Since 2012, the UK has been using a major government study on neonicotinoid pesticides as evidence that they are safe and do not adversely affect bumblebees, an important environmental pollinator. Recently, a bee expert reexamined the study’s findings and discovered that the opposite is true. Neonicotinoids, even in small doses, are very bad for bumblebees.
Professor Dave Goulson of the University of Sussex authored the new analysis of the study, which was published in PeerJ on Wednesday.
Whereas the government’s Food & Environment Research Agency (FERA) concluded that there was no clear relationship between colony performance and pesticide exposure, Goulson argues that “a simple re-analysis of this data set demonstrates that these data in fact do show a negative relationship between both colony growth and queen production and the levels of neonicotinoids in the food stores collected by the bees.”
The most pertinent question is, how did FERA draw the reverse conclusion from its own data? Its 2012 study was cited by the UK government as evidence that a proposed moratorium on the use of neonicotinoids was unnecessary, which could have significantly affected the country’s agricultural industry.
In his paper, Goulson says the results of the study’s initial residue-based analysis “do not seem to be accurately represented in the summary or discussion.” The site-based analyses, too, “are not informative.”
What is clear – and most alarming – from the FERA study is that bumblebees are regularly exposed to neonicotinoids clothianidin and thiamethoxam in nectar and pollen, including bees on control farms where no neonics are used.
“This experiment shows clearly that bumblebees on normal, working farms in the UK are exposed to mixtures of neonicotinoids,” Goulson wrote, “and that the dose they receive is sufficient to reduce nest growth and reduce the number of queens produced. Even doses of clothianidin below 0.3 parts per billion appear to be enough to do significant harm.”
The FERA study is technically the first to show a direct link between neonicotinoid use and bee impairment, but that revelation has arrived a month after researchers in Scotland also demonstrated that neonicotinoids impair bumblebee brains.
A combination of laboratory and field studies by researchers at the Universities of St. Andress and Dundee showed that even low neonicotinoid exposure reduced bumblebee colonies by an estimated 55 percent and healthy brood cells by 71 percent.
“This is not proof that neonicotinoids are solely responsible for the decline in insect pollinators,” said Dr. Chris Connolly of Dundee’s School of Medicine, “but a clear linear relationship is now established. We can now be confident that at these levels, neonicotinoids disrupt brain function, bee learning and the ability to forage for food and so limit colony growth.”