Genetic and molecular oxidative stress responses in honeybees exposed to pesticide residues

Abstract

Pesticides pose a significant challenge to non-target organisms, particularly honeybees (Apis mellifera Linnaeus, 1758). Worker honeybees encounter pesticide residues during foraging in both open fields and hives, and these residues have been identified in bee products. However, the effects of these pesticides on bees at detected concentrations are not well understood. Therefore, this study aimed to assess the potential impacts of pesticide residues, including seven fungicides, six insecticides, and three herbicides, on gene expression and the activities of enzymes related to oxidative stress in worker bees. The following enzymes were included in the study: glucose oxidase, cytochrome P-450, acetylcholinesterase, general esterases, glutathione-S-transferase, butyrylcholinesterase, catalase, and adenosine triphosphatase. The results showed that chlorpyrifos (15.30 ng·ml-1), cypermethrin (10.72 ng·ml-1), and pendimethalin (3.42 ng·ml-1) significantly affected gene expression and the activities of the tested enzymes, while the control group and other pesticides did not. Untreated bees had higher specific enzyme activity and gene expression compared to most of the pesticides tested. Results from fludioxonil (14.45 ng·ml-1) and tolclofos-methyl (18.14 ng·ml-1) closely resembled those of the control group, indicating that these fungicides, at the tested concentrations, may not pose a threat to bee health. This research offers valuable insights into the potential negative effects of pesticide residues on the physiological balance of bees.