抄録
A study was conducted to determine the most effective conditions for enhancing the learned response by Ascogaster reticulatus Watanabe, an egg-larval parasitoid of the smaller tea tortrix, Adoxophyes sp. (Lepidoptera : Tortricidae). Female parasitoids were found to learn tea leaf extract with the host egg mass and walk along an extract-treated line. We compared the learned response of females with zero to five oviposition experiences as well as females with various lengths of oviposition time (from contact with host to different lengths of oviposition). Furthermore, we investigated the effect of the length of intervals between experiences on the learned response of females. The learned response of females tended to increase with the number of conditionings (1-3 times) and the oviposition time during conditioning (0-120 s×3). However, responses were low after a single conditioning regardless of oviposition time. The length of the intervals between conditionings (5-120 min) did not affect the learned response of females. It is suggested that learned response through experience is essentially a gradual process in which the number of experiences and the oviposition time during conditioning are major elements.
