Data from: Predator perception of Batesian mimicry and conspicuousness in a salamander

In Batesian mimicry a palatable mimic deceives predators by resembling an unpalatable model. The evolution of Batesian mimicry relies on the visual capabilities of the potential predators, as prey detection provides the selective force driving evolutionary change. We compared the visual capabilities of several potential predators to test predictions stemming from the hypothesis of Batesian mimicry between two salamanders: the model species Notophthalmus viridescens, and polymorphic mimic, Plethodon cinereus. First, we found mimicry to be restricted to coloration, but not brightness. Second, only bird predators appeared able to discriminate between the colors of models and non-mimic P. cinereus. Third, estimates of salamander conspicuousness were background-dependent, corresponding to predictions only for backgrounds against which salamanders are most active. These results support the hypothesis that birds influence the evolution of Batesian mimicry in P. cinereus, as they are the only group examined capable of differentiating N. viridescens and non-mimetic P. cinereus. Additionally, patterns of conspicuousness suggest that selection from predators may drive the evolution of conspicuousness in this system. This study confirms the expectation that the visual abilities of predators may influence the evolution of Batesian mimicry, but the role of conspicuousness may be more complex than previously thought.

在贝茨拟态（Batesian mimicry）中，可食性拟态者通过模仿不可食性模型物种来欺骗捕食者。贝茨拟态的演化依赖于潜在捕食者的视觉能力，因为猎物探测所产生的选择压力是驱动演化改变的核心动力。本研究针对两种蝾螈间的贝茨拟态假说展开验证，比较了多种潜在捕食者的视觉能力：其中模型物种为绿螈（Notophthalmus viridescens），多态拟态物种为红背蝾螈（Plethodon cinereus）。

研究得到三项核心结论：其一，拟态仅局限于体色特征，而非亮度维度；其二，仅鸟类捕食者能够区分模型物种与非拟态型红背蝾螈的体色差异；其三，蝾螈的醒目程度评估结果依赖于背景环境，仅在蝾螈活跃度最高的栖息背景下，其醒目程度才符合拟态假说的预测。

上述结果支持了“鸟类驱动红背蝾螈贝茨拟态演化”的假说，因为在所检测的类群中，鸟类是唯一能够区分绿螈与非拟态型红背蝾螈的类群。此外，醒目程度的变化模式表明，捕食者带来的选择压力可能推动了该系统中物种醒目特征的演化。

本研究证实了“捕食者的视觉能力可影响贝茨拟态演化”这一预期，但醒目程度的作用可能比此前预想的更为复杂。