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More than mimicry？ Evaluating scope for flicker-fusion as a defensive strategy in coral snake mimics

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Current Zoology 2014年第1期60卷 123-130页

作者： Georgia C. TITCOMB david w. KIKUCHI david w. pfennig Department of Biology University of North Carolina at Chapel Hill Chapel Hill NC 27599-3280

Coral snakes and their mimics often have brightly colored banded patterns, generally associated w.th w.rning colora- tion or mimicry. How.ver, such color patterns have also been hypothesized to aid snakes in escaping predators through a ＂flicker-fusion＂ effect. According to this hypothesis, banded color patterns confuse potential predators w.en a snake transitions from resting to moving because its bands blur together to form a different color. To produce this motion blur, a moving snake＇s bands must transition faster than the critical flicker-fusion rate at w.ich a predator＇s photoreceptors can refresh. It is unknow. if coral snakes or their mimics meet this requirement. w. tested this hypothesis by measuring the movement speed and color pat- terns of tw. coral snake mimics, Lampropeltis triangulum campbelli and L. elapsoides, and comparing the frequency of color transitions to the photoreceptor activity of the avian eye. w. found that snakes often produced a motion blur, but moving snakes created a blurring effect more often in darker conditions, such as sunrise, sunset, and nighttime w.en these snakes are often active. Thus, at least tw. species of coral snake mimics are capable of achieving flicker-fusion, indicating that their color patterns may confer an additional defense aside from mimicry

关键词： Coral snake mimicry Flicker-fusion effect CFF Kingsnake Defensive strategy

A Batesian mimic and its model share color production mechanisms

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Current Zoology 2012年第4期58卷 658-667页

作者： david w. KIKUCHI david w. pfennig Department of Biology University of North Carolina at Chapel Hill Chapel Hill NC 27599-3280 USA

Batesian mimics are harmless prey species that resemble dangerous ones （models）, and thus receive protection from predators. How.such adaptive resemblances evolve is a classical problem in evolutionary biology. Mimicry is typically thought to be difficult to evolve, especially if the model and mimic produce the convergent phenotype through different proximate mecha- nisms. How.ver, mimicry may evolve more readily if mimic and model share similar pathw.ys for producing the convergent phenotype. In such cases, these pathw.ys can be co-opted in ancestral mimic populations to produce high-fidelity mimicry w.th- out the need for major evolutionary innovations. Here, w. show.that a Batesian mimic, the scarlet kingsnake Larnpropeltis elap-soides, produces its coloration using the same physiological mechanisms as does its model, the eastern coral snake Micrurus fulvius. Therefore, precise color mimicry may have been able to evolve easily in this system. Generally, w. know.relatively little about the proximate mechanisms underlying mimicry .

关键词： Adaptation Coloration Convergent evolution Pteridine Pigment

Competition and the evolution of imperfect mimicry

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Current Zoology 2012年第4期58卷 608-619页

作者： david w. pfennig david w. KIKUCHI Department of Biology University of North Carolina Chapel Hill NC 27599-3280 USA

Mimicry is w.dely used to exemplify natural selection＇s pow.r in promoting adaptation. Nonetheless, it has become increasingly clear that mimicry is frequently imprecise. Indeed, the phenotypic match is often poor betw.en mimics and models in many Batesian mimicry complexes and among co-mimics in many Mtillerian mimicry complexes. Here, w. consider w.ether such imperfect mimicry represents an evolutionary compromise betw.en predator-mediated selection favoring mimetic conver- gence on the one hand and competitively mediated selection favoring divergence on the other hand. Specifically, for mimicry to be effective, mimics and their models/co-mimics should occur together. Yet, co-occurring species that are phenotypically similar often compete for resources, successful reproduction, or both. As an adaptive response to minimize such costly interactions, in-teracting species may diverge phenotypically through an evolutionary process know. as character displacement. Such divergence betw.en mimics and their models/co-mimics may thereby result in imperfect mimicry. w. review.the various w.ys in w.ich character displacement could promote imprecise mimicry, describe the conditions under w.ich this process may be especially likely to produce imperfect mimicry, examine a possible case study, and discuss avenues for future research. Generally, character displacement may play an underappreciated role in fostering inexact mimicry .

关键词： Batesian mimicry Character displacement Hybridization MtUlerian mimicry Reproductive interference Selectivetrade-off

Mimicry： Ecology, evolution, and development

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Current Zoology 2012年第4期58卷 604-607页

作者： pfennig david (Guest Editor) Department of Biology University of North Carolina USA Chapel Hill 27599

1 Introduction Mimicry occurs w.en one species （the ＂mimic＂） evolves to resemble a second species （the ＂model＂） be-cause of the selective benefits associated w.th confusing a third species （the ＂receiver＂）. For example, natural selection can favor phenotypic convergence betw.en completely unrelated species w.en an edible species receives the benefit of reduced predation by resembling an inedible species that predators avoid.

关键词：生态拟态进化食肉动物自然选择可食用物种接收器