Mixture toxic effects of thiacloprid and cyproconazole on honey bees (Apis mellifera L.)

Authors: LV, LU - Zhejiang Academy Of Agricultural Sciences; LI, WENHONG - Guizhou Academy Of Agricultural Sciences; LI, XINFANG - Zhejiang Academy Of Agricultural Sciences; WANG, DOU - Zhejiang Academy Of Agricultural Sciences; WENG, HONGBIAO - Zhejiang Academy Of Agricultural Sciences; Zhu, Yu Cheng; WANG, YANHUA - Zhejiang Academy Of Agricultural Sciences

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2023
Publication Date: 1/20/2023
Citation: Lv, L., Li, W., Li, X., Wang, D., Weng, H., Zhu, Y., Wang, Y. 2023. Mixture toxic effects of thiacloprid and cyproconazole on honey bees (Apis mellifera L.). Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2023.161700.
DOI: https://doi.org/10.1016/j.scitotenv.2023.161700

Interpretive Summary: Exposure to pesticides remains one of the critical factors for the population decline of insect pollinators. It is urgently necessary to assess mixture effects in pollinator risk assessments since they are often exposed to numerous agricultural chemicals. In the present work, we explored the mixture toxic impacts of thiacloprid (THI) and cyproconazole (CYP) on honey bees. Our findings revealed that THI possessed higher acute toxicity to A. mellifera (LC50=216.3 mg a.i. L-1) than CYP (LC50=601.4 mg a.i. L-1). It’s worth noting that the mixture of THI and CYP exerted acute synergistic effect on the pollinators. At the same time, the activities of detoxification enzyme CYP450s and neuro target enzyme AChE, as well as the expressions of seven genes (CRBXase, CYP306A1, CYP6AS14, apidaecin, defensing-2, vtg, and gp-93) associated with detoxification metabolism, immune response, development, and endoplasmic reticulum stress, were significantly altered in the combined exposure compared with the corresponding individual exposures of THI or CYP. These data indicated that the mixture of THI and CYP could disturb the physiological homeostasis of bees. Our study would provide a theoretical basis for in-depth study on the impacts of pesticide mixtures on the health of honey bees. Besides, our work also have important guidance significance for the rational application of pesticide mixtures to effectively protect pollinators in agricultural production.

Technical Abstract: Pesticide exposure remains one of the main factors in the population decline of insect pollinators. It is urgently necessary to assess the effects ofmixtures on pollinator risk assessments because they are often exposed to numerous agrochemicals. In the present study, we explored the mixture toxic effects of thiacloprid (THI) and cyproconazole (CYP) on honey bees (Apis mellifera L.). Our findings revealed that THI possessed higher acute toxicity to A. mellifera (96-h LC50 value of 216.3 mg a.i. L -1) than CYP (96-h LC50 value of 601.4 mg a.i. L -1). It's worth noting that the mixture of THI and CYP exerted an acute synergistic effect on honey bees. At the same time, the activities of detoxification enzyme cytochrome P450s (CYP450s) and neuro target enzyme Acetylcholinesterase (AChE), as well as the expressions of seven genes (CRBXase, CYP306A1, CYP6AS14, apidaecin, defensing-2, vtg, and gp-93) associated with detoxification metabolism, immune response, development, and endoplasmic reticulum stress, were significantly altered in the combined treatment compared with the corresponding individual exposures of THI or CYP. These data indicated that a mixture of THI and CYP could disturb the physiological homeostasis of honey bees.Our study provides a theoretical basis for in-depth studies on the impacts of pesticide mixtures on the health of honey bees. Our study also provides important guidance for the rational application of pesticide mixtures to protect pollinators in agricultural production effectively.