In light of our discussion of adaptive phenotypic variation, I thought this Proc. of the Royal Society B article would be an interesting point for discussion:
The article explores the convergence of evolutionary, social, and genetic factors in the discussion of what drives the remarkably diverse displays of primate facial coloring. The article suggests that facial coloring is powerfully driven by the need for more complex patterns of social recognition especially among sympatric groups with overlapping ranges and that some of the most diverse displays are observed under these conditions. It also proposes a more fluid model for understanding the genetic processes underlying changes in facial coloring. In the past facial coloring has been understood as a more "permanent" evolutionary adaptation, but the alternative biological pathways supported by these authors' data involve more evolutionary flexibility, allowing for more variation in phenotypic displays over time (as is observed in many of the Neotropical primates under consideration).