Neonympha mitchellii
Mitchell's satyr

This species is only found in the United States. There are two recognized subspecies; Neonympha mitchellii mitchellii (Mitchell's satyr) and N. mitchellii francisi (Saint Francis' satyr). Historically there were 30+ isolated populations of N. mitchellii mitchellii in the states of Michigan, Ohio, Indiana, New Jersey, and possibly Maryland. Currently, there are 19 known populations remaining, 17 in Michigan and 2 in northern Indiana (C. Tansy, USFWS, personal communication, Hyde et al. 2001). (Hyde et al., 2001; US Fish and Wildlife Service, 1998)

There are 12 known populations of Saint Francis' satyrs in the southeastern United States. The first identified population was discovered in the Sandhills region of North Carolina in 1983. In 1998, intensive survey efforts located 10 more populations in Virginia, and in 2000 one population was discovered in Alabama. (Glassberg, 2001; Hall, 1993; Roble et al., 2001; US Fish and Wildlife Service, 1996)

Most known habitats for Mitchell's satyrs are peatlands ranging on a continuum from prairie/bog fens to sedge meadow/swamps. They are sedge dominated, usually by Carex stricta, and have scattered deciduous and coniferous trees such as tamarack (Larix laricina) and red cedar (Juniperus virginianus). The fens are comprised of a mosaic of community types. Mitchell's satyrs restrict their activities to the interface zone between open sedge meadows and dense stands of shrubs or tamarack savannah areas. Shuey (1998) suggests a minimum habitat size of 8 ha (20 acres). (Kost, 2000; Rabe et al., 2002; Shuey, 1997; Szymanski and Shuey, 2002; Szymanski, 1999)

In North Carolina, Saint Francis' satyrs occur in sedge dominated, acidic, boggy wetlands within the Sandhills region. These are sedge meadows surrounded by open, fire-maintained forestland, and open, hillside seepages. In Virginia, they are found in open canopy, bulrush (Scirpus spp.) and sedge (Carex spp.) dominated, boggy seepage wetlands. There is light to moderate grazing by livestock at these sites. Habitat size ranges from 0.16 ha (0.4 acres) to 8 ha (20 acres), with the majority between 0.16 ha and 1.21 ha (0.4 - 3.0 acres). They differ from the northern sites in that they are neither calcareous wetlands or bog fens (it should be noted there are very few calcareous wetlands in Virginia), yet they are similar in vegetative structure. There is very limited shrub cover at the Virginia sites, primarily smooth alder (Alnus serrutalata). There are ground water seepages and springs at most sites, and mud or gravel bottom streams in all sites. The dominant plant species is bulrush (Scirpus expansus). (Roble et al., 2001)

Mitchell's satyrs are small, brown butterflies that are unmarked on the upper surface of the wings. They can be identified by rows of round, black, yellow-ringed ocelli (eyespots) along the margins of the ventral wings. There are two orange lines that border the undersides of both fore- and hind-wings. Females are slightly lighter in color. The forewings of the males range from 1.6 - 1.8 cm; females are larger, ranging from 1.8 - 2.1 cm. ("Mitchell's Satyr Photos", 2001; Opler and Krizek, 1984)

Saint Francis' satyrs have subtle differences from Mitchell's satyrs. They possess a much darker ground color, and the eyespots are usually more irregular in shape and have thinner rings encircling them. Roble examined individuals from Virginia and North Carolina and found that both populations have the frequent presence of obliquely oriented third and fourth hind ocelli. (Roble et al., 2001)

The eggs of both subspecies are greenish-white to cream colored and become tan when they age. They are spheroidal or rounded cubical, with a diameter of 0.8 - 1.0 mm. The surfaces of the eggs are covered with five or six-sided shallow cells that are described as "irregularly polygonal" (McAlpine 1960). The dark head of the larvae is visible one to two days before hatching. (McAlpine, Hubbell, and Pliske, 1960)

McAlpine et al. (1960) give a detailed description of all larval stages from captive-reared individuals. The measurements that follow the larval descriptions are from these individuals and may or may not reflect the sizes found in natural settings. The first instar larvae have a pale ochre or light yellow-green color after they first emerge. After feeding their color changes to light lime green. Their heads are medium to dark violet brown to black with a silky sheen, and are very large and bilobate. They have pale white lateral stripes and a bifurcate (two-branched) tail. Their lengths at emergence were 2.5 - 3.0 mm and their final lengths before molting were 4.5 - 6.0 mm. Second instar larvae possess a light lime green body. Their heads are smaller in relation to their bodies than in first instar. Their heads and bodies are covered irregularly and densely with small, fleshy, light colored papillae. The white striping is more pronounced in this stage. Their lengths at emergence were 4.5-6.0 mm and their final lengths before molting were 7.5-11 mm. The lime green color deepens slightly in the third instar stage. Their heads and bodies are very densely covered with whitish papillae. The white striping in this stage is more pronounced. Their lengths at emergence were 7.5-11 mm and their final lengths before molting were 9-13 mm. Fourth instar larvae are very similar to the previous stage. Different shades of lime green begin to appear in longitudinal bands. Their lengths at emergence were 9-13 mm and their final lengths before diapausing were 11-16 mm. Fifth instar larvae are very similar to fourth instar larvae. The surfaces of their heads are rough, covered with fine green and white papillae. Their lengths were 11-19 mm. Sixth instar larvae differ only in length from the previous stage. Their lengths were 19-28 mm. Szymanski and Shuey (2002) recorded larval lengths of 15-38 mm in two wild individuals. (McAlpine, Hubbell, and Pliske, 1960; Szymanski and Shuey, 2002)

