Effects of bifenthrin on the survival, physiology and gut microbiota in honeybees (Apis mellifera L.)

Bifenthrin is widely used for pest control in nectariferous crop, which may harm honeybees Apis mellifera L. health. This study aimed to investigate effects of sublethal concentrations of bifenthrin on survival, feeding, immune and detoxification related genes expression and the gut microbiota in honeybees.

The honeybees were fed with 5 mg/L and 0.5 mg/L bifenthrin for 7 d, and the survival and food consumption in each group were calculated. Changes in the expression of immune and detoxification related genes in honeybee midguts were detected by qPCR, and the abundance and structural of gut microbiota was analyzed by 16S rDNA sequencing technology.

The results showed that: (1) 5 mg/L bifenthrin significantly reduced the survival and pollen consumption (P < 0.05), but had no significant effect on the consumption of bifenthrin-containing syrup water in honeybees; (2) 5 mg/L bifenthrin significantly inhibited CYP6AS3 and CYP6AS10 expression in the bee midgut (P < 0.05), while up-regulated the expression of Abaecin, Apidaecin, Defensin and Hymenoptaecin (P < 0.05); 0.5mg /L bifenthrin significantly inhibited Lysozyme and CYP6AS10 expression (P < 0.05), while up-regulated the expression of Apidaecin and Defensin (P < 0.05); (3) Bifenthrin treatment induced changes in the diversity of the gut microbiota, and affected the abundance of specific bacteria.

This study indicated that bifenthrin exposure not only damaged the survival and food consumption, but also influenced the immune and detoxification systems in the midgut and intestinal homeostasis in honeybees.