scholarly journals Avian predators taste–reject aposematic prey on the basis of their chemical defence

2006 ◽  
Vol 2 (3) ◽  
pp. 348-350 ◽  
Author(s):  
John Skelhorn ◽  
Candy Rowe
Keyword(s):  
Chemical Defence ◽  
Warning Signal ◽  
Selective Advantage ◽  
Evolutionary Stability ◽  
Theoretical Problem ◽  
Chemical Production ◽  
Warning Coloration ◽  
Avian Predators ◽  
Unpalatable Prey ◽  
Evolutionarily Stable

Avian predators learn to avoid defended insects on the basis of their conspicuous warning coloration. In many aposematic species, the level of chemical defence varies, with some individuals being more defended than others. Sequestration and production of defence chemicals is often costly and therefore less defended individuals enjoy the benefits of the warning signal without paying the full costs of chemical production. This is a fundamental theoretical problem for the evolutionary stability of aposematism, since less defended individuals appear to be at a selective advantage. However, if predators sample aposematic prey and selectively reject individuals on the basis of their chemical investment, aposematism could become evolutionarily stable. Previous research aimed at testing whether birds can use taste to discriminate between palatable and unpalatable prey has been confounded by other experimental factors. Here, we show that birds can taste and reject prey entirely on the basis of an individual's level of chemical defence and more importantly, they can make decisions on whether or not to consume a defended individual based upon their level of chemical investment. We discuss these results in relation to the evolution of aposematism, mimicry and defence chemistry.

scholarly journals When more is less: the fitness consequences of predators attacking more unpalatable prey when more are presented

2010 ◽  
Vol 6 (6) ◽  
pp. 732-735 ◽  
Author(s):  
Hannah M. Rowland ◽  
Elizabeth Wiley ◽  
Graeme D. Ruxton ◽  
Johanna Mappes ◽  
Michael P. Speed
Keyword(s):  
Empirical Support ◽  
Warning Signal ◽  
Fixed Number ◽  
Visual Signal ◽  
Fitness Costs ◽  
Avian Predators ◽  
Fitness Consequences ◽  
Unpalatable Prey

In 1879, Fritz Müller hypothesized that mimetic resemblance in which defended prey display the same warning signal would share the costs of predator education. Although Müller argued that predators would need to ingest a fixed number of prey with a given visual signal when learning to avoid unpalatable prey, this assumption lacks empirical support. We report an experiment which shows that, as the number of unpalatable prey presented to them increased, avian predators attacked higher numbers of those prey. We calculated that, when predators increase attacks, the fitness costs incurred by unpalatable prey can be substantial. This suggests that the survival benefits of mimicry could be lower than Müller proposed. An important finding is, however, that these costs decline in importance as the total number of available prey increases.

Selection by parasites for clonal diversity and mixed mating

1994 ◽  
Vol 346 (1317) ◽  
pp. 271-281 ◽  
Keyword(s):  
Computer Simulations ◽  
Inbreeding Depression ◽  
Reproductive Strategies ◽  
Deleterious Mutation ◽  
Clonal Diversity ◽  
Evolutionary Stability ◽  
Mixed Mating ◽  
Dioecious Populations ◽  
Cross Fertilization ◽  
Evolutionarily Stable

On theoretical grounds, coevolutionary interactions with parasites can select for cross-fertilization, even when there is a twofold advantage gained by reproducing through uniparental means. The suspected advantage of cross-fertilization stems from the production of genetically rare offspring, which are expected to be more likely to escape infection by coevolving enemies. In the present study, we consider the effects that parasites have on parthenogenetic mutants in obligately sexual, dioecious populations. Computer simulations show that repeated mutation to parthenogenesis can lead to the accumulation of clones with different resistance genotypes, and that a moderately diverse set of clones could competitively exclude the ancestral sexual subpopulation. The simulations also show that, when there are reasonable rates of deleterious mutation, Muller’s ratchet combined with coevolutionary interactions with parasites can lead to the evolutionary stability of cross-fertilization. In addition, we consider the effects that parasites can have on the evolution of uniparental reproduction in cosexual populations. Strategy models show that parasites and inbreeding depression could interact to select for evolutionarily stable reproductive strategies that involve mixtures of selfed and outcrossed progeny.

