EFFECTS OF PESTICIDES ON THE ABILITY OF HONEYBEES TO WITHSTAND COLD STRESS CONDITIONS

Pesticide exposure in the honeybee (Apis mellifera) produces multiple adverse outcomes, affecting survival, behavior, and the capacity to withstand biological and environmental stressors. While honey bees may naturally face cold-stress conditions, especially during late-season periods, the additional harmful effects induced by pesticides are significant. The potential interactive effects between pesticides and exposure to low temperatures have not received adequate attention and therefore form the primary focus of this study. Three specific pesticides were examined: imidacloprid (100 µg/l), glyphosate (2500 µg/l), and fludioxonil (14.5 µg/l). The study evaluated how these pesticides affect the honeybees’ ability to endure exposure to low temperatures through parameters such as time until narcosis (TUN), time until recovery (TUR), and post-recovery survival rates. Results indicated that TUN and TUR were more negatively affected in pesticide-treated groups than in controls, with fludioxonil exerting the smallest effect. Imidacloprid showed the most severe negative effects, followed by glyphosate. Regarding survival post-recovery, the highest mortality within 72 hrs was observed in the imidacloprid group, followed by glyphosate and then fludioxonil, whereas untreated bees showed the highest survival. Overall, exposure to the insecticide imidacloprid significantly impaired honeybees’ ability to withstand low-temperature stress, leading to reduced survival relative to exposure to the herbicide or fungicide, which do not primarily target insects. These findings underscore added adverse effects of pesticide exposure on honeybees, an aspect that remains insufficiently explored in the literature