Plants and Animals
Neonympha mitchellii mitchellii Mitchell's satyr
Key Characteristics
Mitchell's satyr is a dark, chocolate brown, medium-sized butterfly with a wing span that ranges from 1.5 to 1.75 inches (3.8-4.4 cm). The ventral surface, or underside, of the forewing and hindwing contains a row of four to five black, yellow-ringed ocelli, or eyespots, with the central three eyespots on the hindwing being the largest. Two orange bands encircle the eyespots. Mature larvae are pale green with pale, longitudinal stripes and a bifurcate tail.
Status and Rank
US Status: LE - Listed Endangered
State Status: E - Endangered (legally protected)
Global Rank: G2T2
State Rank: S1 - Critically imperiled
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Barry | 3 | 2012 |
| Berrien | 3 | 2022 |
| Branch | 1 | 2024 |
| Cass | 5 | 2024 |
| Jackson | 4 | 2024 |
| Kalamazoo | 4 | 2009 |
| Lenawee | 1 | 1980 |
| St. Joseph | 2 | 2008 |
| Van Buren | 3 | 2022 |
| Washtenaw | 3 | 2024 |
| Wayne | 1 | 1931 |
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.
Habitat
In Michigan, this butterfly occurs in southern part of the state, where it is found in prairie fens, a natural community dominated by sedges, grasses, and other graminoids, but also rich in forb diversity. Prairie fens are often found associated with other natural communities, including tamarack swamps, wet prairie, sedge meadow, and shrub-carr, where the satyrs are occasionally found. Mitchell's satyrs are often found within 3 m of woody vegetation, such as native shrubs or tamarack (Larix laricina; Barton and Bach 2005). Larvae consume various species of sedges, including Carex buxbaumii, C. lasiocarpa, C. leptalea, C. prairea, C. sterilis.
Specific Habitat Needs
Host plant needed in: Prairie fen; Rich tamarack swamp; Southern wet meadow.
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.
Management Recommendations
The primary threat to the continued survival of this species is habitat loss and modification as well as insecticides from agricultural activities. Many of the wetland complexes occupied currently have been altered or drained for agriculture or development. Hydrological alteration is responsible for extirpating the single known satyr population in Ohio. 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 satyr 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.
Active Period
Flight from second week of June to second week of July
Survey Methods
The best way to survey for this species is to conduct visual surveys while meandering through suitable habitat, particularly along the interface of open wetland habitat and shrubby/forested vegetation. This species' behavior and activity appear to be strongly influenced by ambient temperatures and solar radiation. Mitchell's satyrs are most active and easiest to observe on warm (75-90F), overcast days, and their activity is significantly reduced during hot (>90F), sunny days. At some sites, Mitchell's satyrs have exhibited a diurnal activity pattern in which individuals are active during the cooler parts of the day (i.e., early morning and late afternoon) and appear to rest during the warmest part of the day (i.e., midday). Larvae are difficult to locate in the field; however, in captive rearing studies they have been observed to overwinter in the fourth instar at the base of tussock sedge (Tolson and Ellsworth 2010). Care should be taken during surveys to not excessively trample habitat, which could damage chrysalides, eggs, and/or larvae.
Meander search through suitable habitat
Survey Period: From second week of June to second week of July
Time of Day: Daytime
Cloud Cover: Overcast
Air Temperature: Warm
Wind: No Wind
References
Survey References
- 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.
Technical References
- Barton, B.J and C.E. Bach. 2005. Habitat use by the federally endangered Mitchell’s satyr butterfly (Neonympha mitchellii mitchellii) in a Michigan prairie fen. American Midland Naturalist 153(1): 41-51.
- Evers, D.C. 1994. Endangered and Threatened Wildlife of Michigan. The University of Michigan Press, Ann Arbor. 412pp.
- Lee, Y. 2002. Special Animal Abstract for Appalachina sayana (Spike-lip crater). Michigan Natural Features Inventory. Lansing, MI. 4pp.
- McAlpine, W.S., S.P. Hubbell, and T.E. Pliske. 1960. The distribution, habits, and life history of Euptychia mitchellii (Satyridae). Journal of the Lepidopterists' Society 14(3):209-226.
- Opler, P.A. and G.O. Krizek. 1984. Butterflies East of the Great Plains. Johns Hopkins University Press, Baltimore. 294pp.
- Opler, P.A. and V. Malikul. 1992. Eastern Butterflies. Houghton Mifflin Company, New York. 396pp.
- Tolson, P.J. and C.L. Ellsworth. 2010. Final Report – Mitchell’s Satyr Larval Mass Rearing Experiments. Final Report submitted to the U.S. Fish and Wildlife Service by the Toledo Zoo Department of Conservation and Research. Unpublished report. 7pp.