Certain mushrooms produce anti-viral compounds that could protect threatened honeybees. Credit: Flickr user Flikkersteph
Paul Stamets has had a life-long love affair with mushrooms, one that goes well beyond their culinary and psychedelic qualities. Wearing his signature hat — made from mushrooms — a turtle pendant and, always, a blue scarf, the nearly 60 year-old mycologist runs Fungi Perfecti, a family-owned farm and business in Shelton, Washington.
Stamets jokes that it only took him three decades to have his epiphany about the relationship between his beloved fungi and the threatened honeybee. He first began to connect the dots after noticing honeybees feeding on the mycelium (root-like filaments) of mushrooms growing among the wood chips in his garden.
Later, through research supported by the National Institutes of Health and the Department of Defense, Stamets showed that certain species in a class of mushrooms called polypores contained substances that were effective against human pathogens such as pox viruses, flu viruses and herpes. He later learned that these same mushroom compounds, present in certain polypores associated with trees and rotting logs, help bees break down pesticides, herbicides, fungicides and other toxins, and bolster the bees’ immune systems.
This is welcome news, because the modern day honeybee faces a litany of health threats. As many as 61 different variables may be at play in colony collapse disorder, the mysterious phenomenon responsible for a mass disappearance of bees in the last decade. Although researchers have yet to identify a specific cause, pathogens play a key role in colony collapse disorder. Scientists, beekeepers and farmers are working feverishly to protect the tiny insect that packs such a huge economic punch. At stake is our food supply and a $15 billion U.S. agricultural industry that depends on bees for pollination.
Mycologist meets entomologist
Early last year, Stamets asked Washington State University entomologist Steve Sheppard to help confirm his hunches about bees and fungi. The two have since joined forces to explore the connections that, as far as they know, no one has ever made before. This unlikely pairing of entomology and mycology could lead to less toxic and more effective ways to control the diseases and pests that are implicated in winter hive losses and colony collapse disorder.
Steve Sheppard credits his great grandfather, a beekeeper in Savannah, Georgia, for his own interest in bees. As a child Sheppard was surrounded by the books and beekeeping inventions his great-grandfather had left behind. It was no wonder then that seeing one of his college professors handle bees captivated him.
“I watched him spread bees around with his hand like they were a bunch of leaves or something,” Sheppard recalls. “It was fascinating seeing someone interact with these social insects that could sting you to death, but didn’t.”
Sheppard would go on to become an entomologist known for his work on the evolution and genetics of honeybees. He now chairs the department of entomology at WSU. He also heads up the APIS Molecular Systematics Laboratory, or the bee lab, where he works with commercial beekeepers to develop practical solutions for the challenges they face.
It’s normal, says Sheppard, for commercial beekeepers to lose five to 10 percent of their hives in winter. But not long after the Varroa destructor mite arrived on the scene in 1987, those losses rose to an average of 15 percent. Since 2006, the rate of loss has doubled. “With a 30 percent loss, commercial beekeepers can still make it, but it’s very tough” says Sheppard. “Imagine losing one third of your cattle in one year.”
Varroa mites spread viruses that can be deadly to bees. Sheppard explained that what keeps many commercial beekeepers up at night is the fact that the pesticides currently used to control mites are becoming ineffective. Mites have such a short life span that they quickly evolve and develop resistance to synthetic pesticides.
Sheppard and Stamets may have found a way around the problem.
Beehives made of mushrooms
The research partners are studying how different mushroom extracts — particularly those with antiviral qualities — affect honeybees. Initial screening has identified extracts which reduce the virus load without hurting the bees. “Steve’s biggest thing is, ‘let’s not harm the bees’,” Stamets says. “I appreciate that, because he protects them like they’re his little children.”
Sheppard and Stamets tested extracts from about a dozen different mushrooms by mixing the extracts with sugar water and feeding different concentrations to different groups of bees (watch the video above). When they compared the results to the control group of bees, which had received only sugar water, they discovered that several extracts had a significant and unexpected impact.
“I was surprised that some actually kept the bees alive longer than bees in the control group,” Sheppard says. “The viral counts were also significantly lower among bees given the fungal extracts.”
The extracts were provided by Fungi Perfecti. They came from mushrooms that grow on birch, willow and Douglas-fir trees, trees that bees visit to collect the resin they use to seal up gaps in their hives. It’s no coincidence, says Stamets, that bees favor trees whose resident fungi come with antiviral properties.
It’s way too soon to explain why bees that received mushroom extracts lived longer, says Sheppard. The initial study did not identify which viruses were affected by the extracts. “This is a really new area,” he says. “Once you find out what’s working, you want to get at why it’s working.”
Stamets and Sheppard are now repeating their extract trials, this time looking at the impacts on bees injected with specific viruses.
They are also assessing the fungus called Metarhizium anisopliae, which is known to parasitize and kill insects. Based on evidence that the fungus can kill Varroa mites without harming bees, Sheppard and Stamets are designing experiments to expose the mites to Metarhizium spores.
One experiment involves a prototype beehive made from mushrooms. The hive’s panels are compressed sawdust that has been mixed with mycelium of the Metarhizium fungus. As the bees do their work, they’ll spread the spores of the parasitizing fungus around the hive — to the detriment of the mites.
Sheppard and Stamets will also try placing pieces of cardboard impregnated with mycelium into standard bee boxes. Sheppard explains that bees don’t like clutter and will tear the cardboard apart to get rid of it, in the process dusting bees and mites with fungal spores.
The research duo plan to put their lab results to the test in the field. Working with one of the largest commercial beekeepers in the state, they intend to set up large-scale experiments with their mushroom extracts. The hope is to establish a sound body of evidence for what could become a commercially viable and sustainable alternative to pesticides. And in so doing, save the honeybees.
“Nature leads us to solutions if we connect the dots, are open minded and think creatively,” Stamets says. “We need to be innovative to create solutions that help tilt the balance to help bees, and ultimately us. Working with Steve Sheppard is a perfect example of scientists working across disciplines to become part of the solution.”
Learn more about bees and sustainable agricultural in WSU’s Green Times blog.