Risto Raimets1, Reet Karise1, Marika Mänd1, Tanel Kaart2, Sally Ponting3, Jimao Song3, James E Cresswell3. 1. Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia. 2. Department of Animal Genetics and Breeding, Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia. 3. Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
Abstract
BACKGROUND: In recent years, concern has been raised over honey bee colony losses, and also among wild bees there is evidence for extinctions and range contractions in Europe and North America. Pesticides have been proposed as a potential cause of this decline. Bees are exposed simultaneously to a variety of agrochemicals, which may cause synergistically detrimental impacts, which are incompletely understood. We investigated the toxicity of the fungicide imazalil in mixture with four common insecticides: fipronil (phenylpyrazoid), cypermethrin (pyrethroid), thiamethoxam, and imidacloprid (neonicotinoids). Ergosterol biosynthesis inhibitor (EBI) fungicides like imazalil can inhibit P450 detoxification systems in insects and therefore fungicide - insecticide co-occurrence might produce synergistic toxicity in bees. We assessed the impact of dietary fungicide - insecticide mixtures on the mortality and feeding rates of laboratory bumble bees (Bombus terrestris L.). RESULTS: Regarding mortality, imazalil synergised the toxicity of fipronil, cypermethrin and thiamethoxam, but not imidacloprid. We found no synergistic effects on feeding rates. CONCLUSION: Our findings suggest that P450-based detoxification processes are differentially important in mitigating the toxicity of certain insecticides, even those of the same chemical class. Our evidence that cocktail effects can arise in bumble bees should extend concern about the potential impacts of agrochemical mixtures to include wild bee species in farmland.
BACKGROUND: In recent years, concern has been raised over honey bee colony losses, and also among wild bees there is evidence for extinctions and range contractions in Europe and North America. Pesticides have been proposed as a potential cause of this decline. Bees are exposed simultaneously to a variety of agrochemicals, which may cause synergistically detrimental impacts, which are incompletely understood. We investigated the toxicity of the fungicide imazalil in mixture with four common insecticides: fipronil (phenylpyrazoid), cypermethrin (pyrethroid), thiamethoxam, and imidacloprid (neonicotinoids). Ergosterol biosynthesis inhibitor (EBI) fungicides like imazalil can inhibit P450 detoxification systems in insects and therefore fungicide - insecticide co-occurrence might produce synergistic toxicity in bees. We assessed the impact of dietary fungicide - insecticide mixtures on the mortality and feeding rates of laboratory bumble bees (Bombus terrestris L.). RESULTS: Regarding mortality, imazalil synergised the toxicity of fipronil, cypermethrin and thiamethoxam, but not imidacloprid. We found no synergistic effects on feeding rates. CONCLUSION: Our findings suggest that P450-based detoxification processes are differentially important in mitigating the toxicity of certain insecticides, even those of the same chemical class. Our evidence that cocktail effects can arise in bumble bees should extend concern about the potential impacts of agrochemical mixtures to include wild bee species in farmland.
Authors: Allison A Camp; Michael A Batres; Wanda C Williams; Robert W Koethe; Kimberly A Stoner; David M Lehmann Journal: Environ Toxicol Chem Date: 2020-11-09 Impact factor: 4.218
Authors: Ivan A Yaremenko; Mikhail Y Syromyatnikov; Peter S Radulov; Yulia Yu Belyakova; Dmitriy I Fomenkov; Vasily N Popov; Alexander O Terent'ev Journal: Molecules Date: 2020-04-22 Impact factor: 4.411