A new study sheds light on exactly what nutrients hemp plants are providing to pollinators, which pollinator likes hemp the most, and which variety of hemp is most popular among bees out of four different varieties.
Researchers narrowed down four strains of hemp and observed which species of bees gather pollen and what nutrients the hemp pollen provides them. Joey—a new hemp variety developed in 2020—was the most popular cultivar among bees.
The study, “Chemical Composition of Four Industrial Hemp (Cannabis sativa L.) Pollen and Bee Preference,” was published July 26 in Volume 14, issue 8 of the peer-reviewed journal Insects, exploring hemp as a nutrient source. The study depicted varieties of bees foraging for pollen, as well as flowers, pollen sacs, and anthers under magnification.
The team of researchers counted 1,826 pollinators which can mostly be broken down into three bee groups: honey bees, bumble bees, and sweat bees. Sweat bees, gaining the name because they are attracted to sweaty people, were found most abundantly in the study, accounting for 84.7% of the entire bee community on all four hemp varieties, however they noted that previous studies listed honey bees as being more prevalent.
Since harvesting pollen was difficult, about 500 grams of mature hemp flowers of each variety were harvested and placed in paper bags that were then put in Ziploc® bags and placed in styrofoam shipping containers with dry ice. Samples were shipped to a commercial analytical laboratory in Wisconsin. The pollen samples were analyzed for levels of moisture, crude fiber, protein, ash, mineral content, amino acids, and fatty acids.
Researchers determined the nutrients the pollen provides and their benefits to bee populations.
“Industrial hemp (Cannabis sativa L.) is a new crop that is grown over a wide geographic area in the United States, providing economic and nutritional benefits to humans,” researchers wrote. “However, the contribution of hemp floral resources (pollen) to bee nutrition is not well understood. We investigated the chemical composition of pollen from four industrial hemp varieties (Canda, CFX-2, Henola, and Joey) and documented the abundance and diversity of bees on the crop using two sampling methods.
Each of the four hemp strains provided different ratios of nutrients, but researchers added that bees need a more diverse supply of nutrients that goes beyond hemp or any one plant.
“Results showed differences in composition among the four hemp varieties,” researchers added. “Overall, the Joey variety was the most preferred by bees, despite expressing lower protein, amino acid, and saturated and monosaturated fatty acid content. Based on our findings, we concluded that industrial hemp pollen provides some nutritional benefits to bees. However, it is important to understand that multiple sources of pollen are needed for sustained bee survival.
Researchers noted that other species, including the longhorn bee, miner bee, and leafcutter bee, are also known to gather pollen from hemp plants.
Importance of Pollinators and Hemp’s Role
Keep in mind that the importance of bees cannot be overstated: The USDA says that “three-fourths of the world’s flowering plants and about 35 percent of the world’s food crops depend on animal pollinators to reproduce.” Hemp is one of many nutrient sources for bees.
High Times covered a similar study in 2018 that identified hemp plants as a source or nutrients for dying bee populations.
Colton O’Brien presented, in a gathering of etymological societies, his discovery of a total of 23 bee genera in traps that he set up in a hemp field.
