental gradient of increasing water availability, likely reflecting a water storage-mechanical support tradeoff. Ontogenetic variation in size, shape, and mechanics results in diversity of habits, for example, rapid length extension, sluggish diameter expansion, and flexible tissues results in a liana, as in Bursera instabilis. Even species of similar habit exhibited notable changes in tissue mechanical properties with increasing size, illustrating the inseparable relationship between organismal proportions and their tissue mechanics in the ontogeny and evolution of morphological diversity. Evolution & development 14: 437-49. Ontogenetic modulation of branch size, shape, and biomechanics produces diversity across habitats in the Bursera simaruba clade of tropical trees 2012 How large should whales be? Clauset, A. The evolution and distribution of species body sizes for terrestrial mammals is well-explained by a macroevolutionary tradeoff between short-term selective advantages and long-term extinction risks from increased species body size, unfolding above the 2 g minimum size induced by thermoregulation in air. Here, we consider whether this same tradeoff, formalized as a constrained convection-reaction-diffusion system, can also explain the sizes of fully aquatic mammals, which have not previously been considered. By replacing the terrestrial minimum with a pelagic one, at roughly 7000 g, the terrestrial mammal tradeoff model accurately predicts, with no tunable parameters, the observed body masses of all extant cetacean species, including the 175,000,000 g Blue Whale. This strong agreement between theory and data suggests that a universal macroevolutionary tradeoff governs body size evolution for all mammals, regardless of their habitat. The dramatic sizes of cetaceans can thus be attributed mainly to the increased convective heat loss is water, which shifts the species size distribution upward and pushes its right tail into ranges inaccessible to terrestrial mammals. Under this macroevolutionary tradeoff, the largest expected species occurs where the rate at which smaller-bodied species move up into large-bodied niches approximately equals the rate at which extinction removes them. 2013 PLoS One 8: e53967. MacLean, R. C., G. Bell and P. B. Rainey The evolution of a pleiotropic fitness tradeoff in Pseudomonas fluorescens The evolution of ecological specialization is expected to carry a cost, due to either antagonistic pleiotropy or mutation accumulation. In general, it has been difficult to distinguish between these two possibilities. Here, we demonstrate that the experimental evolution of niche-specialist genotypes of the bacterium Pseudomonas fluorescens that colonize the air-broth interface of spatially structured microcosms is accompanied by pleiotropic fitness costs in terms of reduced carbon catabolism. Prolonged selection in spatially structured microcosms caused the cost of specialization to decline without loss of the benefits associated with specialization. The decline in the cost of specialization can be explained by either compensatory adaptation within specialist lineages or clonal competition among specialist lineages. These results provide a possible explanation of conflicting accounts for the cost of specialization. 2004 Proceedings of the National Academy Of Sciences of the United States of America 101: 8072-7. 2008 The pleiotropic cost of host-specialization in Tobacco etch potyvirus Host-range expansion is thought to allow viruses to broaden their ecological niches by allowing access to new resources. However, traits governing the infection of multiple hosts may decrease fitness in the original one due to the pleiotropic effect of adaptive mutations that may give rise to fitness tradeoffs across hosts. Here, we have experimentally examined the consequences of host-specialization in the plant pathogen Tobacco etch potyvirus (TEV). Replicate populations of TEV were allowed to evolve for 15 serial undiluted passages on the original tobacco host or on pepper, a novel host. Virulence and biologically active viral load were evaluated during the course of the experiment for each lineage on both potential hosts. In agreement with the tradeoff hypothesis, lineages evolved in the novel host experienced substantial increases in virulence and virus accumulation in its own host, but suffered reduced virulence and accumulation on the original host. By contrast, lineages evolved on the ancestral host did not increase virulence or viral load on either host. Genomic consensus sequences were obtained for each lineage at the end time point. The potential relevance for the evolution of virulence and virus fitness of the characterized mutations is discussed. P. Agudelo-Romero, F. de la Iglesia and S. F. Elena Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 8: 806-14. Neuron 76: 616-28. Heitz, R. P. and J. D. Schall 2012 Neural mechanisms of speed-accuracy tradeoff Intelligent agents balance speed of responding with accuracy of deciding. Stochastic accumulator models commonly explain this speed-accuracy tradeoff by strategic adjustment of response threshold. Several laboratories identify specific neurons in prefrontal and parietal cortex with this accumulation process, yet no neurophysiological correlates of speed-accuracy tradeoff have been described. We trained macaque monkeys to trade speed for accuracy on cue during visual search and recorded the activity of neurons in the frontal eye field. Unpredicted by any model, we discovered that speed-accuracy tradeoff is accomplished through several distinct adjustments. Visually responsive neurons modulated baseline firing rate, sensory gain, and the duration of perceptual processing. Movement neurons triggered responses with activity modulated in a direction opposite of model predictions. Thus, current stochastic accumulator models provide an incomplete description of the neural processes accomplishing speed-accuracy tradeoffs. The diversity of neural mechanisms was reconciled with the accumulator framework through an integrated accumulator model constrained by requirements of the motor system. Ho, T., S. Brown, L. van Maanen, B. U. Forstmann, E. J. Wagenmakers and J. T. Serences 2012 The optimality of sensory processing during the speed-accuracy tradeoff When people make decisions quickly, accuracy suffers. Traditionally, speed-accuracy tradeoffs (SATs) have been almost exclusively ascribed to changes in the amount of sensory evidence required to support a response ("response caution") and the neural correlates associated with the later stages of decision making (e.g., motor response generation and execution). Here, we investigated whether performance decrements under speed pressure also reflect suboptimal information processing in early sensory areas such as primary visual cortex (V1). Human subjects performed an orientation discrimination task while emphasizing either response speed or accuracy. A model of choice behavior revealed that the rate of sensory evidence accumulation was selectively modulated when subjects emphasized accuracy, but not speed, suggesting that changes in sensory processing also influence the SAT. We then used fMRI and a forward encoding model to derive orientation-selective tuning functions based on activation patterns in V1. When accuracy was emphasized, the extent to which orientation-selective tuning profiles exhibited a theoretically optimal gain pattern predicted both response accuracy and the rate of sensory evidence accumulation. However, these relationships were not observed when subjects emphasized speed. Collectively, our findings suggest that, in addition to lowered response thresholds, the performance decrements observed during speeded decision making may result from a failure to optimally process sensory signals. The Journal of neuroscience : the official journal of the Society for Neuroscience 32: 7992-8003. Speed-accuracy tradeoff in olfaction The basic psychophysical principle of speed-accuracy tradeoff (SAT) has been used to understand key aspects of neuronal information processing in vision and audition, but the principle of SAT is still debated in olfaction. In this study we present the direct observation of SAT in olfaction. We developed a behavioral paradigm for mice in which both the duration of odorant sampling and the difficulty of the odor discrimination task were controlled by the experimenter. We observed that the accuracy of odor discrimination increases with the duration of imposed odorant sampling, and that the rate of this increase is slower for harder tasks. We also present a unifying picture of two previous, seemingly disparate experiments on timing of odorant sampling in odor discrimination tasks. The presence of SAT in olfaction provides strong evidence for temporal integration in olfaction and puts a constraint on models of olfactory processing. Neuron 51: 351-8 Rinberg, D., A. Koulakov and A. Gelperin 2006 Proceedings. Biological sciences / The Royal Society 273: 1907-12. Illes, A. E., M. L. Hall and S. L. Vehrencamp In a variety of songbirds the production of trilled song elements