Conflict over sex ratio and male production in paper wasps

Kin selection theory has been used to generate several useful frameworks in the field of evolutionary ecology. We briefly review the research on two main theoretical predictions for sex ratio variation among colonies, and for worker policing, using a relatedness framework in paper wasps. Contrary to the studies of advanced eusocial wasps, conclusive evidence showing worker control of sex ratio has not been shown in primitively eusocial Polistes, which suggests that collective worker control is not active at the primitively eusocial stage when colony size is small. Worker control of colony investment might be facilitated in an advanced eusocial system when colony size is large. Therefore, a relatedness-based theoretical framework does not seem to be important in explaining the sex ratio variation among colonies of Polistes wasps. Worker policing, however, has been observed in monogynous and monandrous colonies of Polistes and Dolichovespula, in which relatedness benefits for workers do not exist. The observed policing behavior seems to be termed as ‘selfish policing’. Fertility signals and egg marking pheromones by queens are the likely proximate factors that determine the fate of workers’ eggs. We also discuss the influence dominance order among workers may play in regulating worker reproduction. This is a form of decentralized regulation, which may be associated with larger colony size.