Three factors suggest that honeybees are spreading the parasites into wild bumblebees. Image courtesy Matthias Fürst

Managed honeybees linked to new diseases in wild bees

Diseases that are common in managed honeybee colonies are now widespread in the UK’s wild bumblebees, according to research published in Nature.

The study suggests that some diseases are being driven into wild bumblebee populations from managed honeybees.

Scientists from Royal Holloway University of London, Queen’s University Belfast and the University of Exeter say the research provides vital information for beekeepers across the world to ensure honeybee management supports wild bee populations.

Dr Matthias Fürst from the School of Biological Sciences at Royal Holloway, who led the study, said: “Wild and managed bees are in decline at national and global scales. Given their central role in pollinating wildflowers and crops, it is essential that we understand what lies behind these declines. Our results suggest that new and emerging diseases, spread from managed bees, may be an important cause of wild bee decline”.

This research assessed common honeybee diseases to determine if they could pass from honeybees to bumblebees. It showed that deformed wing virus (DWV) and the fungal parasite Nosema ceranae - both of which have major negative impacts on honeybee health - can infect worker bumblebees and, in the case of DWV, reduce their lifespan.

Honeybees and bumblebees were then collected from 26 sites across the UK and screened for the presence of the parasites. Both parasites were widespread in bumblebees and honeybees across the UK.

The researchers also looked at how the diseases spread and studied genetic similarities between DWV in different pollinator populations. Three factors suggest that honeybees are spreading the parasites into wild bumblebees: honeybees have higher background levels of the virus and the fungus than bumblebees; bumblebee infection could be predicted by patterns of honeybee infection; and honeybees and bumblebees at the same sites shared genetic strains of DWV.

Professor Juliet Osborne, of the Environment and Sustainability Institute at the University of Exeter’s Penryn Campus in Cornwall, said: “This study shows that we need to support beekeepers as much as possible in finding ways to improve the health of their honeybee colonies, and reduce the risk to wild bee populations.  

“We encourage beekeepers to monitor their colonies carefully and take steps to reduce varroa mite infestation and disease levels where they can. To this end, we continue to do research at the Environment and Sustainability Institute to help beekeepers and bee populations which are essential for pollinating our vegetable and fruit crops.”

While recent studies have provided anecdotal reports of the presence of honeybee parasites in other pollinators, this is the first study to determine the epidemiology of these parasites across the landscape. The results suggest an urgent need for management recommendations to reduce the threat of emerging diseases to our wild and managed bees.

This study is part of the Insect Pollinators Initiative, joint-funded by the Biotechnology and Biological Sciences Research Council (BBSRC), Defra, the Natural Environment Research Council (NERC), the Scottish Government and the Wellcome Trust. It is managed under the auspices of the Living with Environmental Change (LWEC) partnership.

The ESI is working with businesses and enterprises across all sectors of the economy in Cornwall, the Isles of Scilly and beyond to translate research and expertise into innovative business practices, products and services in order to respond to the challenges of environmental change. It has been funded by the ERDF Convergence Programme (£22.9M) and the South West Regional Development Agency (£6.6M), with significant support from the Higher Education Funding Council for England.

Date: 19 February 2014