January 5, 2016

expert reaction to new research on pollen and pesticides

Publishing in the journal Environmental International a group of scientists has published their work investigating bees’ collection of pollen and their exposure to pesticides.

Dr Mike Garratt, an ecologist at the University of Reading’s Centre for Agri-Environmental Research, said:

“This study provides important new evidence identifying potential routes of exposure of bees to a number of different agrochemicals, including neonicotinoids and fungicides, traces of which have been found in the pollen of crops and wild flowers. Some of these chemicals can have negative impacts on bees and so this exposure presents a risk to these important pollinators in the British countryside.

“However pesticide use is not the only reason for bee decline. Other research has shown that climate change and habitat loss are also important and these, in conjunction with pesticide exposure, may be increasing the vulnerability of many pollinators.

“An outright ban on neonicotinoids may not reverse bee decline and it is unrealistic to expect farmers to abandon pesticides altogether, which would most likely have a negative impact on crop yields and much higher food prices for UK shoppers. It is important to consider that, in the absence of neonicotinoids, which other insecticides would be used and what negative effects these may also have on non-target species in the UK countryside.

“What is needed is a fully thought through and long term policy, supported by more research, helping farmers to follow best practices minimising risks to bees and other pollinators and provide the best possible stewardship of the countryside. This should encourage them to reduce spraying, encourage wildlife habitats, while still maintaining high yields.”

Dr Scott Hayward, Lecturer in Molecular Ecophysiology at the University of Birmingham, said:

“This is an important paper that highlights the cocktail of pesticides (insecticides and fungicides etc) used in agriculture, as well as providing further context regarding the levels consumed by two key pollinator species – honey bees and bumble bees. Crucially, the paper sets out how these pesticide ‘doses’ experienced by bees fall within levels that previous research have deemed detrimental to foraging behaviour and colony health.

“It is perhaps unsurprising that monoculture-dominated agricultural landscapes, which are also typically exposed to regular pesticide applications, seem to present a greater threat to bee health than urban landscapes. This is probably because urban environments have more patchy pesticide use, and because urban gardens or parks typically provide a greater diversity of uncontaminated pollen and nectar resources. Interestingly, however, unlike the tightly regulated use of pesticides in agriculture, the domestic use of pesticides is not controlled in any way. Many commercial garden sprays still contained neonicotinoids following the EU ban of their use in agriculture, and so further studies are needed in a much wider selection of urban sites to better understand exposure levels in the typical UK garden or park.”

Prof. Nigel Raine, Rebanks Family Chair in Pollinator Conservation at the University of Guelph in Canada, said:

“This is important information on the actual levels of pesticides bees can be exposed to in urban and rural landscapes. Multiple fungicides and insecticides were found in the pollen of both crops and wild flowers, and collected by bees as food for their offspring. The potential interactive effects of these pesticide combinations are currently poorly understood for bees, and this study may under-estimate the extent of exposure as not all classes of pesticide were analysed.

“Average levels of the neonicotinoid thiamethoxam in pollen collected by bumblebees in rural areas were appreciably higher than exposure levels used in many recent laboratory or semi-field studies. This study reinforces the field-relevance of such experiments showing effects on bee behaviour, colony function and pollination following controlled neonicotinoid exposure.”

‘Widespread contamination of wildflower and bee-collected pollen with complex mixtures of neonicotinoids and fungicides’ by Arthur David et al. published in Environmental International.

Declared interests

Dr Mike Garratt is an employee of the University of Reading working on research funded by UK research councils, Europe FP7, DEFRA and the UK Insect Pollinators initiative. He is convenor of Royal Entomological Society Pollination Special Interest Group and a member of the British Ecological Society, Royal Entomological Society, Society for Conservation Biology, and has involvement with the WorldBeeProject charity.

No others declared