Blues: Smith’s blue (Euphilotes enoptes smithi)

(Lepidoptera: Lycaenidae: Polyommatinae: Scolitantidini)

Profile prepared by Scott Hoffman Black and Mace Vaughan, The Xerces Society for Invertebrate Conservation

Smith’s blue is found in scattered colonies in coastal areas of Central California. It uses two habitats, coastal sand dunes and cliff/chaparral, and experts agree that these habitats are endangered: More than 50 percent of the coastal sand dune system has been destroyed or altered significantly by activities such as sand mining, urbanization, and recreation or invasion by exotic plants. Smith’s blue is associated with two species of buckwheat in all life stages, and the presence of these plants is a key habitat requirement.

red list profile

conservation status

Xerces Red List Status: Critically Imperiled
Other Rankings:

Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
Mexico: N/A
USA – Endangered Species Act: Endangered
USA – state status: None
NatureServe: G5T1T2
IUCN Red List: N/A

The Ventana Wilderness Alliance recently (July 2002) discovered a number of previously unknown populations of the Smith’s blue butterfly on recently acquired U.S. Forest Service lands near the Monterey/San Luis Obispo county line. Dr. Richard Arnold positively identified the presence of Smith’s blue at these locations.

The Smith’s blue was listed as a federal endangered species on June 1, 1976 (Federal Register 41:22041-22044).

Recovery Plan: Smith’s Blue Butterfly Recovery Plan. (Final; 11/9/84)
Critical Habitat: Proposed. (Federal Register 42:7972-7976; 02/08/77)

The California Endangered Species Act does not allow listing of insects, so despite its precarious status, Smith’s blue has no protection under state legislation. The California Department of Fish and Game includes this butterfly on its Special Animals list.

description and taxonomic status


The Smith’s blue is a member of the family Lycaenidae (gossamer wing). Smith’s blue is small, slightly less than one inch across. On the dorsal side of the wings, males are bright lustrous blue, whereas females are brown with a band of red-orange marks across the hind wings. The ventral sides are whitish-gray, speckled with black dots and with a band of red-orange marks crossing the hind-wings near the outer edge.

Taxonomic status

Euphilotes enoptes smithi (Mattoni), 1955, is the current name for Smith’s Blue. When originally described, Smith’s blue was named Philotes enoptes smithi. In 1975, Shields reviewed the genus Philotes and reclassified this butterfly as Shijimiaeoides enoptes smithi (the name used during the ESA listing process in 1976). Soon after, Mattoni (1977) revised the tribe Scolitantidini and transferred S. e. smithi to the genus Euphilotes. More recently, Pratt and Emmel (1998) proposed splitting the E. e. smithi into two subspecies based on their hostplant preference. The authors concluded that E. e. smithi feeds solely on seacliff buckwheat (Eriogonum parvifolium), found on cliffs and in chaparral, and that the new subspecies, E. e. arenacola (Marina blue), feeds only on seaside buckwheat (Eriogonum latifolium), found in coastal sand dunes. In this profile, Smith’s blue is considered to be a single subspecies, E. e. smithi.

life history

Smith’s blues spend their entire lives in association with two species of buckwheat, seacliff buckwheat (Eriogonum parvifolium) and seaside buckwheat (Eriogonum latifolium). These plants are obligate hostplants for the larvae and the principle nectar sources for adults. They also provide mating sites. The butterflies generally spend their lifetime within 200 feet of the hostplant on which they emerged. Emerging in late summer and early autumn, the adults mate and lay eggs on the flowers of these host plants. The eggs hatch shortly thereafter and the larvae begin to feed on the flowers of the plant. Ants help the larvae survive by protecting them from predatory spiders and parasitic wasps. In return the tending ants profit by feeding on a sugary substance the caterpillar excretes from the surface of its abdomen. Following several weeks of feeding and development, the larvae pupate, sheltering in the layer of litter beneath the buckwheat plants. Pupae remain dormant for a ten- month period, until the following year, when, as the buckwheats again flower, the new adults emerge.


