Safe for landing? (Image: Paul Oomen/Getty)

Do neonicotinoid pesticides kill bumblebees? We still don’t know, but the latest research is alarming – and casts doubt on the integrity of science.

One of the UK’s top bee researchers this week claimed that a study quoted two years ago by UK ministers to justify opposing a European Union ban on neonicotinoids actually shows that the pesticides can harm the insects.

The study, by Helen Thompson of the government’s Food and Environment Research Agency, found “no clear consistent relationships” between pesticide residues and measures of the health of bee colonies, such as the number of new queens. “The absence of these effects is reassuring but not definitive,” she said.


But Dave Goulson of the University of Sussex in Brighton has reanalysed the data and says that in fact the results “strongly suggest that wild bumblebee colonies in farmland can be expected to be adversely affected by exposure to neonicotinoids”.

Strong links

Bees are in sharp decline in the UK and elsewhere. The reasons are disputed, but much attention has been given to neonicotinoids, which are widely applied as insecticides to arable crops visited by bees, such as oilseed rape.

Several studies showing the damage caused by force-feeding bumblebees with pesticide-treated pollen were enough to persuade the EU to temporarily ban use of the pesticides in 2013. But the Thompson study – published online by the government, but never peer reviewed – was the first to look at bees that were foraging in the wild.

Thompson put 40 colonies of bees near rape fields treated with the pesticides and compared their subsequent health with 20 control colonies. She also looked at the level of pesticide residues in pollen and nectar taken from hives. Although described as a pilot study, the reported absence of a strong link was enough to persuade the then UK environment minister Owen Paterson to declare days afterwards that “we did not see grounds for a ban based on our field trial data”.

But Goulson says the data “quite clearly showed a negative relationship between pesticide levels and colony success”. The study found 50 per cent fewer new queens in the hives near the pesticide-soaked fields – even though detailed analysis found that the “control” colonies were also contaminated by neonicotinoids.

Scientific scandal

“This is a scandal,” said Matt Shardlow of the charity Buglife, which has campaigned on the issue. “The scientific process appears to have been deliberately manipulated to agree with the environment secretary’s views.”

Thompson now works for agribusiness Syngenta, which manufactures some pesticides. She was not willing to speak on the record to New Scientist about Goulson’s conclusions, but is understood to have submitted a new study on the issue for publication.

There could be a simpler explanation though. James Cresswell, a bee specialist at the University of Exeter, UK, says: “These counter-interpretations sometimes happen in literature. It’s unusual, but not at all unprecedented.”