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Study uncovers missing link between neonicotinoids and bees

Staff writer |
Researchers in France found the missing link behind the different conclusions reached by tests on neonicotinoids and bees in the laboratory and in the field.

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Research findings from France have shed more light on the links between neonicotinoid use and bee healthScientists from state agricultural research institute INRA, said that lab-based tests consistently show impacts on bee health from neonicotinoid pesticides, whereas field studies don’t appear to show effects on the performance of honeybee colonies.

Debate over systemic insecticides - of which neonicotinoids are the most prominent class, commonly used as seed dressings - is hotting up again, as the European Commission is expected to review its partial ban on three neonicotinoids before the end of the year.

The Commission’s measures, which restrict neonicotinoid treatments of flowering crops, were introduced in 2013 in light of a growing body of evidence that the products were harmful to bee health, though pesticide manufacturers, industry groups and some member state governments have strongly opposed the restrictions.

The French scientists were looking at the impacts of one neonic, thiamethoxam sold as Cruiser OSR, at the order of France’s food safety agency ANSES. However, bees were also unexpectedly exposed to imidacloprid, another neonicotinoid which was banned from use on sunflowers in France in 1999.

Their findings suggest that the pesticides do harm honeybees because bees in crops treated with neonics died off at a quicker rate, but that whole colonies alter their behaviour, producing more worker bees to make up for the high losses in response to exposure.

However, this process delays the production of male drones in the colonies, whose job is to breed.

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