‘Frosty’ Looking Tanana Arctic Butterfly Is A Hybrid, And The Only One Native To Alaska

The Tanana Arctic butterfly looks unlike any butterfly you’ve seen.

Its wings are the color of a penny and are speckled with large white spots on the underwings, giving it a “frosty” look. The insect perfectly fit its cold environment, the Tanana-Yukon River basin in Alaska’s interior, National Geographic reported.

This cold weather butterfly makes its home in the region’s spruce and aspen forests. It lives only a couple months after its larvae mature for two years, subsisting on sedges and grasses.

The Tanana Arctic has the distinction of being Alaska’s first new species in 28 years, and the story of how the bug was discovered and how it came to develop its unique coloring is also unusual.

This species had been hiding right under experts’ noses for 60 years, and it took lepidopterist (butterfly expert) Andrew Warren a few years and some trips to Alaska to confirm the find, Smithsonian added.

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Warren works at the Florida Museum of Natural History’s McGuire Center for Lepidoptera and Biodiversity. One day, he was doing working over the collections he oversees at the center when he noticed something weird about a butterfly called O. chryxus. That species is a rare Arctic breed found in the Rockies. But this one didn’t look like an O. chryxus to Warren. It was bigger and darker, its genitalia was different, it had that “frosted” look, and it was collected in Alaska.

“To me it was surprising that no one had noticed this before.”

He enlisted the help of fellow scientists and visited the state himself to see more specimens. Since he arrived late in the season, he only studied collections and not live butterflies.

What he found was that this little bug was masquerading as O. chryxus, but it was really something else entirely. The mistake was easy to understand, however. The Tanana Arctic looks pretty similar, but Warren discovered that it also shared traits with O. bore, which is also from that region.

The Tanana butterfly that had been hiding in plain sight for decades is a hybrid of both O. chryxus and O. bore. According to the Christian Science Monitor, these two species may have mated before the last ice age.

The range of this hybrid corresponds to an area of Alaska that was free of ice sheets in the last ice age, 28,000 to 14,000 years ago. The region is called Beringia, a strip of land between Alaska and Asia, and it became a refuge for many species. Gradually, the two species drifted further apart, and the Tanana Arctic carved out its own niche in the region.

Then, the climate changed. Beringia became less friendly for butterflies, and the Chryxus moved south and settled in Colorado; the species still lives there. O. bore stayed put, as did the hybrid.

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Not only is the Tanana Arctic the only butterfly native to Alaska, it also represents the first time scientists have seen the insects mate in this way, Warren said.

‌”Hybrid species demonstrate that animals evolved in a way that people haven’t really thought about much before, although the phenomenon is fairly well studied in plants. Beringia … served as a refuge where plants and animals waited out the last ice age and then moved eastward or southward from there.”

The hybrid is one of a handful known to exist. Scientists will now confirm that the Tanana Arctic butterfly really is a hybrid by sequencing its genome; they already known it shares mitochondrial DNA with O. bore. They also want to know how it survived the Arctic.

And because butterflies react quickly to changes in their climate, keeping a keen eye on the new species could help scientists pinpoint changes in the very sensitive Arctic ecosystem caused by global warming.

“This butterfly has apparently lived in the Tanana River valley for so long that if it ever moves out, we’ll be able to say ‘Wow, there are some changes happening,’ ” Warren said. “This is a region where the permafrost is already melting and the climate is changing.”

The Tanana Arctic butterfly has been named Oeneis Tanana.

[Image via Benny Marty/Shutterstock]