Effects of neonicotinoid residues in Apis cerana indica bees and bee products: LC-MS/MS analysis and dietary risk assessment in a sunflower field study

Abstract

Colony decline has been a global challenge in recent years among the honey bee population, and no exception is Apis cerana indica F., a widely domesticated bee in India. Of the many reasons and factors suggested behind the issue, the use of insecticides is also the most linked. Insecticide residues in honey and pollen endanger honey bees and humans above a specific concentration, thus warranting our establishment of their critical daily pesticide residue exposure levels. This study developed a simple multi-residue method for analyzing neonicotinoids in honey, pollen, and bees using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). This method had better linearity (0.005 to 0.5 µg mL− 1), the limit of detection (LOD) (0.002–0.008 µg g− 1), the limit of quantification (LOQ) (0.025 µg g− 1) and recovery (70 to 120%) for the five neonicotinoid analytes. A survey among farm colonies and a controlled field experiment detected neonicotinoid residues (0.025 to 0.456 µg g− 1) in bee products. Field experiments in sunflowers indicated that foraging neonicotinoid-contaminated food increased bee mortality in the descending order of clothianidin > thiamethoxam > imidacloprid > thiacloprid. Neonicotinoids influenced bees' foraging behavior, resulting in lower colony growth measurements (food, brood area, and bee population). Poor-quality seed sets and decreased yield in sunflower due to neonicotinoid-exposed bee colonies' poor field performance. The dietary risk evaluation of neonicotinoid residues in bees and bee products showed moderate to high risk (hazard quotient > 5) for brood and foragers and less than 1 for humans, indicating unacceptable risk to Indian bee colonies but tolerable by humans. Neonicotinoid effects must be further investigated through risk analysis in order to ensure native bees safety while following crop protection activities.