Post-copulatory grooming: a conditional mating strategy?

Animals of diverse taxa show different conditional mating strategies: they adjust their behaviour according to social and environmental situations, which may bring diverse (fitness) advantages for an individual. Especially in primates, mating is often associated with other social behaviours, such as grooming. Here, we study Barbary macaque post-copulatory grooming: we investigate for the first time whether males and females modify their grooming initiations after mating depending to the type of copulation (i.e. with or without ejaculation) and female lactation state. Our results show that males and females adjust grooming initiations conditional on copulation type, with males initiating grooming after copulations with ejaculation and females after non-ejaculatory mating. Moreover, lactating females tend to start grooming the males they just mated with more than vice versa, whereas there is no such a difference for grooming initiations after copulations with non-lactating females. These data indicate that Barbary macaques show post-mating grooming strategies that vary depending on the type of copulation that occurred and in dependence of female reproductive state. These grooming initiation patterns may reflect sex-specific mating interests and potentially serve to increase fitness: females, in particular lactating females, may benefit from initiating grooming to secure protection for themselves and their offspring and reduce harassment. Males may profit from grooming females after ejaculatory copulation by keeping them from mating with another male and thus potentially decreasing sperm competition.