What makes eyespots intimidating? - the importance of pairedness

Background: Many butterflies possess striking structures called eyespots on their wings, and several studies have sought to understand the selective forces that have shaped their evolution. Work over the last decade has shown that a major function of eyespots is their ability to reduce predation by being intimidating to attacking predators. Two competing hypotheses seek to explain the cause of intimidation, one suggesting ‘eye-mimicry’ and the other their ‘conspicuousness’ as the reason. There is an on-going debate about which of these better explains the effectiveness of eyespots against predation. We undertook a series of indoor experiments to understand the relative importance of conspicuousness and eye-mimicry, and therefore how predator perception may have influenced the evolution of eyespots. We conducted choice tests where artificial paper models mimicking Junonia almana butterflies were presented to chickens and their preference of attack recorded. Results: We first established ...背景：许多蝴蝶的翅部生有被称为眼斑（eyespots）的醒目结构，已有多项研究致力于解析驱动其演化的选择压力。过去十余年的研究表明，眼斑的核心功能之一是通过威慑攻击中的捕食者，从而降低个体被捕食的概率。目前存在两种相互竞争的假说，用以解释该威慑效应的成因：其一为“拟态眼状结构（eye-mimicry）”，其二为“醒目性（conspicuousness）”。学界仍在持续争论，二者中哪一种更能合理阐释眼斑对抗捕食的有效性。为探究醒目性与拟态眼状结构的相对重要性，进而揭示捕食者的感知如何影响了眼斑的演化，我们开展了一系列室内实验。本实验设置了选择范式：将模拟眼蛱蝶（Junonia almana）的纸质人工模型呈现给家鸡，并记录其攻击偏好。结果：我们首先确立了……