Microbial Contributions to Primate Reproduction

Reproduction is a complex process, and microbes play a far greater role than previously imagined. This review explores the ways that microbiomes influence the rich tapestry of reproductive processes and outcomes within the primate lineage, including pre-copulatory and post-copulatory mechanisms. We discuss microbiomes in a sexual selection framework, specifically how they might influence mate choice and sexual competition across multiple sensory modalities. We then consider how copulatory behavior and mating systems may in turn shape reproductive microbiomes. Moving to post-copulatory processes, we discuss the potential impact of microbes on cryptic choice and sperm competition and call for additional research in this area. Finally, we explore the influence of microbes on pregnancy outcomes, emphasizing evolutionary perspectives often overlooked in clinical research. Importantly, we compare human studies to those on nonhuman primates, bridging the two areas of inquiry and outlining future research directions. Our aim is to highlight the vast potential for microbes to contribute to all stages of reproduction, and to inspire creative, synthetic future research that moves forward this fascinating area of inquiry.