The Arctic Skipper is a member of the family Hesperiidae, the large worldwide family of butterflies known as skippers. In Washington there are 29 species of skippers, most of which are categorized in two subfamilies, the Pyrgine or “spreadwing” skippers, and the Hesperine or “grass” skippers. But there is one exception; the Arctic Skipper belongs to a third subfamily, the Heteropterinae. This subfamily has ties to the old world, indeed C. palaemon is a native resident in Eurasia as well as our area. Skippers in this subfamily often hold their wings outspread, similar to the spreadwing skippers, but the larvae feed on grasses, similar to the grass skippers.

Carterocephalus palaemon is an uncommon skipper found in the mountainous parts of Washington and Oregon, including the Cascades, Olympics and NE WA. Beyond Cascadia it is found in Alaska and much of Canada, extending south to California and the Colorado Rockies, also into the upper Midwest and New England. This circumpolar species is also found in Europe and east across N Eurasia to the Pacific. It occurs in moist, woodland mountain habitats from near sea level to 7000 feet, favoring forest clearings along riparian corridors. In our area populations are small and isolated and fluctuate. The flight period here is mid May-late July.

The Arctic Skipper is single-brooded. A diapausing mature larva was found in mid October in a rolled leaf nest on Phalaris arundinacea (Reed Canary Grass) near Leavenworth. It was in an upright tied leaf nest on the upper part of the grass near a blade tip; the nest was similar in appearance to that of the Woodland Skipper, except that it had fewer silk cross-ties; it was fully silk-lined on the inside and there was no wax. After overwintering, on Feb 9 the larva was removed from refrigeration and it pupated 5 days later without feeding; the adult eclosed 12 days later. Larval hosts are poorly documented but include Calamagrostis purpurascens (Purple Reedgrass), Bromus spp. and probably other grasses. Females lay their eggs singly on grass blades. Early instars pull together the edges of a grass blade forming a hollow open-ended tubular nest secured with silk cross ties. Feeding larvae often clip grass blades and the terminal 2-3 inch tips fall. Larger larvae require larger grass blades to construct nests; if only smaller blades are available they may tie several together. Carterocephalus palaemon has 5 instars and protection is based on concealment in nests, flinging frass and nocturnal feeding to avoid predators. The larvae at all stages are very slender, elongate and striped, and can be confused with only a few other Cascadia skippers. Thymelicus lineola has highly distinctive eggs and pupae, and L4-L5 have striped heads. In Oarisma garita the head capsule is greenish in all instars. The larvae of Amblyscirtes vialis differ in color in all instars and the pupae lack projections. The head capsule of Euphyes vestris larvae is distinctly marked and the pupae are black.

The adult Arctic Skipper is unmistakable with its strongly spotted wings and golden-brown colors and should not be confused with any other skipper in our area. Very little is known about this species in the US, including larval host grasses, natural enemies and other factors affecting abundance and distribution. Populations in Washington seem fairly volatile, and the species has been seen in only small numbers for the past several years in some of its normal haunts. Adults nectar readily on flowers and live for up to 3 weeks. Males perch ~3-4 feet above ground level, darting out in search of mates.

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