Coral snakes predict the evolution of mimicry across New World snakes

Batesian mimicry, in which harmless species (mimics) deter predators by deceitfully imitating the warning signals of noxious species (models), generates striking cases of phenotypic convergence that are classic examples of evolution by natural selection. However, mimicry of venomous coral snakes has remained controversial because of unresolved conflict between the predictions of mimicry theory and empirical patterns in the distribution and abundance of snakes. Here we integrate distributional, phenotypic and phylogenetic data across all New World snake species to demonstrate that shifts to mimetic coloration in nonvenomous snakes are highly correlated with coral snakes in both space and time, providing overwhelming support for Batesian mimicry. We also find that bidirectional transitions between mimetic and cryptic coloration are unexpectedly frequent over both long- and short-time scales, challenging traditional views of mimicry as a stable evolutionary ‘end point’ and suggesting that ...

贝氏拟态（Batesian mimicry）指无害物种（拟态者）通过欺骗性模仿有毒物种（模型者）的警戒信号来威慑捕食者，这种拟态现象产生了显著的表型趋同（phenotypic convergence）案例，而这些案例是自然选择驱动进化的经典范例。然而，关于有毒珊瑚蛇的拟态现象一直存在争议，原因在于拟态理论的预测与蛇类分布及丰度的实证模式之间存在未解决的矛盾。在此，我们整合了所有新大陆蛇类的分布、表型及系统发育数据（phylogenetic data），以证明无毒蛇类向拟态色型的转变在时空上均与珊瑚蛇高度相关，这为贝氏拟态提供了压倒性的支持。我们还发现，拟态色型与保护色（cryptic coloration）之间的双向转变在长期和短期尺度上均出乎意料地频繁，这挑战了将拟态视为稳定进化‘终点’的传统观点，并表明……