Host Moth Scales; a Cue for Host Location for Ascogaster Reticulatus Watanabe (Hymenoptera: Braconidae)

Abstract

Ascogaster reticulatus WATANABE (Hymenoptera: Braconidae) is an egg-larval parasitoid of the smaller tea tortrix Adoxophyes sp. (Lepidoptera: Tortricidae). Host finding behavior of A. reticulatus was observed and the role of host wing scales analyzed. Female parasitoids released on tea twigs in a container tended to search more actively on the leaves on which host moths had stayed overnight than on control leaves. A. reticulatus females responded with antennal searching to the leaves which were closer to the oviposition site of the host. Higher searching activity was found on leaves with moth scales. Female parasitoids released in an arena (20 cm dia., 5 cm ht.) changed their behavior from straight to meandering walk after contact with an area treated with female wing scales, wing extract, or egg-mass extract, Parasitoids could locate a host egg mass placed in the center of the treated areas more efficiently than one in an area without treatment, although more time was required. Female parasitoids may use kairomones from host moth scales scattered around the oviposition site as a cue to find host egg masses. © 1990, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.