Sonoran Blue (Philotes sonorensis [Felder & Felder])
Wing span: 7/8 - 1 inch (2.2 - 2.5 cm).
Identification: Our only blue with red spots on forewing. Upperside silvery blue; forewing of both sexes with red spots at outer margin; hindwing of female also with red spots.
Life history: Males patrol with a weak flight near the host plant for females. Eggs are laid singly on the leaves, and caterpillars bore into them to feed. Chrysalids hibernate under stones.
Flight: One flight from February-March.
Caterpillar hosts: Stonecrop (Dudleya species) in the Crassulaceae family.
Adult food: Not reported.
Habitat: Rocky washes, outcrops, and cliffs in desert.
Range: Very local. Placer County, California west to Santa Clara County; along coast through southern California to Baja California.
Conservation: Subspecies extinctis occurred in the upper San Gabriel river wash in southern California, but has been extinct since 1968 when its habitat was destroyed.
The Nature Conservancy Global Rank: G3 - Very rare or local throughout its range or found locally in a restricted range (21 to 100 occurrences). (Threatened throughout its range).
Management needs: Protect colonies from habitat modification.
Scott, J. A. 1986. The butterflies of North America. Stanford University Press, Stanford, Calif. 583 pages, 64 color plates. Tilden, J. W. 1986. A field guide to western butterflies. Houghton-Mifflin Co., Boston, Mass. 370 pages, 23 color plates.
Author: Jane M. Struttmann
State and Regional References:
Brown, J.W., Real, H.G., and D.K. Faulkner. 1992. Butterflies of Baja California. Lepidoptera Research Foundation, Beverly Hills, Calif. Comstock, J.A. 1927. Butterflies of California. Privately published, Los Angeles, Calif. [Facsimile available from Entomological Reprint Specialists, Los Angeles, Calif.] Dameron, W. 1997. Searching for butterflies in southern California. Flutterby Press, Los Angeles, Calif. Emmel, T.C. Editor. 1998. Systematics of western North American butterflies. Mariposa Press, Gainesville, Florida. Emmel, T. C. and J. F. Emmel. 1973. The Butterflies of Southern California. Natural History Museum of Los Angeles County Science Series No. 26. Garth, J.S. and J.W. Tilden. 1986. California Butterflies. California Natural History Guide 51. University of California Press, Berkeley and Los Angeles. Langston, R.L. 1981. The Rhopalocera of Santa Cruz Island, California. Journal of Research on the Lepidoptera 18: 24-35. Miller, Scott E. 1985. Butterflies of the Califorenia Channel Islands. Journal of the Research on the Lepidoptera 23: 282-296. Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Orsak, L.J. 1977. The Butterflies of Orange County, California. Museum of Systematic Biology, University of california, Irvine. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo. Steiner, J. 1990. Bay Area Butterflies: The Distribution and Natural History of San Francisco Region Rhopalocera. Hayward, Calif.: Hayward State University, Masters Thesis. Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. Houghton Mifflin Co., Boston, Mass. Tilden, J.W. 1965. Butterflies of the San Francisco Bay Region. California Natural History Guide 12. University of California Press, Berkeley and Los Angeles.