Western Tiger Swallowtail (Papilio rutulus Lucas)
Wing span: 2 3/4 - 4 inches (7 - 10 cm).
Identification: Upperside of hindwing with upper-most marginal spot yellow or lacking. Underside of forewing with separate yellow spots forming marginal band. Hindwing has narrow marginal spots and no orange tint except for 2 spots near end of inner margin.
Life history: Males patrol canyons or hilltops for receptive females. Females lay eggs singly on surface of host plant leaves. Caterpillars feed on leaves and rest on silken mats in shelters of curled leaves. Chrysalids hibernate.
Flight: One flight from June-July.
Caterpillar hosts: Leaves of cottonwood and aspen (Populus), willows (Salix), wild cherry (Prunus), and ash (Fraxinus).
Adult food: Nectar from many flowers including thistles, abelia, California buckeye, zinnia, and yerba santa.
Habitat: Woodlands near rivers and streams, wooded suburbs, canyons, parks, roadsides, and oases.
Range: Western North America from British Columbia south to southern New Mexico and Baja California; east to western South Dakota and southeast Colorado. A rare stray to central Nebraska.
Conservation: Not usually required.
Management needs: None noted.
The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
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. 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:
Elrod, M.J. 1906. The Butterflies of Montana. Bulletin of the University of Montana 30: 1-174. Ferris, C.D. and F.M. Brown. 1980. Butterflies of the Rocky Mountain States. University of Oklahoma Press. Norman. Layberry, R.A., Hall, P.W. & Lafontaine, D.J., 1998. The Butterflies of Canada. University of Toronto Press, Toronto, ON. 280 pp. Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo. Tilden, J.W. and A.C. Smith. 1986. A Field Guide to Western Butterflies. Houghton Mifflin Co., Boston, Mass.