Neonympha mitchelliiMitchell's satyr

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Geographic Range

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; "Recovery Plan for the Mitchell's Satyr Butterfly <<Neonympha mitchelli mitchellii>>", 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; "Saint Francis' Satyr Recovery Plan", 1996)

Habitat

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)

Physical Description

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, et al., 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, et al., 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, et al., 1960)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range wingspan
    1.6 to 2.1 cm
    0.63 to 0.83 in

Development

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, et al., 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, et al., 1960)

Reproduction

Males spend most of their time patrolling for females. Male-to-male chases are common and resemble territorial behavior. Females are relatively inactive and stay down in the vegetation. No courtship behaviors have been recorded. Mating and oviposition generally occur in mid-late afternoon. (Darlow, 2000; Roble, et al., 2001)

Mating takes place soon after females emerge. Mitchell's satyr females exhibit two behavioral stages prior to egg-laying. First, the females engage in a dispersal flight followed by an inspection flight. They fly just below or at the level of the vegetation seeking out appropriate host plants. In the second stage, the females make a short hop down into the vegetation after a brief resting period. They will either lay eggs immediately, or begin fluttering low in the vegetation. Egg laying will then commence if the substrate is accepted. If it is rejected, the female will engage in another dispersal flight. (Darlow, 2000; McAlpine, et al., 1960; Roble, et al., 2001; "Saint Francis' Satyr Recovery Plan", 1996; "Recovery Plan for the Mitchell's Satyr Butterfly <<Neonympha mitchelli mitchellii>>", 1998)

Females tend to oviposit in the interface zones between habitat patches (most often within one meter of shrubs), laying their eggs close to the ground on a variety of small forbs. Oviposition has also been observed to occur on dead leaves (Legge and Rabe 1996). Eggs have been placed on the undersides of leaves and on stems, and are most often laid in clusters. (Darlow, 2000; Legge and Rabe, 1996; Szymanski and Shuey, 2002; Szymanski, 1999)

  • Breeding interval
    Mitchell's satyrs reproduce once per year, Saint Francis' satyrs breed twice per year in North Caroloina, once in Virginia; breeding interval in Alabama unknown.
  • Breeding season
    Flight dates for Mitchell's satyr range from late June through mid-July. In Virginia, Saint Francis' satyrs fly from early to late July. Saint Francis' satyr populations in North Carolina are active from early May through early June and again from late July through late August.
  • Range eggs per season
    107 (high)

There is no parental care in this species. Females supply their eggs with nourishment, but once they have laid their eggs, they have no further interaction with their offspring.

  • Parental Investment
  • pre-fertilization
    • provisioning
  • pre-hatching/birth
    • provisioning
      • female

Lifespan/Longevity

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.

Behavior

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)

Communication and Perception

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.

Food Habits

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, et al., 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)

  • Plant Foods
  • leaves
  • nectar

Predation

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

Ecosystem Roles

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.

  • Ecosystem Impact
  • pollinates

Economic Importance for Humans: Positive

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.

  • Positive Impacts
  • ecotourism
  • research and education

Economic Importance for Humans: Negative

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

Conservation Status

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; "Mitchell's Satyr Butterfly - Endangered Species Fact Sheet", 1999; "Saint Francis' Satyr Recovery Plan", 1996; "Recovery Plan for the Mitchell's Satyr Butterfly <<Neonympha mitchelli mitchellii>>", 1998)

Contributors

George Hammond (editor), Animal Diversity Web.

Matthew Wund (editor), University of Michigan-Ann Arbor.

Barb Barton (author), Special Contributors.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

chemical

uses smells or other chemicals to communicate

diapause

a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

marsh

marshes are wetland areas often dominated by grasses and reeds.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nectarivore

an animal that mainly eats nectar from flowers

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

References

Recovery Plan for the Mitchell's Satyr Butterfly <<Neonympha mitchelli mitchellii>>. Ft. Snelling, MN: US Fish and Wildlife Service. 1998.

Saint Francis' Satyr Recovery Plan. Asheville, NC: US Fish and Wildlife Service. 1996.

US Fish and Wildlife Service Region 3. 1999. "Mitchell's Satyr Butterfly - Endangered Species Fact Sheet" (On-line ). Endangered Species. Accessed 02/18/03 at http://midwest.fws.gov/endangered/insects/mitchell.html.

