BACILLUS MYCOIDES: A NOVEL INDIGENOUS ISOLATE FOR PROTECTING HONEYBEES FROM PESTICIDE INDUCED TOXICITY

Abstract

The extensive use of neonicotinoid insecticides, particularly imidacloprid in agricultural pest management has raised significant concerns regarding their negative impacts on honeybee health and pollination services. The study evaluated the protective potential of the beneficial gut-associated bacterium Bacillus mycoides against imidacloprid-induced toxicity in the Indian honeybee, Apis cerana. A preliminary toxicity assay was performed using five imidacloprid concentrations (0.5, 1, 2, 5 and 10 ppm) to determine the 72-h median lethal concentration (LC₅₀), which was estimated to be 0.896 ppm. Newly emerged worker bees were assigned to four treatment groups: control, B. mycoides treated, imidacloprid exposed and imidacloprid + B. mycoides. Bee survival was assessed using Kaplan–Meier survival analysis. Significant variation in survival rates was observed among treatments (log-rank test, P < 0.0001). Imidacloprid exposure alone resulted in the lowest survival (2.00 ± 0.82 bees), whereas supplementation with B. mycoides significantly enhanced survival (6.00 ± 0.82 bees; Tukey’s HSD, P < 0.001). The survival of bees treated with B. mycoides alone was comparable to that of the untreated control group (9.25 ± 0.50 and 8.75 ± 0.50 bees, respectively). These findings indicate that B. mycoides mitigates imidacloprid-associated toxicity and improves the resilience of A. cerana under pesticide stress.