Wild bees are feeding you

This is the first instalment of a series of environmentally-themed pieces submitted by doctoral researchers at the University of Michigan. This collaboration between the University of Michigan and University of Edinburgh began when a professor at the University of Michigan forwarded a link to the IANS blog, along with the opportunity to connect with its editors, to PhD students in Michigan's School of Natural Resources and Environment. After an initial meeting over Skype, two of Michigan's doctoral students were lucky enough to jet over to Edinburgh and participate in a lovely weekend workshop with IANS' staff. From there, the collaboration was born!

By Maria-Carolina Simao (Contributor)

If it's a sunny day and you happen to pass by a vegetable garden, you may notice some flowers in bloom, and perhaps a honeybee or two. You may think you've just witnessed the best pollinator of your food, but you're wrong.

For decades, honeybees have been regarded as the most valued pollinators of the world. Agriculture has become increasingly dependent on pollinators, as evidenced by the global increase in managed honeybee colonies from 40 million to 76.2 million since 1961 [1]. However, since 2005, North America and Europe have been experiencing worrisome declines in their honeybee populations, with scientists still trying to understand why. The declines have caused a great deal of concern over the future of agriculture, prompting awareness campaigns, various local government initiatives, and even increased federal funding to help protect honey bee populations.

Although honeybees do contribute greatly to our global food system, there are actually about 20,000 other bee species in the world, doing the same job–and often doing it better–but receiving little recognition. Honeybees used to be wild, but are now primarily managed by humans and less commonly found in the wild. The majority of wild bees look nothing like the honeybee; some are plain black, some are furry, and others are brilliant metallic greens, blues, and purples, among other colors. The vast majority of these bees live and breed in the wild, and not in hives kept by beekeepers.

Studies have determined that when diverse groups of wild bees visit crops, the food produced is bigger and better. In 41 crops surveyed around the world, for example, wild bees were found to play a role in increasing the production of almonds, blueberries, cherries, coffee, and strawberries, to name a few [2]. In another study in Indonesia, pumpkin patches with 10 bee species experienced 50% increases in pumpkin production than patches with 5 bee species [3]. A coffee farm in another part of Indonesia experienced a nearly 25% increase in coffee production in farms visited by more bee species [4].

Wild bees from around the world. From top left and going clockwise, Phenacolletes mimus  from Australia, Euglossa spp. from Guyana, Augochlora pura from United States of America, and Dasypoda plumipes from the United Kingdom. All photos are credited to Sam Droege, USGS. 

Wild bees from around the world. From top left and going clockwise, Phenacolletes mimus  from Australia, Euglossa spp. from Guyana, Augochlora pura from United States of America, and Dasypoda plumipes from the United Kingdom. All photos are credited to Sam Droege, USGS. 

Scientists suspect that diverse groups of bees result in better pollination because wild bees can be more efficient at placing pollen on a flowers’ receptive stigma. In addition, different bee species may pollinate different sections of a flowers stigma more efficiently, making it more likely that a flower attains maximum pollination. In apple orchards in Canada, for example, researchers found various wild bee species deposited pollen every time they visited apple blossoms, whereas honeybees left no deposited pollen 38% of the time [5]. As a result, researchers found higher apple production in the orchards visited by more wild bees.

 The problem is, along with honeybees, wild bees are also in trouble, but we know much less about them. We know they depend on the availability of flowers in a landscape, along with places to nest, e.g. in the ground, holes in trees, dried stems, or even crevices of bricks or stones [6,7]. If we want to preserve these important species, we need more research and we need to make sure we provide them with their needed habitats. This includes avoiding the use of harmful pesticides, planting more native flowers, and providing undisturbed soil sites for bee nests.

So this summer, how about you plant some wild flowers, minimize your pesticides, sit back and let the wild bees keep feeding you?


Maria-Carolina is a Ph.D. candidate in the School of Natural Resources and Environment at the University of Michigan. Her dissertation focuses on how urban landscapes impact wild bees communities, and whether changes in wild bee communities affect food production in urban agriculture gardens. Growing up Carolina wanted to be an astronaut, but soon found out she missed the height requirement by 0.05m, and so she decided to study the contents of Earth instead. When she's not catching bees, Carolina enjoys dancing (salsa in particular) and trying new foods.

[1] VanEngelsdorp et al. “A historical review of managed honey bee populations in Europe and the United States and the factors that may affect them.” Journal of Invertebrate Pathology, 103(2010):S80-95

[2] Garibaldi et al. “Wild pollinators enhance fruit set of crops regardless of honey bee abundance.” Science, 6127(2013): 1608-11

[3] Hoehn et al. “Functional group diversity of bee pollinators increases crop yield.” Proceedings of the Royal Society B, 1648(2008): 2283-91

[4] Klein et al. “Fruit set of highland coffee increases with the diversity of pollinating bees.” Proceedings of the Royal Society B, 1518(2003):955-961

[5] Martin et al. “Pollination services are mediated by bee functional diversity and landscape context” Agriculture, Ecosystems and Environment, 200(2015):12-20

[6] Arnett Jr., Ross H. American Insects. Boca Raton, Florida: CRC Press LLC, 2000. Print.

[7] Marshall, Stephen. Insects: Their natural history and diversity. Buffalo, New York: Firefly Books, 2006. Print.