The disappearance of subordinate foundresses in paper wasps: eviction by nestmates or reproductive strategy?

Videotaped observations (371.3 h) were conducted in 1995, 1996, and 1997 on 50 multiple-foundress colonies of the social wasp Polistes fuscatus. Obser vations were made during the mid-preworker, late-preworker, and early-postw orker stages of the colony cycle. The vast majority of lost subordinate cof oundresses (62 of 77) disappeared during the time interval from 2 weeks bef ore to 4 weeks after the emergence of the first workers. The loss of subord inates did not appear to be the result of senescence or foraging-related mo rtality. Lost subordinates were from productive and presumably healthy colo nies. In colonies containing two or more subordinates, lost subordinates ha d significantly greater dominance ranks than expected. There was no behavio ural evidence that lost subordinates were evicted from their colony by quee ns, other subordinate foundresses, or workers. Lost subordinates were not o bserved to renest, join sister colonies, or adopt orphaned nests. Our resul ts indicate that lost subordinates leave colonies of their own volition. In direct evidence from other studies suggests that subordinates may disperse and usurp colonies from other sites.