is constrained by a performance tradeoff between how fast a bird can repeat trill units (trill rate) and the range of frequencies each unit can span (frequency bandwidth). High-performance trills serve as an assessment signal for females, but little is known about the signal value of vocal performance for male receivers. We investigated the relationship between trill rate and frequency bandwidth in banded wren (Thryothorus pleurostictus) songs. Trilled song elements showed the same performance tradeoff found in other passerines and individuals differed in performance of some trill types. We tested the hypothesis that males of this species assess each other based on trill performance with a two-speaker experiment, in which territory owners were presented with alternating renditions of the same song type manipulated to differ in trill rate. Subjects were significantly more likely to approach the faster trill stimulus first. However, subjects that received trill types closer to the performance limit spent less time close to the fast speaker. Our results show that male banded wrens discriminate and respond differently to songs based on their vocal performance. Thus, performance of physically challenging songs may be important in intra- as well as inter-sexual assessment. Vocal performance influences male receiver response in the banded wren 2006 tuataras from New Zealand: 2 spp lizards, snakes, and worm lizards: approximately 9,150 spp Weihs, D. The dictionary definition of stability as "Firmly established, not easily to be changed" immediately indicates the conflict between stability and maneuverability in aquatic locomotion. The present paper addresses several issues resulting from these opposing requirements. Classical stability theory for bodies moving in fluids is based on developments in submarine and airship motions. These have lateral symmetry, in common with most animals. This enables the separation of the equations of motion into two sets of 3 each. The vertical (longitudinal) set, which includes motions in the axial (surge), normal (heave) and pitching directions, can thus be separated from the lateral-horizontal plane which includes yaw, roll and sideslip motions. This has been found useful in the past for longitudinal stability studies based on coasting configurations but is not applicable to the analysis of turning, fast starts and vigorous swimming, where the lateral symmetry of the fish body is broken by bending motions. The present paper will also examine some of the aspects of the stability vs. maneuverability tradeoff for these asymmetric motions. An analysis of the conditions under which the separation of equations of motions into vertical and horizontal planes is justified, and a definition of the equations to be used in cases where this separation is not accurate enough is presented. Stability versus maneuverability in aquatic locomotion 2002 Integrative and Comparative Biology 42: 127-34. PLoS computational biology 5: e1000627. Fromer, M. and J. M. Shifman 2009 Natural proteins often partake in several highly specific protein-protein interactions. They are thus subject to multiple opposing forces during evolutionary selection. To be functional, such multispecific proteins need to be stable in complex with each interaction partner, and, at the same time, to maintain affinity toward all partners. How is this multispecificity acquired through natural evolution? To answer this compelling question, we study a prototypical multispecific protein, calmodulin (CaM), which has evolved to interact with hundreds of target proteins. Starting from high-resolution structures of sixteen CaM-target complexes, we employ state-of-the-art computational methods to predict a hundred CaM sequences best suited for interaction with each individual CaM target. Then, we design CaM sequences most compatible with each possible combination of two, three, and all sixteen targets simultaneously, producing almost 70,000 low energy CaM sequences. By comparing these sequences and their energies, we gain insight into how nature has managed to find the compromise between the need for favorable interaction energies and the need for multispecificity. We observe that designing for more partners simultaneously yields CaM sequences that better match natural sequence profiles, thus emphasizing the importance of such strategies in nature. Furthermore, we show that the CaM binding interface can be nicely partitioned into positions that are critical for the affinity of all CaM-target complexes and those that are molded to provide interaction specificity. We reveal several basic categories of sequence-level tradeoffs that enable the compromise necessary for the promiscuity of this protein. We also thoroughly quantify the tradeoff between interaction energetics and multispecificity and find that facilitating seemingly competing interactions requires only a small deviation from optimal energies. We conclude that multispecific proteins have been subjected to a rigorous optimization process that has fine-tuned their sequences for interactions with a precise set of targets, thus conferring their multiple cellular functions. Tradeoff between stability and multispecificity in the design of promiscuous proteins Tokuriki, N., F. Stricher, L. Serrano and D. S. Tawfik 2008 How protein stability and new functions trade off Numerous studies have noted that the evolution of new enzymatic specificities is accompanied by loss of the protein's thermodynamic stability (DeltaDeltaG), thus suggesting a tradeoff between the acquisition of new enzymatic functions and stability. However, since most mutations are destabilizing (DeltaDeltaG>0), one should ask how destabilizing mutations that confer new or altered enzymatic functions relative to all other mutations are. We applied DeltaDeltaG computations by FoldX to analyze the effects of 548 mutations that arose from the directed evolution of 22 different enzymes. The stability effects, location, and type of function-altering mutations were compared to DeltaDeltaG changes arising from all possible point mutations in the same enzymes. We found that mutations that modulate enzymatic functions are mostly destabilizing (average DeltaDeltaG = +0.9 kcal/mol), and are almost as destabilizing as the "average" mutation in these enzymes (+1.3 kcal/mol). Although their stability effects are not as dramatic as in key catalytic residues, mutations that modify the substrate binding pockets, and thus mediate new enzymatic specificities, place a larger stability burden than surface mutations that underline neutral, non-adaptive evolutionary changes. How are the destabilizing effects of functional mutations balanced to enable adaptation? Our analysis also indicated that many mutations that appear in directed evolution variants with no obvious role in the new function exert stabilizing effects that may compensate for the destabilizing effects of the crucial function-altering mutations. Thus, the evolution of new enzymatic activities, both in nature and in the laboratory, is dependent on the compensatory, stabilizing effect of apparently "silent" mutations in regions of the protein that are irrelevant to its function. PLoS computational biology 4: e1000002. 2008 K. L. Bishop, A. K. Pai and D. Schmitt PLoS One 3: e3808. The metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evolution of locomotor behavior. The assumption that energetic economy is the most important target of natural selection underlies many analyses of steady animal locomotion, leading to the prediction that animals will choose gaits and postures that maximize energetic efficiency. Many quadrupedal animals, particularly those that specialize in long distance steady locomotion, do in fact reduce the muscular contribution required for walking by adopting pendulum-like center of mass movements that facilitate exchange between kinetic energy (KE) and potential energy (PE). However, animals that are not specialized for long distance steady locomotion may face a more complex set of requirements, some of which may conflict with the efficient exchange of mechanical energy. For example, the "stealthy" walking style of cats may demand slow movements performed with the center of mass close to the ground. Force plate and video data show that domestic cats (Felis catus, Linnaeus, 1758) have lower mechanical energy recovery than mammals specialized for distance. A strong negative correlation was found between mechanical energy recovery and diagonality in the footfalls and there was also a negative correlation between limb compression and diagonality of footfalls such that more crouched postures tended to have greater diagonality. These data show a previously unrecognized mechanical relationship in which crouched postures are associated with changes in footfall pattern which are in turn related to reduced mechanical energy recovery. Low energy recovery was not associated with decreased vertical oscillations of the center of mass as theoretically predicted, but rather with posture and footfall pattern on the phase relationship between potential and kinetic