Comparative toxicities of commonly used agricultural insecticides to four honey bee species (Hymenoptera: Apidae) in Vietnam

Authors: PHAM, THAI H. - Vietnam Nationall University; PHAN, NGOC T. - Vietnam Nationall University; TRINH, DUY D. - University Of Arkansas; DUONG, HA N. - University Of Missouri; TRAN, PHUONG T. - University Of Missouri; NGUYEN, HANH D. - Vietnam Nationall University; Reddy, Gadi; JUNG, CHULEUI - Andong National University; JOSHI, NEELENDRA - University Of Arkansas

Submitted to: Environmental Toxicology and Pharmacology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2024
Publication Date: 12/6/2024
Citation: Pham, T.H., N.T. Phan, D.D.Trinh, H.N.Duong, P.T. Tran, K.D. Nguyen, G.V.P.Reddy, C.Jung,and N.K.Joshi. 2024. Comparative toxicities of commonly used agricultural insecticides to four honey bee species (Hymenoptera: Apidae) in Vietnam. Environmental Toxicology and Pharmacology. 113. https://doi.org/10.1016/j.etap.2024.104605.
DOI: https://doi.org/10.1016/j.etap.2024.104605

Interpretive Summary: Beekeeping is an essential agricultural activity in Vietnam that offers an invaluable source of income and contributes to poverty alleviation. In this study, we found that the four bee species differ in degree of sensitivity to the insecticides: bifenthrin, imidacloprid, thiacloprid, thiamethoxam, and chlorantraniliprole. Among the honey bee species emerged as the most susceptible to insecticides across all tested groups. We compared the relative sensitivity of these species and discussed the potential of these findings as baseline information for conducting future field-realistic studies. The findings of this study highlight the importance of incorporating species-specific toxicity responses into pesticide risk assessments and county-specific regulatory frameworks. Enhancing existing pesticide databases by incorporating response curve slopes, LD50 values with their 95% confidence intervals, and detailed information on the timing of mortality assessments is essential. This will enable more accurate risk assessments and better-informed decisions regarding pesticide selection.

Technical Abstract: Beekeeping for honey production is a vital economic activity in Vietnam, significantly contributing to the nation's agricultural exports and poverty alleviation. However, the widespread use of pesticides, exacerbated by the lack of strict regulations, poses serious challenges to beekeeping and potentially has negative consequences. This study examined the oral toxicities of five commonly used agricultural insecticides on four honey bee species prevalent in Vietnam: the Asian honey bee (Apis cerana), European honey bee (A. mellifera), giant honey bee (A. dorsata), and dwarf honey bee (A. florea). The insecticides tested were bifenthrin, imidacloprid, thiacloprid, thiamethoxam, and chlorantraniliprole. Groups of adult bees were exposed to at least five concentrations of each insecticide, diluted in distilled water. Mortality was assessed every 12 hours for the first 48 hours and then every 24 hours up to 10 days post-exposure. Response regressions were analyzed to determine LC50 values, slopes of response curves, and LD50 and LD90 ratios. The results indicated that toxicities were variable to each pesticide and species. Imidacloprid and thiamethoxam were the most toxic and chlorantraniliprole and befenthrin least. A. florea was the most sensitive to all pesticides. These findings highlight the need to develop a pesticide risk assessment and regulatory framework for honey bee species beyond A. mellifera.