SOURCE OF SEX-PHEROMONE OF THE EGG-LARVAL PARASITOID, ASCOGASTER-RETICULATUS WATANABE (HYMENOPTERA, BRACONIDAE)

A sex pheromone of Ascogaster reticulatus Watanabe (Hymenoptera: Braco nidae), identified as (Z)-9-hexadecenal, elicits males' antennal mate- searching behavior. In order to localize the source of sex pheromone p roduction, each body part was separated and extracted with hexane and then subjected to 9-cm Petri dish bioassay. The highest activity was f ound in thorax extract. Among legs, wings, and thorax, legs have the h ighest activity. Among fore, middle, and hind legs, hind legs have the highest activity. Among coxa and trochanter, femur, tibia, and tarsus , tibia has the highest activity. From these results, the presence of a tibial sex pheromone gland was suggested.