Abstract: 【Aim】 This study aims to identify the electrophysiologically active components of the volatiles from corn silk that elicit responses from the antennae of Monolepta signata adults, and to explore the influence of these active compounds on the behavioral preferences of this insect, so as to provide a basis for screening potential behavioral regulators for M. signata. 【Methods】 Dynamic headspace adsorption was employed to collect volatiles from corn (variety Xianyu 335) silks. The electrophysiologically active compounds from corn silk to the antennae of M. signata adults were identified from the volatiles by gas chromatography-electroantennographic detection (GC-EAD) and gas chromatography-mass spectrometry (GC-MS). Furthermore, electroantennogram (EAG) technique was employed to evaluate the EAG responses of M. signata to the electrophysiologically active volatile compounds from corn silks. Finally, the behavioral responses of M. signata adults to the above-mentioned volatile compounds were assessed using a Y-tube olfactometer. 【Results】 Four active compounds were identified from corn silk volatiles: nonanal, azulene, octanol and decanal. Both female and male adults of M. signata exhibited EAG responses to the four active compounds, showing concentration-dependent characteristics with concentrations increasing. Among them, 100 μg/μL of nonanal elicited the strongest EAG response in both sexes, while 0.1 μg/μL of octanol elicited the weakest EAG response. Behavioral attraction assays demonstrated that octanol at the concentrations of 1, 10 and 100 μg/μL, as well as decanal at the concentrations of 10 and 100 μg/μL, significantly attracted female adults of M. signata. Meanwhile, nonanal and octanol at the concentrations of 10 and 100 μg/μL, along with azulene and decanal at the concentration of 100 μg/μL, showed significant attractive effect on male adults of M. signata. 【Conclusion】 Four compounds of corn silk volatiles, i.e., nonanal, azulene, octanol and decanal, have attractive effects on either female or male adults of M. signata, and can be considered as candidate components for developing attractants against this pest.

Key words: Monolepta signata, corn silk, volatile compounds, behavioral response, GC-EAD