Virginia’s vanishing bee: State works to save rusty patched bumblebee

By: - September 8, 2020 12:02 am

A rusty patched bumble bee in Bath County, 2018. (Ellison Orcutt, Virginia Department of Conservation and Recreation)

In 2019, the bee met the bulldozer, and the bee won. 

In July of that year, a federal appeals court in Richmond for the second time yanked a permit for the now-cancelled Atlantic Coast Pipeline. And the decision brought into the spotlight a small creature that for years has been retreating into Virginia’s shadows: the rusty patched bumble bee. 

Once a familiar sight to millions, this fuzzy bee, with the distinctive splash of color emblazoned on its back that gives it its name, once ranged over much of the eastern and midwestern United States. For generations, it would have been as familiar a part of summer as the high drone of cicadas and the rolling fields of Virginia’s Piedmont. 

But some 25 years ago, the rusty patched bumble bee began to disappear. Eventually the U.S. Fish and Wildlife Service found that the species was “so imperiled that every remaining population is important for its continued existence.” It became the first bee to be included on the agency’s endangered species list in 2017. 

The precariousness of the population would become an unlikely roadblock to the 600-mile Atlantic Coast Pipeline that utility giants Dominion Energy and Duke Energy intended to build from West Virginia to North Carolina, with more than half crossing Virginia. In major rulings in 2018 and then 2019, the U.S. 4th Circuit Court of Appeals overturned Fish and Wildlife permits for the project. One of the bases for the ruling was the court’s conclusion that the agency had been incorrect in finding that the pipeline wouldn’t jeopardize the rusty patched bumble bee. Somehow, Chief Judge Roger Gregory wrote in 2019, the agency had determined “that the killing of more bees than have been found in most locations in the past two decades would not jeopardize the continued survival or recovery” of the species. 

This summer, still lacking Fish and Wildlife approval as well as seven other permits, Dominion and Duke cancelled the Atlantic Coast project. The bee, along with three other endangered or threatened species with populations in the pipeline’s path, had won. 

Still, it was a paper victory. Only 6 percent of the pipeline was ever built. And so the project’s demise left unchanged the rusty patched bumble bee’s perilous position. Even as scientists race to discover what factors are driving its demise, the population continues to shrink.

A dwindling population

Until the last decades of the 20th century, the rusty patched bumble bee (Bombus affinis) could be found in 28 states in the U.S., from Maine to northern Georgia and as far west as the Dakotas. 

Like many other bee species, the rusty patched lives in large colonies, sometimes as many as 1,000 strong, led by queens. The bee has an unusually long life cycle, emerging early in the spring and remaining active until late fall, when it overwinters in cavities in the ground. A “generalist” pollinator, it isn’t discriminating when it comes to food, browsing on such common plants as thistle, red clover, bee balm and goldenrod. 

More notably, the rusty patched bumble bee is one of a group of species that can “buzz pollinate,” a pollination technique where it grabs onto a plant and then vibrates its body at a high frequency to shake loose tightly packed pollen that might otherwise be difficult to access. Not all bees buzz pollinate — honeybees, for example, don’t. But buzz pollination is essential for the reproduction of a range of plants, including crops like blueberries, apples and tomatoes. 

Despite its once-abundant numbers and the diversity of its diet, once the rusty patched bumble bee began to disappear, it happened rapidly. Since the late 1990s, U.S. populations have dropped by almost 90 percent; many of the bee’s advocates have never seen it in the wild. 

In Virginia, where the species once ranged widely, the bee in recent years has only been observed in four counties: Bath, Highland, Augusta and Rockingham, with the most sightings in the former two locations. 

How large the colonies that live in those counties are is uncertain. Jason Bulluck, director of the Virginia Department of Conservation and Recreation’s Natural Heritage program, which aims to conserve Virginia’s biodiversity, said the populations “could very well be widespread in those counties,” but the department hasn’t been able to inventory their full extent.

