Reakirt's Blue (Hemiargus isola [Reakirt])
Wing span: 3/4 - 1 1/8 inches (2 - 2.9 cm).
Identification: Upperside of male light blue with darker veins and dusky border; female darker. Underside of forewing with postmedian row of 5 round black spots circled with white.
Life history: Males patrol for females with an erratic flight during daytime. Females lay eggs singly on flower buds of host during midday. Caterpillars eat flowers and seedpods, sometimes leaves; and are tended by ants which presumably protect the caterpillars in return for their sugary secretions.
Flight: All year in South Texas; 3 broods from March-November in the remainder of its residential range; migrates north once each year after hibernating in the south.
Caterpillar hosts: Many plants in the pea family (Fabaceae) including yellow sweet clover (Melilotus officinalis), rattleweed (Astragalus), mesquite (Prosopis), indigo bush (Dalea), mimosa (Albizia), and indigo (Indigofera) species.
Adult food: Flower nectar from a variety of herbs including spearmint and white sweet clover.
Habitat: Grasslands, fields, desert, meadows, weedy areas, creeksides.
Range: Resident from southern California, the Southwest, and Texas through Mexico and Central America to Costa Rica. Summer migrant north and east through the Mississippi River states to Wisconsin and Ohio.
Conservation: Not required.
The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Management needs: None reported.
Opler, P. A. and G. O. Krizek. 1984. Butterflies east of the Great Plains. Johns Hopkins University Press, Baltimore. 294 pages, 54 color plates. Opler, P. A. and V. Malikul. 1992. A field guide to eastern butterflies. Peterson field guide #4. Houghton-Mifflin Co., Boston. 396 pages, 48 color plates. 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.