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Mission Blue Plebejus icarioides missionensis


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Mission Blue
© Edward S. Ross/U. S. Fish and Wildlife Service

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Family: Lycaenidae, Gossamer-wing Butterflies view all from this family

Description The Mission Blue (Plebejus icarioides missionensis or Aricia icarioides missionensis) is a blue or lycaenid butterfly subspecies native to the San Francisco Bay Area of the United States. The butterfly has been declared as endangered by the US Federal Government. It is a subspecies of Boisduval's Blue (Aricia icarioides).

The endangered Mission Blue has a wingspan of about 21–33 millimetres (0.83–1.3 in). Larvae are extremely small and rarely seen. The males' top wing grades from ice blue in the center to deep sky blue (misregistered as turquoise/cyan to violet by most photographic equipment, the wing color carries no hint of green or purple, strictly capturing an enthralling spectrum of purest, clearest, richest, brightest blue) exhibiting a dazzling iridescent fluctuation in range under direct, full sunlight. Black margins on the upper wing sport "long, white, hair-like scales." A constellation of jet-black dots (misregistered as dull gray by most photographic equipment) frames the extremities of the ventral surface, its pattern adroitly complimenting the wing shape thrown into spectacular relief against the shimmering silvery pearlescent background, with a fascinatingly muted hint of dark ice blue bleeding faintly up from the body and permeating the veins throughout for the palest, most delicate of emphases. Body shape, eyes, antennae, and appendages possess it of a uniquely exquisite poise. Males' body is dark-blue/brown. Females' upper wings are dark brown, but otherwise mirror males'.

The larvae will only feed on the leaves of the three host lupine plants (Lupinus albifrons, Lupinus formosus, and Lupinus variicolor) native to their habitat. The plants are necessary for survival for the Mission Blue. Thus, the butterfly's fate is closely tied to that of the three species of lupine as the plants provide food and shelter for the butterfly in its larval stage. The adult Mission Blue drinks the nectar of a variety of flowers, many in the sunflower family, using its long proboscis which extends from the underside of its head.

Dimensions The endangered Mission Blue has a wingspan of about 21–33 millimetres (0.83–1.3 in).

Endangered Status The Mission Blue, a subspecies of the Boisduval's Blue, is on the U.S. Endangered Species List. It is classified as endangered in California. A number of California's coastal butterfly species have declined as their habitat has been overtaken by development or altered by the introduction of non-native plants that squeeze out the native plants on which the butterflies rely. Mission Blues will feed and lay their eggs only on various lupine species, and as these plants became rarer in the San Francisco-Marin area, so did the butterflies. Currently, the San Mateo County Parks and Recreation Department is managing 2,000 acres of habitat for the Mission Blue on San Bruno Mountain. In addition to restoring native vegetation and protecting the habitat from recreational overuse, the department is exploring ways to balance the needs of an endangered species with those of the human population.

Habitat Scrub, shrub & brushlands.

The Mission Blue depends on a very specific host plant called the lupine. As such, its habitat is restricted solely to the U.S. state of California. More specifically, it is limited to a range of five known areas where Mission Blue colonies have been confirmed. Those areas are subject to a range of conservation and habitat restoration action.

Range California.