Sex differences in face but not colour learning in Polistes fuscatus paper wasps

When males and females have distinct behaviour, learning may vary between the sexes. Polistes fuscatus wasps provide an interesting model to study sex differences in learning because males and females have different social behaviour. Female wasps have highly variable facial patterns used for individual face recognition, live in cooperative groups where interactions depend on individual face recognition and excel at learning female faces. In contrast, male wasps lack the type of variable facial patterns necessary for individual face recognition and do not participate in the type of social interactions known to favour individual recognition in females. Instead, males leave the nest soon after adulthood and devote their energy to mating. Given the behavioural differences between males and females, females may be more adept at learning wasp faces than males. Here, we train male and female P. fuscatus to discriminate between pairs of female P. fuscatus face images and pairs of colours. Females learned to discriminate between pairs of face images more accurately than males. However, males and females were equally adept at colour learning, indicating that there are no generalized sex differences in learning. The sex differences in face, but not colour, learning are consistent with the adaptive specialization hypothesis, which posits that cognitive abilities are selected to solve particular social or ecological problems. Overall, general learning capacity is similar across male and female wasps, but face learning is shaped by sex-specific recognition behaviour.