Making the task more difficult is the bee’s generalist nature. “They’re not specialists,” said Bulluck. “They don’t have a specific host plant that they are tied to, and maybe not a specific habitat.” That’s usually good for survival — the loss of a single plant species won’t wipe out a whole population in one fell swoop — but bad for scientists trying to hunt down individuals to document. 

Many theories, little consensus

There is little consensus among scientists about what’s causing the rusty patched bumble bee’s disappearance, although theories abound.

Habitat loss and fragmentation is one leading hypothesis. Another is the negative effects of neonicotinoids, a class of insecticides developed in the 1990s that have become the most widely used pesticides in the world. 

“They really exploded in use over the past 20 years or so, and that really lines up really well with the decline of the rusty patched bumble bee,” said Lucas Rhoads, an attorney with the Natural Resources Defense Council, which has been involved in litigation with the U.S. Fish and Wildlife Service over the species. 

Still another possibility is a pathogen known as Nosema bombi, which may have spread from more resistant laboratory-bred bees to wild populations like the rusty patched bumble bee with devastating results.

“Probably the fungal pathogen alone wouldn’t have caused this decline,” said Rich Hatfield, a conservation biologist with the Xerces Society for Invertebrate Conservation, the organization that first petitioned for the addition of the rusty patched bumble bee to the endangered species list. “But when you add it on top of other stressors like pesticides and climate change and habitat loss, you sort of have the straw that breaks the camel’s back.”

The Midwest region of the Fish and Wildlife Service arrived at a similar conclusion in a recent summary of the variables that may underlie the species’ decline. 

“It appears that no one single factor is likely responsible, but these threats working together have likely caused the decline,” the agency wrote.

One of 475

Despite Fish and Wildlife’s conclusion that habitat loss may have contributed to the disappearance of the rusty patched bumble bee, the agency announced last week it wouldn’t be “prudent” to designate critical habitat for the species, a label that would force the federal government to scrutinize any of its actions that might degrade habitat for the bees.

“The present or threatened destruction, modification or curtailment of habitat is not the primary threat to the species, and the availability of habitat does not limit the conservation of the rusty patched bumble bee now, nor will it in the future,” the agency concluded Aug. 31.

Hatfield said Fish and Wildlife’s decision is not scientifically well-founded. 

“The Fish and Wildlife Service acknowledges that we know very little” about the species, and particularly how and where it overwinters, he said. “You can’t say we know very little about its life cycle and yet its habitat is plentiful.”

“Removing the option for designated critical habitat takes a conservation tool out of the toolbox,” he said. “I don’t think I’m at a stage where I think we’re ready to remove options.”

The decision came just days after another agency, the Virginia Department of Wildlife Resources (previously known as the Department of Game and Inland Fisheries), designated the rusty patched bumble bee as the “2020 focal species” and committed $25,000 to habitat restoration in the state for the bee as part of its Restore the Wildlife initiative. 

Bulluck was undeterred by the federal decision, citing the pathogen hypothesis as well as the bee’s generalist tendencies and historically wide range. 

A rare bee known as Osmia illinoensis, Rockingham County, 2019. The bee is  considered imperiled both globally and in Virginia. (Sam Droege, U.S. Geological Survey)

“There’s no reason to believe that there’s a specific habitat type that’s driving their distribution,” he said. 

Furthermore, he noted, the rusty patched bumble bee isn’t the only bee species in a tight spot in Virginia.

“I don’t want to say it’s just a bee, but it’s one of 475 species of bee that we have documented in the state,” he said. Of those, 456 are native, and about 20 are considered rare on either a state or global level. 

“Perhaps the greatest value there is increasing awareness of people that pollinators are imperiled,” he said. “And when they are gone, their services will be gone.”

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Sarah Vogelsong
Sarah Vogelsong

Sarah is Editor-in-Chief of the Mercury and previously its environment and energy reporter. She has worked for multiple Virginia and regional publications, including Chesapeake Bay Journal, The Progress-Index and The Caroline Progress. Her reporting has won awards from groups such as the Society of Environmental Journalists and Virginia Press Association, and she is an alumna of the Columbia Energy Journalism Initiative and Metcalf Institute Science Immersion Workshop for Journalists.