Effects of hormonal, sexual, and social history on mating and pair bonding in prairie voles

The interactive effects of hormones, sexual history and cohabitation on sexual and social behaviors were examined in pairs of ovariectomized female and sexually experienced male prairie voles (Microtus ochrogaster). Monitoring with time lapse video tape revealed that females in estradiol benzoate (EB)-induced estrus, and their male partners engaged in high levels of sexual activity which continued intermittently for at least 3 days (until observations were arbitrarily terminated). In conjunction with other studies, these results indicate that the hormonal condition of the female at the time of testing is a major determinant of sexual activity. Prior hormonal, copulatory, or cohabitation experience did not significantly influence sexual responses between females and unfamiliar male partners. However, affiliative behaviors, such as side by side contact, were higher in pairs that were familiar due to prior sexual and cohabitational experience. These results indicate that social and sexual behaviors are independently regulated. Other behaviors, including nasogenital investigation and autogrooming were influenced by the hormonal and sexual history of the female. The implications of these behavioral patterns for reproductive activation, pair bonding, and incest avoidance are discussed.