Effect of Mated Condition on Dominance Interactions and Nesting Behavior in the Social Wasp, Polistes fuscatus (Hymenoptera: Vespidae)

Abstract

The reproductive division of labor of eusocial insect societies creates a conflict of interest among the individuals in a colony. Dominant individuals gain the greatest direct fitness benefit as the primary or sole egglayers for the colony. Physical and chemical defense of her reproductive prerogative and differential oophagy of subordinate laid eggs enable a queen to police her subordinates and suppress the subordinates' ovarian development (Pardi, 1948; Gervet, 1964; West-Eberhard, 1969; Reeve, 1991). Overt aggression among colony members is particularly apparent in the societies of primitively eusocial Hymenoptera such as Polistes (Vespidae), Mischocyttarus (Vespidae), and Bombus (Apidae), among others (Pardi, 1948; West-Eberhard, 1969; Dropkin and Gamboa, 1981; Reeve, 1991; Gadagkar, 1991). Subordinates gain indirect reproductive benefit by helping raise related offspring, but may also maximize their overall fitness by secretly laying eggs, manipulating offspring sex ratios, policing the egg-laying of other workers, or attempting to usurp the nest (West-Eberhard, 1969; Reeve and Nonacs, 1992; Goodnight et al., 1996; Ratnieks and Boomsma, 1997; Monnin and Ratnieks, 2001; Foster et al., 2002). In some cases females are not mated and can only lay male destined eggs (Suzuki, 1981, 1993; Ito and Yamane, 1985; Page et al, 1989; pers. obs.). Joiners derive a reduced indirect fitness benefit if the dominant cofoundress is unmated and can only produce male offspring. Bumble bee workers confined with unmated reproductive females had increased levels of juvenile hormone in their blood and exhibited overt aggression toward the unmated bee (Bloch et al., 1996). That the mated status of a female is detectable either by chemical cues or behavioral cues (or both) is supported by this bumble bee study and others showing differing levels of aggression toward mated and unmated females in social insect colonies (Bloch et al, 1996; Gobin et al, 1999; Piatt et al, 2004). One would predict that during the early stages of nest establishment the mated condition of competing wasps or bees would be an important factor in the establishment of dominance and in whether or not a female will be joined. In this study, I set out to establish the effects of mated status in Polistes fuscatus (Fab.) on 1) dominance interactions and behavior, 2) nest related behavior, and 3) reproductive development.