Pupae are generally light lime green in color, except the venation of the wing sheaths and the abdomen, which are slightly darker and bluish. There is some pale green or whitish mottling. Pupae are stout and truncate at the anterior end and taper posteriorly. Pupal lengths were 10.5-15.5 mm. (McAlpine, Hubbell, and Pliske, 1960)

Larvae in both subspecies go through five molts before pupation. In univoltine populations, larvae undergo three molts before diapausing in the fall. There are two additional molts in the spring followed by pupation in June. (Legge and Rabe, 1996; McAlpine, Hubbell, and Pliske, 1960)

In captive reared Mitchell's satyrs, the duration of the egg stage was 7-11 days; first instar 11-18 days; second instar 11-16 days; third instar 16-27 days; the fourth instar diapaused from early September to late May; fifth instar 15-18 days; and the six instar 20-25 days. The pupal stage lasted 10-15 days. (McAlpine, Hubbell, and Pliske, 1960)

The lifespan for an adult is approximately three weeks. If they are dormant in the winter, then they may live up to a year at most.

Mitchell's satyrs are most active on warm, overcast days, and tend to reduce their activities during sunny days. There is little activity when temperatures rise above 32° C (90° F). In contrast, Saint Francis' satyrs are active on hot days. Nectaring by Mitchell's satyrs had only been recorded once by researchers prior to Darlow's work in 2000. It is unclear why nectaring was so prevalent at these two Michigan sites during 2000, but it accounted for a substantial portion of female observations. (Darlow, 2000; Roble et al., 2001; Shuey, 1997)

Home Range

Limited data suggests that Mitchell's satyrs have very small home ranges of less than .05 hectares (Szymanski and Shuey 2002). The average individual appears to use only a small portion of seemingly suitable habitat within a patch. In two study sites in Michigan during 1997-98, males used on average 4% of available habitat, with the exception of one site in 1997 where they occupied 15%. Females used 10% at one site and 5% at the other in 1998. Due to their short life spans and restricted environmental conditions suitable for activity, adult Mitchell's satyrs primarily confine their activities to reproduction. (Szymanski and Shuey, 2002; Szymanski, 1999)

There have been no reports of communication in this species. Potential mates probably rely on chemical senses and vision to communicate. Females probably locate suitable egg-laying sites with a combination of visual and olfactory cues.

Mitchell's satyr larvae appear to feed on a variety of sedges and possibly one or more species of bulrushes (Scirpus spp.). Larvae have been reared to maturity on Carex alopecoidea and Scirpus atrivirens, but rejected Carex stricta, a species commonly thought of as the main foodplant (McAlpine 1960). Larvae accepted Carex stricta and Carex prairea during foodplant studies by Szymanski and Shuey (2002). Legge and Rabe (1996) confirmed larval feeding on Carex lasiocarpa and saw evidence of feeding on C. stricta. Saint Francis' satyrs are believed to feed on sedges as well, particularly Carex expansus. Other potential foodplants include C. stricta, Carex vulpinoidea, and bulrush (Scirpus atrivirens). (Legge and Rabe, 1996; McAlpine, Hubbell, and Pliske, 1960; Roble et al., 2001; Szymanski and Shuey, 2002)

Adult Mitchell's satyrs have been observed nectaring on mountain mint (Pycanthemum virginianum), black-eyed susan (Rudbeckia hirta), and swamp milkweed (Asclepias incarnata). Adult Saint Francis' satyrs are known to nectar on swamp milkweed (A. incarnata), common milkweed (Asclepias syriaca), yarrow (Achillea millefolium), Queen Anne's lace (Daucus carota), and crown vetch (Coronilla varia). (Darlow, 2000; Roble et al., 2001)

We don't have specific information on predators of these satyrs. Common predators of butterflies (Lepidoptera) include birds, spiders, ants, and parasitic wasps.

The role of N. mitchellii in the ecosystem is that of prey for the previously mentioned predators. They may also serve as pollinators to some degree, and the larvae may be significant herbivores on sedge plants.

There are no known adverse affects of Neonympha mitchellii on humans.

Individuals traveling to observe these butterflies contribute to local economies directly, and to the national economy through the purchase of field equipment such as binoculars, field guides, and cameras.

Both Mitchell's satyr and Saint Francis' satyr are listed as endangered by the U.S. Fish and Wildlife Service. Mitchell's satyr is also listed as endangered in the state of Michigan.

The decline of Mitchell's satyr across its range has been attributed to several factors related to habitat loss; 1) destruction due to development, 2) changes in hydrology, 3) invasion by aggressive native (Typhall spp.) and non-native plant species, and 4) suppression of natural disturbance events important to maintain fen habitat such as fire and possibly beaver (Castor canadensis) activity. (Hall, 1993; Hall, 1994; Rabe et al., 2002; Roble et al., 2001; Shuey, 1997; Szymanski, 1999; US Fish and Wildlife Service Region 3, 1999; US Fish and Wildlife Service, 1996; US Fish and Wildlife Service, 1998)