Precopulatory behaviour in male rats: ethological analysis and functional considerations

Ethologically derived procedure was used to determine the appearance of precopulatory behavioural elements in adult male rats in the course of interaction with a behaviourally strictly defined female partner, the so-called Presenting female. The data obtained were tabulated in sequence tables of elements. Two versions were used with the aim to analyze an expected value for each cell and comparing this with the observed value. Flow diagrams were constructed to depict the appearance of the individual precopulatory elements as well as transitions among them. The results can be summarized as follows. The appearance of precopulatory elements in males interacted with Presenting female proceeds in a certain sequence. After the partners are close together, the typical sequence of short body-sniffing, anogenital exploration and touching the flank was found. The other elements - climbing over, circling around, manipulation, standing on - lack a similar regularity; the relations among them are rather complicated. If the male is not able to pass from the precopulatory to the copulatory phase, he reverts very often to the exhibition of the two out of three formerly exhibited elements, i.e. anogenital exploration and touching the flank. However, there are considerable interindividual as well as intraindividual differences in total frequencies of precopulatory elements. The results are discussed from a point of view of the optimum goal-directness of sexual interaction and compared with those achieved in the previous studies in which different stimulus females were used. Further, the function of the individual precopulatory elements of male rats in sexual interaction is reviewed. Finally, the precopulatory interaction is considered to be a communicative process by means of which the sex partners are approaching the transition into the copulatory phase.