from DEFRA:

> While this assessment cannot exclude rare effects of neonicotinoids on bees in the field, it suggests that effects on bees do not occur under normal circumstances. This assessment also suggests that laboratory based studies demonstrating sub-lethal effects on bees from neonicotinoids did not replicate realistic conditions, but extreme scenarios. Consequently, it supports the view that the risk to bee populations from neonicotinoids, as they are currently used, is low.

> Evidence suggests that populations of bees in free-ranging situations do not normally experience the levels of neonicotinoids that result in sub-lethal toxic effects. This, together with the dilution effect of bees not always feeding upon treated crops, is the most likely reason why field studies do not demonstrate the same effects as studies where bees are given artificial doses of pesticide.

> Insects are significant pollinators of crops like oilseed rape where yields can collapse in the absence of pollinators [12-18]. In the UK, neonicotinoids have been used as seed treatments on OSR for 10 years. This suggests that if pesticide use was reducing pollinator effectiveness then this would also be detrimental to crop productivity. Consequently, the claim that treatment of OSR with neonicotinoids kills pollinators is partly countered by the success of the crops themselves.

© Crown copyright 2013
You may re-use this information free of charge in any format or medium, under the terms of the Open Government Licence. 
This document/publication is also available on our website at:
http://www.defra.gov.uk/environment/quality/chemicals/pesticides/insecticides-bees/

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