Chronic exposure to sublethal concentrations of Boral® 500 SC (sulfentrazone) induces sex- and age-dependent metabolic and behavioral effects in Drosophila melanogaster.

Sulfentrazone (SULF) is a widely used herbicide characterized by environmental persistence and potential off-target dispersion, yet its chronic sublethal effects on insects remain insufficiently understood. Because conventional toxicity assessments often prioritize lethality endpoints, they may overlook functional impairments that compromise organismal fitness. Here, we used Drosophila melanogaster as an integrative insect model to evaluate whether chronic exposure to sublethal concentrations of the commercial formulation Boral® 500 SC (SULF) affects development, female reproduction, locomotor performance, metabolic status, longevity, and stress resistance. The herbicide did not significantly affect developmental parameters, but significantly reduced longevity in both female and male flies. Moreover, exposure impaired climbing locomotor performance and exacerbated age-related functional decline. In females, a significant reduction in body weight was observed at 7 days of age, along with decreased carbohydrate levels at 30 days, whereas males exhibited increased lipid accumulation at 30 days of age. Oviposition rate was significantly reduced at 0.25 mg/L and 0.5 mg/L, and females exposed to 0.5 mg/L also displayed reduced resistance to paraquat-induced oxidative stress. Principal component analysis (PCA) revealed significant correlations between metabolic and behavioral parameters, highlighting the central role of energy reserves in mediating physiological and behavioral dysfunctions. Collectively, these findings demonstrate that Boral® 500 SC induces biologically relevant sublethal effects in D. melanogaster, suggesting that current regulatory methodologies may substantially underestimate the ecological risks of SULF to insects, thereby potentially contributing to population declines in non-target species.