Autumn, 2019
Pacific Northwest
I’ve become interested in fungi over the past few years and am both enamored and overwhelmed by them. They are so amazing. The other domains of life almost can’t live without fungi but then in some cases, we almost can’t live with certain of them. As is the case for most living things, they have both beneficial and detrimental qualities. Here I will focus on the more positive and salutary aspects of these critters, at least for us. And they are almost critters as fungi are evolutionary-wise considered closer to the animal kingdom than to the plant kingdom.
Because of my interest in fungi, I recently viewed a documentary film: “Fantastic Fungi.” The documentary was fantastic both for its content as well as its incredible cinematography (e.g. time lapse growth) and graphics. That was great in itself but the documentary also proposed a fascinating idea - that some of these fungi might have therapeutic properties useful in combating the significant problems of Colony Collapse Disorder (CCD) that is killing pollinating bees and compromising much of our agriculture. For major film Reviews here. To view the Trailer, here, you’ll see what I mean.
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Shortly after viewing this film, the Northwest Mushroomers Association hosted a speaker who is intimately involved in the bee work shown in the film and who works for mycologist, Paul Stamets, (a TED Talk presenter) who was instrumental in putting this film together. He is also the one who hypothesized the possible bee – fungi connection that might help save, or contribute to saving the pollinating bees.
I was initially going to write about the Polypores as an important and interesting order of fungi that have been used in folk medicine around the world including Asia and Europe. Extracts from these fungi have a number of pharmacological activities and are known to have some significant health promoting qualities. As it turns out, it is also this taxonomic order that includes the fungi that appear to be beneficial in sustaining bee colonies by combating the viruses that are directly implicated in bees’ demise.
I will begin by describing the polypores themselves and then review the studies that used their extracts to combat viral infections that lead to the bees’ early death.
The Polypores
The Polypores are a group of fungi of the order polyporales (Division of Basidiomycota, Class of Agaricomyetes). Members of the 1,800 or so species found in this order have numerous spore producing structures located in tubes or pores under their cap, hence “polypore”.
One feature that is largely (but not totally) consistent across the polypores is that their fruiting bodies, also called brackets, shelves or conks, protrude from some surface such as a living tree, log or stump as are the turkey tails in the lead photo. Occasionally they might even have stems (stipes). These fungi are masters of decomposition and are essential to forest ecology as they break down dead and dying vegetable matter, along with some living matter.
As is true in many areas of biology today, the taxonomy is in major flux. Taxonomic systems that seemed relatively clear even 30 years ago are now all changed and changing - thanks to the advent of DNA and other methods of analyses — no longer is appearance and “look alike”, good enough for classification. As a result technical names of many fungi today differ from what we might have learned a few years back. More often the common name applied remains with the fungus and are often quite descriptive. Again I point to the turkey tail below:
Another genus of polypores that is being tested for anti-viral properties is Ganoderma. There are several species of this genus that have a long history of purported medicinal properties. Foremost is G. resinaceum (lucidum — Reishi) a long used fungus in Chinese medicine as well as in other cultures.
Also used was a common Northwest bracket: G. applanatum or artist’s conk shown at the right. This one is called artist’s conk because if one draws on the underside of the bracket where the pores exude their spores, it will leave an image. Also characteristic of this polypore is that its spores tend to leave a dusting of their tan color on nearby surroundings as seen on the dead tree to the right.
I think this is Ganoderma oregonance. It is very like, if not identical to G. lucidum and G. tsuge and G. resinaceum. If so, it is an example of the Reishi fungus called the “mushroom of immortality” and is purported to have medicinal properties and is the source of one of the tested extracts in studies to be described below.
Yet another Polypore examined in the bee studies goes by various names and is one that seems to have been recently renamed in the official taxonomies. Until recently it was Fomes fomentarius although I now see reference to it as Fomes excavatus — there remains controversy.
The Fomes shown below also goes by several common names such as hoof conk, tinder conk and iceman’s conk. These last two common names are connected to an interesting bit of history. This fungus was found on the body of the 5,300 year old mummified body, Otzi discovered in the Tyrolean alps on the border of Italy and Austria in 1991. Apparently it was common to carry such fungi as they are readily combustible (as tinder) and provided a easy means to start a fire. But that wasn’t the only fungus found on Otzi.
Birch polypore on the left is another fungus included in the bee-virus trials based on its long history of having medicinal qualities. Otzi also carried two pieces of this polypore threaded onto strips of hide. It is said to have antibiotic and styptic properties.
