SCHMAEMAN, C.N.*; VONHOF, M.J.; MENDON�A, M.T.; Auburn Univ.., Auburn, AL; Western Michigan Univ., Kalamazoo, MI; Auburn Univ., Auburn, AL: Multiple Mating and Paternity Outcomes in Big Brown Bats: A Preliminary Study

Very little is known about the mating systems of temperate vespertilionid bats. What is known is that temperate vespertilionids can store sperm for an extend period of time and mate with multiple males. What is unknown is what factors account for mating success. Mechanisms can be pre-copulatory (i.e., female choice based on some extrinsic male quality) or post-copulatory (i.e., mating order, sperm competition, or genetic compatibility). Big brown bats (Eptesicus fuscus) are one of the most common of the temperate vespertilionid bats of North America and are the subject of our study. Over the last 5 years, we documented the reproductive behavior of these bats in captivity. From Dec-Mar (the breeding season) 1999-2003, male and female bats were housed in large environmental flight cages and given varying temperature regimens that stimulate mating activity. In each of the seasons, individuals were observed nightly for 8-hour periods and scored for attempted and successful mounts by males. Males varied in the number of different females that allowed successful mounts (i.e. intromission). However, there was no male quantitative or qualitative quality (e.g., weight, body size, or health) that accounted for differences in male intromission success. Females also varied in the number of different males over the season they would allow to successfully intromit. We documented the order of mating of males for each multiple-mated female. Additionally, skin samples were taken from all the adult bats and the offspring produced by the matings to determine paternity. Bats were genotyped at nine highly variable autosomal microsatellite loci and one X-linked locus. Data on the relationship between mating order and paternity will be discussed.