Skippers: MacNeill’s saltbush sootywing (Hesperopsis gracielae)

(Lepidoptera: Hesperiidae: Pyrginae)

Profile prepared by Mace Vaughan and Matthew Shepherd, The Xerces Society for Invertebrate Conservation

MacNeill’s sootywing is found in desert washes, alkali flats, and arid canyons, particularly if they support scrub or chaparral vegetation, along the Colorado River from southwest Utah through southern Nevada and western Arizona. This sootywing is also found in the Coachella Valley, California, and south into Baja California and Sonora, Mexico. Larval hostplants are various saltbushes. Specific threats are not documented, though it is likely that MacNeill’s sootywing is susceptible to human disturbance from activities such as recreation, development, and livestock grazing.

red list profile

conservation status

Xerces Red List Status: Vulnerable
Other Rankings:

Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
Mexico: None
USA – Endangered Species Act: None
USA – state status: None
NatureServe: G2G3
IUCN Red List: N/A

MacNeill’s Sootywing is uncommon with a restricted range.

description and taxonomic status

MacNeil’s sootywing is a small, dark butterfly in the family Hesperiidae (skippers). Its wingspan is 20 to 32 mm (¾ to 1¼ inches). The wings are black above and below with a checkered fringe. On the upperside, the forewing is mottled with gray and has a submarginal row of dark bars and the hindwing may have pale spots. The underside of the hindwing has a few pale spots.

Taxonomic status

Hesperopsis gracielae (MacNeill), 1970. This is usually treated as a full species. Scott (1986) considered it a subspecies of H. alpheus (W. H. Edwards), 1876, but this is not generally accepted. Common names include McNeill’s saltbush sootywing and MacNeil’s sootywing.

life history

Habitat for MacNeil’s sootywing is desert washes, alkali flats, and arid canyons, particularly if they support scrub or chaparral vegetation. Larval hostplants are various saltbushes, including fourwing saltbush (Atriplex canescens), big saltbush (A. lentiformis), and silverscale saltbush (A. argentea ssp. expansa).

Adults fly between April and October, particularly in the two periods of April to May and July to October. Males patrol hostplant patches and gulches to find females. Females lay eggs directly on the hostplants, on the leaves of which the caterpillars will feed. They probably hibernate as fully fed caterpillars.

distribution

Along the Colorado River from southwest Utah through southern Nevada and western Arizona. This sootywing is also found in the Coachella Valley, California, and south into Baja California and Sonora, Mexico.


Courtesy of Butterflies and Moths of North America, Big Sky Institute.

threats and conservation needs

Specific threats are not documented, though it is likely that MacNeill’s sootywing is susceptible to human disturbance from activities such as recreation, development, and livestock grazing.

Conservation needs include maintaining suitable habitats and minimizing human disturbance in areas of known populations.

Little is known of this butterfly. Life stage history studies to elucidate phenology and habitat use would be valuable. Surveys should be conducted through its known range to establish details of distribution and population status.

references

Opler, P. A., and V. Malikul. 1992. A Field Guide to Eastern Butterflies. Peterson Field Guide #4. Houghton-Mifflin Co., Boston, MA.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, CA.

Stanford, R. E., and P. A. Opler. 1993. Atlas of Western USA Butterflies Including Adjacent Parts of Canada and Mexico. Denver and Fort Collins, CO.

Tilden, J. W. 1986. A Field Guide to Western Butterflies. Houghton-Mifflin Co., Boston, MA.

additional resources

Big Sky Institute, Butterflies and Moths of North America: Macneill’s saltbush sootywing (Accessed 1/21/09)

NatureServe Explorer (Accessed 9/23/08)

Nearctica; Butterflies and Skippers of North America: McNeill’s Sootywing. (Accessed 5/11/05)

citation

Vaughan, D. M., and M. D. Shepherd. 2005. Species Profile: Hesperopsis gracielae. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation.

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