FERNANDEZ, A. F.*; MORRIS, M. R.; Ohio University: The importance of sexual selection in the maintenance of primate trichromatic vision.

Foraging efficiency theory has dominated the literature on the evolution of primate trichromatic color vision over the past twenty years; however, recent empirical studies propose that its implications may have been over stated. Our analyses suggest a novel alternative hypothesis. Whereas primate trichromacy seems to have initially evolved to increase foraging efficiency, it may be maintained through sexual selection. Testing the hypothesis that sexual selection has played a role in the evolution of color vision in primates, we examined the correlation between mating system, red hair and red skin with the presence of trichromacy. Phylogenetic comparative analysis found that within those clades of primates exhibiting trichromacy, color vision is significantly correlated with the evolution of red-orange pelage and gregarious mating systems that promote sexual selection. Similar to studies of birds and fishes suggesting that mating preferences evolved from food preferences, a preference for red leaves and fruits in primates would have represented a pre-existing receiver bias for colors with high chroma and saturation, thereby providing a mechanism by which sexual selection drove the evolution of red pelage in primates. Future investigation of the sexual selection hypothesis is necessary to reveal whether red-orange pelage serves as indicator of mate quality and to further examine the roles of visual signals in mate competition and choice in primates.