Image of Oeneis tanana
March 19, 2016

Alaska’s first new butterfly species in decades is an ancient hybrid, study claims

The first new butterfly species discovered in the Alaskan wilderness in nearly three decades may be a rare hybrid between two related species, each of which have adapted to the harsh conditions of the Arctic environment, new research from a University of Florida lepidopterist (butterfly and moth scientist) claims.

In a paper published this week in the Journal of Research on the Lepidoptera, Andrew Warren and his colleagues present a theory suggesting that the Tanana Arctic (Oeneis tanana), the first new butterfly species found in the region in 28 years and possibly its only endemic butterfly, is potentially the result of a rare, unusual hybridization of two related species.

“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,” Warren, who is also the senior collections manager at the McGuire Center for Lepidoptera and Biodiversity at the Florida Museum of Natural History on the UF campus, said Wednesday in a statement.

“Scientists who study plants and fish have suggested that unglaciated parts of ancient Alaska... served as a refuge where plants and animals waited out the last ice age and then moved eastward or southward from there,” he added. “This is potentially a supporting piece of evidence for that.”

Researchers plan to sequence the new butterfly’s genome

The Tanana Arctic lives in the spruce and aspen forests of the Tanana-Yukon River Basin, areas that experienced little or no glaciation during the last ice age some 28,000 to 14,000 years ago, Warren and his colleagues explained. Learning more about the how the creature came to be may provide new insight into this geological history of arctic North America, they added.

Furthermore, studying the new species may also shed light on the evolution of hybrid creatures as a whole, the authors noted. Their findings suggest that, at some point in the distant past, two related species – the Chryxus Arctic (O. chryxus) and the White-veined Arctic (O. bore) – might have mated, and that their hybrid offspring went on to evolve into the Tanana Arctic.

Some time later, during the coldest span of the last ice age, the Tanana Arctic and White-veined Arctic remained in Beringia, an unglaciated region including the land mass that once connected what is now Alaska with Asia, while the Chryxus Arctic was forced to the Rocky Mountains. If true, this means that all three species called Berignia home prior to the last ice age.

The new species, which is very similar in nature to the Chryxus Arctic, was hiding in plain sight for more than six decades until Warren and his colleagues discovered it due to the unique white speckles on its underside, as well as its larger size and darker color in comparison to its relatives. The new species was also found to have a DNA sequence that is nearly identical to a population of White-veined Arctics located nearby, which they said supports the hybrid hypothesis.

“Once we sequence the genome, we’ll be able to say whether any special traits helped the butterfly survive in harsh environments,” Warren said, adding that the new study is the “first of what will undoubtedly be many on this cool butterfly.” He added that additional field work will be needed to see if the Tanana Arctic also lives in the easternmost reaches of the Yukon.

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Image credit: University of Florida