MALE SONG STIMULATION OF FEMALE REPRODUCTION IN CANARIES - FEATURES RELEVANT TO SEXUAL DISPLAYS ARE NOT RELEVANT TO NEST-BUILDING OR EGG-LAYING

Recent studies conducted in our laboratory have demonstrated that a sp ecial type of song phrase ('sexy' phrases) containing bipartite syllab les composed of abrupt frequency falls and short silences stimulate fe male canaries to solicit for copulation. The study was undertaken to d etermine whether sexy phrases also facilitated other aspects of the re productive activity of the female canary, namely, nest-building and eg g-laying. During the first experiment, we studied the effect of sexy a nd non-sexy songs on copulation solicitation displays in 1-year-old fe males without reproductive experience and in mature females with previ ous reproductive experience. We confirmed that sexy songs elicited mor e sexual responses than did non-sexy songs in yearlings and in mature Females. During the second experiment. we studied the effect of male s ongs on nest-building activities and egg-laying in 1-year-old inexperi enced females, and in mature, experienced females. The songs of, consp ecific males significantly triggered and increased nest-building behav iour in female canaries whatever their age or reproductive experience. In contrast, song effects on egg-laying were only found in young fema les. One-year-old inexperienced females exposed to sexy or non-sexy so ngs laid more eggs and laid earlier than did 1-year-old inexperienced controls; no such differences were observed in mature, experienced fem ales. The efficiency of songs in promoting nest-building or egg-laying appeared to be unrelated to their efficiency in eliciting sexual resp onses. No difference was found between females exposed to sexy songs a nd females exposed to non-sexy songs; differences were only found betw een control and the two groups of song-exposed females. This result de mands further experiments in order to determine whether other song phr ase types may account for the stimulating effects of male song on fema le nest-building and egg-laying.