Plants and Animals
Oarisma poweshiek Poweshiek skipperling
Upper surfaces are dark brown with an orange costal area on the forewing. The undersurface of the hindwing has veins covered with white scales; basal area veins are dark brown without white scales. The caterpillar is pale green with a dark green dorsal band outlined by cream lines.
Status and Rank
US Status: LE - Listed Endangered
State Status: T - Threatened (legally protected)
Global Rank: G1 - Critically imperiled
State Rank: S1 - Critically imperiled
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Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Sedgy meadows, cinquefoil seeps and open fens. High quality tall grass prairie.
Specific Habitat Needs
Host plant needed in: Prairie fen.
Natural Community Types
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
The primary threat to the continued survival of this species is habitat loss and modification. Many of the wetland complexes occupied currently have been altered or drained for agriculture or development. Wetland alteration also can lead to invasion by exotic plant species such as glossy buckthorn (Rhamnus frangula), purple loosestrife (Lythrum salicaria), common buckthorn (Rhamnus cathartica), and the common reed (Phragmites australis). In addition, landscape-scale processes that may be important for maintaining suitable poweshiek habitat and/or creating new habitat, such as wildfires, fluctuations in hydrologic regimes, and flooding from beaver (Castor canadensis) activity, have been virtually eliminated or altered throughout the species' range. The widespread use of neonicotinoid pesticides could be a cause for the decline in this species as most sites are adjacent to, or downslope from, row crop agriculture.
Flight from fourth week of June to third week of July
The Poweshiek skipperling has one generation per year. This species overwinters as a half grown larvae. Larvae are present from mid-July to September. In Michigan, adults of this species have been observed flying typically from late June to mid-July although adults have been seen as early as June 9. The best way to survey for this species is to conduct visual surveys while meandering through habitat looking for flowers and nectaring adult butterflies. Adults nectar on shrubby cinquefoil, white clover, lobelia, and black-eyed Susan. A pair of close focusing binoculars may be used to help locate individuals. Most butterfly surveys should be conducted on warm, sunny days with little to no wind.
Visual, aerial net
Survey Period: From fourth week of June to third week of July
Time of Day: Daytime
- Klots, A.B. 1951. Peterson Field Guides: Eastern Butterflies. Houghton Mifflin Company, Boston. 349pp.
- Martin, J.E.H. 1977. The Insects and Arachnids of Canada (Part 1): Collecting, preparing, and preserving insects, mites, and spiders. Publication 1643. Biosystematics Research Institute, Ottawa.
- Evers, D.C. 1994. Endangered and Threatened Wildlife of Michigan. The University of Michigan Press, Ann Arbor. 412pp.
- Glassberg, J. 1999. Butterflies through Binoculars: The East. Oxford University Press, New York. 242pp.
- Nielsen, M.C. 1999. Michigan butterflies and skippers: A field guide and reference. Michigan State University Extension Bulletin E-2675, East Lansing. 248pp.
- Stehr, F. W. 1997. Michigan Lepidoptera Survey Sites and Seasonal Occurrence of Michigan's Listed Species Annual Report 1997. 30 pp.+ MI Lepidoptera Survey Data Collection Form