In the American agricultural landscape, industrial hemp, Cannabis sativa (Cannabaceae), is a newly developed and rapidly growing crop. Hemp lacks nectar but, as an exclusively wind-pollinated crop, produces an abundance of pollen in agricultural landscapes during a period of time referred to as floral dearth. Researchers have found that a number of bee species are attracted to these pollen plumes, yet the diversity of floral visitors and their use of hemp in a variety of agricultural contexts remains uncertain.
On hemp farms in New York state, repeated sweeps of nets collected bees visiting the hemp flowers. Cultivar varieties that differed in both the landscape context and the phenotypic characteristics were sampled. All bee visitors were then identified to the species level, finding the hemp supported 16 different species of bee.
Some interesting variables were identified including:
- The abundance of bees visiting hemp flowers was negatively influenced by landscape simplification but did not impact the community’s species richness.
- On the other hand, plant height was closely associated with the richness and abundance of bee species for hemp plots of taller varieties were found to attract a wider range of bee species.
All and all, the study concluded, hemp has the ability to provide a vital nutritional resource to a diverse population of bees. Especially during a time of nectar scarcity. This is due to its temporally specific flowering phenology and can thus help maintain agroecosystem-wide pollination services for other crops in our landscape. As hemp production increases around the globe, farmers, agribusinesses, and policymakers should take hemp’s attractiveness to bees and its role in supporting bee populations into account, when designing pest management strategies.
“Industrial hemp can play an important role during the cropping season in providing sustained nutritional options for bees,” wrote study author Colton O’Brien, a Colorado State University soil and crop scientist.
It can be noted that earlier studies looking at crops such as genetically modified canola flowers did not yield the same amount or variety of bees. Perhaps this is because hemp offers habitat, in addition to food.
The introduction of more pollinating crops on a continent where most of the acreage is devoted to non-pollen producing mono-crops covered by bee-harming insecticides is crucial to the survival of bees and the habitats they inhabit. Giving such important urgency to the term “Plant Hemp Trees & Save the Bees!”
Fortunately, the Farm Bill of 2018 legalized the cultivation of hemp in the United States. Hemp acreage in the US went from 80,000 acres in 2018 with projections of up to as many as 741,000 acres by the end of 2020. Reports also forecast by 2023 that number will grow to 2.3 million acres under cultivation, with permits pending approval for more and more…which makes US very hempy;)