Geographic differences in individual recognition linked with social but not nonsocial cognition.

Cognition is a complex trait with multiple components that may vary independently or in concert. Thus far, we know little about how geographic differences in behavior are linked with different aspects of cognition. Behavioral differences could be linked with cognition in three ways: with multiple aspects of cognition, some but not other aspects of cognition, or no cognitive differences. Here, we compare cognitive performance in two populations of wasps that differ in their capacity for individual face recognition. Individual recognition involves keeping track of multiple individual relationships and responding appropriately, so it is thought to increase social complexity. As a result, we predicted Michigan wasps that use individual recognition may have better cognitive performance than Pennsylvania wasps that are not able to individually recognize conspecifics. We find that Michigan wasps are more adept at individual face learning than Pennsylvania wasps. However, the populations perform similarly on other cognitive tasks, including color learning and memory, reversal learning, and odor learning and memory. Therefore, population differences in social behavior affect individual face learning, but are not linked with generalized differences in cognition. These findings suggest that socially complex societies may influence the evolution of social cognition specifically.