Insects and Insecticides

Written evidence submitted by Prof Simon Potts

1. Executive Summary

1.1. Wild pollinators (bumblebees, solitary bees, hoverflies and other insects), not managed honeybees, are the main pollinators of crops and wild flowers in the UK.

1.2. Both wild pollinators and managed honeybees are in decline in the UK and the drivers of pollinator loss are likely to be multi-factorial.

1.3. About 20% of cropped area in the UK needs insect pollination and demand for pollination services is increasing.

1.4. The total value of pollination services to UK agriculture was £603 million in 2010.

1.5. The cost of replacing insect pollination with artificial means would be ~£1.9 billion and therefore does not present a viable alternative.

1.6. The public would be willing to pay between £1.3-1.8 billion per year to conserve pollinators.

1.7. Pollination of wild plants underpins a suite of other ecosystem services (e.g. carbon sequestration, soil and water quality, and biodiversity) which is likely to have a very high, but currently unknown , value.

1.8. Multiple m itigation options are available to minimise the impacts of pesticides on pollinators. These include reducing overall application, improving application technologies, replacing pesticides with biocontrol and other IPM strategies, and landscape management to provide additional pollinator habitats.

1.9. It is recommend that Defra undertakes or funds research to conduct cost benefitsanalyses and multi-stakeholder risk assessment s of the various mitigation scenarios to understand the impact son fa r mer livelihoods , food security, pollinator conservationa ndpublic opinion.

2. Introduction

2.1. I am Professor of Biodiversity and Ecosystem Services at the School of Agriculture, Policy and Development, reading University, with more than 20 years’ experience working on pollinators and pollinationservices. I was the lead author for the Chapter on Pollination in the UK National Ecosystem Assessment (Smith et al. 2011).

2.2. I have a number of professional roles advising or providing evidenceto national and international organisations including: UK Parliamentary Office of Science and Technology; Defra; Natural England; UK Science and Innovation network (FCO); UK Office of Government Commerce - Starting Gate review "Healthy Bees Implementation"; European Environment Agency; European Commission DG Agriculture and DG Environment; Food and Agricultural Organisation of the United Nations; International Commission of Plant-Pollinator Relationships; and IUCN Task force on declining pollinator services.

3. Background

3.1. Pollination is a critical ecosystem service for agricultural crop production and the maintenance of wild flower diversity. Pollination levels depend both on the supply of pollinators (i.e. the availability of sufficient numbers of the right sort of pollinators in the right place at the right time) and the demand from plants (i.e. the area and type of crops needing pollination).

3.2. The main pollinators of crops and wild flowers in the UK are bees (honeybees, bumblebees, solitary bees) and hoverflies, and to a lesser extent other flies, wasps, beetles and butterflies.

4. Supply of Pollinators

4.1. Wild pollinators, not managed honeybees, are the main pollinators in the UK. In 2007, UK populations of honeybees were only capable of supplying a maximum of 34% of pollination service demands of crops even under favourable assumptions; dropping from 79% in 1984 (Breeze et al. 2011). The actual current contribution is expected to be closer to 15%.

4.2. Wild pollinators, including bumble bees, solitary bees and hoverflies and other insects are therefore estimated to be responsible for ~85% of crop pollination services (Breeze et al. 2011).

4.3. While yet to be fully assessed, wild pollinators, rather than managed honeybees, are likely to be the main pollinators of wild flowers.

4.4. Wild pollinators are in severe decline in the UK. More than half of British landscapes, where sufficient data was available, have shown significant declines in wild bee diversity since 1980 (Biesmeijer et al. 2006). Some areas have also seen significant declines in hoverfly diversity, while other have shown no change or increases.

4.5. Honeybees are in severe decline in the UK. Almost all honeybees are managed, and feral colonies are extremely rare in the UK. The number of honeybee colonies has dropped significantly between 1985 and 2005: England 54% loss, Wales 23% loss, and Scotland 14% loss (Potts et al. 2010a). There has been a modest increase in the number of colonies in some areas very recently.

4.6. Drivers of pollinator loss in the UK are likely to be multi-factorial and include: loss and fragmentation of habitat, environmental chemicals including pesticides and herbicides, pests and pathogens, climate change and invasive species (Potts et al. 2010b). However, the relative contribution of each driver and their synergistic effects are largely unknown.

