SOCIAL CONTRACTS IN WASP SOCIETIES

THE stability of social groups requires that conflicts among group members somehow be resolved. Recent models predict that subordinates may be allowed limited reproduction by dominant colonymates as an inducement to stay and aid dominants1-3. 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.