Reproductive Inhibition in Female Cactus Mice (Peromyscus eremicus)

Abstract

Female Peromyscus eremicus born into freely growing populations generally failed to reproduce prior to 180 days of age, although asymptotic population size varied from nine to 27 among nine experimental groups. Also, fewer females housed individually with both parents gave birth to any offspring prior to 180 days of age than did control females or females housed with their father only. Those daughters that gave birth did so at a significantly more advanced age than did controls or females kept in father-daughter pairs. Reproductively inhibited females experienced normal estrous cycling and in many cases copulated successfully with their fathers as determined by the presence of spermatozoa in the reproductive tract. Females that copulated continued to exhibit uninterrupted, regular estrous cycling. Reproductive inhibition in females housed in the presence of the mother is interpreted as a strategy, which may result in the maximum long-term genetic contribution by the individuals involved.