Pesticides short-circuit bee brains: study PESTICIDES used by farmers to protect crops or bee hives can scramble the brain circuits of honeybees, affecting memory and navigation skills needed to find food, scientists say. This in turn threatened entire colonies of bees whose pollinating functions are vital for human food production, they wrote in the journal Nature Communications. The team observed honeybee brains in the lab after exposing them to neonicotinoid pesticides used on crops, and organophosphates, the most widely used group of insecticides in the world - in this case coumaphos - sometimes used to control mite infestations in beehives. Exposed to similar concentrations of the two pesticides as they would encounter in the environment, the learning circuits of the bee brains soon stopped working, said the researchers. "Together, the two classes of pesticide showed a greater negative effect on the bee brain and are predicted to inhibit honeybee learning," co-author Christopher Connolly of the University of Dundee's Medical Research Institute told AFP. "Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated with food," added colleague Geraldine Wright of Newcastle University's Centre for Behaviour and Evolution. Disruption in this important function has profound implications for honeybee colony survival because bees that cannot learn will not be able to find food. The finding comes amid a fierce debate on the continuing use of neonicotinoids. Two weeks ago, European nations rejected a proposed two-year ban on the brain-targeting group of insecticides following opposition by the agrochemical industry. Beekeepers in Europe, North America and elsewhere are worried by so-called colony collapse disorder - a phenomenon in which adult bees abruptly disappear from beehives - which has been blamed on mites, a virus or fungus, pesticides or a combination thereof. Bees account for 80 per cent of plant pollination by insects. Without them, many crops would be unable to bear fruit or would have to be pollinated by hand. The researchers said their findings should prompt a rethink of pesticide use.