检索结果-南通市图书馆

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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 coloration 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 patterns of tw. coral snake mimics,Lampropeltis triangulum campbelliandL. 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-fiision, indicating that their color patterns may confer an additional defense aside from mimicry.

关键词：防御性模仿珊瑚蛇运动模糊移动速度颜色模式评估

Competition and the evolution of imperfect mimicry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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 Müllerian mimicry complexes. Here, w. consider w.ether such imperfect mimicry represents an evolutionary compromise betw.en predator-mediated selection favoring mimetic convergence 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, interacting 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：竞争力模仿进化表型特征适应性反应自然选择相互作用复合物

Inducible competitors and adaptive diversification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2013年第4期59卷 537-552页

作者： Beren w. ROBINSON david w. pfennig Department of Integrative Biology University of Guelph Guelph Ontario N 1G 2W 1 Canada Department of Biology University of North Carolina Chapel Hill NC 27599 USA

Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversification holds that the evolution of phenotypic differences betw.en populations and species—and the formation of new.species—stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, w. discuss how.competition plays at least tw. key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of “inducible competitors”. Second, once such competitively induced plasticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allow. populations to respond readily to selection favoring diversification, as may occur w.en competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays tw. important roles in adaptive diversification—one w.ll-know. and the other only now.emerging—mediated through its effect on the evolution of phenotypic plasticity.

关键词：竞争对手多样化诱导进化生物学表型变异生态学理论自适应可塑性

Mimicry： Ecology, evolution, and development

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Together, these papers offer a sense of the breadth of questions and approaches that make mimicry an exciting field, 150 years after Bates (1862) initial discovery.

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