Protecting honey bee health: The role of polyphenolic supplements in oral administration of deltamethrin

Introduction: Deltamethrin (DTM) is widely used in forestry, professional agriculture, and amateur farming. However, its application presents specific risks to pollinating insects. DTM disrupts the physiology of honey bees (Apis mellifera), causing abnormalities in behaviors such as dancing and foraging, as well as issues like memory impairment, hypofertility, and hypothermia [1]. Antioxidant compounds incorporated into bee diets can defend bees against the adverse effects of various pesticide classes [2-3]. This study aimed to evaluate the potential of the polyphenolic fraction of bergamot (BPF) to mitigate the harmful effects of DTM exposure.

Materials and Methods: Twelve experimental groups consisting of 20 honey bees each were established. Under controlled laboratory conditions, honey bees were exposed to oral DTM administration for three days at a concentration of 21.6 mg/L. Additional experimental groups received BPF (1 mg/kg) in combination with the specified toxic DTM doses. Abnormal behaviors—including a curved-down abdomen, hyperactivity, apathy, motion coordination issues, and moribundness—were observed and recorded at 1, 2, and 3 days post-treatment. Survival rates were also assessed for each group.

Results: By day 3 of the experiment, all honey bees in the groups exposed solely to the highest DTM dose (21.6 mg/L) had perished. Conversely, in the groups treated with both BPF and DTM (21.6 mg/L), a survival rate of 46% was observed after 3 days. Overall, groups receiving only toxic DTM doses exhibited lower survival rates (day 1 = 38%, day 2 = 25%) compared to those treated with the BPF and DTM combination (BPF + DTM: day 1 = 86%, day 2 = 72%). Additionally, honey bees exposed to the BPF/DTM combination displayed fewer abnormal behaviors compared to those treated with DTM alone.

Conclusions: Oral administration of BPF can reduce the harmful effects of DTM. However, further research is necessary before recommending the inclusion of BPF in honey bee diets, despite the promising positive effects observed.