The repeatability of a sexual conflict over mating

Measuring individual variation in mating behaviour is an integral part of s tudies of sexual selection and of considerable theoretical importance. Few studies, however, have examined individual variation in mating behaviour in a sexual conflict system and considered how individual variation influence s the strength and consistency of the resulting sexual selection. We examin ed variation in mating behaviour of male and female pairs in the seaweed fl y, Coelopa frigida. Sexual selection in seaweed flies occurs as a result of a sexual conflict over mating, with larger males generally able to overcom e female rejection responses. We explored male and female mating conflicts and examined the variation in conflict outcomes within and between pairs. F irst, female willingness to mate was unaffected by short-term mating experi ence, allowing us to examine repeated interactions between a male and a fem ale. Second, the outcomes of the sexual conflict over mating (copulation or rejection), and components of the mating interaction (number of copulation s and time the male is mounted), were strongly repeatable. Third, the patte rns of sexual selection on male size were consistent across mounts. Individ ual pairs consistently gave the same outcome to the mating conflict and yie lded consistent sexual selection. Sexual conflict systems can thus be studi ed in the same way as those with more traditional forms of sexual selection and yield important insights into the links between variation in mating be haviour and sexual success. (C) 2001 The Association for tile Study of Anim al Behaviour.