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Xerces Blue

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description Xerces Blue Overview

The Xerces blue, Glaucopsyche xerces, was a small butterfly native to coastal sand dunes on the San Francisco Peninsula in California. It had blue wings in males and browner coloration in females, with distinctive pale spots on the hindwing undersides. Habitat destruction associated with urban development eliminated its specialized dune environment, and the last generally accepted sighting occurred in 1941; it is commonly cited as a prominent example of human-caused insect extinction in the United States.

help Xerces Blue FAQ

Is the Xerces Blue butterfly still alive?

No, the Xerces Blue butterfly is completely extinct. It was last seen in the wild in the early 1940s. The last confirmed sighting of the butterfly occurred in the sand dunes of the San Francisco Bay Area in 1941.

Why did the Xerces Blue go extinct?

The Xerces Blue went extinct primarily due to the destruction of its highly specific habitat. The butterfly relied solely on plants growing in the coastal sand dunes of San Francisco. As these dunes were rapidly developed for housing and military bases in the 1930s, the butterfly lost its food source and died out.

How did the Xerces Blue get its name?

The butterfly was named after the French entomologist Pierre André Latreille's genus classification, "Glaucopsyche xerces." The name Xerces itself is derived from Xerxes, the ancient Persian king. Interestingly, the conservation group, the Xerces Society, later adopted this name to honor the extinct butterfly and highlight invertebrate conservation.

Where did the Xerces Blue butterfly live?

The Xerces Blue was endemic only to the San Francisco Bay Area in California. It lived specifically in the shifting coastal sand dunes along the Pacific Ocean. It was never found anywhere else in the world, making it a highly localized and vulnerable species.

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