The combination of two pesticides commonly used on UK fields can have damaging effects on the behaviour of bumblebees and cause their colonies to collapse, new research by British scientists has found.
The findings, which come from a Government-funded study, represent the fifth major piece of research to appear this year linking the worldwide and worrying declines of bees to pesticides, and in particular to the use of the relatively new nerve-agent pesticides, the neonicotinoids.
This new study is considered particularly important because bees forage widely so are likely to encounter more than one type of pesticide.
Published last night in Nature online, the study reports that exposure to two commonly used pesticides, one a neonicotinoid and the other from a different pesticide family, a pyrethroid, at concentrations approximating what might be found in the field, impaired the natural foraging behaviour of bumblebees. This led to increased numbers of deaths and in some cases the failure of colonies. The compounds involved were made by major agrochemical manufacturers: the most widely used neonicotinoid, imidacloprid, manufactured by Bayer and already implicated in problems with bees in earlier studies, was one, while the pyrethroid was lambda-cyhalothrin, originally developed by Syngenta.