ROLE OF PESTICIDES IN BEE DECLINE
Scientists call for evidence-driven debate
An international panel of scientists including Professor Lin Field from Rothamsted Research, which receives strategic funding from the BBSRC, is today calling for an evidence-driven debate over whether a widely used type of insecticide is to blame for declines in bees and other insect pollinators.
An EU ban on certain neonicotinoid insecticides was introduced in December 2013 because of fears they are harming pollinating insects. Pollination by insects is critical for many crops and for wild plants but at the same time neonicotinoids are one of the most effective insecticides used by farmers. Potential tensions amongst the agricultural and environmental consequences of neonicotinoid use have made this topic one of the most controversial involving science and policy.
A restatement of the scientific evidence on neonicotinoids has today been published in the Proceedings of the Royal Society B. The restatement, from a group of nine scientists led by Professor Charles Godfray and Professor Angela McLean of the Oxford Martin School at Oxford University, clarifies the scientific evidence available on neonicotinoids, to enable different stakeholders to develop coherent policy and practice recommendations.
One of the authors Professor Lin Field from Rothamsted Research said "It was a pleasure to work with my co-authors who all have diverse expertises, relevant to the debate over the potential effects of neonicotinoids on pollinators, but all wanted to look at evidence rather than opinion. It is essential that we base decisions in this important area on science, so that we find the best way forward to ensure both pollinator success and good crop protection strategies for food production."
Professor Charles Godfray said: “Pollinators are clearly exposed to neonicotinoid insecticides, but seldom to lethal doses, and we need a better understanding of the consequences of realistic sub-lethal doses to the insect individual, bee colony and pollinator population.”
Professor Angela McLean added; “A major question to be addressed is what farmers will do now that they face restrictions on the use of neonicotinoids. Will they switch to crops that need less insecticide treatment or might they apply older but more dangerous chemicals?”
The restatement describes how much insecticide is present in a treated plant and how much is consumed by pollinators. It goes on to summarise how neonicotinoids affect individual bees and other pollinators, and the consequences at the colony and population levels.
In reaction to this study, Professor Ian Boyd, Chief Scientific Advisor at Defra said: “It is essential that policies on the use of pesticides are built on sound scientific evidence. This paper provides an independent assessment of this subject which will provide clarity and authority in order to help people make more informed choices."
Paul de Zylva, from Friends of the Earth, commented: “This project is an important step toward much needed public and scientific debate and scrutiny. The Government should support and fund both more open science and safer ways to grow crops as part of its National Pollinator Strategy due in July.”
• Since their introduction in the 1990s, the use of neonicotinoids has expanded so that today they comprise about 30% by value of the global insecticide market
• Insects are important for pollinating many UK crops, including strawberry, raspberry, apple, pear, plum, tomato and many vegetables.
• The populations of both managed honeybees and wild pollinators were declining before the widespread use of neonicotinoids, with habitat change and honeybee disease thought to be particularly important causes.
• A series of experiments have raised the possibility that widespread neonicotinoid use may exacerbate pollinator decline, though other studies find fewer effects of the insecticide.
See Notes to Editor for position statement, issued 21/05/2014.
• The paper (Proc. R. Soc. B 281: 20150558) and electronic supplementary material is open access and available here http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2014.0558. A concatenated version can be downloaded at http://www.futureoffood.ox.ac.uk/news/neonics.
• This summary is the second in a planned series of “restatements”, part of a project led by Professors Angela McLean & Charles Godfray from the Oxford Martin School at the University of Oxford. They are designed to help policy-makers access scientific evidence in controversial topics. To do this, a group of respected scientists who represent the range of views on a particular topic are convened. They together write the “restatement” of the evidence. The restatement is a series of paragraphs designed to be: concise and jargon-free, as policy neutral as possible, and each assigned a score denoting the strength and nature of the underlying evidence. Before publication each restatement is sent to a large number of interested parties and the group prepares the final version in the light of their comments.
• Also taking part in the project were: Tjeerd Blacquière from Wageningen University and Research Centre, the Netherlands; Linda Field from Rothamsted Research; Rosemary Hails and Adam Vanbergen from the NERC Centre for Ecology and Hydrology; Gillian Petrokofsky from Oxford University; Simon Potts from Reading University and Nigel Raine from the University of Guelph, Canada.
• The EU has banned the use of three types of neonicotinoids on crops attractive to bees for a minimum of two years.
