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Food Security and biodiversity: Honeybee Decline in Europe

The European honeybee is the world’s most important commercially-managed pollinator. Despite some recent increases in colony numbers, overwintering colony losses are unsustainably high and the number of colonies is insufficient to meet the demand for pollination services in many parts of Europe. Colony losses have an effect on the economy and food production and in the EU this has led decisive action in not only identifying the causes of decline within the Bee population, but how European stakeholders can combat this problem, with initiatives spearheaded by the European Food Safety Alliance (EFSA). The European Commission has taken action through its continual co-financing the surveillance of honey bee colony losses, alongside restricting the use of certain harmful pesticides, such as neonicotinoids and fipronil in 2013.

The first presentation given by Dr David Chandler focussed on the causes behind the decline of honeybee colonies in Europe. In particular, David discussed the impact of the Varroa Mite, a parasite which feeds on honeybees and is a vector for various viruses, which have been shown to cause decline in infected colonies. There are a variety of treatments currently being developed to tackle Varroa however regulatory and economic barriers to their adoption remain. David also discussed the impact that neonicotinoid pesticides have had on honeybee populations. Studies from throughout Europe were presented which showed a potential for such pesticides to cause honeybee death however the evidence base is very small and further studies are required.

Following on from this presentation, Professor David Evans presented the work of his group in sequencing the genome of the wide range of deformed wing viruses (DWV) normally present within a honeybee colony. David’s work has shown that the presence of Varroa mite leads to selection for a particular strain of DWV which causes colony decline. Work is currently underway to investigate this strain further with a view to potential future treatments.

Finally, Professor Matt Keeling discussed modelling the spread of Varroa mite on bee populations on Jersey, the spread of the small hive beetle in Italy and on the spread of the Asian hornet in France. Such models can be useful in developing policies to combat the spread of invasive pests.

Dr David Chandler is Principal Research Fellow at the Warwick Crop Centre in the School of Life Sciences at the University of Warwick. He is an expert in the microbial control of arthropod pests, IPM in horticulture, and honeybee health. He has research interests in understanding the biology of insect pathogens, with particular emphasis on the physiology and ecology of entomopathogenic fungi and their development and use as biopesticides, His work encompasses laboratory, glasshouse and field studies, and he has worked on a range of crop types, including protected edibles, ornamental crops, soft and top fruit, field vegetables, and arable crops. He has been an advisor to the European Parliament Agriculture Committee on IPM and has acted as an external assessor for research programmes run by the US Department of Agriculture.

Professor David Evans group study the biology, pathogenesis and transmission of DWV in honeybees, using a combination of molecular, reverse genetic and systems-based methods. In recent studies (Moore et al., 2011) we have demonstrated that a recombinant form (RF) of DWV predominates after Varroa transmission. We have investigated the virus population in the bee before and after transmission, the response of the bee to virus infection (e.g. by microarray analysis of changes in host gene expression) and the sequence of the virus population replicating in the Varroa mite. The results of these studies will have implications for the diagnosis and potential therapeutic treatment of DWV-mediated infections in managed honeybee colonies.

Professor Matt Keeling is a joint Professor between the School of Life Sciences and the Mathematics Institute, Director of Warwick Infectious Disease Epidemiology Research (WIDER). Matt’s interests span epidemiology, ecology and evolution. He focuses on the roles of spatial interactions and stochasticity (randomness), and how these can affect the dynamics, control and persistence of biological organisms. More specifically, Matt has recently studied a range of applied epidemic problems, from the optimal vaccination of individuals during a pandemic influenza outbreak to the prediction and control of foot-and-mouth disease in Britain and the USA. He is particularly interested in the development of new models and techniques that will provide greater insights into population dynamics. Much of this new methodology centers around "pair-wise" approximation models for network-based processes, or moment-closure methods for stochastic processes.