Behaviour 2019
 Reproductive Success Preserves Fidelity in Female California Mice (Peromyscus californicus)
Amber Valentino1, Elizabeth Becker1,2. 1Saint Joseph's University, Philadelphia, PA, United States; 2Lawrence University , Appleton, WI, United States

California mice, with their life-long pair bonds and exclusive mating, are a rare example of a strictly monogamous mammal. Yet under lab conditions, examples of infidelity, more from females than males, has been observed. While factors such as the environment, mate guarding and mate choice have been implicated in maintaining sexual exclusivity, the role of previous reproductive success (RS) on extra-pair copulations is understudied. To examine the effects of prior RS (0, 1, or 3 litters) on behavior (aggression, affiliation and copulation) and future reproductive outcomes (whether or not they produced a litter), paired females underwent an infidelity test and were then re-housed with a novel male (NM). As expected, we found that females with the greatest RS (3 litters) were significantly more aggressive and significantly less affiliative toward a NM than females with less RS (0 or 1 litters). Additionally, we found that females with less RS engaged in significantly more copulations than females with greater RS. Findings from our study suggest that greater RS with a mate may aid in preserving fidelity, while less RS may contribute to infidelity among females of a monogamous species.