Gentry's Giant-Skipper (Agathymus gentryi Roever)
Wing span: 2 - 2 1/2 inches (5.1-6.3 cm).
Identification: Similar to Bauer's Giant-Skipper but postmedian spot row of orange-yellow spots on upper surface of forewing forms a straight row, and does not in Bauer's Giant-Skipper.
Life history: Adults have a noisy, fast flight. From early morning to noon males perch near host plants to wait for receptive females. Eggs are laid singly on the host and fall to the base of the plant. A young caterpillar crawls to a leaf tip and burrows inside where it eats pulp and then hibernates. In the spring the caterpillar makes a new burrow in a leaf base where it feeds on sap until becoming inactive for the summer. Before pupating, the caterpillar enlarges the opening of its burrow and makes a silk trap door from which the adult can emerge.
Flight: Late September to late November (1 flight).
Caterpillar hosts: Agave deserti subspecies simplex.
Adult food: Females never feed; males sip moisture from mud.
Habitat: Arid rocky desert mountains ranges.
Range: Southwestern Arizona west to southeastern California.
Conservation: Conserve and manage stands of required caterpillar host plant.
The Nature Conservancy Global Rank: G3G4 - Very rare or local throughout its range or found locally in a restricted range OR Apparently secure globally, though it might be quite rare in parts of its range, especially at the periphery. All subspecies are of conservation concern.
Management needs: No specific needs reported.
Bailowitz, R. A., and J. P. Brock. 1991. Butterflies of southeastern Arizona. Sonoran Arthropod Studies, Inc., Tucson, Arizona. 342 pages. Roever, K. 1998. Descriptions of new Agathymus (Lepidoptera: Megathymidae) from the southwestern United States. Pages 491-499 in: Emmel, T.C., editor. 1998. Systematics of Western North American Butterflies. Mariposa Press, Gainesville, Fla. 878 pp.
Author: Paul A. Opler
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.