Skippers: ottoe skipper (Hesperia ottoe)

(Lepidoptera: Hesperiidae: Hesperiinae)

Profile prepared by Matthew Shepherd, The Xerces Society

The ottoe skipper is a prairie-dependent species that is found on a range of prairie types from southern Manitoba and eastern Montana south along the high plains to north Texas; east through Nebraska and Kansas to central Illinois and southwest Michigan. It appears that the ottoe skipper has always been a rare species, and the massive loss of prairie habitat during the past two centuries has made it rarer still. Conversion of prairie to agriculture and to a lesser extent, development has, and continues to be, the greatest threat to both the distribution and abundance of the ottoe skipper. The larval hostplants are a range of grasses, including fall witchgrass, little bluestem, and sideoats grama.

red list profile

conservation status

Xerces Red List Status: Vulnerable
Other Rankings:

Canada – Species at Risk Act: Endangered
Canada – provincial status: MB: Threatened
Mexico: N/A
USA – Endangered Species Act: None
USA – state status: IL, MI, MN: Threatened
IA, MT: Species of Concern
NatureServe: G3G4
IUCN Red List: N/A

It appears that the ottoe skipper has always been a rare species, and the massive loss of prairie habitat during the past two centuries has made it rarer still. The importance of protecting the remaining prairie habitat is well-recognized by conservation organizations and significant areas of prairie are now protected for wildlife. However, most of these are not managed with butterflies in mind with the result that although the habitat is protected, the ottoe skipper is not.

description and taxonomic status

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The ottoe skipper is a medium sized butterfly in the family Hesperiidae (skippers). Its wingspan is between 1¼ and 1 11/16 inches (3.2 to 4.3 cm). The uppersides of the wings are a warm orange-brown. The male has an obvious dark stigma (black or dark gray) and black borders. The female has more diffuse black borders. The undersides of the wings are yellow-orange, unmarked in males and sometimes with faint markings on females.

Hesperia ottoe (W. H. Edwards), 1866.

life history

The ottoe skipper is a prairie-dependent butterfly, although it is found on a range of regional prairie types, from undisturbed tall- grass and mixed grass prairies on the Great Plains to sand prairies and old fields with surviving prairie flora near the Great Lakes. The larval hostplants are a range of grasses, including fall witchgrass (Leptoloma cognatum), little bluestem (Schizachyrium scoparium), and sideoats grama (Bouteloua curtipendula). In Minnesota, ottoe skippers have been recorded ovipositing on various forbs, such as blacksamson echinacea (Echinacea angustifolia). In these cases, the forbs are not larval hosts: the newly hatched larvae dropped off the flowers to feed on the grasses below.

There is a single brood between June and August, during which period males perch near host plants waiting for females. Eggs are laid singly, and the resultant caterpillars build shelters from grass blades tied with silk an inch or two above the soil surface, within which they live.

Adults are avid nectar feeders and require abundant flowers to maintain a population. Nectar sources include milkweeds (Asclepias sp.), vetch (Vicia sp.), alfalfa (Medicago sativa), bush houstonia (Houstonia sp.), purple coneflower, leadplant (Amorpha canescens), compassplant (Silphium sp.), sunflower (Helianthus sp.), and blazing star (Liatris sp.). To find sufficient nectar, adults may forage in oak savannah and scrub areas.

distribution

Southern Manitoba and eastern Montana south along the high plains to north Texas; east through Nebraska and Kansas to central Illinois and southwest Michigan.


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

threats and conservation needs

Threats

The ottoe skipper is a prairie-dependent species. Since European settlers arrived, 98 percent of U.S. mixed grass prairie has disappeared. Conversion of prairie to agriculture and to a lesser extent, development has, and continues to be, the greatest threat to both the distribution and abundance of the ottoe skipper. The remaining prairie has often been degraded through grazing, fire suppression, or neglect to the point where it can no longer support populations of this skipper. In other cases, poor timing or too great a frequency of management activities—such as mowing or prescribed fire—has led to loss of hostplants, removal of nectar sources at critical periods, and destruction of larvae.

Conservation needs

The over-riding need is to retain prairies and keep the open landscape. To achieve this, vegetation management must be practiced. Further research is needed to clarify the specific seasonal/monthly timing of management, but it is likely that a combination of fire, grazing, and mowing will be necessary. Whichever tool is used, it must be well timed to ensure adequate nectar sources for adults and to minimize the impact on the above ground shelters of larvae. For example, burning may occur every three years, but not in extensive patches. Divide the site into many management units and treat several each year. Adults are strong fliers—they have been recorded traveling up to a mile between suitable patches of habitat—and thus can recolonize burned areas.

Monitoring of known populations should be done to plan prairie management and assess the impacts of any actions. Further studies into appropriate habitat management techniques would be important. Surveys should be done to identify additional populations and assess population status. Given the wide range of this butterfly, life history studies should be done in each region to identify regional differences in ecology and also habitat management.

references

Opler, P. A., and G. O. Krizek. 1984. Butterflies East of the Great Plains. Johns Hopkins University Press, Baltimore, MD.

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: ottoe skipper (Accessed 1/21/09)

Canada Biodiversity Information Facility; Species Bank: ottoe skipper (Accessed 5/10/05)

NatureServe Explorer (Accessed 9/23/08)

Nearctica; Butterflies and Skippers of North America: Ottoe Skipper (Accessed 5/10/05)

Michigan State University Extension; Michigan Natural Features Inventory: Ottoe Skipper (Accessed 5/10/05)

Wisconsin Butterflies; ottoe skipper (Accessed 9/17/08)

citation

Shepherd, M. D. 2005. Species Profile: Hesperia ottoe. 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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