The European Food Safety Authority (EFSA) is conducting an in-depth review into pesticides and their possible effects on bees. Its report is expected to be published in December this year.
Over the past decade or so there have been numerous reports of declines in bee colonies, particularly in the North America and Western Europe regions. No single contributing factor has been attributed to these declines, but much speculation suggests the result could be due to adverse effects of intensive agriculture and pesticide use. Many studies have been conducted on this issue and earlier this year a new development occurred with the publication of two studies alleging links between the use of neonicotinoids and the increase in honey bees' mortality.
EFSA has expressed doubts over any links these pesticides have with bee colony decline, highlighting a lack of conclusive data to support the theory that these common pesticides have adverse effects on bees. However, despite EFSA's doubts, the findings of these studies have prompted some EU Member States to call for a reassessment of neonicotinoids and this has resulted in a clear difference in opinion – and implementation of different legislative measures – across the EU. In France, for example, thiamethoxam (one type of neonicotinoid) has been banned following conclusions by French scientists that it has adverse affects on honeybees' abilities to find their way back to their nests.
EFSA's current review is focusing on the effects of a series of neonicotinoids, including thiamethoxam, imidacloprid, clothianidin, acetamiprid and thiacloprid, which are used to protect crops from locusts, aphids and other pests.
Nevertheless, EFSA continues to maintain that there is no clear evidence that exposure to pesticides is causing declines in bee colonies. EFSA bases these conclusions on a review of scientific literature that it commissioned the UK Food and Environment Research Agency to carry out. The review was based on various references containing data on exposure routes for bees, pesticide mixtures and pesticide interactions with disease. The data revealed that nectar-foraging bees were likely to experience the highest exposure to pesticides, and that a direct overspray of pesticides contributed to contaminated nectar. However, the study also revealed that there were a variety of other routes by which bees could be exposed to pesticides, such as from dust and pollen. The review also revealed that there was insufficient data relating to realistic levels and combinations of pesticides and, in addition, that there was insufficient data on the effects of a wider range of pesticides on bumblebees and solitary bees, which are commonly bigger than honey bees.
New study
EFSA published the UK Food and Environment Research Agency's review in September, but stressed that it has so far not reviewed its findings, is yet to come to any decision on this issue and that the review constitutes only a part of EFSA's ongoing wider work programme analysing the declines in bee colonies.
Since then, in October this year, the results of a new study analysing the effects that pesticides have on bees has been published by researchers Dr Richard Gill and Dr Nigel Raine of Royal Holloway, University of London. This study appears to bridge some of the important gaps in data that were identified by EFSA; whereas previous studies tended to examine the impact of certain pesticides on individual honey bees, this latest study provides significant information about the effects that combinations of pesticides (which would realistically be found in fields) would have on colonies of 40 bumblebees.
Dr Gill and Dr Raine's study will no doubt provide a significant contribution to EFSA, not only as part of its wider reviews on bee colony decline, but also in relation to its current review into the effects of neonicotinoid insecticides which is expected in December.
