COURTSHIP FEEDING AND MATE CHOICE IN THYNNINE WASPS (HYMENOPTERA, TIPHIIDAE)

Females of two species of thynnine wasps, Megalothynnus klugii and Macrothynnus sp., attract mates while perched upright on vegetation close to the ground. When given an experimental choice between two females of different sizes, males of M. mlugii carry off the copulate with the larger female significantly more often than they do the smaller one. No such preference was exhibited by males of Macrothynnus sp. Females of both species resist being removed from their calling perches and large males succeed more often than small ones in carrying away very large females. Despite mechanisms allowing a preference for large partners by both males and females in M. klugii, there is no evidence, in nature, of positive assortative mating according to body weight in this species. Various conditions, especially a scarcity of ferilisable females, may severely limit the choice of mates by males of these wasps.