Animal Diversity Web

Ge­o­graphic Range

The Uncas skip­per, Hes­pe­ria uncas, ranges across Canada from Saskatchewan to Al­berta, and down into the United States through the Rocky Moun­tains and Great Plains. From the Great Plains its range ex­tends south to Texas and New Mex­ico.

There are two iso­lated pop­u­la­tions, one in south cen­tral Mex­ico and the other in Min­nesota. In Min­nesota, a small pop­u­la­tion only ex­ists in the sand dunes of Sher­burne County. This pop­u­la­tion is 500 kilo­me­ters east of its known lim­its in the Dako­tas. This pop­u­la­tion in Min­nesota is dif­fer­ent, phe­no­typ­i­cally, than that of the pop­u­la­tion in the Great Plains. Two re­cent sight­ings of H. uncas males in south­west­ern Min­nesota might in­di­cate a wider dis­tri­b­u­tion in the east­ern side of South Dakota, how­ever lack of habi­tat in this area would likely pre­vent the es­tab­lish­ment of a pop­u­la­tion. (Cof­fin and Pfan­n­muller, 1988)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Uncas skip­pers can pri­mar­ily be found in both al­ka­line and short grass­lands, as well as grassy al­ka­line flats. Some west­ern pop­u­la­tions ap­pear com­monly clus­tered on this­tles in south­west­ern road ditches by the dozens. Uncas skip­pers in Cal­i­for­nia are lo­cated at higher el­e­va­tions in the White Moun­tains of Mono and Inyo. (Brock, 2003; Garth and Tilden, 1986; Glass­berg, 2001)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• desert or dune
• savanna or grassland

• Other Habitat Features
• suburban

• Range elevation

  989 to 8100 m

  3244.75 to 26574.80 ft

• Average elevation

  5500 m

  18044.62 ft

Phys­i­cal De­scrip­tion

The Uncas skip­per is very sim­i­lar to other skip­pers that it flies with, but this but­ter­fly is small at 28 to 34 mm long, with a ro­bust body, an­gled forewings, and shorter, more round hind wings. Its wingspan av­er­ages 3.1 to 3.81 cm. On the un­der­side of its wings, the Uncas skip­per has ex­ten­sive hind­wings of white chevron with con­nected spots, with white veins and blotchy dark brown to black mark­ings. The white spots ori­en­tate in­wardly and out­wardly by dark green shades. The pop­u­la­tions lo­cated in Mono County, Cal­i­for­nia have re­duced hind­wing white vein­ing and often have dark brown to black mark­ings. Like all skip­pers, Uncas skip­pers have an­ten­nas that are rel­a­tively short which have clubbed ends and tips that curve back­wards.

Males and fe­males dif­fer greatly on the upper side of the wings. Males will typ­i­cally have a brown­ish or­ange darker col­oration. Small light col­ored spots can be seen near the forewing tips. Males also have a lin­ear black band of scent scales that are used in courtship. These scales are placed on the long axis of the forewings. Fe­males tend to be darker, with larger white spots on the forewings. Uncas fe­males tend to have larger, and more broad wings which is a char­ac­ter­is­tic found in skip­pers. Both sexes will be­come duller with age as the scales fall off, but the pat­tern will never dis­ap­pear.

The eggs ap­pear green­ish white and are hemi­spher­i­cal. The young lar­vae form is pale brown, and the head is a darker brown with cream spots and streaks in the front. ("Hes­pe­ria uncas", 2014; Cof­fin and Pfan­n­muller, 1988; Glass­berg, 2001; "Hes­pe­ria uncas", 2014; Opler, 1999)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

