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Herbivore-induced plant volatiles enhance field-level parasitism of the mirid bug Apolygus lucorum

Authors Xiu, Chunli; Dai, Weijian; Pan, Hongsheng; Zhang, Wei; Luo, Shuping; Wyckhuys, Kris A. G.; Yang, Yizhong; Lu, Yanhui

Journal BIOLOGICAL CONTROL , AUG 2019,:135

DOI 10.1016/j.biocontrol.2019.05.004

Abstract In China, the braconid wasp Peristenus spretus Chen & van Achterberg (Hymenoptera: Braconidae) is a native endoparasitoid of the mirid bug Apolygus lucorum (Meyer-Mir) (Hemiptera: Miridae). Castor bean (Ricinus communis L.) is a preferred host plant of A. lucorum, and P. spretus adults are attracted to its herbivore-damaged flowering plants. Here, we used headspace collection to sample the volatiles emitted by A. lucorum-damaged flowering R. communis plants, and employed gas chromatography-electroantennography (GC-EAD) to identify two electrophysiologically-active compounds. Active compounds were identified as m-cymene and 4''-ethylacetophenone. Electrophysiological activities were confirmed by EAG, with a gradient of five doses of each compound eliciting significant antennal responses. Next, in Y-tube olfactometer bioassays, female P. spretus were attracted to two synthetic volatile compounds at two different concentrations (10 mg/ml and 100 mg/ml). Under field conditions, A. lucorum parasitism rates - as recorded in volatile-baited barrel traps - for the two compounds were significantly higher than those for mineral oil (control). Our findings emphasize the important role of herbivore-induced plant volatiles in the P. spretus host selection process, and provide a potential way to enhance in-field parasitoid populations and improve biological control of A. lucorum.

Species covered 蓖麻 Ricinus communis