Data from: Dorsal and ventral plumage coloration evolve as distinct modules with different environmental correlations

Many animals exhibit contrast between their dorsal and ventral coloration. If selection acts differently on dorsal versus ventral coloration, ancestral covariance between these traits should break down, leading eventually to independent modules of trait evolution. Here, we compare the evolution of feather color across body regions for a clade of Australasian songbirds (Meliphagoidea). We find evidence for three modules of covarying color regions. Among these modules, ventral feathers evolve with high lability, evolving at 3 times the rate of dorsal plumage and 20 times the rate of flight feathers. While both dorsal and ventral plumage are darker with more precipitation and vegetation, we find that dorsal plumage is twice as similar to colors in satellite photos of background substrates. Overall, differential selection on ventral and dorsal colors likely maintains these as distinct modules over evolutionary time scales – a novel explanation for dorsoventral contrast in pigmentation.