Managed bees' impact on wild bees
The mission of the UMN Bee Lab is to promote the conservation, health, and diversity of bee pollinators through research, education, and hands-on mentorship. In our work with all bees, managed honey bees as well as wild, native bees, we are mindful of potential risks honey bees pose to native bees. We strive to find solutions to promote healthy honey bees while protecting native bees.
Honey bees aren’t native to North America? Please explain the difference between honey bees and native bees.
Honey bees are not native to North America. The honey bees that beekeepers manage in the US have European origins. They first appeared on US land in the 1600’s and rapidly became established across the country. Native bees boast amazing diversity and over 400 different species have been identified in Minnesota. Approximately 4000 species of native bees have been described in North America. Unlike our social honey bees that live in colonies that can be comprised of 50,000 bees, most native bees do not live in large colonies and are are solitary. They nest in tunnels in the ground (why undisturbed ground is so important in your landscaping) and stems (why leaving your flower stems can help bees).
Does keeping bees help their populations?
Unlike some native bees, honey bees are not at risk of going extinct. You may have heard there are more honey bee colonies dying now than there were 10 or 20 years ago. This is true, but beekeepers are able to create new colonies by splitting the colonies that lived. Thanks to the hard work of these beekeepers, the number of honey bee colonies overall is pretty stable, despite increased colony losses. This means that we do not need more people keeping bees to help honey bee populations.
Can honey bees cause problems for native bees?
Honey bees have unique attributes that have led to our ability to domesticate them. However, unlike other domestic animals, we cannot fence them in. The foragers from managed honey bee colonies roam freely within several miles of their colony, covering thousands of acres of land. Across the land surrounding their hive, honey bees will forage on flowers, usually focusing on the flowers that produce the most nectar. Wild, native bees are also using these flowers. When flowers are abundant, there can be enough flowers to support all bees, but when resources are low, the large numbers and communication skills of honey bees give them an advantage over native bees, possibly depriving native bees of needed food. An additional risk at shared flowers is the spread of diseases among different bees. Many pathogens can transfer from one bee to another at flowers. When honey bees are kept close together it increases the risk of infection.
As people become more aware of the importance of native pollinators, there is growing concern about negative impacts of honey bees on native pollinators. With our current knowledge, it is difficult to make specific recommendations to limit these impacts. Honey bee colonies should only be placed in areas with more than enough flowers to support them. We know that planting more flowers will increase the likelihood that there will be enough food for all the bees. We also suspect that having more flowers will decrease the number of flowers that are being shared, and so decrease the likelihood of spreading diseases. While we have some ideas of what might be enough to support honey bees, we don’t have a good idea of how much is enough for honey bees and native bees together.
The safest bet to keep native bees healthy is to reduce their exposure to honey bees. If you are keeping honey bees and want to do all you can to help other pollinators, keep your colonies as healthy as you can and provide abundant flowers in the area surrounding your apiary.
I love supporting bees and the local food movement. Are there any problems with harvesting honey from bees I keep in my backyard in the city?
Urban beekeeping has become very popular and many people in cities around the world have started keeping more bees in the cities. One problem with this is that each of those colonies needs acres of flowers and there is not enough room for that in urban areas. Another problem is that many of these beekeepers are new to beekeeping and do not know how to keep their colonies healthy. Since there are many more colonies close to each other, urban areas can become a hotbed of honey bee pests and diseases. Both honey bees and native bees do better when honey bee colony numbers are limited and there are enough flowers to support all bees. Some urban areas are home to native bees that are at risk of extinction and need all the help they can get to survive.
Can other managed bees such as bumble bees or mason bees impact wild bee populations?
While it is important to have pollinators other than honey bees available for crop pollination, these other managed bees also carry risk to wild bees as carriers of pests and diseases. Some species have also been moved outside of their natural range and have caused problems for the native bees. Bombus dahlbomii, one of the largest bee species in the work, is at risk of extinction due to pathogen spillover from the imported European bumble bee, Bombus terrestris. For more information on the imapt of managed bumble bees on wild bumble bees, see From Humble Bee to Greenhouse Pollination Workhorse: Can We Mitigate Risks for Bumble Bees? by Elaine Evans.