Abstract: 【Aim】 In this study, the potential side effects of the sublethal doses of imidacloprid on the midgut bacteria of the worker bees of Apis mellifera ligustica was investigated under laboratory conditions so as to provide a theoretical basis for the biosafety assessment of pesticides. 【Methods】 Newly emerged bees were fed on syrups with different sublethal doses of imidacloprid (0.005 mg/L, 0.015 mg/L and 0.045 mg/L) and pure sugar syrup with 0.3% acetone, and samples were collected after 3, 6, 9, 12 and 15 d, respectively. The population structure of bacteria in the midgut of honeybees in the four treatment groups was analyzed using next-generation sequencing after the genomic DNA was gained from intestinal bacteria. 【Results】 The results of sequence analysis showed that the midgut bacteria in A. mellifera ligustica mainly belong to Proteobacteria and Firmicutes. The composition of dominant midgut bacteria and the richness estimators in the same period were analyzed for statistical significance among the four treatments by performing a T-test, and no significant differences were observed (P>0.05). 【Conclusion】 The results suggest that the sublethal doses of imidacloprid does not induce significant changes in the composition of the honeybee gut bacterial community under laboratory conditions.

Key words: Apis mellifera ligustica, biosafety, imidacloprid, sublethal effect, intestinal community, next-generation sequencing