Bivoltinism as an Antecedent to Eusociality in the Paper Wasp Genus Polistes.

To learn the evolutionary trajectories of caste differentiation ineusocial species is a major goal of sociobiology. We present anexplanatory framework for caste evolution in the eusocial wasp genusPolistes (Vespidae), which is a model system for insect eusocialevolution. We hypothesize that Polistes worker and gyne castes stem fromtwo developmental pathways that characterized the bivoltine life cycleof a solitary ancestor. Through individual-based simulations, we showthat our mechanistic framework can reproduce colony-levelcharacteristics of Polistes and, thereby, that social castes can emergefrom solitary regulatory pathways. Our explanatory frameworkillustrates, by specific example, a changed perspective forunderstanding insect social evolution. [ABSTRACT FROM AUTHOR]