The dominance hierarchy in primitively eusocial insect societies has been shown to be mainly regulated through aggressive interactions. Females that are generally more dominant stand out and occupy the queen position, meaning that they monopolize reproduction while others perform other tasks. Chemical communication is important for maintaining social cohesion. Cuticular hydrocarbons are recognized as the main molecules responsible for mediating social interactions, especially nestmate recognition and queen signalling. Many highly eusocial groups have been studied in recent years, but primitively eusocial groups, which are key to understanding the evolution of social behavior, remain unexplored. In this study, we investigated the connection between cuticular hydrocarbons in females expressed in different social contexts in the primitively eusocial wasp Mischocyttarus cerberus. Colonies in two different ontogenetic phases, pre- and post-worker emergence, were used. We observed and categorized behavioral interactions between individual females and collected all individuals in a nest to obtain information on size, ovary activation and chemical composition. Furthermore, we conducted experiments in which the alpha (dominant) females were removed from nests to produce a new dominance hierarchy. We found that females in different hierarchical positions had small chemical difference corresponding with ovary activity. Our results support the hypothesis that cuticular hydrocarbons are associated with social context in this primitively eusocial species, with some compounds being associated with hierarchical position and ovarian activity.
Keywords: Chemical communication; Cuticular compounds; Fertility cues; Mischocyttarus wasps; Queen replacement.