Adverse Effects of Commonly Used Acaricides on the Reproductive Physiology of Drone Honeybees (Apis mellifera L.)

This study evaluated the adverse effects of three widely used commercial acaricides (amitraz, flumethrin, and formic acid) on the reproductive physiology and quality parameters of drones (Apis mellifera caucasica), commonly used for the control of the destructive pest, Varroa destructor. The experiment was conducted on 20 colonies at the Bayburt University Beekeeping Application and Research Station during the spring-summer of 2025. The acaricides were applied to different experimental groups shortly before the drone cells were capped. Key reproductive quality parameters including body weight, sexual maturity rate, sperm viability, sperm concentration, and semen volume were assessed. The results showed that all three acaricide applications had statistically significant negative effects (p<0.05) on all measured reproductive parameters. Notably, the amitraz and formic acid treatments caused the most significant decreases in sperm viability and sperm concentration. Furthermore, compared to the control group, significant reductions were observed in both sexual maturity rates and drone body weights. The amitraz treatment group, in particular, exhibited the lowest sperm concentration (0.90±0.04×106/μL), a finding that aligns with the most substantial decrease in body weight (52.24 mg lower than the control). These findings clearly demonstrate that the common acaricidal compounds used against Varroa mites pose potential physiological and reproductive risks to drone. This highlights a critical concern for sustainable beekeeping, especially in queen bee rearing programs, and underscores the need for careful consideration of treatment methods and timing.