Critter Catalog

What do they look like?

Dukes' skippers range in size from 32-38 mm (1¼-1½ in) and have short, rounded wings. Females are slightly larger than males. The upper surfaces of the wings in both sexes are deep brown. The females have a hindwing band that has two to three pale yellow spots. Males have a black stigma on the forewing. The underside of the hindwings are light brown with pale yellow rays. (Opler and Krizek, 1984; Pyle, 1995; Scott, 1986)

The caterpillars of this species have a black head and light green body. The pupae nest in sedge leaves; they tie themselves into the upper portion of plants with silk. (Nielsen, 1999)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes colored or patterned differently

• Range wingspan

  32 to 38 mm

  1.26 to 1.50 in

Where do they live?

There are three populations of Dukes' skippers Euphyes dukesi, all are in the eastern North America: 1) along the Atlantic Coast from southeast Virginia to northern peninsular Florida, 2) the lower Mississippi Valley from central Missouri and southern Illinois south to the Gulf Coast, and 3) southern Ontario, southeastern Michigan, northeastern Indiana, and northern Ohio. (Opler and Krizek, 1984)

Individual populations appear to be widely separated, a contributing factor in their rarity. (Iftner, et al., 1992; Nielsen, 1999; Opler and Krizek, 1984; Shuey, 1996)

• Biogeographic Regions
• nearctic
  • native

What kind of habitat do they need?

This species prefers shaded wetlands dominated by the plant that the caterpillars eat. They eat different plants in different parts of their range. (Iftner, et al., 1992; Nielsen, 1999; Opler and Krizek, 1984; Pyle, 1995; Scott, 1986)

• These animals are found in the following types of habitat
• temperate

• Wetlands
• marsh
• swamp
• bog

How do they grow?

Duke's skippers probably follow the general butterfly life cycle of egg, 5 larval stages, pupae and adult. Caterpillars are known to overwinter in the fourth larval stage, and emerge in the springtime to feed. They will then molt one last time before they become pupae. They are probably in teh pupal stage for one or two weeks. (Opler and Krizek, 1984)

• Development - Life Cycle
• metamorphosis
• diapause

How do they reproduce?

Males are often seen patrolling over the tops of sedges and will perch in search of females. (Scott, 1986; Iftner, et al., 1992)

• Mating System
• polygynandrous (promiscuous)

The time of mating differs depending upon where the population is in the species' range. After mating, females lay their eggs under the leaves of their host plants. After hatching, the larvae undergo several molts and hibernate in the fourth larval stage. (Glassberg, 1999; Iftner, et al., 1992; Nielsen, 1999; Opler and Krizek, 1984; Pyle, 1995)

• Key Reproductive Features
• semelparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal
• oviparous

• How often does reproduction occur?

  Dukes' skippers are univoltine in the north to trivoltine in the south.

• Breeding season

  Each flight period lasts approximately one month.

No parental care is given for Dukes' skippers.

• Parental Investment
• no parental involvement

How long do they live?

From hatching through the death of the adult stage, a Dukes' skipper probably lives about a year or less. Several months of that time may be spent dormant in the winter. The estimated lifespan of an adult Dukes' skipper in the wild is approximately three weeks.

• Typical lifespan
  Status: wild

  1 (high) years

How do they behave?

Dukes' skippers have a weak flight pattern and are most often seen flying within sedges or visiting nectar plants. They frequent sunlit patches of their host plants and can be seen feeding on the nectar of a variety of plants. (Iftner, et al., 1992; Nielsen, 1999; Shuey, 1995)

• Key Behaviors
• flies
• diurnal
• motile
• sedentary
• hibernation
• solitary

How do they communicate with each other?

It is not known how this species communicates. In many butterflies, there are courtship rituals that occur prior to mating. Chemical signals ("pheromones") are also generally important in communication among butterflies.

• Communication Channels
• visual
• chemical

• Other Communication Modes
• pheromones

• Perception Channels
• visual
• tactile
• chemical

What do they eat?

Dukes' skipper larvae feed on Carex laucustris in the north and Carex hyalinolepis in the south. They are also reported to eat Carex walteriana, and Rhynchospora. In Florida, the primary food plant of Duke's skippers has been identified as Rhynchospora inundata, but they are also known to use Rhynchospora miliacea and a species of Carex. (Glassberg, 1999; Opler and Krizek, 1984; Scott, 1986; Shuey, 1995)

Adults eat the nectar of buttonbush, common milkweed, swamp milkweed, joe-pye weed, blue mistflower, pickerelweed, hibiscus species, sneezeweed, alfalfa, and red clover. (Iftner, et al., 1992; Nielsen, 1999; Opler and Krizek, 1984; Scott, 1986)

• Primary Diet
• herbivore
  • folivore
  • nectarivore

• Plant Foods
• leaves
• nectar

What eats them and how do they avoid being eaten?

