Impact and mitigation of emergent diseases on major UK insect pollinators

The mysterious death of thousands of honey bee colonies in the USA in the winter of 2005/06, termed Colony Collapse Disorder, focused media attention on the plight of bees, the world's primary pollinators. In the UK, both the honey bee and the 24 species of bumble bee play a major role in crop and wildflower pollination, and both have been suffering serious declines. Exotic (non-native) and newly emergent (native, but with increasing virulence) diseases are considered a major cause of decline in bees and consequently they are one of the greatest challenges to bees in the UK. The single-celled microsporidian 'fungus' Nosema ceranae is an exotic infectious disease of the honey bee that primarily attacks the gut of the bee. We have shown that it has spread worldwide, including the UK, within the last ca. 10 years, and it has been implicated in honey bee colony collapses in the USA (2005/06) and Spain (2007/08). Deformed Wing Virus (DWV) is the major disease organism associated with Varroa destructor mites of honey bees. This emergent disease replicates inside the bee, causing deformed wings and reduced longevity and is responsible for considerable honey bee colony mortality in the UK. Both disease organisms have recently been detected in bumble bees. Thus, both N. ceranae and DWV pose major threats to the UK's principal pollinators. Investigations of pollinator diseases typically focus on single-species interactions (one disease organism and one pollinator species). However, most parasites have multiple hosts and most hosts have multiple parasites. Here, we will take a multidisciplinary, ecological systems-based approach to understand the virulence (e.g. reduced longevity) and transmission of these two major disease organisms, N. ceranae and DWV, and detrimental synergies between them, on the UK's major pollination service providers: the honey bee and bumble bees. We will undertake laboratory epidemiological experiments (in which we look at the impact of a disease organism(s) on its host and the progression of disease from initial infection through to host mortality or recovery), state-of-the-art 'post-genomic' analyses and high-resolution radar tracking of individual insects to determine disease virulence and transmission. Using these data, we will parameterise a novel epidemiological model that will allow risk assessment of these emergent diseases on UK pollinators. Taking advantage of the complete genomes of both N. ceranae and DWV, we will undertake country-wide screening of pollinators to provide the evidence base of current disease strain prevalence. We will also refine innovative approaches for combating disease impacts. Specifically we will investigate the role of 'lactic acid bacteria' (the 'good guys' found naturally in healthy bee guts) and so-called RNAi technology (=RNA interference - short stretches of RNA that may interfere with viral replication inside a host) in curing bees of N. ceranae and DWV, which would provide long-term sustainable solutions to these disease organisms. For ca. £1.6 million (75% FEC), this interdisciplinary project will combine expertise from three leading UK bee and pollination research groups at Queen's University Belfast, Royal Holloway University of London and Rothamsted Research with mathematical modellers (Royal Holloway), pioneering microbiologists at the University of Lund (Sweden) and the world leader in RNAi technologies for bee diseases: Beeologics (USA). It will elucidate the impact and epidemiology of two increasingly important parasites on the UK's principal insect pollinators. Results will provide the evidence base for policy on disease mitigation strategies for government (conservation and agricultural advisory bodies) and major stakeholders (beekeepers, bumble bee importers). As well as serving as a model study of emergent pollinator diseases, project results will feed directly into husbandry practices and approaches to mitigate disease impact.

