El Segundo Blue Butterfly

Euphilotes battoides allyni (Shields, 1975)
Date of listing: 1976
Federal Status: Endangered
State Status: None

In the shadow of the Los Angeles International Airport one of the last remaining populations of the El Segundo Blue may be found. Named for the dune system which it inhabits, the El Segundo Blue has found its home increasingly coveted by humans. The airport’s construction, oil refining, sand mining and urban development have all claimed large portions of the dune system.

The El Segundo Blue Butterfly, in the family Lycaenidae, emerges during summer when the flowers of its host plant, Dune Buckwheat (Eriogonum parviflorum), open. The adult life of these butterflies is relatively short, only a few days, during which time they mate and lay eggs. The eggs hatch within a week or so of their deposition. The larvae feed on the flower heads of the host plant for approximately one month before they molt to their pupal stage. Then when the next summer arrives the cycle begins anew.

The development threats to the El Segundo Blue’s habitat have been largely halted. The butterfly now persists on three fragments of habitat, the L.A. airport site being the largest of these. There are other threats, as well. The host plant is competing with several introduced plants, including other Eriogonum species on which The El Segundo Blue cannot feed. In addition, several of the introduced plants actually act to stabilize the dune system, a situation which inhibits the success of the host plant.

In order to ensure the future of the El Segundo Blue, the U.S. Fish and Wildlife Service, as well as officials from the L.A. Airport and Standard Oil have undertaken important dune management programs which focus on removing exotic plants and reestablishing the sites’ native vegetation. In addition, several sites are currently being examined for their potential as reintroduction sites for the species.

For further reading:
Arnold, R.A., 1983. Ecological studies of six endangered butterflies (Lepidoptera: Lycaenidae): Island biogeography, patch dynamics, and design of habitat preserves. University of California Publications in Entomology 99: 1-161.

Mattoni, R.H.T., 1990. The Scolitantidini 1: Two new genera and a generic rearrangement (Lycaenidae). Journal of Research on the Lepidoptera 16(4): 232-242.

Oppewall, J. C., 1976. The saving of the El Segundo blue. Atala 3(2): 25-28.

US Fish & Wildlife Service – Environmental  Conservation Online

Xerces Society

Butterflies and Moths of North America


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