Xerces Blue Butterfly Confirmed to Be First U.S. Insect to Go Extinct Due to Human Activity

The first insectile casualty of human activity in the United States was recorded around 80 years ago, new research has confirmed. The insect, the Xerces blue butterfly, died out in the mid-20th century as a result of pronounced habitat loss, according to the Florida Museum of Natural History. Its extinction raised awareness of the importance of ecological conservation.

First described in 1852, the Xerces blue butterfly was known for its iridescent sapphire-colored wings. Once common, the butterfly could be seen flitting about among the sand dunes of the San Francisco Peninsula, its native habitat, through the early 1940s. Around that time, it disappeared off the face of the earth, much to lepidopterists' dismay.

"We sort of lost a piece of the biodiversity puzzle that made up the tapestry of the San Francisco Bay area when this species was driven to extinction," Corrie Moreau, Ph.D., a professor of arthropod biosystematics and biodiversity at Cornell University and a co-author of the study, told Science News.

A butterfly in Dubai's Butterfly Garden.
The Xerces blue butterfly was recently confirmed to be the first U.S. insect to go extinct as a result of human activity. This is a stock image of a butterfly in Dubai's Butterfly Garden. Karim SAHIB / AFP/Getty Images

Nowadays, little tangible evidence exists to prove that the Xerces blue butterfly once existed. The Florida Museum of Natural History is one of the only institutions in the United States to have specimens in its collection, according to its website.

Earlier this month, the new study resolved a decades-old debate about the butterfly's taxonomy. Since it went extinct, "some have questioned whether it was truly a distinct species, or simply an isolated population of another living species," called the silvery blue, the study authors wrote. Published in the July issue of the journal Biology Letters, their findings have confirmed that the Xerces blue butterfly was indeed a distinct species, making its loss all the more tragic.

By sequencing DNA harvested from a portion of a 93-year-old specimen at the Field Museum of Natural History in Chicago, the authors wrote, they were able to determine that the butterfly possessed a unique genetic lineage. While it is closely related to the silvery blue, it belongs to a different evolutionary clade, the scientific term for a single individual and all its descendants.

In theory, the Xerces blue butterfly is a candidate for "resurrection," Moreau told Science News. Resurrection, also known as de-extinction, is the practice of employing cutting-edge technologies such as cloning to essentially bring a species back from the dead. However, Moreau believes that scientific priorities lie elsewhere.

"Maybe we should spend that time and energy and money on ensuring that we protect the blues that are already endangered that we know about," she said.

Likewise, the western monarch butterfly is desperately in need of ecological support. Since the 1980s, western monarch numbers have declined by a staggering 97 percent, alarming researchers. Within the next two decades, they say, the iconic black-and-orange insect could follow in the Xerces blue butterfly's footsteps.