Responses of Fishes, Amphibians, and Reptiles to Neonicotinoids

Neonicotinoids are systemic insecticides that are commonly applied in agriculture fields in over 120 countries throughout the world. The extensive use of neonicotinoids in agriculture and veterinary medicine causes soil contamination, and their residues are further transferred to the aquatic environment. According to recent monitoring studies undertaken in several countries, these pesticides, with residual levels in the low ng/L–μg/L range, contaminate streams, rivers, and lakes worldwide. Furthermore, neonicotinoids pose a significant environmental risk for non-target terrestrial species such as mammals, birds, reptiles, semiaquatic species such as amphibians, and aquatic organisms such as fish, crabs, shrimps, and oysters. Non-target animal species are affected directly (through acute or chronic toxicity) or indirectly (via the food chain) by neonicotinoids. This chapter describes the toxicity of neonicotinoids to non-target species, including fishes, amphibians, and reptiles. It also covers their biochemical, physiological, and behavioural responses to neonicotinoids. The data presented here show that both short-term and long-term exposure to neonicotinoids resulted in significant toxic effects, including neurotoxicity, genotoxicity, hepatotoxicity, immunotoxicity, carcinogenesis, endocrine disruption, and reproductive toxicity. This led to mortality, malformation, behavioural changes, and reproductive failure in animal species at various life stages in non-target animals. The findings indicate that neonicotinoids may have direct and indirect effects on wildlife, including aquatic vertebrates like fish, semiaquatic vertebrates like amphibians, and terrestrial vertebrates like reptiles. As a result, there is a need for further research and regulation to mitigate the potential harm caused by neonicotinoids to non-target animals and ecosystems.