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Rare Species Guide
Oarisma garita (Reakirt, 1866) |
Garita Skipperling |
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Basis for ListingThe Garita Skipperling (Oarisma garita), also known as the Garita Skipper, is a grassland species ranging from northern Mexico north through the Great Plains and Rocky Mountains to the Canadian parklands (Layberry et al. 1998; Lotts and Naberhaus 2017). It reaches its eastern limit in southern Manitoba and northwestern Minnesota (though there is a possibly introduced, disjunct population near Mantoulin Island, Ontario). In the late 1980s, the Garita Skipperling was discovered to be a breeding resident in the Aspen Parklands Subsection in Kittson County, where colonies were confirmed in three sites (Cuthrell 1991). There is also a record from the late 1960s from Clay County (Red River Prairie Subsection) that may represent a brief, adventive establishment. All locations in Kittson County are in native prairie habitat on sandy soils. This habitat was always a patchy component of the landscape in the region, and conversion of lands to crop production, overgrazing, aggregate mining, and succession to woodland have further reduced the amount. DescriptionThe Garita Skipperling is a small butterfly, smaller and more delicate looking than most other skippers in Minnesota. Forewing length (base to apex) is 1.1-1.3 cm (0.4-0.5 in.) in both sexes. Antennae are short and relatively stout and have blunt-tipped clubs. Although capable of rapid flight, this skipperling more typically flies erratically just above the grass tops at a speed that is relatively easy to follow with the eye. Its flight is somewhat moth-like and lacks the skipping quality that gives the family its name. HabitatHabitat for the Garita Skipperling in Manitoba is described as dry and moist virgin prairie, with hollows or bases of hills favored in dry prairie (Klassen et al. 1989). Dry prairie seems to be the preferred habitat in North Dakota, where the Poweshiek Skipperling occupies moister prairie (McCabe and Post 1977). In Minnesota, the Garita Skipperling has been observed in prairie openings on sandy soils in either old dune formations or outwash deposits. In all cases, moister swales or hollows occur together with the drier hillocks or swells. Dominant grasses of the drier prairie include little bluestem (Schizachyrium scoparium var. scoparium), junegrass (Koeleria macrantha), porcupine grass (Hesperostipa spartea), and needle-and-thread grass (Hesperostipa comata). In one of these locations there are scattered small gnarled bur oaks (Quercus macrocarpa). Biology / Life HistoryThe Garita Skipperling has a single annual generation. All observations of this species in Minnesota have been in the first half of June, though the flight period probably extends somewhat into July as it does in North Dakota and Manitoba (McCabe and Post 1977; Royer 1988; Klassen et al. 1989). It overwinters as a partly grown larva and completes development the following spring (Scott 1986). Conservation / ManagementSmall colony sizes due to past habitat loss and further habitat destruction are the primary threats facing the Garita Skipperling in Minnesota. All habitat that is not protected by permanent dedication for conservation is at risk of destruction for agricultural production, aggregate mining, or development. Loss of the unprotected habitat at the sites where this skipperling is known to occur will make the colonies even more vulnerable. Extirpation could result from natural events (such as severe drought or hailstorms) or human caused ones (such as insecticide application), as well as from the vagaries of normal population processes (for example, by chance all adults in one generation are males). Loss of genetic diversity is another possible threat. Even where protected, the habitat in northwestern Minnesota is strongly susceptible to woodland invasion and requires active management intervention to maintain it. The Garita Skipperling is probably highly sensitive to fall or spring prescribed burns, as larvae and pupae are likely to be exposed to lethal temperatures based on what is known about the Poweshiek Skipperling (personal observation). Even the lower energy output of fire in dry prairie would be devastating to completely unconcealed larvae. Accordingly, the use of prescribed fire as a habitat management tool must be judicious. A site should be subdivided and the units burned in a rotation that leaves enough larval habitat unburned to assure population survival and recolonization of burned areas between burns. This may be difficult for small sites. Haying may provide a suitable option in these cases; Swengel (1998) provides evidence that late-summer haying is more favorable for several prairie skippers than rotational burning. Mowing should not occur until eggs have hatched (late July). Conservation Efforts in MinnesotaFollowing the discovery of the Garita Skipperling in Kittson County, the Minnesota DNR conducted more intensive surveys in the Tallgrass Aspen Parklands Province of northwestern Minnesota that confirmed its status as a breeding population. All three locations where skipperlings were found are substantially protected from destructive development. No conservation efforts specifically targeted to this skipperling have been undertaken; however, prescribed burning at the smallest site is conducted in accordance with guidelines that reduce risk to grassland insects. The other two sites are being managed to maintain prairie and savanna and to reverse woodland encroachment, and both have enough habitat that prescribed burning should not pose great risk of extirpation. The last observation of a Garita Skipperling in Minnesota was in 2007; searches in 2014 and several subsequent years have been unsuccessful. Additional survey work on this species is needed. Several programs and resources are available to land managers and landowners to help protect and manage remaining prairie parcels including the Native Prairie Bank Program, the Native Prairie Tax Exemption Program, and a prairie restoration handbook. Authors/RevisionsRobert P. Dana, Ph.D. (MNDNR), 2025 References and Additional InformationBird, C. D., G. J. Hilchie, N. G. Kondla, E. M. Pike, and F. A. H. Sperling. 1995. Alberta butterflies. The Provincial Museum of Alberta, Edmonton, Alberta. 349 pp. Cuthrell, D. L. 1991. The butterflies of Kittson and Roseau counties, Minnesota, with special emphasis on the Dakota Skipper (Hesperia dacotae) [Skinner]. Final report submitted to the Nongame Wildlife Program, Minnesota Department of Natural Resources. 48 pp. Klassen, P., A. R. Westwood, W. B. Preston, and W. B. McKillop. 1989. The butterflies of Manitoba. Manitoba Museum of Man and Nature, Winnipeg, Manitoba. 290 pp. Layberry, R. A., P. W. Hall, and J. D. LaFontaine. 1998. The butterflies of Canada. University of Toronto Press, Toronto, Ontario. 280 pp. + color plates. McCabe, T. L., and R. L. Post. 1977. Skippers (Hesperioidea) of North Dakota. North Dakota Insects Publication No. 11, Schafer-Post Series. Agricultural Experiment Station, University of North Dakota, Fargo, North Dakota. 70 pp. Opler, P. A., H. Pavulaan, R. E. Stanford, and M. Pogue, coordinators. 2006. Butterflies and moths of North America: Garita Skipperling (Oarisma garita). Bozeman, Montana: NBII Mountain Prairie Information Node. Royer, R. A. 1988. Butterflies of North Dakota: an atlas and guide. Science Monograph Number 1, Minot State University, Minot, North Dakota. 192 pp. Scott, J. A. 1986. The butterflies of North America: a natural history and field guide. Stanford University Press, Stanford, California. 583 pp. Swengel, A. B. 1998. Effects of management on butterfly abundance in tallgrass prairie and pine barrens. Biological Conservation 83(1):77-89. |