Two scientists in Washington state have teamed up to save the honey bee from invasive Varroa mites. They’re investigating an elixir derived from an unconventional source: a mushroom
It’s no secret that the domesticated European honey bee, Apis mellifera, is in big trouble. The not-for-profit Bee Informed Partnership estimates that 28.1% of the colonies managed in the United States were lost during the winter of 2015–2016. But these losses were not restricted to the winter months: summer losses for 2015 were nearly identical to winter losses. Thus, beekeepers lost 44.1% of their colonies between April 2015 and March 2016. This is close to the highest annual loss rate over the 6 years that Bee Informed has collected annual colony loss data.
What is killing honey bees? The most prevalent cause of death is due to infestation by the invasive Varroa mite, Varroa destructor. This parasite is a serious problem that has plagued American beekeepers since it was first detected in the United States in 1987. Varroa mites weaken and kill bees, their pupae and their developing embryos by sucking their haemolymph — bee blood.
“I always think of it as having something about the size of a pancake feeding on you,” said Steve Sheppard, who is a beekeeper and chair of the Entomology Department at Washington State University.
These mites also spread viral diseases, and they are suspected to be a key contributor to another serious problem, Colony Collapse Disorder (CCD).
But regardless of how Varroa mites kill bees, the mites’ abbreviated life span allows them to rapidly develop resistance to the synthetic chemicals that are used to control them. This spells trouble for beekeeping — and ultimately, for the security of the human food supply.
“There’s a tremendous need to develop methods to control Varroa mites that are sustainable, and [that] don’t rely on these chemicals, allowing beekeepers to get off a chemical treadmill,” Professor Sheppard explained.
To help the bees, Professor Sheppard teamed up with author and mycologist Paul Stamets, founder of Fungi Perfecti. They recently announced that they may have discovered a way to kill Varroa mites without killing bees: a mushroom.
Mr. Stamets told Professor Sheppard about a mushroom extract that was highly attractive — and highly lethal — to termites. Might this mushroom extract also kill the Varroa mites that are plaguing bees?
Initial lab tests on honey bees infected with Varroa mites were promising: bees exposed to this mushroom extract survived whilst their mites quickly died. Of course, these are preliminary findings that must be followed up with more research to determine whether and how this extract can be used to help an entire colony to survive.
But mushrooms are proving useful at warding off other diseases, too. According to Professor Sheppard, an extract made from the Amadou mushroom, Fomes fomentarius, reduced the Deformed Wing Virus in honey bees by more than 1,000 times, compared to controls. Mr. Stamets and Professor Sheppard are also growing a large quantity of another fungus, Metarhizium, that attacks and kills the Varroa mite, but doesn’t harm honey bees, in preparation for more studies.
“Our research goal is to improve honey bee health, and the results look promising,” Professor Sheppard said.
“I’m hoping that people will recognize mushrooms for the important roles they play in ecosystems that we are just now beginning to discover — before it’s too late,” Mr. Stamets added.
This video provides an interesting overview of their research project.
8 June 2017, Erratum: An image of a polypore mushroom was originally used in this piece. However, the mushroom being used to control Varroa mites is not a polyphore mushroom. The image was replaced with a picture of Fomes fomentarius, which Mr. Stamets says can be used to treat Deformed Wing Virus in honey bees.
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Originally published at Forbes on 5 June 2017.