Worker biting interactions and task performance in a swarm-founding eusocial wasp (Polybia occidentalis, Hymenoptera: Vespidae)

Workers in many insect societies interact via body contact with their nest mates, and social biting and other forms of contact may play a general role in regulating task performance. Here I present evidence that social biting affects task performance without direct reproductive conflict in Polybia occidentalis, a swarm-founding eusocial wasp. Polybia occidentalis workers engaged in social biting with nest mates. Most workers that were active on the nest surface participated in biting interactions, but individuals differed significantly in their rates of biting and of being bitten. Rates of being bitten corresponded with nonrepro-ductive task performance: more biting was directed at foragers than nonforagers, and foraging rates were correlated with rates of being bitten. Furthermore, some on-nest workers initiated foraging activity immediately after they were bitten. Together these patterns suggest that social biting influences foraging rates by increasing workers ’ probabilities of leaving the nest. Variation in biting rates did not correspond with differences in reproductive physiology: highly active biters and recipients did not differ in body size or in ovary development. In P. occidentalis and in other eusocial insects with large worker forces, biting and other types of social contact among workers may regulate task performance independently of direct reproductive competition. Key words: body size, foraging, ovary development, polyethism, reproductive conflict, social organization. [Behav Ecol 12:353–359 (2001)] Division of nonreproductive tasks among workers, or po-lyethism, is a key adaptation promoting the evolutionary and ecological success of eusocial insects (Wilson, 1990). A