Imidacloprid, one of the most commonly used insecticides, is highly toxic to bees and other beneficial insects. The regulatory challenge to determine safe levels of residual pesticides can benefit from information about the time-dependent toxicity of this chemical. Using published toxicity data for imidacloprid for several insect species, we construct time-to-lethal-effect toxicity plots and fit temporal power-law scaling curves to the data. The level of toxic exposure that results in 50% mortality after time t is found to scale as t1.7 for ants, from t1.6 to t5 for honeybees, and from t1.46 to t2.9 for termites. We present a simple toxicological model that can explain t2 scaling. Extrapolating the toxicity scaling for honeybees to the lifespan of winter bees suggests that imidacloprid in honey at 0.25 μg/kg would be lethal to a large proportion of bees nearing the end of their life.
Source: Rondeau, Gary, Sanchez-Bayo, Francisco, Tennekes, Henk A., Decourtye, Axel, Ramirez-Romero, Ricardo, Desneux, Nicolas (2014) - Delayed and time-cumulative toxicity of imidacloprid in bees, ants and termites. Scientific Reports 4, Article number: 5566 doi:10.1038/srep05566
Published 04 July 2014
http://www.nature.com/srep/2014/140704/srep05566/full/srep05566.html
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Gary Rondeau comments
What started out as a bit of curiosity about the time-dependent toxicity of insecticides led to a blog piece I did a little over a year ago titled Time-dependent Toxicity of Imidacloprid in Bees and Ants. I thought my results were interesting enough to get a comment from other scientists that were looking at the time-dependent toxicity question so I sent out the link to a few. With the encouragement of especially Dr.Francisco Sanchez-Bayo at the University of Sydney in Austrailia, I went ahead expanded the research and we turned that blog post into a paper. I am especially grateful to my co-authors, especially Francisco Sanchez-Bayo and Nicolas Desneux, who shepparded the manuscript through the journal submission and review process.
So please take a look at the real thing. We were published in Nature’s online publication Scientific Reports.
Delayed and time-cumulative toxicity of imidacloprid in bees, ants and termites,
Gary Rondeau, Francisco Sanchez-Bayo, Henk A. Tennekes, Axel Decourtye,
Ricardo Ramırez-Romero & Nicolas Desneux, Scientific Reports 07/2014; 4(5566):8. DOI: 10.1038/srep05566
Source: Squash Practice, July 7, 2014
http://squashpractice.wordpress.com/2014/07/07/blog-post-gets-published/