CONTEXT-DEPENDENT NESTMATE-DISCRIMINATION IN THE PAPER WASP, POLISTES-DOMINULUS - A CRITICAL TEST OF THE OPTIMAL ACCEPTANCE THRESHOLD-MODEL

We present evidence that nestmate discrimination in the eusocial paper wasp, Polistes dominulus, is context dependent. We compared aggressio n levels between nestmates and non-nestnates in dyads consisting of a pair of either nestmates or non-nestmates, and triads consisting of ei ther three nestmates, three non-nestmates, or two nestmates and a non- nestmate. In 130 of the 237 total trials, a nest fragment (containing both brood and eggs) from the nest of some, all or none of the interac tants was placed into the interaction arena. Polistes dominulus worker s recognized and discriminated nestmates from non-nestmates, familiar from unfamiliar nest material and neighbours from non-neighbours. Thes e findings suggest that nestmate and neighbour discrimination are cont ext dependent: discrimination occurs when either the presence of a nes tmate pi a familiar nest fragment indicate the proximity of the colony . The context-dependent variation in aggression levels is best describ ed by multiple, context-dependent shifts in an acceptance threshold. T hus this Study provides the most extensive, critical support yet obtai ned for Reeve's (1989, American Naturalist, 133, 407-435) optimal acce ptance threshold model. (C) 1998 The Association for the Study of Anim al Behaviour.