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

• Range length

  28 to 34 mm

  1.10 to 1.34 in

• Range wingspan

  3.3 to 3.81 cm

  1.30 to 1.50 in

De­vel­op­ment

Pupae emerge dur­ing the spring or sum­mer, de­pend­ing on the re­gion. In South Dakota and much of its range, H. uncas has two gen­er­a­tions, one in May and June, the other in July to Sep­tem­ber. In Min­nesota, it has only one gen­er­a­tion in June and July. After emerg­ing from pu­pa­tion, adults take flight and find mates. Eggs are laid, and hatch after about 10 days. In the first gen­er­a­tion, lar­vae go through sev­eral in­star stages, pu­pate, and then emerge as adults. In the sec­ond gen­er­a­tion (or for the only gen­er­a­tion in Min­nesota), lar­vae de­velop until the fourth or fifth in­star, and then go into hi­ber­na­tion for the win­ter. They emerge again in late spring or sum­mer, and pu­pate for 2 to 3 weeks be­fore emerg­ing as adults and be­gin­ning the cycle again. ("Hes­pe­ria uncas", 2014)

• Development - Life Cycle
• metamorphosis
• diapause

Re­pro­duc­tion

Based on sim­i­lar species in the genus, fe­male Uncas skip­pers prob­a­bly mate shortly after emer­gence and will rarely re­mate. The males will look for re­cep­tive fe­males by perch­ing on low veg­e­ta­tion or di­rectly on bare sand. Males use the scent scales on their wings to pro­duce pheromones for courtship. Many males will also col­lect on hills or ridges, which may draw the at­ten­tion of fe­males, though lit­tle is known for sure about this be­hav­ior. Re­cep­tive fe­males re­spond to males by de­scend­ing into the veg­e­ta­tion where mat­ing fol­lows. ("Hes­pe­ria uncas", 2014)

• Mating System
• polygynous

De­pend­ing on the area, Uncas skip­pers can have one or two gen­er­a­tions per year. In South Dakota and most of its range, there are two gen­er­a­tion per year, with adults pre­sent from May to June and July to Sep­tem­ber. In Min­nesota, there is one gen­er­a­tion per year from June to July. After mat­ing, the fe­male finds plants to oviposit on; all ob­served ovipo­si­tions of H. uncas have been made on hairy grama (Boutelous hir­sute), which is a tufted grass. The fe­male will lay only a sin­gle egg be­fore mov­ing on to the next tuft. (Glass­berg, 2001; "Hes­pe­ria uncas", 2014)

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

• Breeding interval

  Females mate once in their lives, while males will mate as much as possible.

• Breeding season

  Depending on the region, mating takes place from late spring to late summer.

Fe­males pro­vide pro­vi­sion­ing in their eggs, as well as lay the eggs on suit­able host plants for the lar­vae to feed upon hatch­ing. After the eggs are laid, there is no more in­ter­ac­tion or care by the par­ents. ("Hes­pe­ria uncas", 2014)

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

Lifes­pan/Longevity

Adults of Hes­pe­ria uncas likely live for about 3 weeks after emerg­ing from pu­pa­tion. ("Hes­pe­ria uncas", 2014)

• Average lifespan
  Status: wild

  21 days

Be­hav­ior

The lar­vae will live in shel­ters that grow in size, that they them­selves built out of silk and plant ma­te­ri­als. The shel­ters are built big­ger and big­ger as the lar­vae grow too. Over­win­ter­ing lar­vae have also been found in shel­ters that have been build under the soil. Adult Uncas skip­pers are very rapid and strong fliers. They have a very fast wing beat that al­most ap­pears to be like a blur to human eyes. ("Hes­pe­ria uncas", 2014)

• Key Behaviors
• flies
• motile
• sedentary
• hibernation

Com­mu­ni­ca­tion and Per­cep­tion

Male Uncas skip­pers have a lin­ear black band of scent scales on their wings that re­lease pheromones dur­ing courtship. Males also may com­mu­ni­cate with fe­males vi­su­ally, as the males col­lect in groups on high ridges be­fore fe­males, likely a vi­sual cue to fe­males. ("Hes­pe­ria uncas", 2014)

