Spotting the top male: sexually selected signals in male Polistes dominulus wasps

Although sexually selected ornaments are common across diverse taxa, little is known about mate choice and sexually selected ornamentation in social insects. Polistes dominulus paper wasps are a good system to study sexual selection, as males have a lek-based mating system as well as sexually dimorphic abdominal spots. Here, we demonstrate that the abdominal spots of male P. dominulus paper wasps function as signals in both inter- and intrasexual selection. Males with smaller, elliptically shaped spots were more dominant over male rivals and were more preferred by females than males with larger, irregularly shaped spots. Furthermore, experimental manipulation of male spots demonstrates that spot morphology acts as a signal. Males with experimentally reduced abdominal spots won a greater proportion of fights and were preferred by females as mates over control males. These results demonstrate that male ornaments are an important mediator of mating dynamics in P. dominulus paper wasps. They also highlight the importance of additional research examining sexually selected ornamentation in social insects.