Temperature influences the toxicity, behavioral, and physiology response of chlorfenapyr, fipronil, imidacloprid, and indoxacarb to Reticulitermes flaviceps

Abstract

A comprehensive understanding of the interaction between pesticides and climate change is critical to the safety of pesticide applications. Many insecticides are actually more toxic at higher temperatures. However, little is currently known about the effect of temperature on the toxicity of chemicals. In order to fill this knowledge gap and improve our understanding of the mechanisms of temperature effects, the present study investigated the toxic, physiological, and behavioral effects of four insecticides, chlorfenapyr, fipronil, imidacloprid, and indoxacarb, on subterranean termites, Reticulitermes flaviceps at different temperatures (24 to 32 °C). The results show that the sensitivity of R. flaviceps to chrofenapyr (LC50 = 8.67–152.49 mg/L), fipronil (LC50 = 10.14–36.84 mg/L), imidacloprid (LC50 = 184.27–326.47 mg/L) and indoxacarb (LC50 = 12.23–46.23 mg/L) substantially increased when the temperature alters from 24 to 32 °C. Additionally, the activities of three detoxification enzymes [glutathione S-transferases (GSTs), carboxylesterase (CarE), and cytochrome P450 (P450)] of R. flaviceps were also measured of four insecticide at various temperatures. Correlation analysis reveals that changes in GSTs CarE and P450 activities of R. flaviceps are closely related to their sensitivity to chlorfenapyr, fipronil, imidacloprid, and indoxacarb. Meanwhile, the speed of action (LT50 value) of four insecticides is positively affected by temperature. In addition, intoxication, ataxia, and moribundity behaviors were observed in most concentrations and temperature combinations for chlorfenapyr, fipronil, and imidacloprid–exposed termite. The findings of our research emphasize that in the context of global climate change, the development and application of pesticides should consider the temperature dimension.