Non-Technical Abstract This project will evaluate the interrelationships among inbreeding, mate choice, and reproduction in the monogamous old-field mouse. Inbred juvenile old-field mice are smaller and suffer increased mortality. Consequently, adults are predicted to maximize offspring production by choosing unrelated mates with which they will produce outbred, healthier pups. Inbred adult female old-field mice suffer reduced fertility. Therefore, males are predicted to maximize offspring production by choosing outbred mates. These predictions will be tested using a controlled experimental design. This study will also investigate potential physiological reasons for the reduced fertility of inbred adult females. Habitat fragmentation and over-harvesting continue to reduce the size of many wild animal populations. When populations are small, and are separated from one another by suburbs and farms, there is increased risk of inbreeding. It is important to understand how this can impact population growth rates. If inbred adults have reduced fertility and if they are rejected as potential mates, small inbreeding populations are at risk of extinction. However, if animals distinguish among potential mates based on their degree of relatedness, the incidence of inbreeding is reduced. The old-field mouse will serve as a good model system in which to address these broadly applicable questions.