Various insects are parasites of butterflies in general. Often, certain types of flies or wasps, called parasitoids, will lay their eggs on or within a caterpillar. The larvae of the parasitoid then eats the caterpillar. (Scott, 1986)

Most predators of butterflies are other insects. Praying mantis, lacewings, ladybird beetles, assasin bugs, carabid beetles, spiders, ants, and wasps (Vespidae, Pompilidae, and others) prey upon the larvae. Adult butterflies are eaten by robber flies, ambush bugs, spiders, dragonflies, ants, wasps (Vespidae and Sphecidae), and tiger beetles. The sundew plant is known to catch some butterflies. (Scott, 1986)

There are also many vertebrate predators including lizards, frogs, toads, birds, mice, and other rodents. (Scott, 1986)

What roles do they have in the ecosystem?

Dukes' skippers most likely serve as minor pollinators. They are prey for a variety of predators.

• Ecosystem Impact
• pollinates

Do they cause problems?

There are no known adverse affects of Dukes' skipper on humans.

How do they interact with us?

Dukes’ skippers are considered uncommon to endangered in much of their range, and thus a subject of interest for nature enthusiasts, who travel and provide economic benefits to the communities they visit. The designation of the Dukes’ Skipper Sanctuary in Findley State Park in Ohio created a potential revenue source from park visitors. (Iftner, et al., 1992)

• Ways that people benefit from these animals:
• ecotourism
• research and education

Are they endangered?

Dukes’ skippers are of conservation concern in all parts of their range, because they are only know from a few widely scattered sites. They are listed as threatened in the state of Michigan. (Iftner, et al., 1992; Nielsen, 1999; Opler and Krizek, 1984)

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  Threatened

Some more information...

Dukes’ skippers were named in honor of W. C. Duke, who lived in Mobile, Alabama. Previous common names include scarce swamp skipper and brown sedge skipper. Dukes’ skippers were assigned to the genus Atrytone in 1923. (Opler and Krizek, 1984; Miller, 1992; Miller and Brown, 1981)

The species was discovered in Ohio in 1980 in Findley State Park, and led to the creation of the Dukes’ Skipper Butterfly Sanctuary by the Ohio Department of Natural Resources, the first of its kind in Ohio. (Iftner, et al., 1992)

Contributors

Barb Barton (author), Special Contributors.

References

Glassberg, J. 1999. Butterflies Through Binoculars: the East. NY: Oxford University Press, Inc.

Holland, W. 1931. The Butterfly Book. Garden City, NY: Doubleday, Doran, and Co..

Iftner, D., J. Shuey, J. Calhoun. 1992. Butterflies and Skippers of Ohio. Ohio Biological Survey Bulletin Vol. 9 No. 1.

Maynard, C. 1891. Manual of North American Butterflies. Boston, MA: DeWolfe, Fiske, and Company.

Miller, J. 1992. The Common Names of North American Butterflies. Washington, DC: Smithsonian Institute Press.

Miller, L., F. Brown. 1981. A Catalogue/Checklist of the Butterflies of America North of Mexico. Lepidopterists/ Society Memoir No. 2.

Nielsen, M. 1999. Michigan Butterflies and Skippers. East Lansing, MI: Michigan State University Press.

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

Pyle, M. 1995. National Audubon Society Field Guide to North American Butterflies. NY: Alfred A. Knopf.

Scott, J. 1986. The Butterflies of North America. Stanford, CA: Stanford University Press.

Shuey, J. 1996. Another new <<Euphyes>> from the southern United States coastal plain (Hesperiidae). Journal of the Lepidopterists' Society, 50(1): 46-53.

Shuey, J. 1995. The biogeography and ecology of <<Euphyes dukesi>> (Hesperiidae) in Florida. Journal of the Lepidopterists' Society, 49(1): 6-23.

Struttman, J. "Dukes' skipper" (On-line ). North American Butterflies. Accessed 04/04/03 at http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/usa/478.htm.

Weed, C. 1926. Butterflies. Doubleday, Page, and Company.