The Beekeeper’s Companion Since 1861
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Notes from the Lab

Notes from the Lab – December 2018

- December 1, 2018 - Scott McArt - (excerpt)

beekeepers inspecting hives

It’s December, which means flu season is starting to kick into high gear. What do you crave when you’re sick? Chicken soup? Echinacea tea? Across the animal kingdom, there’s growing evidence that you’re not alone – caterpillars and moose and even bees seek out dietary items that can potentially make them healthier. This is the topic for our thirteenth “Notes from the Lab,” where we highlight “Extracts of polypore mushroom mycelia reduce viruses in honey bees,” written by Paul Stamets and colleagues and published in the journal Scientific Reports [8:13936 (2018)].

Highlighting the importance of simply observing bees in nature (as we all do – it’s a major joy of beekeeping, right?), Stamets noticed something interesting when he was watering his Garden Giant mushroom patch one day. Honey bees were visiting the mushrooms. Paul Stamets has devoted a good portion of his life to finding myriad uses for mushrooms, including making fungal extracts for human health purposes (for more information, check out his business, called Fungi Perfecti: So, it probably shouldn’t come as a surprise that he decided to test whether the mushrooms had medicinal properties when consumed by bees.

Stamets and colleagues decided to culture and make extracts of several species of fungi, then feed them to sick bees. Specifically, they cultured four polypore fungi – Fomes fomentarius, Ganoderma applanatum, G. resinaceum and Trametes versicolor. These fungi are found in forests in either the eastern United States and Canada or the Pacific Northwest. Once they’d cultured enough of each species, they created extracts and fed them to sick bees in laboratory cage trials, testing whether deformed wing virus (DWV) and Lake Sinai virus (LSV) loads in the bees improved, or not, compared to bees from cages that were fed sugar syrup as a control. For the cultures that appeared most promising in cage trials, the authors assessed them further in field trials, again testing whether the bees had reduced loads of DWV and LSV after treatment.

So, what did they find? Did the mushroom extracts help the sick bees? In the laboratory cage trials, Stamets and colleagues found that two of the four fungal extracts significantly reduced DWV and LSV in the bees. And importantly, the magnitude of the effect was quite large. The 1% F. fomentarius extract reduced DWV levels over 800-fold and the 1% G. applanatum extract reduced LSV levels nearly 500-fold. Because these extracts showed great promise, the authors then made larger batches and fed them to 5-frame nucs in the field. Low and behold, they found similar results. Twelve days after receiving a ….