Cannabis, Bees and Pollination – The Cannabis Science Blog

Honey and bumble populations in the US and other countries have been rapidly declining at an annual rate of 30%-50% over the past two decades.  While the exact causes of these declines are still largely unknown, reductions in the sizes honey and bumblebee populations have had a negative effect on pollination of many crops, fruits and vegetables that have begun to affect agricultural yields (1, 2)

Industrial hemp, Cannabis sativa (Cannabaceae), is a newly introduced and rapidly expanding crop in the American agricultural landscape. As an exclusively wind-pollinated crop, hemp lacks nectar but produces an abundance of pollen which is attractive to a range of bee species (3, 4)

A team of researchers at Cornell University reported that hemp production in New York state supports at least 16 different species of bees (4). Interestingly, hemp plant height had a noticeable effect on bee populations with taller plants attracting a more abundant and broader diversity of bee species (Flicker et al).

The researchers suggested that “because of its temporally unique flowering phenology, hemp has the potential to provide a critical nutritional resource to a diverse community of bees during a period of floral scarcity and thereby may help to sustain agroecosystem-wide pollination services for other crops in the landscape.”

Finally, it was suggested that as hemp cultivation in the US continues to increase, growers, land managers and policy makers ought to consider its value in supporting bee communities and use hemp’s attractiveness to bee when developing possible pest management strategies.

References

1. Camerona,1, JD Loziera , JP Strangeb , JB Koch et al. Patterns of widespread decline in North American bumble bees. PNAS 2010; 108:662-667.
2. G Di Pasquale, C Alaux , Y  Le Conte, JF Odoux et al. Availability of Pollen Resources Affect Honey Bee Health PLOS ONE  DOI:10.1371/journal.pone.0162818 September 15, 2016
3. JS Dalio Cannabis sativa-an important subsistence pollen source for Apis mellifera J. of Pharmacol and Biol Sci 2012 1:1-3.
4. NR Flicker, K Proveda, H Grab. The bee community of Cannabis sativa and corresponding effects of landscape composition. Environ Entomol 2019 49;197-202

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