A new scientific study reveals a potentially dire situation for Minnesota's state bee, the endangered Rusty Patched Bumble Bee.
As the Entomological Society of America posted today on the X platform:
For rusty patched bumble bees, low genetic diversity between colonies and other genetic factors underscore the fragility of their limited populations, according to a new study.
— Entomological Society of America (@EntsocAmerica) April 9, 2024
đź”— Genetic Analysis Guides Conservation of Endangered Bumble Bee https://t.co/zmn9lVazV8
At Minnesota Public Radio, Dan Gunderson reports in Study finds Minnesota state bee in tough shape:
For the first time, researchers have analyzed the DNA of rusty patched bumble bees across the insect’s range. The results add urgency to efforts to conserve the endangered species.
Using a non-lethal technique, scientists collected tiny leg sections from bees to determine their genetic makeup. They found low genetic diversity, and inbreeding.
“The numbers of colonies that those individuals represent are much lower than expected,” said lead author John Mola from Colorado State University. “Even in areas like the Upper Midwest, where the rusty patched bumblebee, at least insofar as insects can become famous, has become a little bit emblematic as a stronghold, this species is still at risk.” . . .
Starting about 25 years ago the bumble bee experienced a precipitous 90 percent population decline.
It was listed as endangered in 2017. In 2019 the rusty patched bumble bee was named the Minnesota state bee. . . .
One of the remaining known populations is found around the Twin Cities.
University of Minnesota researcher Elaine Evans has been observing the rusty patched bumble bees for 20 years.
This DNA analysis reinforced her concern that just adding more habitat might not be enough to save the species.
“As bee conservationists we all just want to think about the bees out there living their best lives out in the wild, having enough habitat out there to do what they need to do,” said Evans. “But the reality of the situation might be they might get to a point where to keep the species going they might need to be brought inside by people and captively raised.”
The study found genetic differences among isolated populations. The Appalachian bees are different genetically from Midwest bees, and the Minnesota bees had genetic variations from other Midwest bees. . . .
Evans is a co-author of the study, which can be accessed through the link in Mola's post:
New paper! Rusty patched bumble bee population genetics. Here's the open access pub: https://t.co/nqWPevBREu
— John M. Mola (@_JohnMola) April 4, 2024
Colorado State University published news of Mola et al's study in Rusty-patched bumblebee’s struggle for survival found in its genes:
A team of researchers has uncovered alarming trends in the first range-wide genetic study of an endangered bee species. The study, led by Colorado State University and published in the Journal of Insect Science, will inform conservation and recovery efforts for the rusty-patched bumblebee – a species that was once common in the United States but has declined from about 90% of its historic range.
The rusty-patched bumblebee was the first bee species to be federally listed as endangered in 2017 through the U.S. Endangered Species Act. Its numbers dropped rapidly starting in the late 1990s, likely due to a combination of pesticides, pathogens, habitat loss and degradation, and climate change.
“If that trajectory continues, this species could blink out in the next couple decades,” said lead author John Mola, an ecologist and assistant professor of forest and rangeland stewardship.
The outlook is dire for remaining populations of this important pollinator, according to the in-depth genetic examination by a large team of collaborators, including federal and state agencies, universities, nonprofits and consultants.
Even in strongholds where the bee is still found, scientists observed fewer colonies than a stable species would have and a high rate of inbreeding, which can threaten the long-term viability of a species. Of the bees sampled, 15% showed evidence of inbreeding, through the presence of what are called diploid males. In bees, males are typically haploid and have only one set of chromosomes, but when they’re inbred, they can have two sets of the same chromosomes and lack genetic diversity.
“When that happens, those populations essentially face a death sentence,” Mola said. “They basically have incompatible genetic systems with other populations of the same species.”
Analysis revealed three genetically distinct populations among rusty-patched bumblebees – in the upper Midwest, central Midwest and Appalachians – that will need to be handled differently for potential recovery efforts. Understanding population differentiation is key for captive rearing programs because bees from different populations might not be genetically compatible or might not survive once they’re released into the wild.