energy. An important implication of these results is the possibility of a tradeoff between stealthy walking and economy of locomotion. This potential tradeoff highlights the complex and conflicting pressures that may govern the locomotor choices that animals make. Whole body mechanics of stealthy walking in cats Multitasking. Cellular structure: cells can be independent - e.g. motor cells 2009 Biophysical Journal 97: 946-57. Matthaus, F., M. Jagodic and J. Dobnikar E. coli superdiffusion and chemotaxis-search strategy, precision, and motility Escherichia coli motion is characterized by a sequence of consecutive tumble-and-swim events. In the absence of chemical gradients, the length of individual swims is commonly believed to be distributed exponentially. However, recently there has been experimental indication that the swim-length distribution has the form of a power-law, suggesting that bacteria might perform superdiffusive Levy-walk motion. In E. coli, the power-law behavior can be induced through stochastic fluctuations in the level of CheR, one of the key enzymes in the chemotaxis signal transmission pathway. We use a mathematical model of the chemotaxis signaling pathway to study the influence of these fluctuations on the E. coli behavior in the absence and presence of chemical gradients. We find that the population with fluctuating CheR performs Levy-walks in the absence of chemoattractants, and therefore might have an advantage in environments where nutrients are sparse. The more efficient search strategy in sparse environments is accompanied by a generally larger motility, also in the presence of chemoattractants. The tradeoff of this strategy is a reduced precision in sensing and following gradients, as well as a slower adaptation to absolute chemoattractant levels. 2004 Swimming efficiencies of fish and cetaceans have been related to a certain synchrony between stroke cycle frequency, peak-to-peak tail/fluke amplitude and mean swimming speed. These kinematic parameters form a non-dimensional wake parameter, referred to as a Strouhal number, which for the range between 0.20 and 0.40 has been associated with enhanced swimming efficiency for fish and cetaceans. Yet to date there has been no direct experimental substantiation of what Strouhal numbers are preferred by swimming cetaceans. To address this lack of data, a total of 248 Strouhal numbers were calculated for the captive odontocete cetaceans Tursiops truncatus, Pseudorca crassidens, Orcinus orca, Globicephala melaena, Lagenorhynchus obliquidens and Stenella frontalis. Although the average Strouhal number calculated for each species is within the accepted range, considerable scatter is found in the data both within species and among individuals. A greater proportion of Strouhal values occur between 0.20 and 0.30 (74%) than the 0.25‚Äì0.35 (55%) range predicted for maximum swimming efficiency. Within 0.05 Strouhal increments, the greatest number of Strouhal values was found between 0.225 and 0.275 (44%). Where propulsive efficiency data were available (T. truncatus, P. crassidens, O. orca), peak swimming efficiency corresponded to this same Strouhal range. The odontocete cetacean data show that, besides being generally limited to a range of Strouhal numbers between 0.20 and 0.40, the kinematic parameters comprising the Strouhal number provide additional constraints. Fluke-beat frequency normalized by the ratio of swimming speed to body length was generally restricted from 1 to 2, whereas peak-to-peak fluke amplitude normalized by body length occurred predominantly between 0.15 and 0.25. The results indicate that the kinematics of the propulsive flukes of odontocete cetaceans are not solely dependent on Strouhal number, and the Strouhal number range for odontocete cetaceans occurs at slightly (‚àº20%) lower values than previously predicted for maximum swimming efficiency. J. J. Rohr and F. E. Fish Journal of Experimental Biology 207: 1633-1642. Strouhal numbers and optimization of swimming by odontocete cetaceans The existing theory of sympatric speciation assumes that a local population splits into two species under one-dimensional disruptive selection, which favors both of the opposite extreme values of a quantitative trait. Here we model sympatric speciation under selection that favors high values of either of the two independently inherited traits, each required to efficiently consume one of the two available resources, but acts, because of a tradeoff, against those possessing high values of both traits. Such two-dimensional incompatibility selection is similar to that involved in allopatric speciation. Using a hypergeometric phenotypic model, we show that incompatibility selection readily leads to sympatric speciation. In contrast to disruptive selection, two distinct modes of sympatric speciation exist under incompatibility selection: under strong tradeoffs both of the new species are specialists, each consuming its own resource, but under moderate tradeoffs speciation may be asymmetric and involve the origin of a specialist and a generalist species. Also, incompatibility selection may lead to irreversible specialization: under strong tradeoffs, the population speciates if it consists mostly of unspecialized individuals, but remains undivided if most of the individuals are specialized to consume one of the resources. Incompatibility selection appears to be more realistic than disruptive selection, implying that incompatibility between individually adaptive alleles or trait states drives both allopatric and sympatric speciation. Artzy-Randrup Y. and A. S. Kondrashov Sympatric speciation under incompatibility selection Proceedings of the National Academy Of Sciences of the United States of America 103: 11619-24. 2006 Rangan, A. V. PLoS computational biology 8: e1002622. 2012 Functional roles for synaptic-depression within a model of the fly antennal lobe Several experiments indicate that there exists substantial synaptic-depression at the synapses between olfactory receptor neurons (ORNs) and neurons within the drosophila antenna lobe (AL). This synaptic-depression may be partly caused by vesicle-depletion, and partly caused by presynaptic-inhibition due to the activity of inhibitory local neurons within the AL. While it has been proposed that this synaptic-depression contributes to the nonlinear relationship between ORN and projection neuron (PN) firing-rates, the precise functional role of synaptic-depression at the ORN synapses is not yet fully understood. In this paper we propose two hypotheses linking the information-coding properties of the fly AL with the network mechanisms responsible for ORN-->AL synaptic-depression. Our first hypothesis is related to variance coding of ORN firing-rate information--once stimulation to the ORNs is sufficiently high to saturate glomerular responses, further stimulation of the ORNs increases the regularity of PN spiking activity while maintaining PN firing-rates. The second hypothesis proposes a tradeoff between spike-time reliability and coding-capacity governed by the relative contribution of vesicle-depletion and presynaptic-inhibition to ORN-->AL synaptic-depression. Synaptic-depression caused primarily by vesicle-depletion will give rise to a very reliable system, whereas an equivalent amount of synaptic-depression caused primarily by presynaptic-inhibition will give rise to a less reliable system that is more sensitive to small shifts in odor stimulation. These two hypotheses are substantiated by several small analyzable toy models of the fly AL, as well as a more physiologically realistic large-scale computational model of the fly AL involving 5 glomerular channels. This Class is for the basic examples of this ontology. All the members are examples of problems in biology and how they have been solved. They can therefore be compared with engineering using TRIZ. 100 Positive: Abscission zone forms a barrier (F_31) Negative: Loss of tissue (F_23) Heslop-Harrison Y. and J. S. Heslop-Harrison Abscission of the stigmas of pearl millet (Pennisetum typhoides (Burman) Stapf et Hubbard) after pollination results from the activation of a specialized zone of tissue near the base. This abscission zone comprises a well-defined stretch of the basal column made up of thin-walled cells lacking a cuticularized epidermis. The penetration of the first few pollen tubes following a compatible pollination results in loss of turgor throughout the tissue, followed by loss of adhesion between the cells and ultimately disruption of the whole zone. Pectolytic enzymes are released concomitantly, but the cellulosic skeletons of the cells persist. Numerous calcium oxalate druses, identified cytochemically and by energy-dispersive x-ray analysis, are present in the cells of the abscission zone; these undergo dissolution after activation of the zone, while simultaneously the druse population in the stigma stump and the upper ovary wall increases. The barrier formed by the degenerating abscission zone tissues excludes pollen tubes arriving after the initial activation and prevents the penetration of pathogens such as ergot and so has a prophylactic role. We suggest that the collapsed abscission zone forms not only a physical barrier but also a chemical one. Dissolution products of the numerous calcium oxalate druses during the breakdown of the tissue are likely to raise the calcium ion concentrations beyond the optimum for pollen-tube growth, thereby preventing further penetration. Inhibited tubes swell at the tips and may show growth disorientation before arrest, responses similar to those seen in pearl millet tubes in culture when exposed to higher than normal calcium ion concentration. 