Data from: Learning of salient prey traits explains Batesian mimicry evolution

Batesian mimicry evolution entails an initial major mutation that produces a rough resemblance to the model, followed by smaller improving changes. To examine the learning psychology of this process, we applied established ideas about mimicry in Papilio polyxenes asterius of the model Battus philenor. We performed experiments with wild birds as predators and butterfly wings as semi-artificial prey. Wings of hybrids of P. p. asterius and P. machaon were used to approximate the first mutant, with melanism as the hypothesized first mimetic trait. Based on previous results about learning psychology and imperfect mimicry, we predicted that: melanism should have high salience (i.e., being noticeable and prominent), meaning that predators readily discriminate a melanistic mutant from appearances similar to P. machaon; the difference between the first mutant and the model should have intermediate salience, to allow further improvement of mimicry; and the final difference in appearance between P. p. asterius and B. philenor should have very low salience, causing improvement to level off. Our results supported both the traditional hypothesis and all our predictions about relative salience. We conclude that there is good agreement between long-held ideas about how Batesian mimicry evolves and recent insights from learning psychology about the role of salience in mimicry evolution.贝茨拟态（Batesian mimicry）的进化通常始于一次可产生与模型物种粗略相似性的重大突变，后续再经由多轮小幅优化修饰逐步完善拟态效果。为探究该过程背后的学习心理学机制，我们以拟态模型为红珠凤蝶（Battus philenor）的北美茴香凤蝶（Papilio polyxenes asterius）的既有拟态研究理论为基础开展实验。实验以野生鸟类作为捕食者，以蝴蝶翅膀作为半人工猎物；我们使用P. p. asterius与P. machaon的杂交后代翅膀来模拟初始突变体，并将黑化性状设定为首个拟态特征。基于过往关于学习心理学与不完善拟态的研究成果，我们提出三项预测：其一，黑化性状应具备较高的显著性（即易于被感知且特征突出），意味着捕食者可轻易将黑化突变体与近似P. machaon的个体区分开来；其二，初始突变体与拟态模型之间的外观差异应具备中等显著性，为拟态的进一步优化留出空间；其三，P. p. asterius与B. philenor最终的外观差异应具备极低的显著性，使得拟态的优化进程趋于停滞。实验结果既验证了贝茨拟态进化的传统假说，也完全契合我们关于相对显著性的各项预测。综上，学界长期以来关于贝茨拟态进化路径的经典认知，与近期从学习心理学视角得出的、关于显著性在拟态进化中作用的研究结论，二者间存在高度一致性。