Effect of prolactin on established incubation behavior in the ring dove.

Abstract

Ringdoves tested for incubation responses to eggs while in nonbreeding condition did not sit. Ss allowed to breed sat by the time the 2nd egg was laid. Ss allowed to sit on eggs for 12 days showed incubation responses at the end of this period; in every S removed from eggs and kept isolated for 12 days, readiness to incubate disappeared. In another group readiness to incubate was maintained by prolactin injected during a 12-day isolation period. Prolactin injected in nonbreeding birds induced no incubation responses. Prolactin, in the dosage used, can maintain incubation which has developed during the normal cycle, but cannot induce it in Ss in which it has not yet thus appeared.