Sex as moderator of early life experience: interaction between rearing environment and sexual experience in male guppies

The effects of learning have been neglected in studies of sexual selection because previous researchers have assumed, implicitly or explicitly, that sexual behaviour is genetically fixed. To understand the role of learning in sexual selection, it is important to investigate how early experience interacts with adult experience to determine the use of different mating strategies. We explored this interaction by comparing the sexual behaviour of male guppies, Poecilia reticulata, raised in different social environments before and after they gained sexual experience. Males raised with other males performed long courtship displays at first, but decreased their courtship after they had gained sexual experience. However, for males raised only with females, sexual experience did not modify courtship duration. Males raised exclusively with females exhibited high rates of forced copulation attempts in their first encounter with a female, but reduced this behaviour after sexual experience. In contrast, males raised with other males did not modify their forced copulations. Adult sexual experience appeared to mitigate the behavioural differences caused by variation in rearing environment. Sexual experience helps males to find an optimal balance between courtship displays and forced copulation attempts. We also show that more males exhibited male–male aggression after sexual experience if they had social interactions with other males early in life. This study highlights that courtship and other sexual strategies are not fixed, and that several potential sources of variation exist in the development of an animalʹs sexual behaviour. Importantly, juvenile and adult experiences can interact to shape sexual behaviour in males.