Primary sex allocation in Trichogramma (Hymenoptera: Trichogrammatidae) and effects of sperm on oviosition behavior

Abstract

The oviposition behaviors of Trichogramma nubilale Ertle & Davis and T. ostriniae Pang & Chen were characterized and compared with thoae of T. chilonis Ishii and T. embryophagum Hartig. The effects of the lack of sperm on oviposition behaviors and on the sex of progeny produced also were examined for both species. Oviposition behaviour of all 4 species are similar, and there is complete correspondence between observed behaviour and the sex of progeny to emerge in mated T. nubilale and T. ostriniae. In females that lack sperm, there is no correspondence between the behavior of either species production of females. These female behave as though they could fertilize their eggs, but they produce all males. The progeny sex determination behavior of Trichogramma species appears to have a fixed expression. Sperm limitations in males may limit their reproductive success both in the laboratory coloay and the field. The reproductive success of sperm-limited females may be limited in the field because females may not find males, and the sons that they produce may not find females.