关键词: 华北大黑鳃金龟, 寄主植物, 取食选择性, 植物挥发物, 趋性反应

Abstract:  【Aim】 This study aims to clarify the relationship between feeding preference and taxis behavior of Holotrichia oblita adults on three plant species. 【Methods】 The taxis and feeding amount of H. oblita adults to Chinese elm (Ulmus parvifolia), wild cotton (Abutilon theophrasti), and castor-oil plant (Ricinus communis) were measured by the scanned leaf image device and Y-tube olfactometers. The volatiles from the three plants were collected by the dynamic headspace volatile collection method and identified by gas chromatography-mass spectrometer (GC-MS), and the active volatile compounds were screened by Y-tube olfactometer. 【Results】 The taxis of H. oblita to R. communis was significantly higher than that to U. parvifolia and A. theophrasti (P<0.05). There was no significant difference in taxis between to U. parvifolia and to A. theophrasti. However, H. oblita adults showed the highest foliar feeding amount to U. parvifolia among these three plants, and displayed nearly equal taxis to A. theophrasti and R. communis. Moreover, no significant difference in foliar feeding amount was found between female and male adults of H. oblita (P>0.05). GC-MS analysis showed that plant volatile compounds in the three plants were largely different. In the olfactory response test with Y-tube olfactometer, (Z)-3-hexenyl isobutyrate, dibutyl phthalate, (Z)-3-hexenyl acetate, linalool, phenol, methyl salicylate, and β-caryophellen at the concentration of 10 μg/μL were found to be more attractive to H. oblita as compared with the control (hexane), while 3-carene, (E)-2-nonenal and α-phellandrene were less attractive than hexane. 【Conclusion】 The taxis of H. oblita to U. parvifolia, A. theophrasti and R. communis is not equivalent to its feeding preference.

Key words: Holotrichia oblita, host plant, feeding selection, plant volatiles, taxis response