Colour pattern variation forms local background matching camouflage in a leaf-mimicking toad

Optimal camouflage can, in principle, be relatively easily achieved in simple, homogeneous, environments where backgrounds always have the same color, brightness, and patterning. Natural environments are, however, rarely homogenous and species often find themselves viewed against varied backgrounds where the task of concealment is more challenging. One result of variable backgrounds is the evolution of intraspecific phenotypic variation which may either be generalized, with multiple similarly cryptic patterns, or specialized, with each discrete color form maximizing concealment against a single component of the background. We investigated the role of phenotypic variation in a highly variable population of the Neotropical toad Rhinella margaritifera using visual modeling and a computer-based detection task. We found that phenotypic variation was not divided into discrete color morphs and all toads were well camouflaged against the forest floor. However, although the whole population may ...