Synergistic effects of imidacloprid on the Perionyx excavatus: Biomarker responses and gene expression profiles

Imidacloprid, a widely used neonicotinoid insecticide, negatively impacts soil biota and harms the environment with long-term use. In this study, we aimed to evaluate the effects of imidacloprid on Perionyx excavatus, an indigenous earthworm species found in India. To evaluate the toxic effects of imidacloprid on earthworms, avoidance behavior, acute toxicity, chronic toxicity, oxidative damage, and functional gene expression patterns were measured. The LC₅₀ value of imidacloprid with 14-day exposure was 1.64 mg kg^-1 and the AC₅₀ value for net avoidance response was 0. 23 mg kg^-1 of imidacloprid at 48 h. Antioxidant and detoxifying enzymes were altered, which led to oxidative damage, lipid peroxidation, and DNA damage in earthworms. Hence, it was confirmed that imidacloprid may cause harmful effects on the biophysical homeostasis of P. excavatus, primarily through oxidative damage and altered gene expression. This present research emphasizes the possible threat of imidacloprid to native earthworms in subtropical ecosystem.