Smith’s Blue Butterfly

Euphilotes enoptes smithi (Mattoni, 1955)
Date of listing: 1976
Federal Status: Endangered
State Status: None

Smith’s Blue Butterfly historically ranged along the coast from Monterey Bay south through Big Sur to near Point Gorda, occurring in scattered populations in association with coastal dune, coastal scrub, chaparral, and grassland habitats. They spend their entire lives in association with two buckwheat plants in the genus Eriogonum. 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. Following several weeks of feeding and development, the larvae molt to a pupal stage, beginning a ten month period of transformation. The following year, as the Eriogonum again flower, the new adults emerge.

Important habitat for the Smith’s Blue is threatened by development and the invasion of non-native plants. Increasing automobile and foot traffic along the coast is causing degradation of the coastal scrub and coastal dune ecosystems. Many introduced plants, primarily European beach grass and ice plant, have served to stabilize the dune systems of the California coast, formerly very active dunes. Many plants, including the Smith’s Blue’s host Eriogonum, are adapted to conditions of active sand and require disruption in order to spread successfully.

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.

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.

US Fish & Wildlife Service – Environmental Conservation Online

Xerces Society

Butterflies and Moths of North America
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