Facial color diversity of Polistes paper wasps

Polistes paper wasps (Hymenoptera: Vespidae) are species-rich group of social insects. Researchers have noted a wide diversity in facial color patterns among species, and for several Polistes species, intraspecific variation in facial color patterns has been linked to signals of quality or individual identity. However, there have been no systematic descriptions of facial color pattern variation across the Polistes genera, limiting our understanding of the frequency of facial color patterns, how unique patterns are among species, and the degree of variation in facial color patterns within species. We photographed pinned museum specimens under visible and ultraviolet (UV) light. When few specimens were available, we included additional photos from iNaturalist, a database of citizen scientist images, resulting in a final dataset of 1,675 images from 131 species. For each species, we provide an image of a representative female face, as well as information on intraspecific variation in female facial color patterns, and sexual dimorphism of facial color patterns, when available. Facial color patterns were common across species and were composed of a mixture of yellow, red-brown, and black pigments. Patterns were similar in visible and UV images. Spectral sensitivity curves for yellow, red-brown, and black pigmented regions have a similar shape for all Polistes species measured. Males frequently had yellow faces, and yellow male faces were correlated with sexual dimorphism. Intraspecific variation in female faces was common. Descriptions of facial color variation in Polistes will be vital to study the mechanisms driving interspecific and intraspecific diversity.