Data from: Mating status correlates with dorsal brightness in some but not all poison frog populations

Sexual signals are important for intraspecific communication and mate
selection, but their evolution may be driven by both natural and sexual
selection, and stochastic processes. Strawberry poison frogs (Oophaga
pumilio) show strong color divergence among populations, but coloration
also varies among individuals of the same population. The importance of
coloration for female mate choice has been studied intensely, and sexual
selection seems to affect color divergence in strawberry poison frogs.
However, the effect of coloration on mating success under field conditions
has received very little attention. Furthermore, few studies examined how
phenotypic variation among individuals of the same color morph affects
mate selection under natural conditions. We measured the spectral
reflectance of courting and noncourting individuals and their background
substrates in three geographically separated populations. In one
population (Sarapiquí, Costa Rica), we found that naturally occurring
courting pairs of males and females had significantly brighter dorsal
coloration than individual males and females not engaged in courtship
interactions. Our field observations suggest that, in the wild, females
prefer brighter males while the reason for the higher courtship activity
of brighter females remains unclear. Overall our results imply that
brightness differences among individuals of the same color morph may
actually affect reproductive success in some populations of strawberry
poison frogs.