No sensitive period for the development of individual face learning in wasps.

Social isolation often has lasting negative effects on social behavior, but less research has tested how the timing of isolation influences its effects. Some behaviors have a sensitive period where experience has particularly strong effects, while other behaviors are more flexible. Here, we test how the timing of social experience influences the development of individual face learning in wasps. Individual face recognition is a key aspect of communication in wasps, so wasps reared in a typical environment are adept at individual face learning. We reared wasps in 5 treatments that differed in the timing and amount of social experience: 14 days isolation, 14 days nest, 7 days nest, 7 days nest then 7 days isolation, and 7 days isolation then 7 days nest. Then, we tested individual face learning. Experience with conspecifics improved individual face learning, but the timing of experience did not impact performance. Wasps reared in normal social environments were adept at learning and remembering faces, while isolated wasps were unable to learn and remember faces. Early isolation did not have a stronger effect than later isolation, indicating that there is no early sensitive period for face learning in paper wasps. Instead, paper wasps exhibit a high level of plasticity in the development of individual face learning. Overall, this work emphasizes the role of plasticity in the development of complex social recognition and offers insight into the conditions where evolution favors high plasticity over rigid sensitive periods in development.