EAPSI: Assessing Butterfly Evolutionary Divergence in a Post-mating, Pre-zygotic Interaction

Plakke Melissa, West Mifflin PA

Investigators

Abstract

This project aims to identify genes that are important for the formation of new species by using reproductive interactions in the Cabbage White butterfly, Pieris rapae. There are two subspecies of P. rapae: P. r. rapae and P. r. crucivora, the latter being endemic to the islands of Japan. These subspecies have diverged in coloration, pheromone profiles, and mate choice behaviors. In addition, research on their reproductive physiology suggests functional mismatches between reproductive proteins may have also arisen during the ~5,000 years that these subspecies have been geographically separated. The specific identities of these mismatched proteins, and their associated genes, remain undescribed. For this project, the researcher will collect butterflies in Japan and compare key reproductive genes between the two subspecies. The research will be conducted at SOKENDAI in Hayama, Japan in collaboration with Dr. Kentaro Arikawa, a leading world expert on butterfly research. In Japan, the researcher will collect biological samples, including DNA from wild caught individuals and RNA from lab-reared virgin females. The DNA sequences and RNA expression levels for genes of interest will be assessed for divergence between the two subspecies. Further, the research will determine whether genes of interest (i.e., those involved in reproductive interactions between the female reproductive tract and male ejaculate) show signatures of adaptive evolution. Such a finding would indicate that these reproductive traits evolve at elevated rates, consistent with the hypothesis that this reproductive interface could play a role in the divergence and/or maintenance of these two subspecies. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.