To copulate or not? The importance of female status and behavioural variation in predicting copulation in a bumblebee

Qualitative variation in female reproductive status and quantitative variat ion in courtship behaviour may both be important in determining whether cop ulation occurs after a mating interaction. However, integrated studies of t hese factors are rare. We examined whether female behaviour, male courtship behaviour and female reproductive status affect, on their own or together, the outcome of mating trials in the bumblebee, Bombus terrestris. We used insemination techniques to manipulate the status of females, enabling us to dissect the relative roles of previous behavioural experience and actual r eproductive status of females. Despite quantitative variation in male and f emale behaviour, the main predictor of copulation was female reproductive s tatus. While two behaviours, female rejection of males and male attempts to copulate, explained 9% of the variation between trials in whether copulati on occurred, on their own they could not predict whether mating occurred. N onbehavioural factors, such as colony of origin and animal age, had no pred ictive power with respect to the occurrence of copulation. Our results sugg est that, despite potential selection on males for courtship behaviour, qua ntitative within-species variation in the precopulatory behaviours we obser ved had little or no effect on whether copulation actually occurs. Rather, the reproductive status of females seems to be the most important determina nt of copulation. (C) 2001 The Association for the Study of Animal Behaviou r.