Honey bees (Apis mellifera) and bumble bees (Bombus spp.) are the UK's principal pollinators yet both are in decline. Emergent infectious diseases are considered a major cause of bee decline. By combining theoretical modelling with empirical high-resolution evidence in an ecological systems approach, our £1.6 million (75% FEC) 3 year multidisciplinary project aims to understand the current and future threats posed by the UK's emergent and exotic honey bee pathogens on its major pollinators, and to develop innovative and sustainable mitigation strategies. We shall develop protocols for the culturing of DWV and N. ceranae so that single variants of these pathogens can be used in experimental investigation, allowing an explicitly experimental approach to host-parasite interactions. The UK's six common Bombus species will then be challenged with these pathogens to determine their susceptibility. Honey bees and bumble bees will then be challenged with one or both pathogens to determine synergies among multispecies parasite assemblages and host susceptibility, host immune response and host behaviour (pathogen transmission) measured in the lab and field as changes in host flight behaviour. These studies will be complemented by analysis of inter-specific host transmission of pathogens using state-of-the-art radar tracking of individual insects. A biologically realistic epidemiological model for a multi-parasite multi-eusocial-host system will be developed and used to refine experimental design and will be parameterised by results derived from these objectives. This model will provide risk assessment of DWV/N. ceranae and other emergent pathogens on the UK's major pollinator species. Two novel control methods, based on lactic acid bacteria of the bee gut and RNAi, will be tested for their efficacy. A countrywide survey of DWV and N. ceranae variants will provide the evidence base of current disease status and potential threats to the honey bee and to bumble bees.

This interdisciplinary project will elucidate the impact and epidemiology of two increasingly important parasites, deformed wing virus (DWV) and the microsporidian Nosema ceranae, on the UK's major insect pollinators: honey bees and bumble bees. The impact of this project will be: 1) a substantially enhanced understanding of the interactions between pathogens and multiple pollinator hosts, knowledge that can be used to predict pollinator population changes and provide opportunities to mitigate parasite impacts with appropriate disease control strategies; and 2) a suite of new tools of vital importance in the study of pollinator pathology. In addition to the scientific community for whom high-impact research articles will be written, both areas will be of direct relevance to the following non-academic sectors: a) policy makers on sustainable pollination service provision, b) commercial and hobbyist beekeepers, c) NGOs and conservationists, d) farmers and industries involved in crop and food production and e) the wider public interested in the environment and pollinator conservation. a) Policy makers: We will use our contacts to ensure the implications of the project results are integrated into policies affecting bee and pollinator management. One route is via our close connections with EU policy makers (COLOSS and a briefing workshop for Members of the European Parliament on pollination and bees). b) Beekeepers: We will speak at beekeeping events, write for beekeeper newsletters and, specific to this project, we will invite regional beekeeping organisations to Rothamsted to see the radar in action (in 2011). We will also present our work at Apimondia, the international congress held specifically to disseminate research results to beekeepers. Through a public participation campaign, we shall engage beekeepers in assessing the risks posed by N. ceranae. c) NGOs and conservationists: We will engage with conservation organisations like Bumble Bee Conservation Trust and Bees Wasps and Ants Recording Society though data sharing and talks at their annual meeting. We will publicise results in targeted articles e.g. in British Wildlife, and dedicated leaflets. d) Farmers and associated industries: Rothamsted Research Association provides a forum for informing and engaging farmers and farming industries, and Osborne's team arrange regular farmer visit days to explain their research. One of these events incorporating this project will be held in 2012. e) General public: We have 15 years experience of disseminating results through the media (television, newspaper and radio) and we will extend these activities to incorporate this project and its results. Rothamsted holds Open Weekends showcasing their science to the public, and we will use this forum to inform on this project. Website: Of benefit to all stakeholders will be a project website. It will outline our research and provide opportunities for the public to engage with us. It will also publicise the prevalence and distribution of disease variants across bee species and will link to relevant NGOs and the new cross research council website on Food Security. All stakeholder event: In 2013, we shall stage an event either at Rothamsted or hosted by the Royal Entomological Society to bring together all stakeholders listed above for a workshop discussing the results of the project, inviting feedback and stimulating initiatives for disease management in wild and domesticated pollinators. Outside the project: We will engage with potential collaborators through data sharing, ensuring that our survey data on parasite distribution and abundance are available to organisations such as the National Bee Unit, FERA, and COLOSS. Exploitation: The project may generate significant exploitable results of considerable economic importance. If innovative control methods are successful, we will as a matter of priority engage with subcontractors and potential funders to undertake field-scale trials.