Ecotoxicological Assessment of Thiamethoxam on the Behavior and Population Dynamics of Eisenia fetida

Neonicotinoid insecticides, such as thiamethoxam, imidacloprid, acetamiprid and others are widely used in agriculture, but their impact on non-target organisms, particularly soil invertebrates like earthworms, is a growing concern. This study investigated the ecotoxicological effects of thiamethoxam on Eisenia fetida, a key soil organism, focusing on behavioral alterations and population dynamics. Earthworms were exposed to varying concentrations of thiamethoxam (control (0mg/kg), low-dose(6mg/kg), and high-dose(26mg/kg)) for 28 days. The results demonstrated dose-dependent detrimental effects. The high-dose group exhibited significant mortality, reduced biomass, aberrant behavior, and cyst formation. Hydro taxis, photo taxis, chemotaxis, and geotaxis tests revealed significant impairments in the high-dose group. These findings underscore the need for rigorous regulation of thiamethoxam and the promotion of sustainable pest management strategies to protect soil biodiversity and ecosystem health.