1997 The pollen tube activated abscission zone in the stigma of pearl millet: structural and physiological aspects. Canadian Journal of Botany-Revue Canadienne de Botanique, 75: 1200-1207. 5 A countershading reflex in cephalopods Ferguson G. P. and J. B. Messenger 1991 Most cephalopods have more chromatophores on the dorsal body surface than on the ventral and these tend to be kept tonically expanded. As a result the dorsal surface is usually darker than the ventral, an effect shown by many animals and known as countershading. We report here that when Sepia officinalis, Loligo vulgaris and Octopus volgaris are rotated 180-degrees around the longitudinal body axis the ventral chromatophores expand, causing darkening, while the dorsal chromatophores retract, causing paling. When animals are rotated through only 90-degrees the chromatophores on the uppermost half of the ventral and dorsal surfaces expand, while those on the lower half retract. This response, which we term the countershading reflex, can be abolished by ablating the statocysts; and experiments in which the direction of incident light is reversed show that the reflex is not driven by sensory input from the eyes. The function of the reflex is presumably to maintain countershading while the animal is momentarily disoriented; this idea is supported by the fact that it lasts only a few seconds. Positive: The animal is less easily seen (F_30) Negative: the reflex requires a fast nervous system (F_25) Proceedings of the Royal Society B, 243: 63-67. 80 70 J Exp Biol, 210: 4136-4149. Positive: Flexible feathers improve unsteady aerodynamics (F_33) Negative: They can't always be controlled (F_01) (Analysis suggests that the negative factor is weight of moving object, which is reasonable) Here we analyse aeroelastic devices in the wings of a steppe eagle Aquila nipalensis during manoeuvres. Chaotic deflections of the upperwing coverts observed using video cameras carried by the bird (50 frames/s) indicate trailing-edge separation but attached flow near the leading edge during flapping and gust response, and completely stalled flows upon landing. The underwing coverts deflect automatically along the leading edge at high angle of attack. We use high-speed digital video (500 frames/s) to analyse these deflections in greater detail during perching sequences indoors and outdoors. Outdoor perching sequences usually follow a stereotyped three-phase sequence comprising a glide, pitch-up manoeuvre and deep stall. During deep stall, the spread-eagled bird has aerodynamics reminiscent of a cross-parachute. Deployment of the underwing coverts is closely phased with wing sweeping during the pitch-up manoeuvre, and is accompanied by alula protraction. Surprisingly, active alula protraction is preceded by passive peeling from its tip. Indoor flights follow a stereotyped flapping perching sequence, with deployment of the underwing coverts closely phased with alula protraction and the end of the downstroke. We propose that the underwing coverts operate as an automatic high-lift device, analogous to a Kruger flap. We suggest that the alula operates as a strake, promoting formation of a leading-edge vortex on the swept hand-wing when the arm-wing is completely stalled, and hypothesise that its active protraction is stimulated by its initial passive deflection. These aeroelastic devices appear to be used for flow control to enhance unsteady manoeuvres, and may also provide sensory feedback. Carruthers, A. C., A. L. R. Thomas, G. K. Taylor 2007 Automatic aeroelastic devices in the wings of a steppe eagle Aquila nipalensis 5 In Manduca sexta, and the dragonfly Aeshna multicolor, flexural stiffness declines sharply from the wing base to the tip, and from the leading edge to the trailing edge; this variation can be approximated by an exponential decline. The wings of M. sexta also display dorsal/ventral asymmetry in flexural stiffness and significant differences between males and females. Finite element models based on M. sexta forewings demonstrate that the measured spatial variation in flexural stiffness preserves rigidity in proximal regions of the wing, while transferring bending to the edges, where aerodynamic force production is most sensitive to subtle changes in shape. Flexural stiffness in insect wings II. Spatial distribution and dynamic wing bending Combes, S. A. and T. L. Daniel 2003 Positive: Wing functions automatically (F_33) Negative: Complexity of shape and stiffness (F_36) (TRIZ analysis suggests that positive should be speed [F_09] and negative should be use of energy [F_19] ) Journal of Experimental Biology, 206: 2989-2997. 20 30 Characterisation of Amyloid Nanostructures in the Natural Adhesive of Unicellular Subaerial Algae Positive: Adhesive is tough although there is a lot of order in the molecule (F_14) Negative: In order to be tough, it has to have sections which are more likely to break - sacrificial (F_31) Mostaert; A. S., C. Giordani; R. Crockett; U. Karsten; R. Schumann; S. P. Jarvis 2009 Raman spectroscopy confirmed the adhesive proteins of two species of alga to be predominantly in beta-sheet and composed of a number of hydrophobic amino acid residues. Congo red and thioflavin-T dyes amyloid-like structures. Probing the adhesives with AFM revealed highly ordered and repetitive mechanical responses indicative of highly ordered structures within the adhesive. The repetitive nature of the sawtooth response is typical of a sacrificial bond and hidden length mechanism that is, we propose, the result of mechanical manipulation of individual molecules within an intermolecular beta-sheet that makes up the generic amyloid structure. The mechanical data show how amyloid provides cohesive strength to the adhesives, and this intrinsic mechanical property of an amyloid-based adhesive explains the ecological success of attachment of these subaerial microalgae on various surfaces. The Journal of Adhesion, 85: 465 - 483. 5 2006 Positive: M.o.p. is cheap and effective (F_14) Negative: Have to be careful what shapes it's used in (F_12) De Blasio F. V. Thriving at high hydrostatic pressure: the example of ammonoids (extinct cephalopods) Suture lines of ancient ammonoids were gently curved and during the evolution of the group became highly complex, in some cases so extensively frilled as to be considered as fractal curves. Numerous theories have been put forward to explain the complexity of suture ammonoid lines. Calculations presented here lend support to the hypothesis that complex suture lines aided in counteracting the effect of the external water pressure. Additionally, it is suggested that complex suture lines diminished shell shrinkage caused by water pressure, and thus improved buoyancy. Bioinspiration & Biomimetics, 1: L1. 5 Negative: Strike speed is relatively low F_09 Positive: There is time enough for the mandibles to contact the prey simultaneously, increasing likelihood of capture F_28 Modulation in the feeding prey capture of the ant-lion, Myrmeleon crudelis Journal of experimental zoology. Part A, Ecological genetics and physiology 315: 602-9. Lambert, E. P., P. J. Motta and D. Lowry 2011 Ant-lions are pit-building larvae (Neuroptera: Myrmeleontidae), which possess relatively large mandibles used for catching and consuming prey. We examined feeding kinematics of the ant-lion, Myrmeleon crudelis. The strike took 17.60 +/- 2.92 msec, characterized by near-simultaneous contact of both mandibles with the prey. Modulation of the angular velocity of the mandibles based on prey location was clearly demonstrated. M. crudelis larvae attempted to contact prey with both mandibles simultaneously by increasing mean angular velocity of the far mandible (65 +/- 21 rad sec(-1) ) compared with the near mandible (35 +/- 14 rad sec(-1) ). Furthermore, kinematic results showed a significant difference for mean angular velocity between the two mandibles (P<0.005). Given the lengthy strike duration compared with other fast-striking arthropods, these data suggest that there is a tradeoff between the ability to modulate strike behavior for accurate simultaneous mandible contact and the overall velocity of the strike. The ability to modulate prey capture behavior may increase dietary breadth and capture success rate in these predatory larvae by allowing responsive adjustment to small-scale variations in prey size, presentation, and escape response. 