Abstract: 【Aim】 This study aims to explore the effects of volatiles from Morus alba branches treated with jasmonic acid (JA) on the behaviors of Aprostocetus prolixus, and to investigate the dynamic changes of the volatiles, so as to provide the theoretical basis for clarifying the mechanism of JA-induced indirect resistance to insects in M. alba. 【Methods】 In this study, the olfactometer was employed to investigate the attractiveness of M. alba branches to A. prolixus at 24, 48 and 72 h post treatment with different JA concentrations. The dynamic changes of chemical components of volatiles from M. alba branches treated with 1 000 μmol/L JA were analyzed by GC-MS at different time points. 【Results】 The results demonstrated  that M. alba branches had no significant attractiveness to A. prolixus at any time point when treated with 10 μmol/L JA. Treated with 100 μmol/L JA, M. alba branches displayed significant attractiveness to A. prolixus only at 48 h post treatment. However, the attractiveness of volatiles from M. alba branches to A. prolixus was significantly higher than that of the control at 24 h (P<0.05) and 48 h (P<0.01) post treatment with 1 000 μmol/L JA. At 72 h post treatment, the attractiveness gradually disappeared. Spearman’s correlation analysis revealed a significantly positive correlation between JA concentration and the attractiveness of branches to A. prolixus (ρ=0.791, P=0.006). Identified by GC-MS, the volatiles of M. alba branches treated with 1 000 μmol/L JA consisted of alcohols, easters, terpenoids, aromatic compounds and nitrogenous compounds. Among them, the terpenoids were predominant and contained 13 components. It was also found that the components and the total emission rate of volatiles altered with extension of the duration of jasmonic acid treatment. At 24 h post treatment, 18 chemical components were emitted from the treated M. alba branches (with 11 more components than those of the control), and their total emission rate was 8.2-fold as high as that of the control. The M. alba branches emitted 22 chemical components at 48 h post treatment (with 15 more components than those of the control), and the total emission rate of these components was 44.6-fold as high as that of the control. At 72 h post treatment, 13 chemical components, six more than those of the control, were detected from the treated M. alba branches, and their total emission rate sharply decreased (3.9-fold as high as that of the control) but was not significantly different from that of the control. 【Conclusion】 The attractiveness of M. alba branches to A. prolixus gradually enhances with the increase of JA concentration. JA can induce the synthesis of volatile chemical components and great emission of volatiles in M. alba branches.

Key words: Aprostocetus prolixus, Morus alba, jasmonic acid, attractiveness, volatiles, temporal change