October 21, 2012

expert reaction to impact of pesticides on bumblebees

A study published in Nature reported that chronic exposure of bumblebees to agricultural pesticides can impair their foraging behaviour.

Dr James Cresswell, Ecotoxicologist  in Biosciences, University of Exeter, said:

“This research adds to what we already know but there is no evidence of an interaction between the different chemicals in the mix, which would be of significant interest.  It certainly wouldn’t be fair to say that this research spells doom for wild bees.”

Prof David Goulson, Professor of Biological Sciences, University of Stirling, said:

“It is great to see more well-performed and realistic research emerging into the impacts of neonicotinoid pesticides on bees. This new work adds another substantial boulder to the rapidly growing mound of evidence which now points to a significant and worrying impact of these chemicals on our wild bumblebees. Given the large scale of their use globally – for example 1.3 million hectares of crop are treated with them in the UK alone each year – the scale of these impacts is likely to be very large. This new study also highlights the threat posed by exposing beneficial insects to mixtures of toxic chemicals, something which all bees face in agricultural environments, but the effects of which are rather poorly understood.”

Dr Alison Haughton, Department of AgroEcology, Rothamsted Research, said:

“There is a growing body of work suggesting there could be sub-lethal effects of neonicotinoids on bees and this paper by Gill et al. adds to this body of evidence.  Since honeybees differ from bumblebees ecologically and biologically this paper can only inform scientists in the methodological approach for assessing effects at the individual and colony level for honeybees, and even here, the approaches used would need to be modified to account for differences between the two types of bee. 

“More research will be required to make a risk-based assessment of the practical implications this could have for farming, pollinators and the service of pollination.  Assessing sub-lethal effects of pesticides on non-target species in a standard and biologically meaningful way is currently not part of the regulatory process, however this is being addressed.  The Pollination Ecology Group in the AgroEcology Department at Rothamsted is actively pursuing this important area.

“Our work in the Pollination Ecology Group has already highlighted critical issues for pollinators, including how disease affects colonies through changes in individuals’ development and behaviour and, the implications of varying levels of nutrition provided by different types of forage in the farmed landscape.”

‘Combined pesticide exposure severely affects individual- and colony-level traits in bees’ by R. Gill et al, published in Nature on Sunday 21 October 2012.