5 2006 Physics of Life Reviews, 3: 162-187. Ant societies display some properties which are usually considered in physico-chemical systems as diagnostic of self-organization. We detail the key role played by feed-back loops, fluctuations, number of interacting units and sensitivity to environmental factors in the emergence of a structured collective behaviour. We stress the specificities of social structures made of complex living units of which the biological features have been selected through evolution. We consider the ability of each ant to process information about environmental and social parameters, to tune its interactions with nestmates and to determine the pattern at the collective level. We emphasize on the parsimony and simplicity of behavioural rules at the individual level which allow efficient processing of information, energy and matter within the whole colony. Positive: The individuals process information reliably (F_27) Negative: Danger of over-regulated behaviour (F_38) or complexity (F_36) - neither of these produces a good match Self-organized structures in a superorganism: do ants "behave" like molecules? Detrain, C., J.-L. Deneubourg 5 Consensus decision making in the ant Myrmecina nipponica: house-hunters combine pheromone trails with quorum responses Positive: Concensus decision quicker and easier (F_27) Negative: Need several individuals to make it (F_24) Cronin A. L. 2012 Consensus decisions enable group-living organisms to coordinate collective tasks without the need for complex cognitive abilities or centralized leadership. Systems of nonlinear positive feedback, such as quorum responses, are thought to be integral to consensus decision processes that seek to optimize decision speed and accuracy while maintaining group cohesion, requirements typical of house-hunting in social insects. Small colonies of individually marked ants (Myrmecina nipponica) were forced to relocate in experimental laboratory arenas, and given a choice of one or two alternative new sites. This species uses pheromone trails to navigate between old and new sites. A quorum threshold apparently governs the switch to brood transport, which marks the final phase of the relocation. Furthermore, there is a strong relationship between inferred quorum threshold and colony size. A demonstration of the use of a quorum rule in M. nipponica would underline the central role of quorum responses in consensus decision making, despite interspecific variation in colony size and differing modes of recruitment and navigation. Animal Behaviour 84: 1243-1251. 35 25 Juvenile hormone induces queen development in late-stage larvae of the ant Harpegnathos saltator. 2012 A link between hormones and developmental plasticity has long been established, but understanding how evolution has shaped the physiological systems underlying plasticity remains a major question. Within the eusocial insects, developmental plasticity helps define a reproductive division of labor through the production of distinct queen and worker castes. Caste determination may be triggered via changes in juvenile hormone (JH) levels during specific JH-sensitive periods in development. The timing of these periods, however, can vary and may relate to phenotypic differences observed among species. In order to gain insight into the evolution of caste determining systems in eusocial insects, we investigated the presence of a JH-sensitive period for queen determination in the ant Harpegnathos saltator. This species displays a number of ancestral characteristics, including low queen-worker dimorphism, and should allow insight into the early evolution of caste determining systems in ants. We identified four larval instars in H. saltator, and we found that the application of a JH analog (JHA) to third and fourth instar larvae induced queen development while treatment of early instars did not. This indicated the presence of a JH-sensitive period for queen determination at the end of the larval stage. These results contrast with what has been found in other ant species, where queen determination occurs much earlier in development. Therefore, our results suggest that caste determination originally occurred late in the larval stage in the ancestral condition but has shifted earlier in development in species that began to acquire advanced characteristics. This shift may have facilitated the development of greater queen-worker dimorphism as well as multiple worker castes. Penick, C. A., S. S. Prager and J. r. Liebig Journal of Insect Physiology, 58: 1643-1649. Positive: Earlier commitment allows greater differentiation (F_35) Negative: Evolution of commitment period takes time (F_15) 5 1999 Chemical mimicry and host specificity in the butterfly Maculinea rebeli, a social parasite of Myrmica ant colonies Akino, T., J. J. Knapp, J. A. Thomas, G. W. Elmes Positive: Larva can disguise itself within the nest (F_35) Negative: It needs to know what the chemical is (F_30) Proceedings of the Royal Society B, 266: 1419-1426. In the wild, freshly moulted fourth-instar caterpillars of Maculinea rebeli, which have no previous contact with ants, appear to be recognized as ant larvae by foraging Myrmica workers, which return them to their nest brood chambers. Three hypotheses concerning the mechanism controlling this behaviour were tested: (i) the caterpillars produce surface chemicals that allow them to be treated as ant larvae; (ii) mimetic compounds would include hydrocarbons similar to those employed by Myrmica to recognize conspecifics and brood; and (iii) the caterpillar's secretions would more closely mimic the profile of their main host in the wild, M. schencki, than that of other species of Myrmica. Results of behavioural bioassays and chemical analyses confirmed all three hypotheses, and explained the high degree of host specificity found in this type of highly specialized myrmecophile. Furthermore, although caterpillars synthesized many of the recognition pheromones of their host species (chemical mimicry), they later acquired additional hydrocarbons within the ant nest (chemical camouflage), making them near-perfect mimics of their individual host colony's odour. 5 Positive: Communication (F_27) Negative: Sound absorption close to the ground (F_03) Bird changes its song at different altitudes to compensate for different acoustics – e.g. sings ‘more slowly and simply close to the ground’ where dense undergrowth damps sound 20 30 Osteoclastic erosion across an abscission line between the dead bone of the antler and the living bone of the pedicle was found to be responsible for the separation. As early as 3 days after castration, osteoclasts and associated lacunae were present on the sides of the pedicle bone. These were then found in progressively deeper locations, by 2 weeks extending across the entire width of the pedicle. Concomitant with the centripetal spread of osteoclasts was the enlargement of Haversian canals, the surfaces of which became lined with osteoclasts. These widening vascular channels within the bone were filled with connective tissue, which in precasting stages formed a mesodermal pad about 1 mm thick. In later stages, a circumferential cleft was excavated beneath the antler burr, and connective tissues from the surrounding pedicle skin invaded the space between the antler and pedicle. After casting, the ingrowing integumental tissues fused with the mesodermal tissues derived from the vascular channels of the pedicle to give rise to an incipient antler bud beneath the scab. The ingrowth of epidermis capable of de novo hair follicle formation gave rise to the skin that envelops the elongating antler. 1992 Goss, R. J., A. Vanpraagh and P. Brewer The mechanism of antler casting in the fallow deer Journal of Experimental Zoology, 264: 429-436. Positive: The antler always matches the bodyweight for force transmission (F_27) Negative: Bone material is lost (F_23) 5 The Journal of Experimental Biology 214: 50-58. Reid, C. R., D. J. T. Sumpter and M. Beekman Positive: Ants mark their route using a combination of chemical and magnetic inputs F_28 Negative: Need lots of ants to increase magnitude of stimulus F_37 2011 Most "nature-inspired" algorithms take only superficial inspiration from biology, and little is known about how real biological systems solve difficult problems. Moreover, ant algorithms, neural networks and similar methods are usually applied to static problems, whereas most biological systems have evolved to perform under dynamically changing conditions. We used the Towers of Hanoi puzzle to test whether Argentine ants can solve a potentially difficult optimisation problem. We also tested whether the ants can adapt to dynamic changes in the problem. We mapped all possible solutions to the Towers of Hanoi on a single graph and converted this into a maze for the ants to solve. We show that the ants are capable of solving the Towers of Hanoi, and are able to adapt when sections of the maze are blocked off and new sections installed. The presence of exploration pheromone increased the efficiency of the resulting network and increased the ants' ability to adapt to changing conditions. In almost all cases, the presence of exploration pheromone led to smaller, less convoluted networks, the use of closer