Losing your head over sex: removal of female control increases copula duration

Differential costs and benefits of copula duration between males and females can lead to sexual conflict. In Queensland fruit flies, Bactrocera tryoni (Q-flies), average copula duration is two hours, but can last for seven hours. During copula, which occurs only once at dusk, sperm and accessory gland fluid are transferred to the female. Longer copula does not result in transfer of more sperm. Accessory gland fluid inhibits re-mating and reduces copula duration of second matings. It is not clear whether males benefit from longer copulations or which sex has control over copula duration. We assessed female control over copula duration in Q-flies by decapitating or removing the head and thorax of females during copula. Copula duration was significantly longer when males mated with decapitated females or female abdomens relative to normal females. We allowed males to mate with normal females, decapitated females, or female abdomens over four consecutive days. Most males mated each day, with some able to commence courtship and re-mate immediately after having mated for 24 hours. Repeatability of male copula duration will be discussed, as well as how removal of female control influences sperm distribution and storage in the female reproductive tract.