Poison frog colors are honest signals of toxicity, particularly for bird predators

Antipredator defenses and warning signals typically evolve in concert. However, the extensive variation across taxa in both these components of predator deterrence, and the relationship between them, are poorly understood. Here we test whether there is a predictive relationship between visual conspicuousness and toxicity levels across 10 populations of the color polymorphic strawberry poison frog, Dendrobates pumilio. Using a mouse-based toxicity assay, we find extreme variation in toxicity between frog populations. This variation is significantly positively correlated with frog coloration brightness, a viewer-independent measure of visual conspicuousness (i.e. total reflectance flux). We also examine conspicuousness from the view of three potential predator taxa, as well as conspecific frogs, using taxon-specific visual detection models and three natural background substrates. We find very strong positive relationships between frog toxicity and conspicuousness for bird-specific percept...反捕食防御机制与警戒信号通常协同演化。然而，学界对捕食者威慑的这两个组成部分在不同类群间的广泛变异，以及二者之间的关联，仍知之甚少。本研究针对10个种群的体色多态草莓箭毒蛙（Dendrobates pumilio），检验视觉显著性与毒性水平之间是否存在预测性关系。通过基于小鼠的毒性检测实验，我们发现不同蛙种群间的毒性存在极端差异。该毒性差异与蛙体色亮度呈显著正相关——体色亮度是一种不依赖观测者的视觉显著性量化指标（即总反射通量）。本研究还借助类群特异性视觉检测模型与三种自然背景基质，分别从三种潜在捕食者类群以及同种蛙类的视角，评估了蛙的视觉显著性。我们发现，针对鸟类特异性感知的蛙类毒性与视觉显著性之间存在极强的正相关关系……