The function and meaning of female rat paracopulatory (proceptive) behaviors

• Male pursuit of the female precedes most sexual interactions.
• Female paracopulatory behavior precedes almost all sexual interactions.
• Males and females equally often initiate sexual interaction.
• Female paracopulatory behavior seems to enhance male sexual motivation.
• The intensity of paracopulatory behavior may represent female sexual motivation.

Female paracopulatory behavior is believed to incite the male to start copulation and to allow the female control over the pace of sexual interaction. It is also supposed to represent female sexual motivation. However, there is little direct experimental evidence for these presumed functions. In the present study, we determined the temporal relationship between female paracopulatory behavior, male pursuit of the female, and male copulatory acts. Groups of 4 intact female and 3 male Wistar rats were housed in a seminatural environment for 8 days. Sociosexual behavior during the entire period of behavioral estrus was analyzed. All episodes of paracopulatory behavior were identified, and the male behavior occurring up to 10 s before or after each episode was determined. Most paracopulatory behaviors were unrelated to male copulatory acts or male pursuit. To the contrary, 96% of copulatory acts occurred within 5 s of female paracopulatory behavior and 83% within 5 s of male pursuit of the female. Sexual interaction was initiated by a male as often as it was initiated by a female. The duration of an episode of paracopulatory behavior or male pursuit was an important determinant of the likelihood that a copulatory act would follow. Copulatory acts were a consequence of a subtle interaction between the male and the female, with the behavior of both being equally important. No support was obtained for the notion that sexual interactions are mainly controlled by the female.