关键词: 茶尺蠖绒茧蜂, 茶梢, 植物挥发物, 触角电位, 行为反应, 互利素, 信息素, 诱集效应

Abstract: In order to screen the infochemicals and their combinations, which effectively attract the important natural enemies Apanteles sp. parasitizing the larvae of tea geometrids Ectropis obliqu Prout, 27 representative volatile compounds from the intact tea shoots and tea shoots damaged by tea geometrids, tea green leafhoppers Empoasca vitis Gothe and tea aphids Toxoptera aurantii Boyer were chosen and prepared into liquid paraffin solution at the dosage of 10 ^-2 g/mL, respectively. The equivalent E-2-hexenal, Z-3-hexen-1-ol and linalool paraffin solution were prepared into blend 1, and the equivalent E-2-hexenal, Z-3-hexen-1-ol, 2-penten-1-ol, E-2-pentenal, Z-3-hexenyl acetate, n-pentanol, n-hexanol and 1-penten-3-ol paraffin solution into blend 2. The female parasitic wasps of 1-2 d old were used as the test insects. The results of electroantennogram (EAG) responses showed that the difference among EAG values from these odor resources reached the significant level of P<0.05. The fatty acid derivatives elicited the strongest antennal-electrophysiological responses, the next were aromatics and isothiocyanate, and the third sesquiterpenes and monoterpenes. The single component eliciting stronger responses were Z-3-hexenyl acetate, E-2-hexenal, methyl salicylate, E-2-pentenal, acetophenone, phenethyl alcohol, benzyl alcohol, benzaldehyde and methyl jasmonate; the single components eliciting weaker responses were 1-penten-3-ol, 2-penten-1-ol, Z-3-hexen-1-ol, geraniol, ocimene, α-terpinen, (+)-cedrol, (+)-3-caren, α-humulen, and β-ionone; the single component eliciting the least responses was Z-jasmone. The blend 1 elicited the highest EAG value, while the blend 2 elicited the low EAG value. Eight odor resources eliciting higher EAG values, including methyl salicylate, E-2-hexenal and blend 1, were selected and used in behaviour assay by Y-shaped olfactometer. The results accorded with those of EAG responses on the whole. So methyl salicylate and E-2-hexenal were again selected, and methyl salicylate solution at the dosage of 10^-3, 10^-2 and 10^-1 g / mL, as well as the blend of methyl salicylate plus E-2-hexenal at the dosage of 10^-2 g / mL were prepared with hexane as solvent. These solutions were loaded onto the lures, which exhibited the intense attraction to Apanteles sp. and other braconids with the dosage gradient effect in the tested tea gardens in Zhejiang, Yunnan, Fujian and Guangdong Province. It is so concluded that the synomones from the tea shoots induced by pests damaging can elicit the strong EAG responses and taxis of Apanteles sp., and the appropriate combinations of synomone plus synomone or common plant volatiles can effectively attract the wasps.

Key words: Apanteles sp., tea shoots, plant volatiles, electroantennogram (EAG), behavioural response, synomone, infochemicals, attraction effect