Pollinator Patch - Wild Bees for Food Crops

Since I started working for Pollination Canada, one of the many things that surprised me was learning that honeybees are not native to North America.  Their proper name, the European honeybee, gives it away. It turns out that these beloved bees sailed across the ocean almost 400 years ago, courtesy of the colonists who landed in Jamestown, Virginia. Since then, honeybees have endeared themselves to us, sharing their sweet honey for our gustatory pleasures, their beeswax for warm candlelight, and helping to pollinate various plants.

It's important to note that honeybees are far from being the only – or even necessarily the most effective – pollinating bees in Canadian agriculture. Pollination refers to the movement of pollen grains, which must be transferred from the male to the female parts of flowers. Without this vital transfer of pollen, the plant is unable to form seeds or develop further into the edible foods that sustain both ourselves and wildlife. Pollinators are keystone species which have an essential role to play in maintaining the structure of ecosystems.  Meet a few of our native pollinating bees:

The native squash bee evolved along with the plants it loves to pollinate: squashes and other cucurbits such as pumpkins, cucumbers and zucchinis. These bees may fly only 500 m from their nests, which are usually located in the ground right under the plants they pollinate. Up to 70% of all native bees are underground nesters. Squash bees are often up before dawn, collecting pollen and eating nectar from the squash flowers. Their day is done by noon at the latest, whereas the sleeping beauties we call honeybees may stream from the hive as late as 9 AM to begin their foraging. If it's windy, rainy or cooler than 15°C, those honeybee divas will not rise from their honeycomb divans. If you could poll honeybees for their preferences, the data would indicate their disdain for squash pollen, but an intense passion for buckwheat or borage pollen, and a willingness and ability to as far as 12km to get it.

For years, honeybee hives were placed amongst blueberry bushes in order to increase yields, but it turns out that the blueberry blossoms require what is called buzz pollination. A blueberry flower is structured in such a way that pollen needs to be released by vigorous shaking. Enter the native bumblebee. Bumblebees have the incredible ability to dislocate their flight muscles from their wings and simply shake a blueberry blossom, accomplishing very efficient pollination. Honeybees do not specialize in buzz pollination. Additionally, bumblebees don't mind the cooler weather and are generally foraging earlier in the spring than honeybees, an important factor for spring fruit crops. Buzz pollination is also necessary for crops such as tomatoes, cranberries and sweet peppers.

One more example of a native pollinator is the Blue Orchard Mason bee (pictured at top) – so called because they line their nests with a leaves mixed with a mud mortar. Just a few hundred of these bees can pollinate the same acre of orchard fruit as 20-30,000 honeybees.  A recent study of almond orchards discovered that honeybees prefer to visit the top blossoms of the trees, while native bees often pollinate the lower ones.

None of this is to malign the dear honeybee, but simply to underscore the important roles required from the collaboration of a number of different bee species to accomplish the myriad of pollination services. Biodiversity is a term which refers to the variety of all living things, including plants and animals and their relationships. It includes the genes these organisms contain, and the ecosystems they form. The more biologically diverse a system is, the more resilient it will tend to be.  From the above examples, you can see that bees have evolved to fill all kinds of niches – they are designed and adapted for different flower morphologies, pollen preferences, foraging temperatures and distances or even times of day.

The widely-reported disappearance of honeybees, called colony collapse disorder (CCD), brought public attention to the issues facing both the honeybee industry and declines in our own native wild bees. What was unknown was the impact of declines in wild bees on crop yields. No one had measured it until recently. In February of this year, a report was published in the journal Science, entitled Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance. The results demonstrate that honeybees neither maximize pollination nor fully replace the contributions that diverse, native bees make to produce food crops. Such conclusions hold especially for fields which have been routinely stocked with honeybee hives, such as almonds, apples, and blueberry. The study supports the notion that an increased diversity of pollinators increases crop yields.

The results of this report support integrated management policies which include both native and managed bees and this plays beautifully into the hands of a program that already exists in North America called Bee Friendly Farming® (BFF). Farmers and gardeners can self-certify to indicate the use of agricultural practices that encourage and improve pollinator health. Bee Friendly Farmers allow at least 6% of their total acreage to provide clean water, nesting sites, and natural forage for native bees through a variety of habitat features.

Grandma was right: variety is the spice of life.

~Kim Fellows, Pollination Canada

References and further resources

Sue Chan’s Recommendations for Conservation of Pollinators on Farmland and A Landowner's Guide to Conserving Native Pollinators in Ontario
Best Management Practices for Pollination in Ontario Crops (relevant beyond Ontario)
NAPPC Agricultural Task Force: Farmer Profiles and Resources

Lucas A. Garibaldi, et al. AM. 2013. Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance. Science (DOI:10.1126/science.1230200).

Claire Brittain, C. Kremen, A.-M. Klein. Biodiversity buffers pollination from changes in environmental conditions. 2013. Global Change Biology 19 (2): 540. DOI: 10.1111/gcb.12043

Loss of Wild Pollinators Serious Threat to Crop Yields, Study Finds. Damian Carrington. March 1st 2013. The Guardian.

Wild Pollinators Increase Crop Fruit Set Regardless of Honey Bees. March 1st 2013. EurekAlert.

Back to March 2013 Newsletter