to just one minimal path, and fewer corrective moves. Increased solution efficiency can be at least partly attributed to the significantly greater velocity, acceleration and turning speed of individual ants when exploration pheromone was present. With two pheromones evidence suggests that a short-lived foraging pheromone, coupled with a longer-lasting exploration pheromone allows the ants to quickly redistribute their foragers to exploit new resources. information provided by the bifurcation asymmetry is ignored by the ants in favour of information from some internal compass that might provide the ants with a sense of directional intention. For individual foragers to return on a direct path to the nest, despite a tortuous outbound path, would require a compass, Contrary to previous studies, our study shows that mass-recruiting ant species such as the Argentine ant can forage effectively in a dynamic environment. Our results also suggest that novel optimisation algorithms can benefit from stronger biological mimicry. Optimisation in a natural system: Argentine ants solve the Towers of Hanoi 25 20 Journal of Insect Physiology, 58: 1517-1524. Positive: Aphids survive the winter (F_15) Negative: Aphids need to sense daylength changing (F_37) Transcriptomic profiling of the reproductive mode switch in the pea aphid in response to natural autumnal photoperiod Le Trionnaire,G. l., S. p. Jaubert-Possamai, J. l. Bonhomme, J.-P. Gauthier, G. g. Guernec, A. l. Le Cam, F. Legeai, J. r. m. Monfort and D. Tagu 2012 During spring and summer aphids reproduce clonally and efficiently by parthenogenesis. At the end of summer they perceive the shortening of day length which triggers the production of sexual individuals - males and oviparous females - that will mate and lay overwintering cold-resistant eggs. Recent large scale transcriptomic studies allowed the discovery of transcripts and functions such as nervous and hormonal signaling involved in the early steps of detection and transduction of the photoperiodic signal. Nevertheless these experiments were performed under controlled conditions when the photoperiod was the only varying parameter. To characterize the response of aphids under natural conditions, aphids were reared outdoor both in summer and autumn and material was collected to compare their transcriptomic profile using a cDNA microarray containing around 7000 transcripts. Statistical analyses revealed that close to 5% of these transcripts (367) were differentially expressed at two developmental stages of the process in response to the autumnal environmental conditions. Functional classification of regulated transcripts confirmed the putative contribution of the neuro-endocrine system in the process. Furthermore, these experiments revealed the regulation of transcripts involved in juvenile hormone synthesis and signaling pathway, confirming the key role played by these molecules in the reproductive mode switch. Aphids placed under outdoor conditions were confronted to a range of abiotic factors such as temperature fluctuations which was confirmed by the differential expression of an important proportion of heat shock protein transcripts between the two seasons. Finally, this original approach completed the understanding of genetic programs involved in aphid phenotypic plasticity. 5 Most sea hares (Opisthobranchia: Anaspidea) release a purple ink when physically disturbed. The ink may excrete unwanted byproducts of metabolism, as a smoke screen, be an anti-feedant, and be a warning signal. We tested two additional potential functions: that ink is a metabolic depressant and/or a noxious or adversive sensory stimulus. When exposed to realistic concentrations of ink from Aplysia dactylomela (Rang), none of five invertebrate species (including A. dactylomela) or two fish species significantly altered their oxygen uptake, and neither of two crab species significantly altered their heart and/or scaphognathite beat rates, suggesting that ink does not function as a metabolic depressant. In contrast, although A. dactylomela did not display strong behavioural responses to ink, behaviour of seven other invertebrates and both fish species was strongly affected by ink, supporting our hypothesis that the ink functions as an irritant. Observed behavioural changes included bristle erection by fireworms, increased mucus production by an opisthobranch, reduced feeding behaviour, increased grooming behaviour, and temporary pauses in heart and scaphognathite beating by crabs, reduced and increased activity by cryptic and exposed sea urchin species, respectively, and rapid swimming by fish. Similar behavioural changes by potential predators would likely lead to reduced predation rates on Aplysia spp. in the field. Our conclusion that ink functions as a sensory irritant is not incompatible with other hypotheses for the function of ink. 1999 Journal of Experimental Marine Biology and Ecology, 234: 185-197. A test of novel function(s) for the ink of sea hares Carefoot,T. H., S. C. Pennings and J. P. Danko Positive: Ink is produced for various protective functions (F_30) Negative: This involves the expenditure of energy (F_23) 0 Journal of the Torrey Botanical Society, 131: 252-256. Advantage: Longevity (F_15) Disadvantage: Energy to make colours (F_22) Rubino, D. L., B. C. McCarthy 2004 Aposematic coloration in plants to advertise physical armaments (spines, thorns, or prickles) has been, until recently, unreported. A preliminary survey of physically armed plants revealed a high incidence of aposematic coloration—the presence of physical armaments colored differently than the structure on which they are borne. Aposematic coloration was found in taxonomically diverse vascular plants. Presence of aposematic (warning) coloration in vascular plants of southeastern Ohio 35 45 Rossel, S., J. Corlija, and S. Schuster Positive: Speed and accuracy of movement of the Archer fish (F_15) Negative: Information is crucial (F_24) Journal of Experimental Biology, 205: 3321–3326. On locating an insect prey on a twig above the water surface, a group of archer fish can shoot it down using powerful jets of water. The insect, dislodged by one of the shots, falls on a ballistic path towards the water surface, where it is devoured by the first fish to arrive. We report that the archer fish can predict the point where the dislodged prey will later hit the water surface and move in a straight line towards that point, thus enabling it to arrive as fast as possible. Only about 100 ms after prey is dislodged, the fish initiate a quick turn that aligns their body axis right towards where the prey will later land, and not to the actual position of the prey at that moment. In contrast to other known examples of three-dimensional target interception in man and animals, archer fish can head straight to the predicted point of catch without the need of any further visual feedback. Moreover, archer fish can predict the point of incidence of a target, regardless of the angle at which the prey takes off with respect to the initial orientation of the fish. To perform this remarkable task, archer fish extract a minimum set of independent variables that fix the point of incidence, but do not extrapolate the target’s spatial trajectory. 2002 Predicting three-dimensional target motion: how archer fish determine where to catch their dislodged prey 0 2012 Proceedings of the National Academy Of Sciences of the United States of America 109: 17495-500. Positive: As spatial heterogeneity increases F_36 Negative: the area available for individual spp. decreases and populations fall below maintenance size to extinction F_30 Area-heterogeneity tradeoff and the diversity of ecological communities Allouche, O., M. Kalyuzhny, G. Moreno-Rueda, M. Pizarro and R. Kadmon Environmental heterogeneity may have a general unimodal rather than a divergent effect on species richness. This result was explained by a tradeoff: as heterogeneity increases, the area available for individual species decreases, reducing populations and increasing the likelihood of extinctions. Here we analyze a distribution database of breeding birds in Catalonia and show that patterns of species richness, abundance, and extinction rates are consistent with the predictions of the area-heterogeneity tradeoff and its proposed mechanisms. We then perform a meta-analysis of heterogeneity-diversity relationships in 54 published datasets and show that empirical data fit the unimodal pattern predicted by the area-heterogeneity tradeoff better than the positive pattern predicted by classic niche theory. Simulations in which species may have variable niche widths along a continuous environmental gradient are consistent with all empirical findings. The area-heterogeneity tradeoff brings a unique perspective to current theories of species diversity and has important implications for biodiversity conservation. 