Data from: Resemblance to the enemy's eyes underlies the intimidating effect of eyespots

Eyespots of some prey are known to deter predators, but the reason for this response has not yet been established, and thus the taxonomically widespread occurrence of this color pattern has remained an evolutionary conundrum. Two alternative hypotheses propose that (1) the eyelike appearance of the pattern falsely indicates the presence of the predator’s own enemy or (2) predators are hardwired to be cautious toward conspicuous prey. Earlier research has pertained mainly to eyespots in butterflies. Here we tested the hypothesis that eyespots resemble eyes by utilizing the lateral position of eyes in fishes. This allowed us to produce eyelike displays that did not have the round appearance of eyespots. Our study indicates that eye mimicry is an important factor evoking hesitation in predators. Moreover, we present direct evidence that this is because predators associate eyelike displays with the threat posed by their own enemies.

部分猎物所具备的眼斑（eyespots）已知可威慑捕食者，然而这一防御效应的内在机制迄今尚未明确，故而这种在分类学上广泛分布的体色模式的演化起源始终是一道进化生物学难题。目前存在两种对立假说：其一，该类眼状外观的图案会虚假暗示捕食者自身天敌的存在；其二，捕食者天生对具有醒目特征的猎物持有戒心。既往相关研究主要聚焦于蝶类的眼斑。本研究借助鱼类眼部的侧生位置，验证了"眼斑可拟态眼部"这一假说，借此构建了不具备眼斑圆形外观的眼状展示模型。本研究结果表明，眼部拟态是引发捕食者产生迟疑行为的重要影响因素。此外，本研究还提供了直接证据，证明该效应的成因在于捕食者会将眼状展示与自身天敌所带来的威胁建立关联。