Multiple exposures to adult males and reproductive activation of virgin female Microtus Ochrogaster.

Virgin female Microtus ochrogaster living in family groups were reproductively activated by twelve 1-hr exposures over a 3-day period to unrelated sexually experienced males. Reproductive activation among virgin females receiving six or eight exposures over a 2- or 3-day period did not differ significantly from that of unexposed control females. Thus, frequent multiple exposures to unfamiliar males (and repeated stimulation by a male urinary chemosignal) can override the reproductive suppression typically experienced by virgin females remaining in family groups.