The evolution of guenon face patterns

抄録

The guenons are a recent primate radiation that exhibit high degrees of sympatry, and commonly form mixed-species groups. Hybridization is possible, yet rare in most populations. Guenons have species-specific colorful face patterns hypothesized to function as signals used in species discrimination. Here, consistent with this, I present our studies showing that guenon faces exhibit character displacement, with species being more facially distinctive specifically from the species that they overlap with geographically. I then show that species can be reliably classified by these facial patterns, including specific components of these faces, and present machine classification data that reveal the specific regions of faces that are diagnostic for species discrimination for each species. I go on to present new experimental data testing these machine classification results back to live guenons, which show that they do indeed focus primarily on those regions when presented with the faces of different species. Collectively, our results suggest that guenon face patterns have evolved as mate discrimination signals that facilitate reproductive isolation between species. Our research adds to our understanding of the relationship between reproductive isolation and phenotypic diversity among the primates.