OPPORTUNISTIC ADOPTION OF ORPHANED NESTS IN PAPER WASPS AS AN ALTERNATIVE REPRODUCTIVE STRATEGY

Adoption of abandoned or orphaned nests by adult females occurs commonly during the colony-founding period of the primitively eusocial paper wasp, Polistes dominulus. Our evidence indicates that adoption reflects: (1) 'making the best of a bad situation,' for queens who have lost their nests; (2) subordinates leaving multiple-foundress associations; and (3) possibly, a 'sit-and-wait' strategy, in which non-nesting females wait for nests to be orphaned. A 'sit-and-wait strategy' implies that wasps facultatively delay personal reproduction rather than that the delay in reproduction is due to physiological constraints (sensu Gadagkar, 1991 a). Orphaned nests with related brood are not more attractive than those bearing unrelated brood, suggesting that nest-adoption has not evolved primarily as a strategy to rescue non-descendant kin. Instead, all wasps tend to adopt nests that theoretically maximize their selfish genetic interests: the most attractive nests were large combs at an advanced stage of development. These nests can produce more workers and are closer to worker emergence, at which time colony survival per unit time dramatically rises. The primary proximate cue for adoption seems to be whether nests contain later-instar larvae or pupae. Since developmental stage of brood correlates with nest size, preferred nests thus tend to be relatively mature and large.