Commonly used pesticides are damaging honey bee brains, studies suggest. Scientists have found that two types of chemicals called neonicotinoids and coumaphos are interfering with the insect’s ability to learn and remember. Experiments revealed that exposure was also lowering brain activity, especially when the two pesticides were used in combination. The research is detailed in two papers in Nature Communications and the Journal of Experimental Biology. But a company that makes the substances said laboratory-based studies did not always apply to bees in the wild. And another report, published by the Defra’s Food and Environment Research Agency (Fera), concluded that there was no link between bee health and exposure to neonicotinoids. The government agency carried out a study looking at bumblebees living on the edges of fields treated with the chemicals. Honey bees around the world are facing an uncertain future. They have been hit with a host of diseases, losses of habitat, and in the US the mysterious Colony Collapse Disorder has caused numbers to plummet. Now researchers are asking whether pesticides are also playing a role in their decline. To investigate, scientists looked at two common pesticides: neonicotinoids, which are used to control pests on oil seed rape and other crops, and a group of organophosphate chemicals called coumaphos, which are used to kill the Varroa mite, a parasite that attacks the honey bee. Neonicotinoids are used more commonly in Europe, while coumaphos are more often employed in the United States. Work carried out by the University of Dundee, in Scotland, revealed that if the pesticides were applied directly to the brains of the pollinators, they caused a loss of brain activity. Dr Christopher Connolly said: “We found neonicotinoids cause an immediate hyper-activation – so an epileptic type activity – this was proceeded by neuronal inactivation, where the brain goes quiet and cannot communicate any more. The same effects occur when we used organophosphates.