80 70 Cartilage is structurally inhomogenous and layered tissue and the local organization of collagen and GAG concentration of the articular cartilage regulate the mechanical properties of the tissue. The structure and composition of the superficial articular cartilage significantly affects the indentation response of the canine knee articular cartilage Journal of Biomedical Materials Research, 48: 99-107. Arokoski, J. P. A., M. M. Hyttinen, H. J. Helminen, J. S. Jurvelin 1999 Positive: Structure imparts strength (F_14) Negative: Area of joint has to be large to keep down stresses (F_05) Biomechanical and structural characteristics of canine femoral and tibial cartilage 100 Under stress it can be expected organisms suffer a disruption in the homeostatic mechanisms that lead to normal developing patterns on morphological structures. Conventionally, fluctuating asymmetry has been used as a developmental instability measurement in bilateral symmetric organisms. But in this manuscript the fractal nature of many structures has been used as an early indicator of stress. Specifically, stress is observed to lead to decreased fractal dimension on bone saggital suture in gazelle skulls and in branch architecture in plants. Scale asymmetry measured as the error in the nonlinear inter body parts equation is related with stress in plants. Particularly, the allometric relationship among leaves arrangement as much as among branch order and size were found to be related with grazing pressure. Positive: Stress leads to reduction in available energy (F_22) Negative: Complexity is reduced (F_36) Scale asymmetry - a tool to detect developmental instability under the fractal geometry 1994 Alados, C. L., J. Escos, J. M. Emlen Scope IFIP Trans. A - Comp. Sci. Tech., 41: 25-36. 5 Amplification and Feedback in Invertebrates Göpfert, M. C., I. B. Allan, K. Akimichi, M. S. Gordon, W. Gerald, D. A. Thomas, H. M. Richard, D. Peter, O. Donata, F. Stuart, K. B. Gary, M. C. Bushnell, H. K. Jon, G. Esther Positive: Ears are very sensitive measuring devices (F_37) Negative: Energy is needed for the positive feedback mechanism (F_19) 2008 Ears achieve their exquisite sensitivity by means of mechanical feedback: by pumping energy into sound-induced vibrations, motile mechanosensory cells amplify the mechanical input of the ear. While this amplificatory feedback has long been thought to be a unique characteristic of vertebrate auditory systems, recent studies have shown that sensitive hearing in invertebrates relies on mechanical feedback as well. Essential features of mechanical-feedback amplification have been documented for the ears of certain insects, including mosquitoes, Drosophila, locusts, and moths. In Drosophila, the source of the feedback has been traced to chordotonal sensory neurons, the insect counterpart of the vertebrate hair cells. Several mutations that abolish the feedback have been identified, and the molecular mechanisms that promote the mechanical feedback in insect auditory systems are beginning to be revealed. As insect chordotonal neurons and vertebrate hair cells appear to be evolutionarily related, the intriguing possibility exists that some of the molecular modules vertebrates and invertebrates employ to improve the sensitivity of hearing are evolutionarily conserved. Academic Press, 293-299 20 30 Journal of Experimental Biology, 205: 1607-1616. Bats compensate for frequency shifts in the echo caused by flight-induced Doppler effects by adjusting the frequency of their echolocation calls. Under natural conditions the bats usually encounter only positive Doppler shifts. Auditory feedback from frequencies below the resting frequency, when presented at similar suprathreshold intensity levels as higher echo frequencies, cause the bat’s call frequency to increase above the resting frequency. However, compensation for negative shifts is less complete than for positive shifts (22% versus 95 %), probably because of mechanical restrictions in the larynx of bats. We propose that auditory feedback follows an antagonistic push/pull principle, with inhibitory feedback lowering and excitatory feedback increasing call frequencies. While the behavioral significance of an active compensation for echo frequencies below RF remains unclear, these behavioral results are crucial for determining the neural implementation of audio-vocal feedback control in horseshoe bats and possibly in mammals in general. Metzner, W., S. Zhang, M. Smotherman Doppler-shift compensation behavior in horseshoe bats revisited: auditory feedback controls both a decrease and an increase in call frequency Positive: Bat controls required frequency of echolocation calls by active feedback (F_35) Negative: Larynx imposes mechanical restrictions on negative shifts (F_33) 2002 0 Positive: Volume improves/increases due to auxin stimulating production of wall-softening factors (F_14) Negative: Effect of softening factor is short-lived (F_16) In abraded coleoptile segments Brefeldin A (BFA) produced, within less than 30 min, a decrease in the incorporation of [H-3]leucine into tightly bound cell-wall proteins in maize (Zea mays L.) coleoptiles, accompanied by an increased incorporation into the intracellular pool of putative cell-wall glycoproteins. Total protein synthesis was not affected. Electron micrographs revealed striking morphological changes in dictyosomes (especially vesiculation of trans-cisternae), accumulation of golgi vesicles and dilation of the endoplasmic reticulum. These effects are taken as indication that BFA interferes with the secretion of cell-wall components. Elongation growth of coleoptile segments in the presence and absence of auxin was inhibited by 80% in 20 mg/l BFA. If BFA was applied to segments growing in the presence of auxin, maximum inhibition was reached after about 30 min, indicating that the growth response depends on an uninterrupted supply of a cell-wall or plasma-membrane component (''wall-loosening factor'') delivered by the secretory pathway. After its secretion, this factor has a rather short growth-effective life time. The inhibition of auxin-mediated growth by BFA was accompanied by an elimination of auxin-induced cell-wall extensibility and by an inhibition of auxin-induced proton excretion. Fusicoccin-induced proton excretion was similarly affected by BFA. It is concluded that both the wall-loosening process underlying elongation growth as well as proton excretion depend on an intact secretory pathway from the golgi apparatus to the cell wall; however, a causal relationship between these processes is not warranted by the data 1994 Planta, 192: 404-413." Inhibition of golgi-apparatus function by Brefeldin-A in maize coleoptiles and its consequences on auxin-mediated growth, cell-wall extensibility and secretion of cell-wall proteins Schindler, T., R. Bergfeld, M. Hohl, P. Schopfer 100 Mechanical tension is a potent stimulator of axonal growth rate, which is also stimulated by osmotic dilution. We wished to determine the relationship, if any, between osmotic stimulation and tensile regulation of axonal growth. We used calibrated glass needles to apply constant force to elongate axons of cultured chick sensory neurons. We find that a neurite being pulled at a constant force will grow 50-300% faster following a 50% dilution of inorganic ions in the culture medium. That is, osmotic dilution appears to cause axons to increase their sensitivity to applied tensions. Experimental interventions suggest that this effect is not mediated by dilution of extracellular calcium, or to osmotic stimulation of adenylate cyclase, or to osmotic stimulation of mechanosensitive ion channels. Rather, experiments measuring the static tension normally borne by neurites suggest a direct mechanical effect on the cytoskeletal proteins of the neurite shaft. Our results are consistent with a formal thermodynamic model for axonal growth in which removing a compressive load on axonal microtubules promotes their assembly, thus promoting axonal elongation. 1995 Journal of Biomechanics, 28: 1429-1438. Lin, C. J., P. Lamoureux, R. E. Buxbaum, S. R. Heidemann Positive: Stretched axon grows quicker (F_09) Negative: Adaptive response (F_35) Osmotic dilution stimulates axonal outgrowth by making axons more sensitive to tension 55 45 1998 Lamoureux, P., R. E. Buxbaum, and S. R. Heidemann Comparing periods in which neurons maintained simple bipolar morphology we find no temporal competition between the two growth cones. That is, periods of above-average growth by one growth cone are not compensated by below-average growth during the same period by its sibling growth cone. Net elongation rate from a single cell body is a linear function of the number of growth cones from 1 to 11. Growth cones behave independently and are not limited by availability of structural precursors. A surplus pool of structural precursors available for normal growth is also indicated by the high capacity for growth from single neurites when experimentally stimulated by mechanical tension. In addition, growing one or more neurites at above average rates does not cause any decline in simultaneous growth cone-mediated outgrowth from a single neuron compared to the 2-3 hour period prior to experimentally induced elongation. This high capacity for growth combined with the often observed, intermittant growth of individual cones suggests that neurite outgrowth is intrinsically limited primarily by poor growth cone 'performance,' not scarcity-driven competition. We postulate that growth cones are poor 'tractors,' exerting too little tension to exploit the available capacity for axonal elongation. Positive: (F_03) Negative: (F_30) Axonal outgrowth of cultured neurons is not limited by growth cone competition Journal of Cell Science, 111: 3245-3252. 