Mechanisms of cryptic female choice in the vaginal tract of a primate species

Understanding processes of mate choice is key to understanding how sexual selection shapes animal behavior and physiology. Mate choice may occur prior to copulation, such as behavioral mate choice, or after copulation, through physiological responses to sperm, but current evidence of the latter among large-bodied mammals is lacking. Here, we tested whether two aspects of female physiology that may contribute to sperm survival- vaginal immune response and pH- are modulated by male genotype in a nonhuman primate, the olive baboon. Specifically, we test if gene expression 1) differs over the course of the ovarian cycle, 2) differs in response to mating, and 3) is influened by the genetic makeup of the mating male. Our findings support genetically-based post-copulatory mate discrimination in primates, shedding light on the interaction between male gametes and the female reproductive tract and potentially explaining variation in conception probability.