Pre-copulatory behaviour in the male Mongolian gerbil: I. Differences in dependence on androgen of component patterns

Abstract

Male behaviour patterns, including ultrasonics, olfactory investigation, grooming and sequences of following of oestrous females during the pre-copulatory period, were described for the Mongolian gerbil. Differences in dependence of these patterns on gonadal hormones were examined by measuring the rates of decline after castration and the degree of restoration following the subcutaneous injection of testosterone propionate (20 μg/2 days/animal). Castration and androgen therapy did not influence the performance of male genital grooming, allogrooming and the olfactory investigation of both female secretory products and the female's body, excluding the posterio-dorsal area. The other male patterns differed in the extent to which they were affected. Thus ventral gland marking, foot-stomping and sequences of follow/dart interactions declined rapidly and were not restored to pre-castration levels by androgen; whereas the upsweep ultrasonic vocalization and olfactory investigation of the female's perineal area declined more gradually, and were completely restored. These consistent differences in both decline and restoration suggest that mechanisms underlying some pre-copulatory patterns are influenced by androgen to a greater degree than others.