By Ruth Thornton
WKTV Contributor
greer@wktv.org
Many homeowners around Michigan have stopped mowing their lawns in May to help bees and other pollinators. It’s part of an international initiative dubbed ‘No Mow May.’
But experts say the practice may be overrated.
“There’s no strong evidence that No Mow May really benefits wild bees,” said Logan Rowe, conservation associate with the Michigan Natural Features Inventory. “There are many other ways that will have a greater impact on native bee populations and communities.”
Besides the familiar honey bee, which was imported from Europe and is not native to the U.S., Michigan boasts around 470 native bee species.
Some have been declining recently, with potentially dire consequences for agriculture and natural communities, that depend on the insects for pollination.
Several Michigan bees are declining
Rowe specializes in rare insects, including the several wild bees that are dwindling or have disappeared altogether. But exactly how many of the state’s native bees are in trouble is not clear, he said.
“We have two species that are state endangered, legally protected. Those are the rusty patched bumble bee and the American bumble bee,” Rowe said.
There’s evidence other native bees aren’t doing well, either, including the four other bumble bees that are designated as “species in greatest need of conservation” in Michigan.
“Habitat loss is probably the biggest threat, but it operates in many different ways,” Rowe said. For example, converting natural areas to agriculture leads to more exposure to harmful pesticides.
Honey bees also can compete with native bees for resources.
“There’s evidence that shows that if a plant species is dominated by honey bees, you’ll get less native bees visiting that plant,” he said.
Honey bees also can transmit harmful pathogens.
“We have an agricultural system that is reliant on honey bees. That doesn’t mean native bees don’t contribute,” Rowe added. “There’s plenty of research that will show that supporting native bees within agricultural landscapes leads to increased crop production.”
Honey bees have different concerns than native bees
But, Rowe said, the concerns around honey bees differ from those around native bees. “Honey bees are managed livestock, essentially. They’re not native bees, so it’s a different type of worry – it’s more of a management concern, as opposed to a species loss concern, because we’re not going to lose honey bees as a species.”
Rufus Isaacs, a professor at Michigan State University, said “There are clear signals that some bee species have declined in some areas, and honey bee numbers have gone through some tough times as well.”
Because so much of U.S. agriculture is dependent on bees, what’s causing their decline needs to be better understood, Isaacs continued.
“We talk about the ‘four Ps,’” he explained – poor nutrition, or a lack of access to flowering plants, pesticides, pathogens and parasites.
While maintaining healthy honey bee populations is essential for agriculture, so is keeping native bees healthy.
For example, Rowe said, “having both honey bees and native bees in a blueberry field in southwest Michigan is going to produce a better crop than either on its own.”
Michigan’s fruit crops largely depend on bees
Most of Michigan’s fruit crops are dependent on bee pollination – including blueberries, apples, cherries and cranberries – as are most vegetable crops, and some nuts, Isaacs said.
On large commercial berry farms, the “farmers need very large numbers of insects to move the pollen among millions [of flowers] that are only going to be open for a couple of days,” Isaacs added.
Much of that is accomplished through large numbers of honey bees farmers bring in seasonally to pollinate their crops. That’s why commercial bee keepers, who move their hives from farm to farm, are so important.
But, Isaacs said, wild bees are more efficient pollinators, especially for crops that are native to the U.S., like blueberries or cranberries. While honey bees need to visit those flowers multiple times to fully pollinate them, it often takes just one visit by a wild bee.
Native bees also are more tolerant of the Midwest climate. While honey bees don’t want to fly when it’s cool or windy, wild bees are adapted to these conditions.
Losing bees and their pollination services could have dire consequences for people, Rowe said. “If we lose wild bees, we could see collapses of our natural communities, and we have no idea what that would mean for the natural areas in the state.”
Michigan Bumble Bee Atlas
Rowe said bumble bees are a good place to start if people are interested in learning more about wild bees.
“Bumble bees are charismatic and fuzzy, and people like them.”
They’re also easier to identify than other bees. That’s part of the reason Michigan Natural Features Inventory and Michigan State University Extension launched the Michigan Bumble Bee Atlas, a community science project in which volunteers look for bumble bees and record any sightings.
What you can do
If you want to help native bees, Rowe recommends planting native flowers and grasses.
“There’s a lot of nesting that can happen in the stems of grasses, in the clumps on the ground.”
Isaacs encourages people to grow a ‘mullet garden’ – tidy in the front, (wildlife) party in the back – where the front yard, where neighbors walk past, is nicely maintained.
“Then, in the back garden that my neighbors can’t see, is where I have the nesting habitat. I’ve got some piles of logs, and some areas that are just like old branches and places that are undisturbed,” he said. That provides native bees with areas to nest.
It’s also best to limit pesticide use, which can harm beneficial insects.
“If you’re really trying to ‘save the bees,’ I don’t think you do that by putting a honey bee hive in your backyard,” Isaacs said. “The best thing you can do is plant flowers, create habitat for them, enjoy all the different kinds of bees that will come if you create a little patch of that in your garden.”
Resources
If you’re interested in helping bees, you can join the Michigan Bumble Bee Atlas as a volunteer – community members of all backgrounds and skill levels are encouraged to participate. Check the website for more information.
You also can take photos of bees and submit them to iNaturalist to help in the effort. More information can be found at iNaturalist.org.
