Honey bee (Apis mellifera) colonies play a keystone role in our ecosystem through the pollination of fruits, vegetables, and flowers. However, for reasons that remain unknown, have been disappearing for the last 15 years. Experts have named this phenomenon "Colony Collapse Disorder", which happens when billions of honey bees all over the world leave their beehives behind to never come back. In some regions, up to 90% of bees have already disappeared! And data suggests that bee colonies are becoming smaller every year.
This has been particularly dramatic in the U.S., where the sharpest decline so far registered took place during this past winter. The number of hives that survive the winter months is an overall indicator of bee health, according to the U.S. Environmental Protection Agency. Beekeepers reported that they'd lost 40% of their colonies during last year. The reasons for this loss are mostly related to stress. However, it is the poor health of their respective habitats that is to be primarily blamed for this sudden decrease. That's why beekeepers have to move toward more ecological and sustainable farming practices that allow bees to keep pollinating in full health.
Can hemp really save the bees?
A major study called 'Bee diversity and abundance on flowers of industrial hemp' was recently published by a group of researchers from Colorado State University in the Journal of Biomass and Bioenergy. They set up 10 traps at industrial hemp crops in northern Colorado and collected bees over a 5-day period during peak blooming season.
Over 20 different types of bees approached hemp, which proved hemp flowers are attractive to this kind of pollinators as a source of pollen to feed their young with. When researchers took a closer look at their collection, they found almost 2,000 bees, 38% of which were classic honey bees. To be more precise, there were 38% Apis mellifera, but also other genera such as Melissodes (25%), Peponapis (16%) and Bombus (5%).
Finding a pollinating crop to improve the habitats of bees is crucial to the survival of our ecosystem. Hemp is a wind-pollinated plant, so bees play no role in their pollination. Surprisingly though, they seem to be very interested in the plant, as proved by the many specimens collected during the research. "Hemp can thus be an ecologically valuable crop whose flowers are attractive to managed honey bees and a wide range of wild bees," the researchers concluded. They were amazed at the bee abundance and diversity found in this crop, which is in fact relatively new in the U.S.
Hemp as a rotation crop
As a wind-pollinated plant, hemp doesn't need the help of facilitators of pollination such as bees to produce seeds or new plants. It's also a dioecious plant, meaning each individual can carry male or female flowers. The hemp that is commonly used to make CBD oil, which accounts for approx. 90% of U.S. hemp production, derives from female plants. However, hemp didn't turn into a commercial crop in the States until the Hemp Farming Act became law as part of the 2018 U.S. Farm Bill. As of then, hemp fields have tripled.
In northern Colorado, hemp flowers between late July and late September, way later than many other commercial crops. By that time, nutritional resources for pollinators are scarce and so hemp becomes a valuable pollen source for honey bees.
But hemp is much more than just a great source of pollen. Research shows that crop diversity contributes to biodiversity conservation. Adding hemp (used for fiber or fuel production) to their crop rotation could benefit farmers greatly. Adding diversity to crop rotations, improves soil health. It's easier to control weeds, pests, and diseases, which benefits bees indirectly.
It's way too soon to figure out whether the introduction of hemp in crop rotation will somehow affect the surrounding ecosystems, mostly when used in rotation with corn and soybean or with plants such as tomato, pumpkin, and pepper. It remains unclear too if it will divert bees away from other specialty crops for the expansion of hemp production could facilitate pollination in nearby crops.
Beware the pesticides
This study also warns farmers that the extensive use of pesticides on hemp, especially when they're in full bloom, could adversely affect the health of bee colonies.
As hemp crops become more widespread, so happens to the pests. That's why it's so necessary to come up with a plan to protect pollinators and fight unwanted insect pests that could damage crops.
For decades, beekeepers have mostly lived off honey production. But now they're more focused on the pollination business (renting of beehives for pollinating fields or gardens). Therefore, bees are more exposed to pesticides, which is already taking a toll on them, as demonstrated this past winter in the U.S. Something has to change.