Behaviour 2019
Color is necessary for specialized face discrimination in the paper wasp, Polistes fuscatus
Christopher M. Jernigan, Jay A. Stafstrom, Natalie C. Zaba, Michael J. Sheehan. Cornell University, Ithaca, NY, United States

Many animals must discriminate among conspecifics to survive and reproduce. However, we are often uncertain which specific traits animals use to facilitate this discrimination. Northern paper wasp females, Polistes fuscatus, possess variably colored facial patterns previously shown to be important in individual recognition. Yet it remains unclear what features of these facial patterns are most important regarding conspecific discrimination (i.e. color, shape, or a combination of both). Our recent neuroanatomical data suggest that color may play an integral role in this behavior. Thus, we set out to behaviorally test whether color is a critical component of facial discrimination. We used an operant conditioning paradigm to test if wasps could learn to discriminate grayscale photographs of P. fuscatus faces equivalently to color versions of the same faces. We found wasps performed significantly better when discriminating between color faces compared to grayscale versions, and wasps trained on grayscale faces did not perform better than chance. This suggests that color is necessary for the specialized face recognition abilities in this species.