Meeting Abstract

52.6  Sunday, Jan. 5 11:30  Mechanisms underlying variance in competitive fertilization success in the highly promiscuous beetle Tribolium castaneum DROGE-YOUNG, E.*; BELOTE, J.; PEREZ, G.; PITNICK, S.; Syracuse University, New York; Syracuse University, New York; Syracuse University, New York; Syracuse University, New York emdroge@syr.edu

Investigating mechanisms that influence competitive fertilization success is critical to our understanding how postcopulatory sexual selection drives the evolution of reproductive characters. Our knowledge of postcopulatory processes, particularly when females mate with more than two competing males, remains limited in part due to the difficulty of discriminating among the sperm of different males within a female’s reproductive tract. Here, we used transgenic lines of the flour beetle, Tribolium castaneum that have males that produce sperm with green or red fluorescent protein tagged heads to identify sources of variance in fertilization success after females are mated to two or more competing males. We then associated patterns of sperm storage to patterns of paternity across the multiple matings. Our results indicate that sperm relevance to fertilization as well as displacement in subsequent matings depends on sperm location in the female reproductive tract. Additionally, we found that male size predicts success in transferring sperm during copulation, in addition to other variables influencing the proportion of focal male sperm in the female reproductive tract.