“This research is invaluable – it helps us refine healthy colony targets and shows us the importance of optimizing conservation efforts in genetically distinct areas, like the Appalachians,” said co-author Tamara Smith, a wildlife biologist with the U.S. Fish and Wildlife Service.
Protecting pollinators
Pollinators, including bumblebees, are critical for food production and support many other species. Pollinators improve ecosystem health and resilience, and many crops and flowering plants depend on them.
“There are approximately 50 species of bumblebee in North America, but there are big differences between bumblebees in the same way that there are big differences between songbirds and hawks,” Mola said. “They’re not substitutable.”
Decline of the rusty-patched bumblebee could be a harbinger of die-offs of other species that were once common.
“Unfortunately, we’re looking at a future scenario where about one in five bumblebee species in the United States could be endangered,” Mola continued.
But there is hope.
The rusty-patched bumblebee’s endangered listing has led to programs that restore habitat and the bee’s preferred plants. Pollinator-friendly home and community gardens make a difference, too, Mola said.
“At times, there can be doom and gloom in conservation, but there are good examples of butterfly species that have been recovered through careful conservation planning,” he added. “The same thing applies with bumblebees.”
Additionally, restoration projects that benefit bumblebees benefit other wildlife and landscape health in general.
Project partners, process
Surveying the rusty-patched bumblebee across its entire U.S. range required a vast network of collaborators with proper permits to collect genetic samples from the endangered species. Sampling involved catching the bees in nets, briefly putting them on ice and clipping off a tiny bit of leg – enough to conduct the study but not so much that it would interfere with their ability to function.
“Numerous partners recognized the importance of collecting these data, and we thank them for their contributions,” Smith said.
The project was mostly funded by the U.S. Geological Survey Science Support Partnership and the Great Lakes Restoration Initiative’s Threatened and Endangered Species Template through the U.S. Fish and Wildlife Service. The study was led by authors Mola, Smith, Ian Pearse (USGS), Michelle Boone (University of Minnesota), Elaine Evans (University of Minnesota), Mark Hepner (Metamorphic Ecological Research and Consulting), Robert Jean (Environmental Solutions and Innovations), Jade Kochanski (University of Wisconsin–Madison), Cale Nordmeyer (Minnesota Zoo), Erik Runquist (Minnesota Zoo), James Strange (Ohio State University), Jay Watson (Wisconsin Department of Natural Resources) and Jonathan Koch (U.S. Department of Agriculture).
Let's hope this research helps to save the species.
Photo: The rusty-patched bumblebee, once common in the United States, has declined from about 90% of its former range. Researchers conducted the first range-wide genetic study of the endangered species to inform recovery efforts. Photo by Jay Watson, via Rusty-patched bumblebee’s struggle for survival found in its genes /Colorado State University.
Related posts
- Rep. Rick Hansen & Mason Sargent: Minnesota making progress in protecting pollinators
- House ag committee approves bill that would let cities regulate use of some pesticides
- O! my! Minnesota's #Lawns2Legumes makes Live Your Best Life list in Oprah Magazine
- Lawns to Legumes program earned great media for MN; 5 GOP senators want to rob funding
- Pollinator Friendly Alliance: the natural world, enviro policy & bringing back a healthy planet
- Good & bad news for pollinators: a news digest
- Pew Charitable Trusts Stateline looks at Minnesota's bee lawn program national buzz
- VIDEO: Watch Republicans get totally offended by neonic-treated corn & soybean seed tag bill
- VIDEO: MN House Enviro Finance endorses $7 million in funding for Clean Water Fund projects
- Background reading on the buzz: here's the study discussed in MPR's "Bee Proud" story
If you appreciate Bluestem Prairie, you can mail contributions (payable to Sally Jo Sorensen, 600 Maple Street, Summit SD 57266) or use the paypal button in the upper right hand corner of this post.
Or you can contribute via this link to paypal; use email [email protected] as recipient.
I'm on Venmo for those who prefer to use this service: @Sally-Sorensen-6
Comments