Abstract: By using a Y-tube olfactometer, this paper studied the selection behavior’s responses of Anastatus japonicus to the volatiles and their individual components emitted from isolated leaves and live plants of different litchi varieties, and to Tessaratoma papillosa. The results showed that among the test litchi varieties, Sanyuehong and Huaizhi had more significant attracting effects to A. japonicus than Nuomici, Guiwei, Feizixiao and Heiye. The two main components of the volatiles from litchi leaves, α-humulene and β-caryophyllene, had no distinct attraction to A. japonicus, but displayed synergistic effect on the host-searching process of natural enemy. When the two components were mixed in equal concentration of 0.3 μl·μl^-1, the attracting effect was most remarkable. In a dual-choice experiment, the selectivity of A. japonicus to T. papillosa eggs was not significant, but very remarkable to T. papillosa female adults and to the water extracts from adult abdomen-tip. In a vessel experiment, the numbers of A. japonicus which made selection to T. papillosa eggs and the settling frequency of A. japonicus on the place of T. papillosa eggs were more than those of other treatments. (E)-2-hexenal, one of the most important components of the volatiles of T. papillosa adult, didn’t have evident attracting effect on the adults of A. japonicus.

Key words: soil microbial biomass, rhizosphere effect., alpine scrub, warming