Home
Donate Sign up for e-network
CENTER for BIOLOGICAL DIVERSITY Because life is good
ABOUT ACTION PROGRAMS SPECIES NEWSROOM PUBLICATIONS SUPPORT

Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

NATURAL HISTORY

SMITH'S BLUE BUTTERFLY } Euphilotes enoptes smithi
FAMILY: Lycaenidae

DESCRIPTION: The Smith’s blue is a small butterfly with a less-than-one-inch wingspan. Adult males are a brilliant blue, while females are brown; both sexes have a red-orange band across the underside of the hind wings. The Smith's blue has a light undersurface ground color with noticeable black markings and a dull black terminal line. Larvae have cryptic coloration, closely resembling that of the buckwheat blossoms in which they hide.

HABITAT: The Smith’s blue lives in and around coastal dunes, inland sand dunes, cliff-side coastal scrub and chaparral, and grassland habitats. It can be found only in association with coast and seacliff buckwheat plants.

RANGE: Historically the Smith’s blue has been restricted to the coastal areas of central California, primarily coastal sand dunes from the Salinas River to Del Rey Creek. The current known distribution is restricted to portions of Monterey, San Mateo, and Santa Cruz counties, and the current range encompasses an 80-mile linear strip along the coast of central California, 45 miles of which lie within Los Padres National Forest.

MIGRATION: Smith’s blue butterflies do not migrate.

BREEDING: Emerging in late summer and early autumn, adults mate and lay eggs on the flowers of seacliff and coast buckwheat. Males emerge first, followed by females about a week later. Early-season males have a difficult time finding mates.

LIFE CYCLE: Eggs hatch shortly after they are laid. Caterpillars mature through four larval stages called instars and form chrysales after three to four weeks. Pupation takes place in the host plant’s flower head or in leaf litter. Eventually pupae fall into leaf litter and topsoil and lie dormant for about 10 months, until their host plant again flowers and new adults emerge. Adult Smith’s blues live for only about one week.

FEEDING: Larvae have chewing mouthparts to feed on the buckwheat plant's flower petals as well as on seeds in the flower head. Adults use a long, tubular proboscis to eat the host plant’s nectar.

THREATS: The main threat to the species is habitat loss and fragmentation due to development, livestock grazing, wildfire suppression, invasion of exotic plants, sand mining, off-road vehicles and bikes, foot traffic, and the maintenance, repair, and use of roads and trails. The Smith’s blue is also directly affected by livestock trampling and dust pollution.

POPULATION TREND: The Smith’s blue butterfly’s population trend is unknown.

Photo © Richard Arnold