Smith’s blues are found in coastal sand dunes and cliff/chaparral areas along the central California coast in Monterey, Santa Cruz, and San Mateo Counties.

threats and conservation needs


The major threat is loss of habitat, especially in the coastal sand dune habitat. These areas have been under intense pressure from development (particularly sand mining and urbanization, including road construction), recreation (hang gliding and off-highway vehicles), military training activities (including explosions), and invasive exotic plants (hottentot fig [Carpobrotus edulis] and European beachgrass [Ammophila arenaria]) introduced for sand dune stabilization. The coastal cliffs and chaparral have generally been less affected by development, due in a large part to their relative inaccessibility. However, grazing, logging, and recreational activities have impacted these areas.

Conservation needs

Several sites along Monterey Bay are now being managed for preservation of Smith’s blue and its hostplants including a preserve established by the U.S. Army at Fort Ord, the nation’s first insect-based preserve. These sites are being replanted with Eriogonum and protected from foot and off-road vehicle traffic. Protection of the occupied sites and management of the vegetation to ensure adequate growth of buckwheat is necessary for the survival of this butterfly. Site management should include limits on recreational access for off-highway vehicles and hang- gliders, as well as control of invasive plants, particularly European beachgrass and sea fig. Both plants stabilize the dunes and remove the dynamic ecosystem that supports the larval hostplants.

As demonstrated by the 2002 discovery of new Smith’s blue colonies, there is a need for additional surveys to identify additional populations, particularly in the mountain areas. A better understanding of why the butterfly uses some areas of Eriogonum but not others would be useful, as would more information on appropriate management and restoration practices for habitat.


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.

Arnold, R.A. 1983. Conservation and management of the endangered Smith’s blue butterfly, Euphilotes enoptes smithi. Journal of Research on the Lepidoptera 22: 135- 153. (Available online Accessed 4/26/05.)

Mattoni, R.H.T. 1954. Notes on the genus Philotes: I. Descriptions of three new subspecies and a synoptic list. Bulletin of the Southern California Academy of Sciences 53:157-165.

Mattoni, R.H.T. 1977. The Scolitantidini. Part 1. Two new genera and generic rearrangement (Lycaenidae). Journal of Research on the Lepidoptera 16:223-242. (Available online Accessed 4/26/05.)

Powell, J.A. 1981. Endangered habitats for insects: California coastal sand dunes. Atala 6:41-55.

Pratt, G. F. and J. F. Emmel. 1998. Revision of the Euphilotes enoptes and E. battoides complexes (Lepidoptera: Lycaenidae). In T.C. Emmel, editor, Systematics of Western North American Butterflies. Pages 207-270. Mariposa Press, Gainsville, Florida.

Shields, O. 1975. Studies on North American Philotes. IV. Taxonomic and biological notes and a new subspecies. Bulletin of the Allyn Museum 28:1-36.

U.S. Fish and Wildlife Servic e. 1984. Smith’s Blue Butterfly Recovery Plan. U.S. Fish and Wildlife Service, Portland, OR. 87 pp.

additional resources

Recovery plan

U.S. Fish & Wildlife Service; Threatened and Endangered Species System: Smith’s Blue Butterfly (Accessed 4/25/05)

U.S. Fish & Wildlife Service, Don Edwards San Francisco Bay NWR; “Dunes Alive – The Endangered Smith’s Blue and Marina Blue Butterflies. A Closer Look at Coastal Dune Wildlife of South Monterey Bay,” by Dave Dixon (Accessed 4/26/05)

NatureServe Explorer (Accessed 4/25/05)

University of California at Berkeley, Essig Museum of Entomology; California’s Endangered Insects: Smith’s Blue (Accessed 4/25/05)

Virginia Tech, Conservation Management Institute; Endangered Species Information System: Smith’s Blue Butterfly (Accessed 4/25/05)


Black, S. H., and D. M. Vaughan. 2005. Species Profile: Euphilotes enoptes smithi. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation.


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