Cannabis is becoming a prevalent crop, but it doesn’t mean your honey will have a buzz

Feature photo by Felix Brönnimann (CC BY-SA 4.0)

Originally appeared in American Bee Journal.

I live in British Columbia’s Fraser River delta, surrounded by agricultural land. The usual crops of hay, corn, blueberries, pumpkins, peas, and potatoes abound. But in the last two years, a new plant has made an appearance in the landscape: cannabis.

In Canada, recreational marijuana, a type of cannabis, was legalized in 2018, and government incentives for producers to officially enter the freshly minted market have had the desired effect. Households (except those in Quebec) are allowed to grow up to four plants, and by 2019, several commercial outdoor growing operations were licensed in BC. In the U.S., 19 states have legalized recreational marijuana, despite it still being federally criminalized.

During the summer around here, the unmistakable musky odor hangs in the air. With cannabis growers now operating beside beekeeping operations, the question is begged: Do honey bees forage on it? As Dr. Heather Grab documented in the journal Environmental Entomology, the answer is yes, but they’re not making cannabis honey.

The hemp bee community

Grab, who is a senior lecturer at Cornell University, and her colleagues wanted to study honey bee and wild bee communities in industrial hemp fields to find out who was foraging there. Hemp is the same species of plant as marijuana (Cannabis sativa), but has been bred to produce very low levels of tetrahydrocannabinolic acid — THCA, which quickly breaks down to THC, the psychoactive agent, with heat. Hemp is used mainly to produce fiber, hempseed, and cannabidiol (CBD), a non-psychoactive cannabinoid that is approved in the U.S. to treat some medical conditions.

The researchers periodically patrolled eleven different hemp fields in New York, nets in hand, and sampled every bee they found landing on hemp flowers. They found that honey bees were by far the most abundant species in the hemp fields, making up 59% of the community. Bombus impatiens, the common Eastern bumble bee, was next at 31%, followed by Lasioglossum hitchensi (Hitchens’ sweat bee, 3%) and fourteen other low-abundance species.

A honey bee foraging on hemp flowers. Photo by Heather Grab

Hemp is a dioecious plant, meaning that male and female flowers appear on separate plants, and the bees were only foraging on the pollen produced by the male plants. Hemp pollen appears to be quite attractive at a time of year (mid to late summer) when there is often not much else blooming in appreciable quantities. “Male plants and flowers are very common in fiber and grain plantings, and bees learn quickly that only the male flowers offer these rewards,” says Grab.

But cannabis is wind-pollinated, so the female flowers don’t have flashy colors or produce a nectar reward to attract pollinators. A lack of nectar also means that there is no such thing as cannabis honey, at least in the conventional sense. “Hemp pollen does contain low amounts of cannabinoids, and these compounds do show up in hive products, but not at high levels,” Grab explains. “So, ‘funny honey’ would need to be made by adding these compounds after extraction of the honey from the bees, and the cannabinoids from the plants.”

Fancy infusions

One company, called Charlotte’s Web, is working on producing a sweet cannabinoid product that is colloquially referred to as “hemp honey,” although it is not exactly honey. The Colorado-based company has secured a patent for a type of honey bee feed that is essentially CBD oil emulsified in water and mixed with beet sugar. The bees will consume the feed, producing something that resembles honey and is loaded with CBD and its derivatives.

I watched a webcast presentation by Edward Palumbo, who is a senior research and development scientist at Charlotte’s Web. Oddly, their CBD-beet sugar feed was a vibrant red color, even though sugar beets are white; I suppose they thought that food coloring made it look more special and sciencey. Palumbo claims that honey bee colonies fed the CBD-beet sugar have lower incidence of colony collapse disorder than colonies that are not fed the special sugar — a statement that is dangerously close to eye-roll territory, especially given that they show no supporting data.

But none of that is relevant to the actual research that the company is engaged in — namely, to develop analytical methods for quantifying CBD and its derivatives, and to see if the honey bees pre-process the CBD into a more bioavailable product (something with a similar effect as CBD, but easier for mammalian cells to utilize).

