Neonicotinoids pose undocumented threats to food webs

Abstract

One of the main lessons that emerged from Silent Spring (1) is that we overuse pesticides at our own peril because human and natural environments are unquestionably linked. It is time to revisit these lessons given current use patterns of neonicotinoid insecticides. Neonicotinoids pose broader risks to biodiversity and food webs than previously recognized. Serious efforts must be made to decrease the scale of their use. Image credit: Shutterstock/lantapix. Since their introduction in the early 1990s, neonicotinoids have become the most widely used insecticides in the world. Their toxicity allows less active ingredients to be used and, compared with older classes of insecticides, they appear to have relatively low toxicity to vertebrates, particularly mammals (2). Neonicotinoids have been repeatedly called “perfect” for use in crop protection (2). Yet recent research calls this perfection into doubt as neonicotinoids have become widespread environmental contaminants causing unexpected nontarget effects. In particular, researchers have found that neonicotinoids can move from treated plants to pollinators and from plants to pests to natural enemies. Worse, transmission through simple food chains portends widespread, undocumented transmission into entire food webs. We believe that neonicotinoids pose broader risks to biodiversity and food webs than previously recognized. Although further research is needed to document the ecosystem-wide transmission and consequences of neonicotinoids to establish their true costs and benefits, serious efforts must be made to decrease the scale of their use. In 2014, the neonicotinoid market exceeded $3 billion and accounted for about 25% of the global pesticide market (3). Neonicotinoids are popular in part because they are very good at what they do. In fact, they are among the most toxic insecticides ever developed. The active ingredient imidacloprid, for example, is 10,000 times more potent to insects than nicotine, the biological inspiration for neonicotinoids and a very toxic compound … [↵][1]1To whom correspondence may be addressed. Email: sdfrank{at}ncsu.edu. [1]: #xref-corresp-1-1