A tiny butterfly has been quietly losing a battle in the US Midwest since the early 2000s. By the time conservation scientists in Michigan began releasing captive-bred Poweshiek skipperlings in 2022, more of the insects often lived in captivity than in the wild. Michigan State University now says the recovered population has expanded enough that the species has been pulled back from the brink of extinction.
It may seem like good news only for a small insect most people have never heard of. But saving it has meant restoring the land around it. "Restoring Poweshiek skipperling populations requires improving prairie and prairie fen habitat," said David Pavlik at MSU's W.K. Kellogg Biological Station. "Over 99 percent of the prairie and prairie fen habitat in the US has been lost. By improving habitat for the Poweshiek skipperling, we're also improving habitat for all species that live there, from the most common to the rarest."
These butterflies, Oarisma poweshiek, once ranged across the Midwest from Iowa to Michigan and into southern Canada. Their numbers have dropped sharply over the past two decades. Habitat loss, wetland destruction, and damaging agricultural practices are thought to have driven the decline. Neonicotinoid pesticides, insecticides known to harm many insects, are a particular concern.
The species still clings on in Manitoba, Canada, but Michigan has become its last true stronghold. Surrounded by the Great Lakes, the state holds rare prairie fen wetlands and has become a vital refuge for many of North America's most endangered butterflies.
Recovery only works if released animals have somewhere to thrive, so habitat restoration came first. Then came breeding. Poweshiek skipperlings spend most of their lives as caterpillars and emerge as butterflies for a critical fortnight in which they must breed. MSU and its partners built hoop houses that recreate the humid conditions the caterpillars need. After metamorphosis, the adults were ready for release, but researchers also needed to track them.
How do you tag a butterfly? You put it briefly to sleep. "We use a very small amount of isoflurane, frequently used to anesthetize humans and animals during medical procedures, in an enclosed container that temporarily puts the butterflies to sleep so that we can safely mark them before release," Pavlik said. "Because we use such a small amount, the butterflies wake up very shortly after we mark them, usually within 30 seconds to a minute."
A first release of 102 butterflies in 2022 aimed to prevent extinction. By 2025, about 1,300 more had joined them. Researchers now say it is possible to see hundreds of these butterflies while walking a prairie fen; in 2022, only nine sightings were documented in the entire United States.
"They are canaries in the coalmine," said Dr. Nick Haddad, a professor at MSU's College of Natural Science. "In the US Midwest and in the US, we have lost a quarter of all butterflies in the past two decades. This includes loss of very common species. Though the endangered species get lots of attention and effort devoted to them, it is not long before other butterflies will follow suit."
If the skipperling can recover here, Haddad's point is that the prairie fens themselves, and the many other species that share them, are moving in the same direction.