New research to beat varroa threat to bee populations

Research being undertaken at the School of Veterinary Science and Medicine at the University of Nottingham by Dr Robert Atterbury is looking for innovative ways to combat the the honey bee ectoparasitic mite, Varroa destructor. Varroa is a serious threat to Apis cerana and Apis mellifera honey bee colonies. Damage to bee colonies threatens productive agriculture and the crops that rely on commercial pollination services. 

A single infestation of varroa mite can destroy an entire colony and then spread rapidly, which is why ongoing research into ridding hives of the parasite is extremely important. Dr Robert Atterbury from the Nottingham University School of Veterinary Medicine and Science is part of a team working on a new solution to the problem.

Robert says: “The Varroa mite was introduced into the UK in the 1990s and has spread nationwide since then. It feeds on larvae and weakens the bees, whilst also transmitting viruses which infect the bees. Conventional control of the mite is usually divided into physical (‘biotechnical’) and medicinal (chemical) treatments. Both of these approaches have their problems. Biotechnical controls are often labour-intensive and only work at certain times of the year. Chemical treatments, while convenient, are often not applied correctly and this can lead to resistance. In addition, development and registration of new chemical treatments is expensive and difficult. With our partners in the project “BeeSave”, we are aiming to develop a new method of controlling varroa which will address some of these problems. “

The School of Veterinary Medicine at Nottingham has an apiary, primarily used for teaching undergraduate veterinary students. The apiary contains up to 10 colonies and has produced up to 150 jars of honey in a season (depending on the weather). Dr. Atterbury has been keeping bees for approximately six years, after taking over from the School’s resident entomologist, Dr. Ruth Blunt. 

“When it comes to nectar, our bees at Sutton Bonington are spoilt for choice. They have access to flowers from a whole range of plants cultivated across the campus as well as crops such as oilseed rape, which they are partial to. Bee keeping is less predictable than in previous decades, partly as a result of the diseases and pests which can affect them, but also because of changes in land use and more unpredictable weather patterns.” said Robert. 

Researchers still learning about varroa mites

Researchers are still learning about the parasite. It was not until new research was published in January 2019 that it was understood that although the varroa parasites are called ‘mites’, they do not actually feed on the blood of bees.

In fact, the new University of Maryland research suggests that varroa mites externally consume and digest the honey bee’s fat body tissue, an organ which serves many of the same vital functions carried out by the human liver, while also storing food and contributing to bees' immune systems.

New acaricidic compounds needed

The race to protect honey bees from varroa mites is an international one.  An article in Nature published in 2018 decribes how a group of researchers in Germany have established that lithium chloride effectively kills Varroa destructor, the first new compound to be registered for that purpose for 25 years. 

Researchers at the University of Georgia Honey Bee Lab are working to address the fact that varroa mites are rapidly adapting to the treatments beekeepers currently use. 

The researchers are members of The Honey Bee Health Coalition, a collaboration of an international team of 12 scientists that is testing chemical compounds that could help beekeepers more effectively treat the varroa mite. The group is receiving funding from the US Foundation for Food and Agriculture Research and from industry.

Varroa mites have an impact on viral development

Research following the spread of varroa mites has demonstrated that the parasites have a direct impact on bee viruses as well as directly vectoring diseases into beehives. 

The arrival of the varroa mite into the Hawaiian honey bee population allowed scientists to investigate changes in the prevalence, load, and strain diversity of honey bee viruses. The selective activity of the mite’s feeding habits actually increased the prevalence of a single viral species, deformed wing virus. 

Sustainable solutions for a range of issues

The essential point of the research being conducted worldwide is to develop solutions that are sustainable, and work for crop producers as well as beekeepers.

The AFTP offers a wide variety of courses on sustainability and the environment, ranging from global food security to soil management and climate change.

Contact us to learn more about our sustainability and environment courses or browse through our course list.

1 Global Honey Bee Viral Landscape Altered by a Parasitic Mite Stephen J. Martin et al. Science 336, 1304 (2012); DOI: 10.1126/science.1220941 Stephen J. Martin,1* Andrea C. Highfield,2 Laura Brettell,1 Ethel M. Villalobos,3 Giles E. Budge,4 Michelle Powell,4 Scott Nikaido,3 Declan C. Schroeder2

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