Over three-quarters of the thousands of bumblebee colonies imported into the UK every year are riddled with parasites, a new study has revealed. Scientists say the discovery has “alarming” implications for the health of the UK’s wild bees and honeybees, many of which are already in serious decline, and that urgent action is required to improve ineffective disease screening and close loopholes.
“These parasites will undoubtedly be spilling over into wild and honey bees and very probably having negative effects on them,” said Professor William Hughes, at the University of Sussex, who led the new research. “It is no great leap to think that damage is already being done.”
The effects include killing bees outright, or harming their ability to learn, which is crucial in finding food. In Argentina, imported parasites are driving native species to extinction.
Over a million bumblebee colonies a year are imported to countries around the world to pollinate greenhouse crops such as tomatoes, with the UK receiving 40,000-50,000. The colonies, sold by a handful of global suppliers, are said by the companies to be disease-free.
But Hughes’s team bought 48 commercially produced bumblebee colonies and used DNA testing to reveal five different parasites in the bees and three in the pollen provided by the suppliers as food. The research, published in the Journal of Applied Ecology, further showed that three of the parasites were able to infect bumblebees and four could infect honeybees.
Hughes said independent checking of producers’ disease-free claims was urgently needed. He said a particular concern was that one of the producers was marketing the colonies for use in peoples’ gardens. “They are selling these to help preserve UK bumblebees, but if the imported colonies have parasites it’s obviously counterproductive.”
Natural England, the government’s wildlife body, licences the use – but not the importing or disease screening – of bee colonies. An NE spokeswoman said the new evidence of risk to UK bees was “persuasive”. But she said current regulations did not allow action against imported bumblebees which are originally descended from native British bees, but reared overseas. “It is therefore of particular concern that this research has revealed that imported bees – descended from British stock – have been found to be carrying disease.”
A spokeswoman for the department of environment, food and rural affairs said: “Imported colonies of non-native bees are required to be screened for parasites and disease. We will continue to work with NE to ensure that growers who break the rules are punished.”
New “tightened” regulations introduced in December require the producers to report the screening they have done and the location of non-native bee colonies imported into the UK to be registered, but no penalties have yet been issued.
Friends of the Earth’s Paul de Zylva said: “Limp regulation has already let in ash die-back and doomed millions of British trees. To avoid the same fate for our wild bumblebeesministers mustensure bee importers comply with stricter rules.”
Bees and other pollinators are vital for three-quarters of the world’s food crops but have experienced major declines in recent decades, due to starvation as their habitat is destroyed, heavy pesticide use and rising disease. “It’s often a combination of all three and that may tip them over the edge,” said Hughes. For example, he said, bees cannot resist a parasite if they are stressed by a lack of food and also weakened by sub-lethal doses of pesticides.
On Tuesday, 23 of the EU’s nations voted successfully to suspend the use of a common pesticide called fipronil because of an acute risk to bees. The UK abstained, as it did when other EU nations voted in favour of banning three neonicotinoid pesticides in April.
Hughes’s team bought the 48 colonies in two separate years, 2011 and 2012, to avoid the risk of sampling an unrepresentative year. The parasites found in the imported colonies included the three main bumblebee parasites (Crithidia bombi, Nosema bombiandApicystis bombi), three honeybee parasites (Nosema apis, Ascosphaera apisandPaenibacillus larvae), and two parasites which infect both bumblebees and honeybees (Nosema ceranaeand deformed wing virus).
This article was written by Damian Carrington for the Guardian UK.