Male density affects female spatial behaviour in the butterfly Proclossiana eunomia

The hypothesis of sexual conflict postulates that the differential male-female spatial distribution in butterfly species in which males are not territorial or do not defend a resource is due to the effect of ardent males on female behaviour. In such species females are often an ephemeral resource as they usually mate once while males are capable of multiple matings. In this system males will maximise their reproductive success by gaining access to many females while reproductive success of females is increased by maximising the rime spent in selection of optimal oviposition sites. We show here that at low male density the distance flown by the female depends on the behavioural pattern displayed immediately before and after her flight. This relation disappeared at high male density. Moreover high male density (1) decreased the duration and the frequency of behaviours related to oviposition and (2) increased the frequency and the duration of male-female interactions. We propose that these two factors contribute to promote female dispersal at high male density. The decision to disperse out of habitats with high density of males might be a trade-off between low-quality reproduction within such habitats and dangers of dispersal out of these habitats