Palumbo presents some evidence showing that when laboratory rats ate CBD honey, they had higher levels of CBD in their blood than rats that ate a conventional CBD oil tincture. This is surprising, given that CBD is fat soluble, not water soluble, so the oil tincture should have been a stronger infusion. The researchers suggest that since honey bees possess detoxification enzymes, they might be able to process CBD into secondary metabolites that are more water soluble.

Whether this is true, and whether those metabolites still have the desired effect, is yet to be determined. Given the weirdly red beet sugar, improbable claims linking CBD and CCD, and a suspicious lack of reporting experimental details, I would take these data with some salt for now.

Propolis with a punch?

Ever since I saw the first cannabis plot show up beside one of our research apiaries, I have wondered if honey bees would collect resin from the plants. If bees collect resins from trees, why not weed? Beekeepers might all of a sudden find more excuses to scrape their equipment and put the debris in their smoker.

I could never get close enough to observe the plants myself (and no, I did not try supplementing my smoker), but Grab thinks resin collection is feasible. “I do think it is possible that honey bees would visit hemp plants to collect resins if other sources were not readily available,” Grab says, but notes that by far the most frequent interactions between bees and cannabis occurred while foraging for pollen.

Resin is secreted from cannabis plants from small, hair-like structures called trichomes, which are concentrated in the female flowers, new leaves, and several other parts of the plant. The secretions are made up of cannabinoids, including CBDA and THCA, the CBD and THC precursors. When the trichomes, which look like slender mushrooms, are touched, their heads burst and release their sticky substance. This response is thought to protect the plant against herbivorous insects, but this role is debated.

A closeup of resin-filled trichomes on a female hemp flower. CC BY-SA 3.0. Photo by Banana Patrol

There is currently no data documenting that honey bees collect cannabis resin, regardless of how feasible this may be. As Grab alludes, whether bees actually collect it may also depend on what other shrubs and trees are growing in the landscape. But there is one more potential way that honey bees could bring cannabinoids home, although it’s a longshot: honeydew.

Honeydew is a sugary excretion from sap-sucking insects like aphids, which can colonize cannabis plants. However, since cannabinoids don’t dissolve very well in water, and honeydew is a water-based excretion, it probably wouldn’t contain appreciable quantities of cannabinoids anyway.

Despite all of these barriers to producing anything close to cannabis honey, the question still burns: Even if the bees only take home the pollen, and even though cannabinoids don’t easily dissolve in water, how much CBD ends up in the honey if the bees are allowed to forage on a hemp plot? Researchers in Modena, Italy, tested honey produced by bees located near a hemp plot and found that it contained about 41 parts-per-billion (ppb) of CBDA (the non-bioactive form) and 4 ppb of CBD (the bioactive form).

At these concentrations, a person would have to eat 25 tonnes of honey to get 100 mg of CBD, which is a typical dose (or, alternatively, heat up a scant 2.2 tonnes to convert the CBDA to CBD first). Just 2.3 tablespoons of “hemp honey” produced by Charlotte’s Web, by comparison, would yield the same amount, which is much more feasible to put in a cup of tea.

But for THC, the psychoactive cannabinoid, there is not yet any good data on concentrations in honey, since the study in Italy was conducted on colonies foraging on hemp grown for fiber (which is, by definition, a low-THC variety). Most cannabis plants for recreational use, with the exception of relatively new plots in Canada and probably the occasional illegal operation, are grown in greenhouses to protect the flowers from being inadvertently pollinated and setting seed, ruining the coveted “bud.”

But even for beekeepers with colonies near outdoor marijuana crops, there is no reason to think that the THC data would be substantially different from the existing CBD data, since it suffers from all the same barriers to collection. There is no such thing as cannabis honey made by honey bees — the closest thing is a honey infusion or beet sugar “hemp honey,” which is still under research and development.

Grab thinks that there will be both opportunities and challenges for beekeepers as the cannabis industry continues to grow. The most obvious benefit is a source of pollen during a typical dearth period, and Grab plans to investigate the hemp pollen nutritional profile and whether it contains beneficial metabolites.

“The two biggest potential issues for beekeepers will be risk of exposure to pesticides when more products start to be registered for hemp,” she says, “and the risk that some regulators might come down on beekeepers who have cannabinoids in their honey, even at very low levels.”