Badges of status in worker and gyne Polistes dominulus wasps

Despite widespread interest in quality signals, a broad understanding of quality that incorporates information about signals used in a variety of contexts remains elusive. For example, relatively little is known about arbitrary signals of quality used during aggressive competition (badges of status). Recently, a new badge of status was found: black facial patterns in Polistes dominulus wasps. Previous work on P. dominulus facial patterns focused on queens, finding that facial patterns predict body size and social dominance. Here, I examine worker facial patterns for the first time. Worker facial patterns provide an interesting comparison with queens and help shed light on two unresolved issues: (1) Is there pre-imaginal caste bias in these primitively eusocial insects? (2) Is badge-of-status elaboration influenced by developmental environment? I show that worker and gyne (future queen) facial patterns are correlated with body size. Larger individuals have a larger proportion of their clypeus pigmented black, corroborating the relationship between body size and facial pattern found previously in queens. Independent of the size relationship, workers and gynes have different facial patterns. Gynes have the disrupted, black facial patterns that signal a high level of quality, while workers have yellow facial patterns associated with a low level of quality. The differences between worker and gyne facial patterns suggest that there is some pre-imaginal caste bias in these eusocial wasps. Workers and gynes are genetically similar but experience different developmental environments, so the differences between worker and gyne facial patterns suggests that badge development is influenced by environmental factors.