Abstract: 【Aim】 This study aims to clarify the electroantennographic and olfactory responses of female wasps of the eulophid Aprostocetus prolixus to volatiles of Morus alba branches induced by jasmonic acid (JA), so as to reveal the chemical mechanisms of indirect resistance in M. alba branches against Apriona germari. 【Methods】 The volatiles from M. alba branches treated with JA were collected by using the dynamic headspace volatile collection method. The electroantennographically active compounds for female wasps of A. prolixus were screened and indentified by coupled gas chromatography-electroantennographic detector (GC-EAD) and GC/MS, respectively, and the differences in emission rates of the EAD-active components between the JAtreated M. alba branches and the water-treated control branches were also compared. Furthermore, the volatile compounds attractive to female A. prolixus were determined by Y-tube olfactometer. 【Results】 The results demonstrated that Z-3-hexenol, β-terpinene, β-phallandrene, perillene, methyl salicylate and other three unknown chemicals from M. alba branches treated with JA elicited significant GC-EAD responses in female wasps of A. prolixus. The emission rates of β-phallandrene, perillene and methyl salicylate from the JA-treated M. alba branches were significantly higher than those from the control branches. Furthermore, β-phallandrene and perillene were detected only in the volatiles of the JA-treated plants. However, there was no significant difference in the emission rate of Z-3-hexenol between the JA-treated plants and the control plants. And 0.1% β-phallandrene, 0.1% perillene and 0.01% and 0.001% methyl salicylate were significantly attractive to female wasps of A. prolixus. 【Conclusion】 The results suggest that highly elevated emission of β-phallandrene, perillene and methyl salicylate from the JA-treated M. alba branches is one of the important mechanisms of the JA-induced indirect resistance in M. alba tree against A. germari.    

Key words: Aprostocetus prolixus, Morus alba, exogenous jasmomic acid, volatiles, electroantennographic response, olfactory response