Broken Silverdrop (Epargyreus exadeus [Cramer])
Wing span: 1 15/16 - 2 7/16 inches (4.9 - 6.2 cm).
Identification: Wings are dark brown. Forewing has small separate amber spots. Hindwing with small separate silver spots and an obscure pale postmedian line.
Life history: Adults perch upside down under leaves at night and on hot or cloudy days. To seek females males perch on branches and tall weeds, and occasionally patrol. Females lay single eggs near the host trees, and the caterpillars must find their proper host. Young caterpillars live in a folded leaf shelter; older ones live in a nest of silked-together leaves. Chrysalids hibernate.
Flight: October in South Texas, many flights from May-November in Mexico and Central America.
Caterpillar hosts: Legumes including Cassia and Phaseolus.
Adult food: Flower nectar.
Habitat: Tropical scrub or forests and nearby edges.
Range: Argentina north through Central America to Mexico. Rare stray to South Texas, southern Arizona, and southern California.
Conservation: Not required for a rare stray.
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 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.
Author: Jane M. Struttmann
State and Regional References:
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.