Ecotoxicological Assessment of Thiamethoxam on the Behavior and Population Dynamics of Eisenia fetida
Sneha Suma Hegde *
Department of Studies in Zoology, Vijayanagara Sri Krishnadevaraya University, Ballari-583105, India.
Ashwini K. Jadhav
Department of Studies in Zoology, Vijayanagara Sri Krishnadevaraya University, Ballari-583105, India.
Roja T
Department of Studies in Zoology, Vijayanagara Sri Krishnadevaraya University, Ballari-583105, India.
Somanath
Department of Studies in Zoology, Vijayanagara Sri Krishnadevaraya University, Ballari-583105, India.
*Author to whom correspondence should be addressed.
Abstract
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.
Keywords: Thiamethoxam, Eisenia fetida, hydro taxis, cysts, biodiversity