• Communication Channels
• visual
• chemical

• Other Communication Modes
• pheromones

• Perception Channels
• visual
• chemical

Food Habits

The lar­val food source for Uncas skip­per is blue grama (Bouteloua gra­cilis) grass and other grasses such as hairy grama (Bouteloua hir­sute). Uncas skip­per adults seek nec­tar and will feed from al­most any flow­ers avail­able, but golden aster (Het­erotheca vil­losa) and hairy puc­coon (Lithos­per­mum car­olin­iense) are the pre­ferred sources of nec­tar. (Cof­fin and Pfan­n­muller, 1988; "Hes­pe­ria uncas", 2014)

• Primary Diet
• herbivore
  • folivore
  • nectarivore

• Plant Foods
• leaves
• nectar

Pre­da­tion

There is no in­for­ma­tion avail­able about the preda­tors of Hes­pe­ria uncas. As quick fliers, they are likely able to evade any ground preda­tors, as well as many air­borne preda­tors. ("Hes­pe­ria uncas", 2014)

Ecosys­tem Roles

Uncas skip­pers, like other but­ter­flies and moths feed on flow­ers nec­tar and there­fore help con­tribute to pol­li­na­tion of plants. ("Hes­pe­ria uncas", 2014)

• Ecosystem Impact
• pollinates

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There are no known pos­i­tive ef­fects of Hes­pe­ria uncas on hu­mans.

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Hes­pe­ria uncas on hu­mans.

Con­ser­va­tion Sta­tus

Under the Min­nesota's List of En­dan­gered, Threat­ened, and Spe­cial Con­cern Species, Herspe­ria uncas is listed as en­dan­gered. This is due to the de­struc­tion of its habi­tat in that state, and only a small pop­u­la­tion in an iso­lated area re­mains there. Con­ser­va­tion ef­forts are un­der­way to pro­tect the pop­u­la­tion and its habi­tat in this area.

On a na­tional level, Hes­pe­ria uncas has no spe­cial con­ser­va­tion sta­tus. ("Hes­pe­ria uncas", 2014)

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Court­ney Chris­tensen (au­thor), Min­nesota State Uni­ver­sity Mankato, Robert Sorensen (ed­i­tor), Min­nesota State Uni­ver­sity, Mankato, An­gela Miner (ed­i­tor), An­i­mal Di­ver­sity Web Staff.

Ref­er­ences

Min­nesota De­part­ment of Nat­ural Re­sources. 2014. "Hes­pe­ria uncas" (On-line). Species Pro­file: Min­nesota DNR. Ac­cessed April 16, 2014 at http://​www.​dnr.​state.​mn.​us/​rsg/​profile.​html?​action=elementDetail&​selectedElement=IILEP65010.

Brock, J. 2003. Kauf­man Field Guide to But­ter­flies of North Amer­ica. New York, United States of Amer­ica: Houghton Mif­flin Com­pany.

Cof­fin, B., L. Pfan­n­muller. 1988. Min­nesota's En­dan­gered Flora and Fauna. Canada: Uni­ver­sity of Min­nesota Press. Ac­cessed March 26, 2014 at http://​mnsu.​summon.​serialssolutions.​com/?​s.​q=uncas+skipper#!/​search?​ho=t&​q=uncas%20skipper&​l=en.

Garth, J., J. Tilden. 1986. Cal­i­for­nia But­ter­flies. United States of Amer­ica: Uni­ver­sity of Cal­i­for­nia Press.

Glass­berg, J. 2001. But­ter­flies Through Binoc­u­lars. New York, United States of Amer­ica: Ox­ford Uni­ver­sity Press, Inc..

Hol­land, J. 2003. Field Guide to But­ter­flies. Canada: Ster­ling Pub­lish­ing Co, Inc..

Opler, P. 1999. A Field Guide to West­ern But­ter­flies. New York: Houghton Mif­flin Com­pany. Ac­cessed April 21, 2004 at http://​books.​google.​com/​books?​id=ilL_​XX1rbNoC&​pg=RA2-PT360&​dq=Holland+field+guide+to+butterflies&​hl=en&​sa=X&​ei=MeJVU5y7HNGKyATKjYKIAw&​ved=0CEQQ6AEwAg#​v=onepage&​q=uncas%20skipper&​f=false.