Androgen influence on mating behavior in selected lines of Japanese quail

Abstract

Bidirectional selection for high and low mating behavior has resulted in lines of Japanese quail that differ significantly in mating frequency. To evaluate the effects of this selection on the endocrine aspects of mating behavior, exogenous testosterone cypionate (TC) was administered to caponized and intact males from selected and control lines. Dosages of TC, administered as a single injection, were 0, 5.0, and 10.0 mg for the caponized and 1.25, 2.5, and 5.0 mg for the intact males. Mating performance was measured by testing each male individually with a series of female tester-flocks for eight 8-min periods. Capons mated within 3 to 4 days postinjection, with the period of peak activity occurring between the eighth and twelfth days. Hypertrophy of the cloacal gland followed a similar pattern. At no TC level was the mating frequency of caponized males from the low mating line equal to that of males from the high mating line. Furthermore, exogenous TC at these dosages failed to stimulate capons from the high and low mating lines to mate as frequently as the intact males of their respective lines. Exogenous TC had a depressing effect upon the mating frequency of intact males from the high mating and control lines but had no influence on those from the low mating line.