Buzzing About Native Bees

Honey bees are easy creatures to care about. These fuzzy, social, and industrious insects make delicious honey for us. They also pollinate our crops, producing billions of dollars in economic value. But there is a whole universe of other bees to love, says Kiley Friedrich – they’re just a bit harder to spot. The “big, fluffy, charismatic bumble bees often get people’s attention,” she says, but the dominant bee species in Minnesota and Wisconsin are actually tiny sweat bees measuring just the length of a pinky nail, along with their cousins, the green metallic bees.

Others include leaf-cutter bees; lovely blue Mason bees; and squash bees, which frequent the large, orange squash blossoms in people’s gardens. “Once you start to know what you’re looking for, you’ll see them everywhere,” says Friedrich. They are the wild, or native, bees, and they number more than 400 species in Wisconsin and Minnesota alone.

A member of the University of Minnesota Bee Lab and unabashed bee enthusiast, Friedrich works hard to generate buzz about native bees. Not only are they beautiful and astoundingly diverse, she says, but they also play underappreciated roles as pollinators. Most people think only of honey bees or butterflies when they hear the word “pollinator,” not realizing there are 4,000 additional bee species in North America, she says. “So, the vast majority of our native pollinators exist in this realm that is pretty unfamiliar for folks.”

If the land mechanism as a whole is good then every part is good, whether we understand it or not… To keep every cog and wheel is the first precaution of intelligent tinkering. – Aldo Leopold, “Conservation,” Round River

Greater awareness can’t come soon enough. According to a recent report by the Center for Biological Diversity, more than half of North America’s and Hawaii’s native bee species are declining. Nearly one in four are at increasing risk of extinction. The Bee Lab works diligently to counter these trends, studying ways to support both honey bees and native bees, and the pollination services they provide.

Busy as these bee researchers are, however, they can’t improve bee habitat and care for bees all on their own. That’s why the lab also has a Bee Squad that reaches out to the public. “[We] help people look at their landscapes, look at their yards,” Friedrich says, “and see what they can do for bees.”

Native Bee Ecology

Scientifically, bees fall into the order Hymenoptera, a group of insects that also includes the wasps and ants. All Hymenopterans have membranous wings and social tendencies, but what sets bees apart is the hairiness of their bodies.

Unlike wasps, which are omnivores or carnivores, bees are strict vegetarians that use the hairs, or setae, on their bodies to collect the pollen they depend on for protein. (Bees get their carbs by sipping nectar.) At the same time, the setae inadvertently benefit plants – conveying pollen from flower to flower as the bee makes its rounds. “The hairy body is the great distinguishing trait of bees,” Friedrich says. “It makes them the efficient pollinators they are.”

The squash bee, Peponapis pruinosa, will seek out pumpkins, squash, and other cucurbits above all else, making it a top pollinator of those plants. Some bees are also loyal to sunflowers, foraging only in patches of sunflowers or other members of the aster family.

But most wild bees in the Midwest are generalists: They’ll visit whatever flowers happen to be blooming at the time, helping to ensure a constant supply of food. And the other thing to know is that nearly all wild bees are solitary, not social.

Friedrich explains that social bees, like honey bees and bumble bees, form colonies or hives where many bees live together and divide labor among themselves. Workers take care of the larvae and construct the hive. The job of the drones is mating with the queen.

Solitary bees, on the other hand, nest individually in the ground or inside the pithy center of a grass stem or reed, which they hollow out to create a space for their eggs. Once the nest is built, the female provisions food for the larvae to eat when they hatch, lays her brood, and then simply flies away.

‍

“The females leave their broods to fend for themselves until the next year when the brood emerges as the next generation of adults,” Friedrich says. “So, there is very little social overlap in these solitary bees. They kind of just do their own thing.”

Bringing Native Bees into Your Backyard

Although the lone wolf lifestyles of native bees make them easy to overlook, their impact on the landscape is becoming more and more obvious. A recent study compared fruit set and apple yields in orchards that hired honey bee hives, versus ones that relied strictly on wild pollinators. It found little difference between the two, suggesting that native bees contribute substantially to the pollination services we usually attribute to honey bees.

Researchers at the Bee Lab are also investigating whether wild bees aid prairie restorations by boosting rates of pollination and seed production. In the meantime, other Bee Lab studies are looking at the flip side: How restoring prairie and other native plant communities helps bees.

On this last front, there’s a lot that everyday citizens can do to pitch in, Friedrich says. Gardening with native plants is a good first step; sunflowers, yellow and purple coneflowers, clovers, stiff goldenrod, and bee balm are all good choices in the Upper Midwest.

Always ask when buying plants from a nursery whether they’ve been treated with pesticides that can harm bees. If they have, see if your nursery will move away from this practice. It’s also essential to choose plants that bloom at different times during the season, especially ones that flower later in the summer. “We want to make sure there isn’t a gap of time without flowers in the landscape, and the bees go hungry,” Friedrich says.

Then, keep your yard as messy as you can tolerate, with small piles of twigs, flower stalks, and grasses for stem-nesting bees to tunnel into and lay their young. Bumble bee queens will overwinter in leaf litter or the bark layers from fallen logs. And as far as ground-nesters go, “open sandy patches in your yard are really great,” Friedrich says. “They allow bees to excavate into the ground as they see fit.”

Her final piece of advice? Don’t just stop to smell the flowers. Take time, too, to appreciate bees. Her personal favorites are the green metallics (featured photo, also courtesy of Friedrich). “They’re these beautiful, bright green, striped bees that are just amazing,” she says. “I could sit and watch them all day.”