50 60 Nearly close-packed populations of the swimming bacterium Bacillus subtilis form a collective phase, the “Zooming BioNematic” (ZBN). This state exhibits large-scale orientational coherence, analogous to the molecular alignment of nematic liquid crystals, coupled with remarkable spatial and temporal correlations of velocity and vorticity, as measured by both novel and standard applications of particle imaging velocimetry. The appearance of turbulent dynamics in a system which is nominally in the regime of Stokes flow can be understood by accounting for the local energy input by the swimmers, with a new dimensionless ratio analogous to the Reynolds number. The interaction between organisms and boundaries, and with one another, is modeled by application of the methods of regularized Stokeslets. Experiments in Fluids, 43: 737-753. 2007 Positive: Force (F_10) Negative: High degree of organisation (-> complexity?) (F_31) Fluid dynamics of self-propelled microorganisms, from individuals to concentrated populations Cisneros, L., R. Cortez, C. Dombrowski, R. Goldstein, J. Kessler 80 70 American Journal of Botany, 87: 1257–1264. Positive: Seeds are shot out a long way (F_04) Negative: This requires power (F_21) 2000 Ballistic seed projection in two herbaceous species Garrison, W. J., G. L. Miller, R. Raspet Most ballistic seeds tested [N 5 74 of 78 in Vicia sativa ssp. nigra (Fabaceae); N 5 25 of 27 in Croton capitatus var. capitatus (Euphorbiaceae)] were projected at angles that would yield a greater distance than the average of seeds with the same initial speed projected at random angles. In addition, the median of fractional distance error (maximum distance 2 x seed distance)/(maximum distance), of the seeds was 0.11 and 0.04 for V. sativa and C. capitatus. Seed projection positions on the plant, which also affect seed projection distance, were found to be primarily from the top of the plant, with 98 of 137 and 407 of 407 fruits in the upper half of the plant for V. sativa and C. capitatus, respectively. Our findings are significant because they suggest that in addition to the ballistic projection mechanism itself, the species studied have additional adaptations that result in enhanced seed projection distance from the parent plant 5 1996 The mechanical structures of bamboos in viewpoint of functionally gradient and composite materials Bamboos are a composite material reinforced axially by fibers. They have a hierarchical gradient structure, that is, a macroscopic gradient structure in culm diameter, culm thickness and node length, and a microscopic one in the bundle sheath distribution. The macroscopic gradient structure leads to a constant surface stress at every height and the microscopic gradient structure provides a strength distribution in radial direction adapting to bending stress due to wind loads. Positive: Very strong (F_14) Negative: . . . but rather complex (F_36) Amada, S., T. Munekata, Y. Nagase, Y. Ichikawa, A. Kirigai. Y. Zhifei Journal of Composite Materials, 30: 800-819. 5 Journal of Experimental Botany, 51: 2085-2093. Bananas are among the largest herbs in the world and their lightweight petioles hold up huge leaves. This study examined how the petioles manage to achieve adequate rigidity to do this, while allowing extensive and reversible reconfiguration in high winds. Morphological and anatomical examination of the petioles and leaves of Musa textilis suggested how these two apparently incompatible abilities are achieved. The hollow U-shaped section of the petiole and the longitudinal stiffening elements in its outer skin give it adequate rigidity, while its ventral curvature help support the leaf without the need for thick lateral veins. These features, however, also allow the petiole to reconfigure by twisting away from the wind, while the leaf can fold away. In addition, two sets of internal structures, longitudinal partitions and transverse stellate parenchyma plates, help prevent dorsoventral flattening, allowing the petiole to flex further away from the wind without buckling. These ideas were tested and verified by a range of mechanical tests. Simple four-point-bending and torsion tests showed that the petioles are indeed far more compliant in torsion than in bending. Axial bending tests and crushing tests showed that petioles could be flexed twice as far and were four times as resistant to dorsoventral flattening when intact than when the internal tissue is removed. The banana petiole, therefore, seems to be an excellent example of natural integrated mechanical design. Ennos, A. R., H.-C. Spatz, T. Speck The functional morphology of the petioles of the banana, Musa textilis Positive: Very compliant in a wind - adaptable (F_35) Negative: Lose out on bending stiffness (F_14) 2000 20 30 Positive: Overstocking the nest encourages bonding behaviour between the nestlings (F_27) Negative: More effort is needed, or the owls are confined to richer areas. (F_19) 2012 Dominant nestlings displaying female-like melanin coloration behave altruistically in the barn owl Roulin, A., A. Da Silva and C. A. Ruppli Animal Behaviour, 84: 1229-1236. In 71% of experimental three-chick broods, nestling barn owls gave food to their siblings on average twice per night. This behaviour prevailed in the first-born dominant nestlings rather than the last-born subordinate nestlings. It was also more prevalent in females. In 81% of the nests, males stole food from siblings more frequently. We suggest that food sharing has evolved in the barn owl because parents store prey items in their nest that can be used by the offspring to feed their nestmates and so derive indirect (kin selection) or direct benefits (pseudoreciprocity or by-product mutualism). The cost of feeding siblings may be relatively low for dominant individuals while the indirect genetic benefits could be high given that extrapair paternity is infrequent in this species. Thus, in situations in which young animals have access to more food resources than they currently need, they can altruistically share them with their siblings. 5 Barnacle cement polymerization involves proteolytic activation of enzymes and structural precursors, transglutaminase cross-linking and assembly of fibrous proteins. Proteolytic activation of structural proteins maximizes the potential for bonding interactions with other proteins and with the surface. Transglutaminase cross-linking reinforces cement integrity. Remarkably, epitopes and sequences homologous to bovine trypsin and human transglutaminase were identified in barnacle cement with tandem mass spectrometry and/or western blotting. Akin to blood clotting, the peptides generated during proteolytic activation functioned as signal molecules, protein aggregation to barnacle larval settlement. There is a highly conserved protein polymerization mechanism. Barnacle cement polymerization is a specialized form of wound healing. The polymerization mechanism common between barnacle cement and blood may be a theme for many marine animal glues. Barnacle cement: a polymerization model based on evolutionary concepts 2009 Dickinson, G. H., I. E. Vega, K. J. Wahl, B. Orihuela, V. Beyley, E. N. Rodriguez, R. K. Everett, J. Bonaventura and D. Rittschof Negative: Barnacle cement has a specialised function (F_16) Positive: The adhesion is based on blood clotting, a conserved evolutionary mechanism (F_35) Journal of Experimental Biology, 212: 3499-3510. 100 Hills, J. M. and J. C. Thomason Marine Ecology Progress Series, 138: 103-115. 1996 A multiscale analysis of settlement density and pattern dynamics of the barnacle Semibalanus balanoides Positive: Settlement related to sophisticated sensing of surface roughness (F_28) Negative: Settlement pattern related to aggregation (F_27) Settlement pattern and density of Semibalanus balanoides (L.) in the Clyde estuary were studied on wood, concrete, steel and sandstone rock during 1994. A new measure - Potential Settling Sites (PSS) - describing surface roughness in relation to S. balanoides settlement using data on cyprid morphology and behaviour was devised. For the surfaces the total number of settlers was best related to the index PSSmin [Settler Density = (5.68 x PSmin) - 4.16 p < 0.01]. Two other measures of surface roughness, ISO number, a standard engineering measure of surface relief, and fractal dimensions, were not related to settler density. Settlement pattern was found to vary with settlement density and spatial scale of analysis. A multi-scale analysis using Morisita's index suggested that S. balanoides were generally settling aggregatedly at low densities (<8 cm(-2)), with strongest aggregations at approximately 30 mm block sizes