Incredibly rare bumble bee ‘ghost’ reappears in Michigan after 25 years

Incredibly rare bumble bee ‘ghost’ reappears in Michigan after 25 years


Scientists have discovered an extremely rare bumble bee species in Michigan for the first time in more than 25 years.



Ecologists believed for years that the rusty-patched bumble bee was likely extirpated from Michigan, which means locally extinct. But now a single specimen found in Kalamazoo is prompting questions about whether a population of the uncommon bee species may be found in Michigan after all.



The discovery of a single deceased rusty-patched bumble bee was made by an insect researcher visiting with family in Michigan.



“The bee was just lying dead in my mom’s driveway, but it was very freshly dead,” said Nathan Rank, an ecology and entomology professor at California’s Sonoma State University.



“It didn’t look all torn up, like you sometimes see with bees that have been around a while,” he said.



Rank snapped some slightly out-of-focus pictures with his smartphone and uploaded the images to a nature-based biodiversity identification app. “I knew immediately we had something special,” he said.


A rare pollinator


The rusty-patched bumble bee gets its name from the rusty-colored hairs found on the second segment of its abdomen.


This public domain photo shows a rusty patched bumble bee, a species listed as an endangered species in 2017, making it the first bumble bee to receive federal protection. Native wildflowers, like this wild bergamot, are the best sources of pollen and nectar for the rare bee species.Mara Koenig



It was the first bee species in the continental United States to be added to the federal endangered species list in 2017. The listing followed a steep population decline thought to be connected to the use of pesticides and insecticides, though it’s also affected by climate change and a disease caused by microscopic fungal parasites.



The rare bumble bee species was also classified as endangered in Michigan in 2023. The last time the insect was confirmed in Michigan was in 1999 in Washtenaw County.



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Rank said he understood the extreme rarity of the specimen because he recently watched the short documentary titled “A Ghost in the Making” about the rusty-patched bumble bee. So, he wanted to be absolutely sure the dead insect was that species.



Rank took the specimen to the biology lab at Kalamazoo College where he first developed an interest in entomology as a student. He grew up in Kalamazoo but now lives in California and studies willow leaf beetles in the Sierra Nevada Mountains.



“I knew given especially how fresh the bee seemed that the best thing to do would be to get it in the freezer right away so whatever DNA it has would be preserved,” Rank said.


This is the dead rusty-patched bumble bee found in Kalamazoo, Michigan this month.Clara Stuligross



Additional high-resolution photos of the bee taken at Kalamazoo College offered further confirmation of the extremely rare species.



The specimen was recently sent for pathogen analysis to better understand the bee’s history and condition, said Clara Stuligross, an assistant professor in the college’s biology department.



Scientists identified the dead bee as a male, which suggests there might be a breeding population in the Kalamazoo area. Bumble bees have smaller colonies, and a less rigid social structure compared to honeybees.



“By this time of the summer, the colony starts to produce males and reproductive females to go out. The males are produced to fertilize the reproductive females, who will then go out and look for nests to do their overwintering,” Rank said.



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That means this single male specimen of the rusty-patched bumble bee may indicate a reproducing population, even if limited enough to have eluded detection for decades. The dead male bee could have finished mating and come to the end of its natural life cycle, Rank said.



The discovery prompted a flurry of excitement among Midwestern entomologists. Multiple scientists descended, insect nets in hand, on the Kalamazoo neighborhood where the bee was found.



“I do a lot of bumble bee work in Michigan and never expected this particular record to pop up in Kalamazoo,” said Logan Rowe, a zoologist and insect expert for the Michigan Natural Features Inventory.



“It’s pretty remarkable that it showed up where it did,” he said.



Rowe, who lives in Kalamazoo, said he immediately started looking for living specimens in the neighborhood and local nature preserves. Much of his work involves searching for rare bees across Michigan and he said the specimen Rank found was in excellent condition.


This is the dead rusty-patched bumble bee found in Kalamazoo, Michigan this month.Clara Stuligross



The question is whether the bee was struck by a vehicle and carried from known remaining populations in Illinois, Indiana, Iowa, Minnesota and Wisconsin. There is also an isolated population in the Appalachian Mountains.



“We don’t know that we’ll find a live one. But I also have a hard time believing that it would be in the shape it’s in if it did get transported. But I can’t confirm a population until I see a population,” Rowe said.



The bee expert said the best way to discover a population of the rare pollinator insect species is for more people to spend time in nature observing native bees, taking photos, and uploading the images to the iNaturalist app or Bumble Bee Watch website.



Pollinator insects are ecologically important because they move pollen from the male parts of plants and flowers to the female parts, allowing seed production. Pollinator species include bees, butterflies, moths, wasps, beetles, and even mammals like bats.