Callippe Silverspot Butterfly

Speyeria callippe callippe (Boisduval, 1852)
Date of listing: December, 1997
Federal Status: Endangered
State Status: None

The Callippe Silverspot Butterfly is a member of the Nymphalidae, or brush-footed butterflies. The Callippe Silverspot has a wingspan of approximately 4.5 cm. As illustrated above, members of this species are mainly orange, tan and brown above. The name “silverspot” refers to silvery patches of scales on the undersides of the wings. Historically this butterfly inhabited grasslands ranging over much of the northern San Francisco Bay region. The type locality, or site from which the subspecies was first recognized, is the city of San Francisco. On the San Francisco peninsula, this butterfly is now only known from San Bruno Mountain (approximately10 miles south of San Francisco). In the East Bay, it was known from Richmond in the north to the Castro Valley in Alameda County. The only remaining population of this butterfly in Alameda County occurs in an undisclosed city park.

The Callippe Silverspot begins its life in early summer when the eggs hatch. The first instar larvae eat their egg shells before going into diapause (a period of inactivity and reduced metabolism). Following the winter rains, the larvae emerge to begin feeding on their host plant, a Violet (Viola pedunculata). Following 2-3 months of feeding and 4 molts, the larvae make a pupation chamber from leaves and silk and then molt into the pupal stage. The pupal stage lasts for only about 2 weeks, at which point the adult butterfly emerges. Adults live for approximately 3 weeks during which time they feed and mate. The main source of sustenance for the adult butterflies is floral nectar. After mating the females seek oviposit (lay eggs) on or near Viola plants (which, as annuals, will be mostly wilted by this time).

The causes of the Callippe Silverspot’s decline are fairly clear. The vast majority of potential butterfly habitat lies under the cities of San Francisco, Oakland, and Berkeley. What open areas there are within this butterflies range are dominated by introduced plant species. Many of these areas are also grazed by cattle, mined, or subject to heavy recreational use. The Alameda County population is particularly small and vulnerable. The San Bruno Mountain population occurs on land that, although private, is largely protected from development. This area is also being managed for the conservation of several additional endangered species, including the San Bruno Elfin and the Bay Checkerspot.


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