Below are a few other common polypores from our neighborhood, although they were not involved in the bee studies.
There are many thousands of polypore fungi, many of which have been little studied. Of those well known, several have been shown to have pharmacological activity and have been used in folk medicine for thousands of years. One such property was that there was evidence that some of the polypores might strengthen immune function and this is what initially caught the interest of bee scientists.
Colony Collapse Disorder and Polypore Extract Studies.
Many of the Bucket readers are well aware of the significant and potentially disastrous demise of pollinating bee colonies throughout the US and abroad. Since first described in 2006, hive owners have been losing about 30% of their hives annually. The loss of these pollinators is referred to as Colony Collapse Disorder (CCD). Most affected are species Apis mellifera that are managed in hives and distributed to farmers in the spring when their various crops are ready to be pollinated.
These managed A. mellifera colonies are estimated to contribute over $15 billion annually to the US agricultural economy through the pollination of numerous fruits, nuts and vegetables
The collapse is thought to be a function of multiple pathogens (mites and viruses) acting together with various environmentally imposed conditions such as pesticides, herbicides, loss of foraging areas and stresses from travel to multiple agricultural sites. These latter stressors are thought to affect immune systems, leaving the bees more vulnerable to the pathogens.
Two of the specific known pathogens targeted in the bee studies to be described are the parasitic mite, Varroa destructor, which is known to be associated with immune deficiency as well as dissemination of several specific viruses, two of which were examined in a series of studies. These viruses are the Deformed Wing Virus (DWV) and Lake Sinai virus (LSV) group. Both of these critters are implicated in Colony Collapse Disorder and have become targets of a series of both lab and field studies beginning in 2015 with the first published report in 2018.
How it started:
A mycologist and commercial mushroom cultivator, Paul Stamets, had observed at his farm that honey bees appeared to have an affinity for the mycelium (the basic fibrous constituent) of certain polypore fungi. It had been known that certain polypore extracts had antiviral activity and also could enhance immune function. Having heard of the CCD, Stamets was curious to see if bees derived any health benefits from the polypore mycelium. To investigate the possibilities, Stamets teamed up with the Entomology Department chair at Washington State University and with the Washington Beekeepers Association. They began a series of studies to see if polypore extract might indeed have salutary health effects on the bees that would enable them to live longer and therefore live to pollinate longer. These bees have a lifespan of only five to six weeks and fly about 500 miles before dying. If this short life is cut even shorter by the viruses, a significant amount of pollination time is lost.
The research began with a series of lab studies in which caged worker bees were fed either sugar syrup or sugar syrup infused with one of several fungal extracts from the polypores shown above.
Honey bees forage on fungal mycelium where they ingest liquid exudates. .. Bees fed extracts from polypore mycelium exhibited lower DWV virus titers. In three different trials, mixing fungal extracts into caged bees’ sucrose syrup food significantly reduced the levels of DWV...
The two extracts found to show the greatest viral load reduction in the lab-based studies were selected for field trials using typical bee hive colonies. The fungal extracts tested were from the Fomes and Ganoderma fungi. Before treatment and after 12 days exposure to either the syrup alone or the the syrup plus extracts, bees were sampled and examined for both DWV and LSV. The bee samples exposed to either of the two fungal extracts showed significant decreases in both viruses relative to controls. The difference was especially large in the LSV where they found a 45,000 — fold reduction over the 12 days of treatment.
Both Fomes and Ganoderma extracts significantly reduced DWV and LSV levels in field trials using 5-frame colonies with bees divided from a common population. Bees were sampled for virus levels at the start of treatment and 12 days later. Colonies fed G. resinaceum extracts exhibited a 79-fold greater reduction in DWV and a 45,000-fold greater reduction in LSV compared to controls fed sugar syrup. Quantitative PCR ΔCt values are normalized to the mean starting virus levels across all groups.
Although not reported in the cited published studies, subsequent trials have now shown that not only were the viral counts significantly reduced, that reduction was associated with greater longevity in the treated bees. A video describing these studies and efforts is available here.
As a final note, Stamets has developed a bee feeder, akin to a bird feeder that he will be selling along with the extracts studied here. It is projected to be available in 2020. I have not tried it and this is not a testimonial. I am just providing the information for the curious.
I will try to keep up on how this research program progresses and share it as more is learned. Stay tuned.
Have you found any interesting fungi in your area lately? If so, please share them us. How are your bees faring these days?