Select Page

Xerces blue

For other uses, see Xerces (disambiguation).

The Xerces blue (Glaucopsyche xerces) is a recently extinct species of butterfly in the gossamer-winged butterfly family, Lycaenidae. The species lived in coastal sand dunes of the Sunset District of the San Francisco Peninsula in California. The Xerces blue is believed to be the first American butterfly species to become extinct due to loss of habitat caused by urban development. The last Xerces blue was seen in 1941 or 1943[3] on land that is now part of the Golden Gate National Recreation Area.[4]

Name

The specific name derives from the French spelling of "Xerxes", the Greek name of the Persian kings Xerxes I and Xerxes II of the fifth century BC.[5] An endangered invertebrate conservation group known as the Xerces Society is named after the Xerces blue.[6][7]

Taxonomy

Genetic analysis of museum specimens published in 2021 confirmed that the Xerces blue represented a distinct species within the genus Glaucopsyche, with its closest relatives being Glaucopsyche australis and Glaucopsyche pseudoxerces, with this group most closely related to Glaucopsyche lygdamus (the silvery blue).[8]

Specimens in California Academy of Sciences

Extinction and ecology

The species was first described and documented in 1852.[9] It was characterized by blue wings with white spots.[10] The butterflies fed on vegetation belonging to the genus Lotus and Lupinus.[10] The loss of the Lotus plant that the butterfly fed on while in its larval stages is believed to be one reason for the extinction of the Xerces blue. The plant could not survive in the disturbed soils due to human development and was no longer available to the Xerces blue.[9][10] Lupinus, the Xerces blue's other vegetative food source, was not suitable for the larval stages.[10]

Preserved specimens are found in California Academy of Sciences, Bohart museum, and the Harvard Museum of Natural History.[9]

Reestablishment efforts

Efforts are ongoing to reestablish related butterflies in the Xerces blue's former habitat. The Palos Verdes blue (Glaucopsyche lygdamus palosverdesensis), which is considered a Los Angeles cousin of the Xerces, is being reared in labs.[citation needed] A new Xerces-like subspecies of the silvery blue (Glaucopsyche lygdamus), which the Xerces blue was thought to be a subspecies of[11] has been discovered as well, and has been analyzed as a potential way to revive the Xerces blue.[12] Successful reintroduction efforts of the silvery blue occurred in 2024 in a collaboration between the Presidio Land Trust, National Park Service, and California Academy of Sciences, among other groups.[13] In 2025, silvery blue offspring were documented in the Lobos Creek Valley Dunes, implying successful reproduction within the Presidio[14]. Releases of silvery blues have continued in 2025[14].

References

  1. ^ World Conservation Monitoring Centre (1996). "Glaucopsyche xerces". IUCN Red List of Threatened Species. 1996: e.T9244A12971422. doi:10.2305/IUCN.UK.1996.RLTS.T9244A12971422.en. Retrieved 20 November 2021.
  2. ^ "NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 1 November 2022.
  3. ^ Powell, J.A.; Hogue, C.L. (1979). California Insects. University of California Press. ISBN 978-0-520-03782-3.
  4. ^ Garth, J.S.; Tilden, J.W. (1986). California Butterflies. University of California Press. ISBN 0520052498.
  5. ^ "xerxes | Origin and meaning of Xerxes by Online Etymology Dictionary". www.etymonline.com. Retrieved 2021-02-20.
  6. ^ "About the Xerces Society | Xerces Society". xerces.org. Retrieved 2021-02-20.
  7. ^ "Mission". www.guidestar.org. Retrieved 2021-02-20.
  8. ^ Grewe, Felix; Kronforst, Marcus R.; Pierce, Naomi E.; Moreau, Corrie S. (July 2021). "Museum genomics reveals the Xerces blue butterfly ( Glaucopsyche xerces ) was a distinct species driven to extinction". Biology Letters. 17 (7): 20210123. doi:10.1098/rsbl.2021.0123. ISSN 1744-957X. PMC 8292013. PMID 34283930.
  9. ^ a b c Resources, University of California Agriculture and Natural. "And Then There Were None: Bohart Museum Remembering Xerces Blue Butterfly In Effort to Help Preserve Other Species". entomology.ucdavis.edu. Retrieved 2017-04-13.
  10. ^ a b c d Tilden, J. W. (1956). "San Francisco's Vanishing Butterflies" (PDF). The Lepidopterists' News: 113–115.
  11. ^ Grewe, Felix; Kronforst, Marcus R.; Pierce, Naomi E.; Moreau, Corrie S. (2021). "Museum genomics reveals the Xerces blue butterfly ( Glaucopsyche xerces ) was a distinct species driven to extinction". Biology Letters. 17 (7). doi:10.1098/rsbl.2021.0123. PMC 8292013. PMID 34283930. S2CID 236144945.
  12. ^ "Wild Genomes - Awarded Projects - Revive & Restore".
  13. ^ Smith, H.R. (April 15, 2024). "There's a New Blue Flitting on Xerces' Old Turf". BayNature. Archived from the original on November 27, 2024. Retrieved May 7, 2025.
  14. ^ a b Smith, H.R. (May 1, 2025). "Survival of the Flittest: Relocated Butterflies Are Spotted in San Francisco". BayNature. Archived from the original on May 2, 2025. Retrieved May 7, 2025.