Does quercetin intake alter the concentration of pesticides in honeybees?

Honey bees regularly ingest quercetin, one of the most abundant phytochemicals in plants. Past research suggests that honey and pollen feeding upregulates the bees’ detoxification system and that dietary quercetin reduces the toxicity of imidacloprid and tau-fluvalinate [1,2].The aim of this study was to investigate the effect of dietary quercetin on the concentration of three pesticides present in honey bees. Honey bees (n = 600) were divided in five groups and fed either quercetin-sucrose paste or only sucrose for 72 h before being exposed to the neonicotinoid imidacloprid (oral exposure), the fungicide tebuconazole or the acaricide tau-fluvalinate (contact exposure). Bees were anesthetized with CO2, frozen, and extracted with a validated QuEChERS method. Finally, the concentrations of all three above-mentioned pesticides were determined by LC-MSMS. Quantification results of the three pesticides in honey bee samples [Fig. 1] displayed that there was a significant difference in concentration of imidacloprid (P = 2 ͯ 10-5) and tau-fluvalinate (P = 3 ͯ 10-2) between the bees that were fed quercetin-sucrose paste and bees that were fed only sucrose. However, there was no significant difference in the level of tebuconazole in the group of bees that were fed quercetin-sucrose paste and bees that were fed only sucrose (P = 4.2 ͯ 10-1). The results of this study demonstrate that honey bee intake of quercetin leads to a reduction in the concentration of imidacloprid and tau-fluvalinate by up regulating the detoxification systems in bees. Hence, quercetin may be a promising bioactive compound in chemo-ecological aspects to counteract the hazard of pesticides.

Fig. 1 Concentration of imidacloprid (A), tau-fluvalinate (B) and tebuconazole (C) in honey bee samples when they were fed quercetin-sucrose paste (white plots) or only sucrose (shaded plots).

• References

• 1 Johnson RM, Mao W, Pollock HS, Niu G, Schuler MA, Berenbaum MR. Ecologically appropriate xenobiotics induce cytochrome P450 s in Apis mellifera. PLoS One 2012; 7: e31051
• 2 Wong MJ, Liao LH, Berenbaum MR. Biphasic concentration-dependent interaction between imidacloprid and dietary phytochemicals in honey bees (Apis mellifera). PLoS One 2018; 13: e0206625