Abstract: 【Aim】 The purpose of this study is to evaluate the effects of flonicamid on the predation ability of the 3rd instar larvae of Harmonia axyridis. 【Methods】 The residual film method was employed to observe and analyze the effects of exposure of the 3rd instar larvae of H. axyridis to 0.146 and 0.292 mg/mL of flonicamid on their predation ability on Aphis gossypii adults, including the predation amount, instantaneous attack rate, handling time and searching efficiency.【Results】 The predatory functional responses of the 3rd instar larvae of H. axyridis treated with 0.146 and 0.292 mg/mL of flonicamid to A. gossypii adults followed the type Ⅱ functional responses, which can be described by Holling’s disc equation. Compared with the control group treated with acetone, exposure of 0.146 and 0.292 mg/mL of flonicamid had negative impacts on the predation functional response parameters and searching efficiency of the 3rd instar larvae of H. axyridis， and the effects on the predation and searching ability became more significant with the increase of the concentration of flonicamid. In the control group, and treatment groups with 0.146 and 0.292 mg/mL of flonicamid, the instantaneous attack rates of the 3rd instar larvae of H. axyridis were 0.9260, 1.4451 and 2.1197, respectively, the maximum daily predation amounts were 392.62, 52.63 and 32.15 individuals, respectively, and the handling time was 0.0025, 0.0190 and 0.0311 h, respectively. 【Conclusion】 Exposure of the 3rd instar larvae of H. axyridis to flonicamid has negative impacts on their predation function on A. gossypii adults. Therefore, in order to better protect and utilize natural enemies, when implementing the prevention and control of A. gossypii using H. axyridis, consideration should be given to reducing or not using chemical pesticides.

Key words: Harmonia axyridis, Aphis gossypii, flonicamid, predation, functional response, searching efficiency