Individual recognition and individual identity signals in Polistes fuscatus wasps vary geographically

Abstract

Geographical variation in animal phenotypes is common, yet we know surprisingly little about how recognition varies across populations. Instead, much recognition research focuses on one or a few populations and assumes recognition behaviour is consistent across a species' range. Here, we show that individual identity signals and individual recognition vary across the geographical range of Polistes fuscatus wasps. Polistes fuscatus in Michigan and New York, U.S.A., have variable facial patterns that signal individual identity and are used by receivers for individual recognition. However, P. fuscatus from Rothrock, Pennsylvania, U.S.A., lack individual identity signals, as they have less variable facial patterns than P. fuscatus from Michigan. Furthermore, P. fuscatus from Pennsylvania are not capable of individual recognition. Pennsylvania P. fuscatus do not learn and remember individual conspecifics during social interactions or during training. The Michigan and Pennsylvania populations are genetically differentiated, but the differentiation is driven by geographical distance, not adaptive differentiation based on recognition differences. Overall, both signals and receiver responses vary across populations of P. fuscatus . Our results suggest that recognition systems may rapidly evolve to produce variation in signals and receiver responses across a species’ geographical range.