by Nicole Rivard
You would be hard pressed to find someone who does not want to save the bees these days. Our lives and the planet depend on it really. One of every three bites of food we eat comes from a crop pollinated by wild bees, honeybees and other pollinators.
We can thank native bumble bees for buzz-pollinating (vibrating their wing muscles so rapidly they sonicate pollen tucked away inside long, tubular flowers) the blossoms that yield blueberries, cranberries, eggplants, tomatoes and peppers. And wild bees are a keystone species in most terrestrial ecosystems.
Fruits and seeds derived from pollination are a major part of the diet of approximately 25 percent of all birds, and of mammals ranging from red-backed voles to grizzly bears, according to the Xerces Society for Invertebrate Conservation.
But the truth is, with more than 150,000 species of sawflies, wasps, bees and ants in the Hymenoptera order of insects—the third largest—we could all use a little help deciphering which bees need the most help, why and what’s the best way to lend a helping hand.
HONEYBEES VS. WILD BEES
Honeybees are actually imports to North America from Eurasia. They are commercially farmed and kept in large comb-filled hives managed by beekeepers, although escapees have created a feral honeybee population in the southern part of the U.S.
“If you have honeybees in your yard in the northern part of the U.S., it’s likely because there is a beekeeper living somewhere around you,” explained Emily May, pollinator conservation specialist for the Xerces Society.
Honeybees are trekked all over the country by commercial beekeepers to pollinate farm crops. Almond crops, for example, depend entirely on the honeybee for pollination at bloom time.
Unfortunately, they are also exploited for their honey (see sidebar on page 28). Beginning in 2006, experts noted significant yearly declines in managed honeybee colonies, which were attributed in part to a phenomenon called Colony Collapse Disorder (CCD).
It’s an abnormal condition that occurs when the majority of worker bees disappears, leaving behind a queen, an abundant supply of food and a few nurse bees. Research attributed CCD to the perfect storm of stressors such as parasites, diseases, pesticides, pollutants, nutritional deficits, habitat loss, effects of climate variability, agricultural production intensification, reduced genetic diversity and management practices.
While beekeepers still lose colonies annually, 40% from April 2019- April 2020, it is no longer because of CCD.
“By focusing efforts on pollinator health, the U.S. today has about 2.8 million honey bee hives, and no incidents of CCD have been reported in several years,” wrote Robert Noweirski, national program leader, National Institute of Food & Agriculture, in his June 24 blog, “Pollinators at a crossroads.”
However, one of the oldest foes of honeybees, the Varroa mite, is still a major threat, as is deformed wing virus, which often come together. As the mites feed on bees, they can spread the virus, while also weakening the bees and making them more vulnerable to pathogens in the environment.
Pesticides also affect honeybees’ immune systems, making them more vulnerable to parasites and pathogens and negatively affecting their ability to digest food. Speaking of food, dwindling sources of nectar and pollen are also menaces to honeybees.
Floral diversity in landscapes has been reduced by intensive agriculture (single crops, few flowering weeds, limited hedgerows) and urbanization. In the U.S. between 1992 and 2012, nearly three acres of agricultural land per minute were lost to development, according to a 2019 American Farmland Trust report. Despite the losses, the overall honeybee population remains relatively stable.
“That’s largely because of the efforts of beekeepers to divide colonies to make new hives,” May said. While there is no denying honeybees face threats, it is our native wild bees, particularly bumble bees, who are currently the most at risk.
THE BUZZ ABOUT BUMBLEBEES
More than one-quarter of all 46 native bumble bee species found north of Mexico are facing some degree of extinction risk, including the American, Crotch’s, Franklin’s, Morrison, obscure, southern plains, variable, western, yellow-banded, yellow and rusty-patched bumble bees, according to an analysis led by the Xerces Society, and coordinated with the International Union for the Conservation of Nature’s North American Bumble Bee Specialist Group.
The rusty-patched became the first bumblebees to receive protection under the Endangered Species Act (ESA) in 2017, following an 87% decline in the species population since the late 1990s, according to the U.S. Fish and Wildlife Service.
Rustypatched bumble bees now remain in just 13 states, down from 28. Habitat loss, alteration and fragmentation, pesticide use, climate change and diseases coming from honeybees all contribute to the declines of native bees, according to May. Other native bee species most at risk include cuckoo bees, leaf-cutter bees, long-horned bees, mason bees, mining bees, sweat bees, Western bees and yellow-faced bees.
Seven yellowfaced bee species once abundant in their native home of Hawaii gained ESA protections in 2016, making them the first bees ever to be listed.
GET BUSY PROTECTING BEES — MOVE BEYOND FLOWERS
You have probably heard how important it is to plant native flowering plants and shrubs to protect bees, but truthfully, it is not enough. It is crucial to stop using pesticides. Neonicotinoids—including, clothianidin, thiamethoxam, and imidacloprid—are a class of insecticides highly toxic to all bees. They are taken up by a plant’s vascular system and expressed through pollen, nectar and guttation droplets from which bees forage and drink.
They are found in popular gardening products like: any of the Bayer 2-in-1, 3-in-1 or All-in-One garden insecticides; Green Light Tree and Shrub Insect Control; Complete Brand Insect Killer; and Ortho Rose and Flower Insect Killer. Backyard barrier sprays for mosquitos containing pyrethroids should also be avoided as they are lethal to bees. Source reduction through the removal of standing water is the best method to control mosquitoes.
There are three things you can provide in your own backyards for wild bees to thrive according to the Xerces Society: flowers from which to gather pollen and nectar; a place to nest; and a sheltered location to overwinter. (For specific native flowering plants and shrubs in your region you can visit xerces.org/lbj.)
Of particular importance is providing blooms early and late in the season. Most bumblebees nest underground in abandoned holes made by squirrels or mice. Some nest on the surface of the ground or in empty cavities of logs, dead trees, under rocks, etc. Queen bumblebees typically overwinter in small cavities just below or on the ground surface, utilizing loose soil or leaf litter, but they also may use woodpiles and rock walls.
SAVE THE STEMS
There are also stem-nesting bees who seek stems that are cut or naturally occurring open stems as places to start a nest in the spring, lay eggs on pollen balls and overwinter. So, leave things like dead raspberry cane or wildflower stalks intact over the winter and do a late “spring cleaning” instead.
That means pruning stalks at different heights from about 8’’ to 24” off the ground to provide more nest cavities. Over the summer bee larvae develop in the stems and then overwinter there. Adult bees emerge in the early spring and start new nests in newly cut dead stems or other naturally open stems.
For more ways to create nesting and overwintering habitat, we love this guide: xerces.org/publications/factsheets/nesting-overwintering-habitat. Rest assured that maintaining a variety of these habitat features will help the wild bees in your backyard.