ON THE EVOLUTIONARY STABILITY OF "TOUGH" BARGAINING BEHAVIOR

2003 ◽  
Vol 05 (01) ◽  
pp. 63-71
Author(s):  
ANDERS POULSEN
Keyword(s):  
Ultimatum Game ◽  
Evolutionary Stability ◽  
Two Stage ◽  
Evolutionary Selection ◽  
Nash Demand Game ◽  
Almost All ◽  
Bargaining Behavior ◽  
Evolutionarily Stable

This paper investigates whether "tough" bargaining behavior, which gives rise to inefficiency, can be evolutionarily stable. We show that in a two-stage Nash Demand Game such behavior survives. Indeed, almost all the surplus may be wasted. We also study the Ultimatum Game. Here evolutionary selection wipes out all tough behavior, as long as the Proposer does not directly observe the Responder's commitment to rejecting low offers.

scholarly journals Linking the evolution and form of warning coloration in nature

2011 ◽  
Vol 279 (1728) ◽  
pp. 417-426 ◽  
Author(s):  
Martin Stevens ◽  
Graeme D. Ruxton
Keyword(s):  
Mate Choice ◽  
Evolutionary Ecology ◽  
Classical System ◽  
Warning Signal ◽  
Current Understanding ◽  
Warning Coloration ◽  
Warning Signals ◽  
Initial Evolution ◽  
Mechanistic Basis ◽  
Future Work

Many animals are toxic or unpalatable and signal this to predators with warning signals (aposematism). Aposematic appearance has long been a classical system to study predator–prey interactions, communication and signalling, and animal behaviour and learning. The area has received considerable empirical and theoretical investigation. However, most research has centred on understanding the initial evolution of aposematism, despite the fact that these studies often tell us little about the form and diversity of real warning signals in nature. In contrast, less attention has been given to the mechanistic basis of aposematic markings; that is, ‘what makes an effective warning signal?’, and the efficacy of warning signals has been neglected. Furthermore, unlike other areas of adaptive coloration research (such as camouflage and mate choice), studies of warning coloration have often been slow to address predator vision and psychology. Here, we review the current understanding of warning signal form, with an aim to comprehend the diversity of warning signals in nature. We present hypotheses and suggestions for future work regarding our current understanding of several inter-related questions covering the form of warning signals and their relationship with predator vision, learning, and links to broader issues in evolutionary ecology such as mate choice and speciation.

scholarly journals DEMONSTRATION OF THE SELECTIVE ADVANTAGE OF MIMETIC LIMENITIS BUTTERFLIES PRESENTED TO CAGED AVIAN PREDATORS

Evolution ◽  
1971 ◽  
Vol 25 (4) ◽  
pp. 692-701 ◽  
Author(s):  
Austin P. Platt ◽  
Raymond P. Coppinger ◽  
Lincoln P. Brower
Keyword(s):  
Selective Advantage ◽  
Avian Predators

scholarly journals Evolutionary Stable Strategies in Games with Fuzzy Payoffs

2020 ◽  
pp. 63-71
Author(s):  
Haozhen Situ
Keyword(s):  
Fuzzy Set ◽  
Evolutionarily Stable Strategy ◽  
Evolutionary Game ◽  
Evolutionary Stability ◽  
Fuzzy Decision ◽  
Stable Strategy ◽  
New Approach ◽  
Fuzzy Payoff ◽  
Evolutionarily Stable ◽  
The Membership Function

Evolutionarily stable strategy (ESS) is a key concept in evolutionary game theory. ESS provides an evolutionary stability criterion for biological, social and economical behaviors. In this paper, we develop a new approach to evaluate ESS in symmetric two player games with fuzzy payoffs. Particularly, every strategy is assigned a fuzzy membership that describes to what degree it is an ESS in presence of uncertainty. The fuzzy set of ESS characterize the nature of ESS. The proposed approach avoids loss of any information that happens by the defuzzification method in games and handles uncertainty of payoffs through all steps of finding an ESS. We use the satisfaction function to compare fuzzy payoffs, and adopts the fuzzy decision rule to obtain the membership function of the fuzzy set of ESS. The theorem shows the relation between fuzzy ESS and fuzzy Nash equilibrium. The numerical results illustrate the proposed method is an appropriate generalization of ESS to fuzzy payoff games.

