Toxicity of Neonicotinoid Pesticide Imidacloprid and Impediment of Ecosystem Services

Abstract

In agro-ecosystems, pollinators perform a variety of ecological services. The ecological role of pollinators and their ecosystem services are critical to the health of many ecosystems. Pollination by birds and bees are recognized as an important ecosystem function maintaining the dynamics of agro-ecosystems. As agriculture covers a significant portion of the globe, it necessitates the evaluation of their ecosystem services. There are overwhelming evidence that pollinators are experiencing tremendous population decline. Global agricultural encroachment, agriculture intensification, changes in cropped pasture, urban development and extensive use of pesticides are the major threats to farmland birds. Despite ecological importance and global awareness, farmland birds and bees are often considered as species of low conservation value. The worldwide use of neonicotinoid insecticides has raised concern over the decline of pollinators in the farmlands globally. Neonicotinoids are neurotoxins, applied to variety of agricultural crops to control sucking and biting pests and are readily incorporated into plant cells, inclusive of pollen and nectar. Among neonicotinoids, imidacloprid is found to have startling effects, disrupting several ecosystem services, inhibiting pollination and threatening global food security. The study focuses on imidacloprid and its wider risk to the environment with effects on non-target pollinators especially birds and bees. Some of the effects on bees include disrupting social behavior, foraging and altered navigation and in birds reduced reproduction and offspring immunity. Though the scientific community is intently examining the potential effects of imidacloprid on pollinators, the research warrants further investigations with field-realistic concentrations and at relevant exposure levels. This would facilitate the functioning of pollinators and promote sustainable agriculture by reducing the impact of neonicotinoids. This review summarizes the potential lethal and sublethal effects of neonicotinoid pesticide imidacloprid on pollinators and other invertebrate groups and also helps us to better understand the extent of their toxicity.