The Dun Skipper is a member of the family Hesperiidae, the large worldwide family of butterflies known as skippers. In Washington State most of our skippers fit into two subfamilies, the Pyrgine or “spreadwing” skippers, and the Hesperine or “grass” skippers. In Washington there are 29 species of skippers, 17 of which are grass (monocot) skippers. The grass skippers include the genus Euphyes, which is represented by only a single species in Washington, the Dun Skipper.

Like all grass skippers the Dun Skipper often holds its wings in two planes, the hind wings horizontal and the forewings elevated at an angle. A common alternate position is with both wings held together over the back, with only the ventral side visible. Euphyes vestris is a relatively uncommon skipper, found across a significant range but generally only in isolated small pockets. The larval food plants of the Dun Skipper include various species of sedges, thus this butterfly is typically found in damp ditch or marsh-edge habitats where sedges thrive. The Dun Skipper is arguably our drabest butterfly, with wings toned in dull golden brown with diffused grayish borders. Ventrally the wings are virtually unmarked, while dorsally on the forewing the female has a few small white spots and the male bears a dark stigma streak. Euphyes vestris is single-brooded and flies in midsummer, with flight records restricted to the months of June and July.

In Washington State the Dun Skipper is found mostly west of the Cascade Mountains, but also occurs in small isolated pockets in Kittitas and Pend Oreille Counties. Beyond Washington State a similar pattern continues along the west coast from BC to California, with most populations west of the mountains, however the species also occurs widely across the US east of the Rocky Mountains.

Euphyes vestris overwinters in the chrysalis stage. Adults eclose beginning in early June, and they apparently mate fairly soon after eclosure. In captivity a female from Kittitas County oviposited about June 27, and the eggs

began hatching around July 6th. Large, stark white, dome­ shaped eggs are laid singly on the contrasting dark green sedge leaves. After hatching and no later than the second instar the larvae create tied nests by pulling together the edges of a sedge leaf and stitching them together with silk threads. The larva lives in such nests throughout development, venturing out to feed apparently at night, and creating new nests as needed for its increasing size. The nests are constructed with one end open for easy access, but just prior to pupation both ends of the nest are silked closed, and the larva surrounds itself with large amounts of a white waxy secretion. Pupation occurs within the waxy material. In captivity the entire larval development from egg hatch to pupation was accomplished in 43 days, which is moderately rapid for a monocot-feeder. The chryaslis remains enclosed in its nest until the following spring when the next generation adult will hatch.

In the wild, larvae can occasionally be found by diligently searching sedges where populations of Euphyes are known to occur. The larvae may occur somewhat later in the season than indicated in the captive rearing notes above; late August and perhaps even early September might be the best time to find late instar wild larvae. The larvae can be found near the base of the sedge leaves where adjacent sedges are nearly touching, providing cover and protection; also one could search for constructed shelters.

Dun Skippers are readily attracted to nectar sources, such as blooming milkweed in eastern Washington habitats. The flight is generally inconspicuous and very low to the ground, and movements can be rapid and darting. As adults rarely venture far from their sedge host plants, look for Euphyes where sedges grow in close proximity to a good nectar source; roadside ditches often provide such habitats. While adults are indeed drably colored these perky little skippers are always a welcome find for butterfliers.

Photos by Dave Nunnallee

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