The San Bruno elfin (''Callophrys mossii bayensis'') is a U.S. federally listed

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

that inhabits rocky outcrops and cliffs in coastal scrub on the

San Francisco Peninsula The San Francisco Peninsula is a peninsula in the San Francisco Bay Area that separates San Francisco Bay from the Pacific Ocean. On its northern tip is the City and County of San Francisco. Its southern base is Los Altos and Mountain View, ...

. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to this habitat in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Its patchy distribution reflects that of its host plant, broadleaf stonecrop (''Sedum spathulifolium'').

Life cycle

Adults of this

butterfly Butterflies are winged insects from the lepidopteran superfamily Papilionoidea, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The oldest butterfly fossi ...

emerge in February and March, when

nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...

providing flowers open. After mating, the female locates host plants on which to deposit her eggs, which hatch within a week. The tiny

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e first feed on the plant's vegetative structures; however, when the

stonecrop ''Sedum'' is a large genus of flowering plants in the family Crassulaceae, members of which are commonly known as stonecrops. The genus has been described as containing up to 600 species, subsequently reduced to 400–500. They are leaf succulen ...

's flowers begin to open, the larvae migrate upward and feed on the flowers themselves. By June most have completed their larval development at which time they evacuate from the host plant to

pupate A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages the ...

in ground litter. They lie dormant as pupae until the following spring, when the

life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from conception to reproduction *Life-cycle hypothesis, in economics *Erikson's stages of psy ...

begins anew. The San Bruno elfin's life cycle holds an interesting aspect, common to many other lycaenids regarding a

symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

interaction with ants. Elfin larvae excrete a sweet liquid known as Honeydew (secretion), honeydew which attracts ants. In exchange for honeydew, the ants often provide protection from harm by predators and parasites, which are principal killers of foliage feeding insects.

Range and habitat

The San Bruno elfin is restricted to a few small populations, the largest of which occurs on San Bruno Mountain. Most of these areas, akin to the distribution of the host plant, are scattered on rocky slopes and ledges, especially east facing (McClintock, 1968). One of these niches is in the vicinity of the old quarry. Its Habitat (ecology), habitat has been diminished in the past by quarrying, off-road recreational vehicles, and urban development as land development pressure on the San Francisco Peninsula continues to fester. To protect the rare species, rare San Bruno elfin as well as the Mission blue butterfly a unique habitat management plan has been implemented on San Bruno Mountain, in which the lower slopes were opened for development while the higher areas were converted to public ownership as critical habitat. This strategy arose as a compromise result of years of conflict between land developers and conservation movement, conservationists regarding this unique piece of real estate, jointly prized for its outstanding habitat features and its economically valuable location. Current management on San Bruno Mountain and in other areas focuses on reduced pesticide use, careful recreation management, and vegetation management. Several areas from which populations had been previously Local extinction, extirpated are also being targeted for revegetation and reintroduction of the butterfly. Another population of San Bruno elfin is known to be established in Montara, California, Montara, on coastal Hill, bluffs about 25 miles (40 kilometers) south of San Bruno Mountain (Alling, 1986). This colony is near the Fitzgerald Marine Reserve. A third colony is found near Rockaway Beach, California in Pacifica, California, Pacifica.

References

* Brown, R.M., "Larva and habitat of ''Callophrys fotis bayensis''" ''Journal of Research on the Lepidoptera'' 8: 49-50 (1969) * Curtis E. Alling, Michael Hogan, Lynn Alexander, et al., "Environmental Impact Report for the West Rockaway Beach Redevelopment Plan prepared for the city of Pacifica", Earth Metrics Incorporated, SCH #85127017, March, 1986 * Elizabeth McClintock and Walter Knight, ''A Flora of the San Bruno Mountains, San Mateo County, California'', Proceedings of the California Academy of Sciences, Fourth Series, Volume XXXII, no. 20, pp. 587–677, November 29, 1968 * Emmel, J.F. and C.D. Ferris, "The biology of ''Callophrys'' (''Incisalia'') ''fotis bayensis'' (Lycaenidae)" ''Journal of the Lepidopterists' Society'' 26 (4): 237-244 (1972) {{Taxonbar, from=Q7413488 Callophrys Butterflies of North America, San Bruno Endemic fauna of California Fauna of the California chaparral and woodlands, San Bruno Natural history of San Mateo County, California Endangered fauna of California, San Bruno Fauna of the San Francisco Bay Area Critically endangered insects ESA endangered species Butterfly subspecies