Abstract: 【Aim】Grapholita molesta is a globally distributed significant pest of Rosaceae fruit trees. After eclosion, female moths require feeding to promote reproductive development. In laboratory settings, honey is commonly provided as a food source. However, honey is prone to fermentation, and the impact of its volatile compounds on the olfactory behavior of female moths of G. molesta remains unclear. 【Methods】The commonly used non-host plant-derived honey (Guanshengyuan) in the laboratory and two host plant-derived honey (Jiangshanqing and Yanglaosi) were selected. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was employed to analyze the changes in volatile components before and after honey fermentation, and the key differential volatile compounds were screened. Electroantennogram (EAG) measurement and oviposition preference behavioral assay were conducted to clarify the olfactory behavioral responses of the 3-day-old mated female moths of G. molesta to four volatile compounds (isoamyl alcohol, ethyl acetate, isoamyl acetate and n-octane) at five concentrations (0.01, 0.1, 1, 10 and 100 μg/μL). 【Results】A total of 40 volatile components were detected from three honey samples, and differences in volatile components and their contents were observed in all the three honey samples before and after fermentation. Ethyl acetate, ethanol and isoamyl acetate were present in all samples, while n-octane was detected in both fermented and unfermented Guanshengyuan and Yanglaosi honey. The three fermented honey samples exhibited relatively high level of isoamyl alcohol, whereas the fermented Jiangshanqing honey lacked the otherwise abundant n-octane in the unfermented status. EAG test results demonstrated that 10 μg/μL isoamyl alcohol, 100 μg/μL ethyl acetate, 100 μg/μL isoamyl acetate and 1 μg/μL n-octane could elicit strong olfactory responses in female moths of G. molesta. Oviposition selection test results revealed concentration-dependent behavioral effects of the fermented honey volatile compounds on the female moths of G. molesta. Isoamyl alcohol showed attractant effects on the female moths of G. molesta at the concentrations of 0.01 and 1 μg/μL, but exhibited repellent effects on the female moths of G. molesta at the concentrations of 10 and 100 μg/μL. Both ethyl acetate and isoamyl acetate at high concentrations (10-100 μg/μL) exhibited attractant effects on the female moths of G. molesta. n-Octane displayed repellent effect on the female moths of G. molesta only at the concentration of 0.1 μg/μL, but demonstrated attractant effects on the female moths of G. molesta at the concentrations of 0.01, 1 and 100 μg/μL. 【Conclusion】 The above results reveal that honey fermentation significantly alters the volatile components and their contents, and isoamyl alcohol, ethyl acetate, isoamyl acetate and n-octane exhibit concentration-dependent regulatory effects on the olfactory and oviposition behaviors of female G. molesta moths, providing theoretical support for the development of olfactory behavior regulation technologies.

Key words: Grapholita molesta, honey, fermentation, volatile compounds, olfactory perception, oviposition selection