Minnesota’s managed and native pollinators

Honey bees (Apis mellifera)

In the United States, the USDA classifies honey bees as livestock. Humans are deeply involved in the placement and care of honey bees, which can be complex and time-consuming. 

How helpful honey bees are for your farm’s production depends on the crop you grow and where your farm is situated in the landscape. For example:

• A diversified vegetable farm with a nearby woodlot and nature reserve will likely have a diverse population of native pollinators. It may not benefit from the addition of honey bees.

• If a diversified vegetable farm is surrounded by corn and soybeans, honey bees could be a big help in getting crops pollinated.

For fruit farmers, the bloom period is short, and good pollination is crucial, making honey bees essential to ensuring the crop receives the necessary pollination.

To learn more about honey bees and their management, visit the University of Minnesota Bee Lab.

Bumble bees (Bombus impatiens)

Bumble bee colonies can be purchased from a few retailers in the United States. The species of bumble bee colonies that can be purchased in the Midwest is the Eastern Bumble Bee (Bombus impatiens), which can also be found wild in Minnesota. Managed bumble bees can also potentially spread pathogens to native bees.

• Commercially produced bumble bees are often used for pollination in greenhouses, as the plants are in an enclosed space that native bees cannot access. Growers may also place them in outdoor areas to increase pollination.

• Unlike honey bees, whose hives can last many years with proper care, commercial bumble bee colonies have a limited lifespan and should be managed in specific ways to protect native bumble bee populations. For example, commercial bumble bee colonies are often adapted to greenhouse production, and the genes that give these bees an advantage in greenhouses aren’t good for our wild bumble bee populations.

• It is recommended in Minnesota that commercial bumble bee hives have a “queen excluder” placed in the hive to keep native bumble bees from intermixing with commercial bumble bees. 

• Commercial bumble bee colonies should also be terminated at the end of the useful period to prevent competition with the native bees that will stay on your farm year after year.

Mason bees (Osmia species)

Mason bees nest in tubes and are sometimes used to pollinate apples and cherries. The most commonly used species is the blue orchard bee (Osmia lignari). These bees are similar in size to honeybees, but are a dark, metallic blue-teal. They nest in stems in the wild, but you can use nesting tubes. Mason bees are available for purchase.

The Sustainable Agriculture Research and Education program offers an in-depth publication on blue orchard bees.

Bumble bees (Bombus species)

Minnesota is home to 25 species of bumble bees. Bumble bee species are social, meaning they live together and work collectively for the group.

Native bumble bees have an annual lifecycle, with one queen starting colonies in the spring, building up a hive of workers that then produces queens in the fall. These new queens survive the winter while the workers and the old queen die, and are some of the first bees to emerge in the spring.

Bumble bee nests are built in abandoned animal burrows, tree cavities, and in other protected, dry places. They are sometimes found under sheds and in compost piles.

Bumble bees are valuable pollinators because of the way they interact with flowers. Bumble bees vibrate when visiting a flower, which releases extra pollen from the flower. This is called “buzz pollination,” and it is beneficial for crops such as blueberries and tomatoes.

Bumble bees will fly in cooler, wetter weather than honey bees do, which is helpful in pollinating fruit crops, like apples and blueberries, that bloom in the early spring for a small window of time.

One bumble bee to be aware of is the Rusty Patched Bumble Bee (Bombus affinis). This bee is a federally listed endangered species. If you farm in an area where this bee lives, you may want to or be required to adjust pesticide applications, the Environmental Protection Agency provides a map that displays Pesticide Use Limitation Areas for products with active Endangered Species Protection Bulletins.

Cellophane bees (Colletes species)

Minnesota is home to 25 species of cellophane bees. These bees are wild, have solitary nests (although individuals often nest near each other), and build their nests in the ground. They are active early in the spring. Some species are known to pollinate apples and blueberries.

Longhorn bees (Eucerini species)

There are 35 species of longhorn bees in Minnesota. They get their name from their long antenna. These bees are solitary and nest in the ground. The most recognizable longhorn bees to vegetable farmers are squash bees, a common name for a couple of species of longhorn bee.

Cucurbits are native to North America, so there are bees that evolved alongside them. There are a few species of native, solitary bees that are referred to as squash bees.

To encourage these bees on your farm, leave patches of bare ground that do not receive tillage. This provides a protected area for squash bee nesting tunnels to go through the winter without being disturbed. Being careful in the use of pesticides also helps protect squash bees where they live in the soil.

Mason bees (Osmia species)

Minnesota is home to 22 species of mason bees. Mason bees are solitary and nest in cavities in trees and hollow stems. Some cap their nests with chewed-up leaves, wood pulp, pebbles, or mud. Many of these species have metallic coloration.

Mason bees fly in even cooler and wetter weather than bumble bees, making them helpful in guaranteeing that spring-blooming fruit crops, such as apples and blueberries, get the pollination they need to produce a large crop of well-shaped, good-sized fruit.

Mason bees are known to pollinate apples, blueberries, tart cherries, strawberries, and raspberries.