Scientists Just Discovered a New Butterfly, and It’s Stunning

Butterflies are some of the world’s most beautiful insects, and there are a lot of them. Researchers believe there are up to 17,500 species of butterflies globally, which come in practically every color under the sun. Butterflies aid in pollination, play a vital role in our ecosystem, and are beautiful to look at. Recently, scientists stumbled upon a brand-new butterfly species: the Satyrium curiosolus. Scientists previously believed this butterfly belonged to the Satyrium semiluna species.

When Was the New Butterfly Discovered?

During a visit to Blakiston Fan in Waterton Lakes National Park, Alberta, in Canada’s Rocky Mountains, researchers spotted a butterfly they thought belonged to the half-moon hairstreak (S. semiluna) species. But upon closer inspection, they realized this butterfly was actually a distinct species and named it after its unique environment: the S. curiosolus, or the curiously isolated hairstreak butterfly. (Isn’t that a cool name? It’s literally because they were curious about how it survived in isolation.) They announced the discovery in an April 2025 study published in ZooKeys.  

The curiously isolated hairstreak butterfly has a wingspan of up to an inch and a half. Its wings are brown on top and gray-brown underneath, with black spots. The Wilder Institute, which was also part of the study along with the Calgary Zoo, shared a picture of the butterfly on X. In it, you can see the gorgeous details of this new species, including the tiny hairlike design on its wings.

How Did the Species Survive?

According to their best estimates, researchers believe that the curiously isolated hairstreak butterflies lived on a small patch of land that never froze during the last ice age, which is known as a “glacial refuge,” according to Vice. It has survived more than 400 kilometers away from its nearest relatives, possibly for up to 40,000 years, making it geologically and ecologically unique.

Because of its extreme isolation and other factors, researchers recommend that S. curiosolus retain its previously assigned endangered status from when it was considered part of S. semiluna.

How Low Genetic Diversity Impacts the Butterfly

“Our whole-genome sequencing of S. curiosolus revealed strikingly low genetic diversity and exceptionally high levels of historical inbreeding compared to the geographically nearest S. semiluna populations in British Columbia and Montana, more than 400 km distant,” co-first author Zac MacDonald, a La Kretz postdoctoral researcher at University of California Los Angeles Institute of the Environment and Sustainability, said in a statement.

Researchers believe that, because these butterflies were so far from their nearest relatives, they were able to eliminate harmful genetic variations, which helped them survive in complete isolation. However, they also have a reduced chance of adapting to changing climate conditions, which puts this species at risk.

Conservation Efforts to Preserve the New Species

To protect this newly discovered species, with an estimated population of around 500 individuals based on recent genomic and field studies, scientists are now working on conservation efforts for the curiously isolated hairstreak butterfly.

Conservationists sometimes introduce closely related species to increase genetic diversity in at-risk populations, but scientists believe this approach would not be effective for this butterfly. “Given the genetic differentiation and the ecological uniqueness of the population…bringing in butterflies from other areas, with differently adapted genomes, could actually decrease the health of the population,” Dr. Dupuis, one of the study’s authors, told BBC Wildlife.

How is S. semiluna Different from S. curiosolus?

Unlike S. semiluna, which lives in sagebrush steppe, S. curiosolus lives in prairie-grassland. Its larvae depend entirely on silvery lupine, a plant that S. semiluna populations in British Columbia are not known to use. Additionally, this species has a unique, mutually beneficial relationship with the ant Lasius ponderosae, which has not been observed in S. semiluna populations. When the curiously isolated hairstreak butterflies are caterpillars, they give these ants a sugary excretion called honeydew, and in return, the ants protect them from predators and offer them a safe haven when it gets too hot outside.

Dr. James Glasier, Conservation Population Ecologist at the Wilder Institute, said in a statement, “With its official recognition as a distinct species, the curiously isolated hairstreak is a powerful example of how long-term isolation shapes biodiversity. But its rarity and extreme specialization also make it incredibly vulnerable — there’s no fallback population to sustain its survival.”

Now that this beautiful butterfly has been discovered, researchers can study it further and support ongoing conservation efforts to protect the species.