Bees hooked on nicotine-like chemicals found in pesticides

BEES become addicted to pesticides in the same way that humans can grow dependent on cigarettes, a study suggests.

The more of the nicotine-like chemicals bees consume, the more they appear to want, scientists found.

The research suggests that the risk of potentially harmful pesticide-contaminated nectar entering bee colonies is higher than was previously thought.

Neonicotinoid pesticides are chemically similar to nicotine, the addictive compound in tobacco. In 2013, the European Union partially banned three widely used neonicotinoids because of evidence that they may be harmful to bees.

The ban has now been extended to cover all crops not grown in greenhouses, despite strong opposition from some groups including the National Farmers’ Union in the UK. However, it could be revoked after Brexit.

In a series of studies, British researchers offered bumblebees a choice of two sugar solutions, one of which was laced with neonicotinoid pesticides. They found that over time the bees increasingly preferred feeders containing pesticide-flavoured sugar.

The research tracked 10 bumblebee colonies over 10 days. Each colony had access to its own foraging area, in which the researchers had set up sugar-dispensing feeders.

Dr Richard Gill, from the Department of Life Sciences at Imperial College London, said: “Given a choice, naive bees appear to avoid neonicotinoid-treated food. However, as individual bees increasingly experience the treated food, they develop a preference for it.

“Interestingly, neonicotinoids target nerve receptors in insects that are similar to receptors targeted by nicotine in mammals. Our findings tick certain symptoms of addictive behaviour, which is intriguing given the addictive properties of nicotine on humans, although more research is needed to determine this in bees.”

The findings are reported in the journal Proceedings of the Royal Society. Almost a quarter of European bumblebee species are threatened with extinction, largely because of the effects of climate change and intensive farming, studies have found.