• Defra is the UK’s Department of the Environment, Food and Rural Affairs.
Neonicotinoids and bees - Rothamsted position statement (21/05/2014)
The European Commission has adopted a proposal (Regulation (EU) No 485/2013 ) to restrict the use of 3 pesticides belonging to the neonicotinoids family (clothianidin, imidacloprid and thiametoxam) for a period of 2 years. An Appeal Committee vote on 29 April 2013 returned an inconclusive opinion where: 15 Member States supported the proposal, 4 abstained and 8 voted against. Since no qualified majority was reached, procedurally, the responsibility on deciding whether to adopt the proposal was with the Commission.
We are concerned that the decision has been made through political lobbying, rather than a comprehensive and sound scientific risk-benefit assessment. In our view, there is still is not enough clear evidence supporting a ban on neonicotinoids. Of course, they can kill bees, they are insecticides; but whether they actually do this, or whether sublethal effects occur and damage the colonies on any important scale, has not been proven. There are many other factors known to affect bee colonies - the varroa mite, the bee viruses spread by the mites, pesticides that beekeepers use to kill the mites, climate effects and flower and nectar availability - all of which need to be taken into consideration. Thinking we can solve the bee problem by a ban on neonicotinoids may mean we overlook these other important factors.
What’s more, the decision does not take account of the risk of the ban on our ability to control insect pests and secure crop yields. Securing, and indeed increasing yields for food security, is a priority in Europe and will require a crop protection strategy to avoid unnecessary losses. At present and until we find reliable and effective alternatives, the control of insect pests (and the crop diseases they carry) will rely on the use of chemical insecticides and banning neonicotinoids will reduce our options.
A major biological risk of removing an entire chemistry is that resistance will develop against the remaining products. This is exactly what has happened in human health with bacterial antibiotic resistance. Or are we willing to accept lower yields, leading to greater imports and potentially higher food prices? The UK has already become a net importer of wheat this year for the first time in a decade. It has also been reported that a ban on neonicotinoids could result in a significant impact to UK oilseed farmers, costing the UK economy £630m each year.
That said, we should not ignore the potential implications of pesticide use on pollinators. Rather than an immediate ban, we should take this opportunity to further study and de-convolute the many possible causes of colony collapse and aberrant foraging behaviour. This will then help us to balance the risks and benefits for crop protection, crop pollination, ecosystem function and our health appropriately.
"We need a proper science-led risk assessment to understand the effects of pesticides (and their active ingredients) on bees, whilst considering the effects on other pollinators (both wild and managed), within the context of farming practice and the wider ecosystem. This will help us balance the risks and benefits for crop protection, crop pollination, ecosystem function and our health appropriately. More work is required to get these data."
About Rothamsted Research
Rothamsted Research is the longest-running agricultural research institute in the world. We work from gene to field with a proud history of ground-breaking discoveries, from crop treatment to crop protection, from statistical interpretation to soils management. Our founders, in 1843, were the pioneers of modern agriculture, and we are known for our imaginative science and our collaborative influence on fresh thinking and farming practices.
Through independent science and innovation, we make significant contributions to improving agri-food systems in the UK and internationally. In terms of the institute’s economic contribution, the cumulative impact of our work in the UK was calculated to exceed £3000 million a year in 20151. Our strength lies in our systems approach, which combines science and strategic research, interdisciplinary teams and partnerships.
Rothamsted is also home to three unique resources. These National Capabilities are open to researchers from all over the world: The Long-Term Experiments, Rothamsted Insect Survey and the North Wyke Farm Platform.
We are strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC), with additional support from other national and international funding streams, and from industry. We are also supported by the Lawes Agricultural Trust (LAT).
For more information, visit https://www.rothamsted.ac.uk/; Twitter @Rothamsted
1Rothamsted Research and the Value of Excellence: A synthesis of the available evidence, by Séan Rickard (Oct 2015)
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The Lawes Agricultural Trust, established in 1889 by Sir John Bennet Lawes, supports Rothamsted Research’s national and international agricultural science through the provision of land, facilities and funding. LAT, a charitable trust, owns the estates at Harpenden and Broom's Barn, including many of the buildings used by Rothamsted Research. LAT provides an annual research grant to the Director, accommodation for nearly 200 people, and support for fellowships for young scientists from developing countries. LAT also makes capital grants to help modernise facilities at Rothamsted, or invests in new buildings.