scholarly journals Multicellularity makes somatic differentiation evolutionarily stable

2014 ◽  
Author(s):  
Mary Elizabeth Wahl ◽  
Andrew Wood Murray
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Germ Cells ◽  
Budding Yeast ◽  
Somatic Cells ◽  
Evolutionary Stability ◽  
Next Generation ◽  
Cell Lineages ◽  
Multicellular Organisms ◽  
Evolutionarily Stable

Many multicellular organisms produce two cell lineages: germ cells, whose descendants form the next generation, and somatic cells which support, protect, and disperse the germ cells. This distinction has evolved independently in dozens of multicellular taxa but is absent in unicellular species. We propose that unicellular, soma-producing populations are intrinsically susceptible to invasion by non-differentiating mutants which ultimately eradicate the differentiating lineage. We argue that multicellularity can prevent the victory of such mutants. To test this hypothesis, we engineer strains of the budding yeastSaccharomyces cerevisiaethat differ only in the presence or absence of multicellularity and somatic differentiation, permitting direct comparisons between organisms with different lifestyles. We find that non-differentiating mutants overtake unicellular populations but are outcompeted by multicellular differentiating strains, suggesting that multicellularity confers evolutionary stability to somatic differentiation.

scholarly journals Coevolution of group-living and aposematism in caterpillars: warning colouration may facilitate the evolution from group-living to solitary habits

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lingzi Wang ◽  
Stephen J. Cornell ◽  
Michael P. Speed ◽  
Kevin Arbuckle
Keyword(s):  
Evolutionary Dynamics ◽  
Strong Support ◽  
Chemical Defence ◽  
Group Living ◽  
Warning Signal ◽  
Comparative Approach ◽  
Transition Rates ◽  
Aggregation Behaviour ◽  
Solitary Living ◽  
Antipredator Mechanisms

Abstract Background Animals use diverse antipredator mechanisms, including visual signalling of aversive chemical defence (aposematism). However, the initial evolution of aposematism poses the problem that the first aposematic individuals are conspicuous to predators who have not learned the significance of the warning colouration. In one scenario, aposematism evolves in group-living species and originally persisted due to kin selection or positive frequency-dependent selection in groups. Alternatively, group-living might evolve after aposematism because grouping can amplify the warning signal. However, our current understanding of the evolutionary dynamics of these traits is limited, leaving the relative merit of these scenarios unresolved. Results We used a phylogenetic comparative approach to estimate phenotypic evolutionary models to enable inferences regarding ancestral states and trait dynamics of grouping and aposematic colouration in a classic model system (caterpillars). We find strong support for aposematism at the root of the clade, and some (but weaker) support for ancestral solitary habits. Transition rates between aposematism and crypsis are generally higher than those between group-living and solitary-living, suggesting that colouration is more evolutionarily labile than aggregation. We also find that the transition from group-living to solitary-living states can only happen in aposematic lineage, suggesting that aposematism facilitates the evolution of solitary caterpillars, perhaps due to the additional protection offered when the benefits of grouping are lost. We also find that the high frequency of solitary, cryptic caterpillars is because this state is particularly stable, in that the transition rates moving towards this state are substantially higher than those moving away from it, favouring its accumulation in the clade over evolutionary time. Conclusions Our results provide new insights into the coevolution of colour and aggregation in caterpillars. We find support for an aposematic caterpillar at the root of this major clade, and for the signal augmentation hypothesis as an explanation of the evolution of aposematic, group-living caterpillars. We find that colouration is more labile than aggregation behaviour, but that the combination of solitary and cryptic habits is particularly stable. Finally, our results reveal that the transitions from group-living to solitary-living could be facilitated by aposematism, providing a new link between these well-studied traits.

Demonstration of the Selective Advantage of Mimetic Limenitis Butterflies Presented to Caged Avian Predators

Evolution ◽  
1971 ◽  
Vol 25 (4) ◽  
pp. 692 ◽  
Author(s):  
Austin P. Platt ◽  
Raymond P. Coppinger ◽  
Lincoln P. Brower
Keyword(s):  
Selective Advantage ◽  
Avian Predators
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