Social contracts in wasp societies

Abstract

THE stability of social groups requires that conflicts among group members somehow be resolved. Recent models predict that sub-ordinates may be allowed limited reproduction by dominant colony-mates as an inducement to stay and aid dominants^1– For such 'social contracts' to be evolutionarily stable, attempted reproductive cheating by dominants must be punishable³. In the eusocial paper wasp, Polistes fuscatus, subordinate queens that co-found nests with dominant queens usually disappear after the first workers emerge, so subordinates lay most of their reproductive-destined eggs just before worker emergence. Thus subordinates should be very sensitive to reproductive cheating during the latter period but relatively insensitive when worker-destined eggs are laid. Here we find in a series of egg-removal experiments designed to mimic egg-eating that subordinates do not change their aggressiveness when worker-destined eggs are removed, but that they greatly increase their aggression when reproductive-destined eggs are removed, especially when the queens are of similar size.