Importance of Female's Precopulatory Behaviour for the Primary Initiation of Male's Copulatory Behaviour in the Laboratory Rat

Publisher Website
Google Scholar
Abstract
Precopulatory and copulatory behaviour of adult (90-100 days old) Wistar male laboratory rats in their first encounter with a female was observed. Four levels of female sexual behaviour, characterized by lordosis, presenting, hopping and darting, were used as the experimental variable. A male was considered to have exhibited precopulatory behaviour if he performed at least three specific activities toward the female, such as anogenital exploration, touching the flanks, climbing over, pursuing. The performance of three intromittory copulations, the first of which had to occur within 10 minutes, was used as a criterion of the initiation of copulatory behaviour. In Experiment 1 it was found that not all the males who exhibit precopulatory behaviour also initiate copulations. With increasing level of sexual behaviour of the female the percentage of males exhibiting precopulatory behaviour hardly changes, but the probability that a male will initiate copulations substantially increases. Whereas no male imtiates copulations with a lordotic (passively receptive) female, a darting female provokes copulations in about 90% of the males. Experiment 2 showed that different breeding conditions, additional testosterone and cadmium intoxication did not influence the established dependence of the male's sexual behaviour on sexual behaviour of the female. Multiple repeated exposures of the males to a presenting female (Experiment 3) led to an increase in the percentage of males