Rachel Petersen

Grant Type

Dissertation Fieldwork Grant

Institutional Affiliation

New York U.

Grant number

Gr. 9921

Approve Date

October 25, 2019

Project Title

Petersen, Rachel (New York U.) "Mechanisms of pre- and post-copulatory choice in female olive baboons, a model for human evolution," supervised by Dr. James Higham

Throughout much of human and primate evolution, dimorphism and coercion may have restricted the role of direct female mate choice, selecting for mechanisms of cryptic choice instead. This study will experimentally explore mechanisms by which olive baboons could engage in cryptic post-copulatory mate discrimination, an interesting model for human evolution due to their high degree of both direct competition (evident from body size dimorphism similar to early hominins), and indirect male-male competition (sperm competition evident from large relative testis volume). Data collection is currently underway at CNRS Primatology Station in Rousset, France. Females are trained to present their hindquarters for vaginal swabbing, offering the unique opportunity to characterize vaginal pH and gene expression across cycles in the absence of copulation, and in response to mating with males of differing genotypes. I will also explore differences in socio-sexual signaling based on mate genotype and its relation to mechanisms of post-copulatory choice. This project will elucidate physiological processes associated with post-copulatory choice, provide an explanation for discrepancies between mating observations and reproductive skew, and provide a greater understanding of female mate choice, an evolutionary mechanism likely to be operating throughout human evolution.