Searching Behavior and Oviposition of the Egg-Larval Parasitoid, Ascogaster reticulatus WATANABE (Hymenoptera : Braconidae)

Abstract

Host-searching behavior of the egg-larval parasitoid, Ascogaster reticulatus WATANABE (Braconidae), was observed in the field and in the laboratory. There was no difference in behavioral patterns between the sexes, but females tended to stay longer in the observation area than males. Host-searching behavior of females was observed on and around the egg mass of the smaller tea tortrix (STT) moth, Adoxophyes sp. In addition to the egg mass, scales of the STT moth and its excretion seemed to be responsible for this activity and may be a cue for the female wasp to find the host. Female A. reticulatus showed a high fecundity on the 1st day of her emergence, and laid more than 700 eggs in total. Without host, the female wasp showed the largest fecundity on the 3rd day of her emergence. A one-day-old host egg mass was most attractive and a 6-day-old one, just before hatching, was least attractive for the wasp. The ability of the female wasp to discriminate between parasitized and unparasitized egg masses was suggested by the difference in the duration of oviposition behavior on these egg masses.