[Behavior response of four Leis axyridis varieties to volatiles from tea and Toxoptera aurantii].

The behavior response of the adults of four Leis axyridis varieties to kairomone from Taxoptera aurantii was determined by Y-shape olfaction instrument. The results showed that when supplied with two-two-combinations of Taxoptera aurantii, Brevicoryne brassicae and Lipaphis erysimi, tea aphids plus aphid-damaged vs. normal shoots, and aphid-damaged vs. normal shoots, Leis axyridis had a preference for tea aphids, tea aphids plus aphid-damaged tea shoots, or aphid-damaged tea shoots. There existed a Logistic curve relationship(P < 0.01) between odor source tendency rate of Leis axyridis and odor source quality, when 8-9 kinds of odor gradients including tea aphids plus aphid-damaged tea shoots, aphid-damaged tea shoots and tea aphids were used as odor sources. The tendency rates of Leis axyridis ab. bimaculata, Leis axyridis ab. conspicua and Leis axyridis var. novemdecimpunctata showed single left-tilting peak curves to the aphid number(P < 0.01). Ether and n-hexane ringes of Toxoptera aurantii body surface also showed an attraction to all varieties. Leis axyridis var. spectabilis was the most sensitive variety.