Varroa mites, honey bees and viruses – an intertwined relationship

Dr Ewan Campbell, University of Aberdeen

Talk: Saturday 21 January 2017 at 2.00pm
The Kinellar Community Hall, Fintray Road, Blackburn AB21 0SS

As beekeepers you will be aware that global apiculture is currently facing a deep crisis, characterized by increasing parasite and pathogen pressure, exposure to a cocktail of agrochemical products and a rapid loss of biodiversity. Not to say that the “beemageddon” as shouted about in the press is true, but our bees are under severe pressure from many different sources!

In Europe, the spread of the parasitic mite Varroa destructor has led to a situation where colonies have to be treated with acaricides in order to keep losses at an acceptable level. At the same time, sustainability of the European beekeeping industry is reduced by a strong contraction of its genetic basis. At least two of the European subspecies of the Western honeybee (Apis mellifera) are acutely threatened by disappearance. In addition, the population size of most others is rapidly decreasing. I currently run 20 research hives in Aberdeen and also have 25 of my own hives so am aware of the annual fight against Varroa mites that we, as beekeepers, have to undertake.

Our research group at the University of Aberdeen has been working on Honey bee health for nearly a decade now and we currently have projects with partners across the globe including the USA, EU and Africa. Research always moves in fits and starts and often involves intertwined projects with different organisations, aims and objectives. Our lab currently has four PhD students working on different projects including Emma Bradford; looking at viruses in mites and honey bees, Ali Hroobi; studying DWV prevalence in Saudi Arabia, Renaud Heckle; studying beekeeping social demographics in Kenya and Craig Christie (part funded by the SBA) developing tools including an artificial feeding system to maintain and breed Varroa mites off the bee host in the lab. In addition to these student projects, myself and Dr Bowman are involved in Europe’s largest honey bee research project; SMARTBEEs.

SMARTBEES aims to stabilize beekeeping within the EU, by characterizing what is left of honeybee diversity, and catalysing the involvement of local breeders in its conservation and improvement. The package of work that Aberdeen is involved with will advance knowledge on the interactions between bees, parasites, and viruses. The project period of four years is about half way through and we are all starting to get exciting results.

So the main focus to our research is the Varroa mite and associated viruses. Dr Bowman spoke to ADBKA a number of years ago when we were developing a new treatment using gene knockdown to kill mites. Over the past five years we have successfully tested and trialed a number of targets to knockdown and kill the mites and at the completion of the project we patented the targets and technology and are currently in discussions with companies to take it further. The regulations on such technology are rightly very strict and so we have a lot of work still to do … but the concept and proof are very much done!

DWV replicates (i.e. reproduce by making new copies of themselves) both in honeybees and Varroa. When Varroa mites suck hemolymph from honeybees, DWV are injected along with saliva. This way Varroa works as a vector for DWV. Relatives of the Varroa mite are known to manipulate the immune system of their hosts. To study the effects of varroa saliva on the bee and on viral replication, we have developed a method to collect saliva from the tiny Varroa mites and have injected this saliva or DWV into bee larvae and pupae from a Varroa free colony with no/very low DWV and are now analyzing their immune response and DWV levels.

At my talk on the 21st January I will present bits and pieces of our research from these different projects but will focus on the research of our PhD student Craig Christie as well as on some exciting results from our SMARTBEEs project on DWV and the mite saliva!

Please come along and find out more about the weird and deadly interactions between mites, bees and viruses.

[Photo: By Gilles San Martin from Namur, Belgium via Wikimedia Commons]

[Photos of the event – see the Gallery]

[For a follow-up of the talk, see the February 2017 Newsletter]

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