5. Demand for Pollination Services

5.1. Most crops and wild flowers need insect pollination. Approximately 84% of European crops depend at least in part on insect pollination services (Williams 1994). About 78% of temperate wild flowers need insect pollination (Ollerton et al. 2011).

5.2. About 20% of the area of UK crops are comprised those which are pollinator dependent; this is a 38% increase since 1989 (Breeze et al. 2011). This trend of increasing area is expected to continue with growing demands for: biofuel crops (e.g. oilseed rape which is insect dependent), locally grown fruits and vegetables, and the uptake of new crops (e.g. blueberries).

5.3. The UK produces only a small proportion of pollinator dependent products and imports the rest from overseas (e.g. 30% apples and 57% of strawberries are UK grown) (Smith et al. 2011).

6. Value of Pollinators to UK Agriculture

6.1. Total pollinator loss for UK agriculture would translate into an annual loss of £603million in 2010 (updated for 2010, from Smith et al. 2011); equivalent to about 13% of total farmgate crop value. However, this estimate fails to take into account the contribution of pollinators to: forage crops, such as clover, which support livestock; small-scale agriculture, such as allotments and gardens; ornamental flower production; and seed production for agricultural crop planting.

6.2. The value of pollinators to UK agriculture is increasing year on year as the area of pollinator dependent crops increases in response to increasing demands biofuels (e.g. oilseed rape), locally grown fruits and vegetables and novel crops (e.g. blueberries) (Breeze et al. 2011).

6.3. The cost of replacing the service provided by insect pollinators with hand pollination is £1.9 billion, and therefore does not present an economically viable option in the UK (Breeze et al. 2012).

7. Other Values of Pollinators

7.1. In addition to crop pollination, the public values pollinators for aesthetic, cultural, and recreational reasons in terms of their inherent conservation worth and that of wild and garden flowers they pollinate, and florally rich landscapes. The public would be willing to pay between £1.3 billion (Breeze 2012) and £1.8 billion (Mwebaze et al. 2010) per year to conserve pollinators.

7.2. Healthy and diverse plant communities rely on insect pollination, and these communities provide a wide range of other ecosystem services. These include the support of wider biodiversity through the provision of food (e.g. seeds and fruit) and shelter for other species including birds, mammals, reptiles and insects. Plants also contribute, to varying degrees, to carbon sequestration, the maintenance soil fertility and structure, flood protection, clean drinking water, and noise regulation (Smith et al. 2011). The contribution of pollinators to these services is indirect, but as the services themselves are likely to be valued at many billions of pounds, the value of pollinators is non-trivial.

8. Mitigation of Insecticide Impacts on Pollinators

8.1. There are a number of options available to mitigate against the impacts of pesticides on pollinators. These fall in to three broad categories: (i) reduction of use of pesticides; (ii) reduction in risk of exposure at point of application; and (iii) landscape management approaches. It is likely that a combination of these would be the most effective approach to safeguarding UK pollinators and pollination services.

8.2. Reduce pesticide applications. Pesticide application rates rose by 6.5% between 2005 and 2010 due to increasing treatment intensity per ha on a number of crops (FERA, 2012). A phased reduction in the application of all pesticides, including neonicotinoids, would be likely to benefit pollinators. In parallel, the adoption of other pest control methods such as supplementing with biocontrol agents or the management of uncultivated areas of farmland to enhance natural enemy populations, would help maintain overall pest control.

8.3. Improved application technologies. Adopting more stringent requirements for famers to use the best available application technologies, such as those reducing the loss of seed coating dust and the latest spray nozzle designs, would help minimise exposure risks.

8.4. Landscape management approaches, using instruments such as Agri-Environment Schemes, could be used to provide four sorts of benefits to pollinators. First, adding non-sprayed elements to the landscape would result in an overall dilution of the total amount of pesticide per unit area; secondly, if these areas were floristically rich then they could provide additional forage resources for both wild and managed pollinators; thirdly, these areas could provide ‘safe heavens’ to effectively reduce exposure of pollinators to sprayed crops; and finally, modifying cropping patterns and rotations so that flowering times were synchronised across a landscape could reduce overall exposure.

