Spatial heterogeneity, predator cognition, and the evolution of color polymorphism in virtual prey

Cryptically colored prey species are often polymorphic, occurring in mul-tiple distinctive pattern variants. Visual predators promote such phe-notypic variation through apostatic selection, in which they attack more abundant prey types disproportionately often. In heterogeneous environ-ments, disruptive selection to match the coloration of disparate habitat patches could also produce polymorphism, but how apostatic and disrup-tive selection interact in these circumstances is unknown. Here we report the first controlled selection experiment on the evolution of prey color-ation on heterogeneous backgrounds, in which blue jays (Cyanocitta cris-tata) searched for digital moths on mixtures of dark and light patches at three different scales of heterogeneity. As predicted by ecological theory, coarse-grained backgrounds produced a functional dimorphism of special-ists on the two patch types; fine-grained backgrounds produced generalists. The searching strategies of the jays also varied with the habitat configura