Plebejus icarioides missionensis Hovanitz, 1937
Date of listing: 1976
Federal Status: Endangered
State Status: None
Cautious optimism surrounds the fate of the Mission Blue Butterfly. Formerly relatively widespread on the San Francisco and Marin peninsulas, the Mission Blue is now restricted to a few sites in these areas. On San Bruno Mountain, in San Mateo Co., 2000 acres of critical habitat for the butterfly is being managed by the county department of Parks and Recreation.
The butterfly’s required habitat is known as coastal scrub, a habitat type widely threatened in California. Late instar larvae of the Mission Blue emerge from a dormant state in early spring as their host plants, perennial lupines (Lupinus albifrons, L. variicolor, and L. formosus), begin their spring growth cycle. The larvae eventually enter the ground to pupate. Several weeks later, as the lupines begin to flower, the adult butterflies emerge to feed on nectar, mate and lay eggs. The eggs hatch within a few days and the larvae eat for a few weeks before they enter dormancy until the following spring when they will complete their development.
Preservation of existing butterfly populations relies on many factors common to butterfly conservation programs: replanting of host plants, removal of introduced plants, and protection of habitat from excessive recreational use and development. This program also illustrates a common problem in endangered species conservation: practices which benefit the species of concern are in some conflict with practices desireable from a human standpoint. It is thought that the host lupines require periodic disturbances in order to successfully reproduce, but many possible disturbances such as fires and landslides are actively managed against in areas designated for recreational use. Although management for such multiple uses often proves difficult, in this case we may be hopeful.
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.
Arnold, R. A., 1987. The Mission Blue Butterfly. In: Audubon Wildlife Report. National Audubon Society, New York.