Michigan Department of Natural Resources. "Mitchell's Satyr Butterfly Neonympha mitchellii mitchellii " (On-line). Michigan Department of Natural Resources. Accessed February 18, 2003 at http://www.michigan.gov./dnr/0,1607,7-153-10370_12145_12204-33013--,00.html.

2001. "Mitchell's Satyr Photos" (On-line image). Accessed 02/18/03 at http://www.vireos.com/mitchellssatyr.html.

Hiawatha National Forest, US Forest Service. "Range Map for Mitchell's Satyr Butterfly" (On-line ). Great Lakes Ecological Assessment.

Darlow, N. 2000. Behavior, Habitat Usage, and Oviposition of the Mitchell's Satyr Butterfly, Neonympha mitchellii mitchellii . Report to the US Fish and Wildlife Service, Ft. Snelling, MN: 43 pp..

Glassberg, J. 2001. Mitchell's satyr rides again. American Butterflies, 9(3): 16-21.

Hall, S. 1993. A rangewide status survey of Saint Francis' satyr, Neonympha mitchellii francisi (Lepidoptera: Nymphalidae). Report to the US Fish and Wildlife Service, Asheville, NC: 44 pp.

Hall, S. 1994. Supplement to the rangewide status survey of Saint Francis' satyr Neonympha mitchellii francisi (Lepidoptera: Nymphalidae) 1993 field season. Report to the US Fish and Wildlife Service: 26 pp.

Hyde, D., M. Rabe, D. Cuthrell, M. Kost. 2001. Surveys for the recovery of Mitchell's satyr butterfly Neonympha mitchellii mitchellii in Michigan. Final report - 2000. Report to the US Fish and Wildlife Service, Ft. Snelling, MN: 1-97.

Kost, M. 2000. Vegetation characteristics of Mitchell's satyr Neonympha mitchellii mitchellii habitat. Report to the US Fish and Wildlife Service, Ft.Snelling, MN: 1-25.

Legge, J., M. Rabe. 1996. Observations of oviposition and larval ecology in caged Mitchell's satyr butterflies Neonympha mitchellii mitchellii (Lepidoptera: Nymphalidae). Report to the US Fish and Wildlife Service, Ft. Snelling, MN: 17 pp.

McAlpine, W., S. Hubbell, T. Pliske. 1960. The distribution, habits, and life history of Euptychia mitchellii (Satyridae). Journal of the Lepidopterists' Society, 14(3): 209-226.

Opler, P., G. Krizek. 1984. Butterflies East of the Great Plains. Baltimore, MD: John Hopkins University Press.

Opler, P., V. Malikul. 1992. A Field Guide to Eastern Butterflies. NY: Houghton Mifflin Co.

Rabe, M., M. Kost, H. Enander, E. Schools. 2002. Use of a GIS based habitat model to identify potential release sites. Report to the US Fish and Wildlife Service, Ft. Snelling, MN: 34 pp.

Roble, S., C. Kessler, B. Grimes, C. Hobson, A. Chazal. 2001. Biology and conservation status of Neonympha mitchellii, a globally rare butterly new to the Virginia fauna. Banisteria, 18: 3-23.

Shuey, J. 1997. Conservation status and natural history of Mitchell's satyr Neonympha mitchellii mitchellii French (Insecta: Lepidopters: Nymphalidae). Natural Areas Journal, 17: 153-163.

Struttman, J. "Butterflies of Michigan, Mitchell's Satyr" (On-line ). Butterflies of North America. Accessed 02/18/03 at http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/mi/131.htm.

Struttman, J. 2004. "Butterflies of New Jersey" (On-line). Butterflies of North America. Accessed November 23, 2004 at http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/nj/131.htm.

Szymanski, J. 1999. Population and spatial ecology of the Mitchell's satyr butterfly, *Neonympha mitchellii mitchellii>> French, in southwestern Michigan. Master's Thesis, University of MN: 78 pp.

Szymanski, J., J. Shuey. 2002. Conservation strategy for Mitchell's satyr butterfly at ...(site name deleted). Report to the US Fish and Wildlife Service, Ft. Snelling, MN: 92 pp.

Wilson, T. "Mitchell's Satyr: An Endangered Butterfly Species Found in the Oakmulgee National Forest" (On-line ). Judson Webspinner. Accessed 02/18/03 at http://home.judson.edu/academic/spinner/butterfly/butterflycount.html.