Meeting Abstract
When females mate with more than one male in a reproductive cycle, post-copulatory sexual selection is hypothesized to favor male traits that allow them to outcompete rivals in their race to the egg and female traits that allow them to exercise choice in sperm use. This in turn can lead to conflict between the sexes and a co-evolutionary arms race as they both attempt to optimize their fitness. While it is well understood that these evolutionary processes can critically influence both male and female traits, female traits driven by post-copulatory sexual selection remain relatively understudied. Here I present my research investigating female reproductive traits in both rodents and arthropods. Using a cross-species comparison of six species of mice in the genus Peromyscus, we recently characterized the viscosity of the fluid collected from various regions of the female reproductive tract using a combination of optical microscopy and fluorescent nanoparticle tracking. From these data, we assessed the relationship between fluid complexity and mating system and established when and how subtle changes in the microenvironment impacts the collective motion of sperm. My previous work in seed beetles (Callosobruchus maculatus) allowed me to establish the pivotal role of female mating behavior in sperm use patterns and sperm competition. My work also suggests that delayed female remating is adaptive for females and is not mediated by sexual conflict driven by male manipulation via components of the ejaculate, as is often assumed. Hinging on male-female and sperm-female interactions, these studies highlight the importance of investigating female traits as well as the co-evolutionary interactions between the sexes for understanding reproductive traits driven by post-copulatory sexual selection.