8.5. Based on expert opinion, it is estimated that the cost of using current agri-environment scheme options for conserving wild pollinators would be in the region of £40-79M for 5 years (Breeze 2012). This was based on mitigating against multiple pressures on pollinators not just pesticides.

9. Recommendations

9.1. Defra to fund research (directly or through Research Councils) to address key knowledge gaps focussed on the costs and benefits of implementing different mitigation actions; this would need to take into account multi-stakeholder risks assessments for farmer livelihoods, food security (including farm productivity, food prices for consumers and reliance on imports) , environmental quality (pollution and harm to wildlife) , pollinator conserva tion and public opinion. These sh ould include cost:benefit analysis and risk assessment of the following scenarios :

9.2. Business as usual with no change in current policy or practice.

9.3. The potential loss in food production following a phased reduction in overall pesticide use: (i) without any substitute pest control methods; (ii) with replacement of neonicotinoids with other available pesticides; (iii) with the use of current biocontrol technologies.

9.4. Adoption of state of the art application technologies.

9.5. Adoption of landscape management practices to protect pollinators using current Agri-Environment Scheme instruments and/or using novel instruments, such as those that may arise under the CAP reform or payment for ecosystem service tools.

9.6. Developing a ‘p olluter pays model’ where the estimated negative impacts of pesticide applications carry a cost which is then used to pay for biodiversity offset to provide habitat elsewhere to protect pollinators.

9.7. Combinations of 9.3 to 9.6.


Biesmeijer, J.C., Roberts, S.P.M., Reemer, M., Ohlemuller, R., Edwards, M., Peeters, T., Schaffers, A.P., Potts, S.G., Kleukers, R., Thomas, C.D., Settele, J., & Kunin, W.E. (2006) Parallel declines in pollinators and insect‐pollinated plants in Britain and the Netherlands. Science 313: 351‐354

Breeze, T.D., Bailey, A.P., Balcombe, K.G., & Potts, S.G. (2011) Pollination services in the UK: How important are honeybees? Agriculture, Ecosystems & Environment 142: 137‐143

Breeze, T.D., Roberts, S.P.M., & Potts, S.G. (2012). The Decline of England's Bees: Policy Review and Recommendations. Friends of the Earth, London.

Breeze T.D. (2012) Valuing UK Pollination Services; PhD Thesis, University of Reading

Food and Environment Research Agency (2012) Pesticide Usage Statistics

Mwebaze P., Marris G.C., Budge G.E., Brown M., Potts S.G., Breeze T.D. and MacLeod A. (2010) Quantifying the Value of Ecosystem Services: A Case Study of Honeybee Pollination in the UK; Contributed Paper for the 12th Annual BIOECON Conference

Ollerton, J., R. Winfree, and S. Tarrant(2011) How many flowering plants are pollinated by animals? Oikos 120: 321-326

Potts S.G., Roberts S.P.M., Dean R., Marris G., Brown M., Jones R., Settele J. (2010b) Declines of managed honeybees and beekeepers in Europe. Journal of Apicultural Research 49: 15-22

Potts, S.G., Biesmeijer, J.C., Kremen, C., Neumann, P., Schweiger, O., & Kunin, W.E. (2010a) Global pollinator declines: trends, impacts and drivers. Trends in Ecology & Evolution 25: 345‐353

Smith, P., Ashmore, M., Black, H., Burgess, P., Evans, C., Hails, R., Potts S.G., Quine, T., Thomson, A., Biesmeijer, K., Breeze, T., Broadmeadow, M., Ferrier, R., Freer, J., Hansom, J., Haygarth, P., Hesketh, H., Hicks, K., Johnson, A., Kay, D., Kunin, W., Lilly, A., May, L., Memmott, J., Orr, H., Pickup, R., Purse, B., & Squire, G. (2011). Chapter 14: Regulating services. In The UK National Ecosystem Assessment Technical Report. UK National Ecosystem Assessment, UNEP‐WCMC, Cambridge

Williams, I.H. (1994) The dependence of crop production within the European Union on pollination by honeybees. Agricultural Zoology Reviews 6: 229-257

2 December 2012 

Prepared 6th December 2012