Description of Mission Blue Butterfly

Appearance

• The mission blue butterfly has a wingspan of about one inch. The male butterfly is iridescent blue on his upper wings, which are outlined with black and white along the edges. The female butterfly is brown, though sometimes with a blue overlay. On their undersides, both the male and female have gray wings with dark spots.

Life Cycle

• The mission blue butterfly's life cycle completes itself once per year. In late fall, the female lays her eggs on leaves, buds and seed pods. When the caterpillars emerge, they feed for a short time and then enter diapause until spring. In the spring, the caterpillars begin feeding again and begin molting. Once they enter into the pupal stage, it is about 10 days before the adult butterfly emerges.

Lupine

• The larvae of the mission blue butterfly must feed upon lupine plants--Lupinus albifrons, Lupinus formosus and Lupinus variicolor. These three plants are native to the California habitat. From eating the lupine plants as caterpillars, the mission blue butterfly takes up some of the toxicity contained in the plant. The butterfly develops a bitter taste, which is believed to deter predators.

Range

• Because of its dependence on lupine for development of the caterpillars, the range of the mission blue butterfly is extremely limited. Within the state of California, there are five known colonies of mission blue butterflies. These colonies are in the Twin Peaks area in San Francisco County, the San Bruno Mountain in San Mateo County, Fort Barker in Marion County, the Marin Headlands Golden Gate National Recreation Area, Laurelwood Park &Sugarloaf Open Space and Skyline Ridge in San Mateo County.

Habitat

• Today, much of the mission blue butterfly's habitat has become unsuitable for habitat because of urban development. In 1976, the mission blue butterfly was added to the endangered species list. The butterfly is often found at elevations of about 700 feet, in coastal scrub habitat. In addition to the need for lupine, a native species of ants have a symbiotic relationship with the adult butterfly. The ants often eat the honeydew excreted by the mission blue butterfly caterpillar and in return keep predators and parasites away from the developing larvae.