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Montana Field Guide

Montana Field Guides

Common Roadside-Skipper - Amblyscirtes vialis

Native Species

Global Rank: G5
State Rank: S5

Agency Status


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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.2 cm. Wing fringes strongly checkered in buff and black. Uppersurface dark brown with tiny white spots; undersurface of forewing with apical violet or gray frosting, subapical spots wider at costal margin forming a white wedge, hindwing dark brown with violet or gray frosting on the outer third.

One flight; June to mid-July in the north and at high elevation, late May to June in most places, late March to mid-May in south, with partial second flight mid-June to early September in south (Scott 1986). May to September in one brood areas, April to August in two brood areas (Glassberg 2001). Late May to July in Canada (Layberry et al. 1998). Mid-May through July in Rocky Mountain states (Ferris and Brown 1981). Early May to late July in Colorado (Scott and Scott 1978; Scott and Epstein 1987), late May to early July in North Dakota (McCabe and Post 1976), late April to late August in Oregon and Washington (Pyle 2002), mid-April to late July in Oregon (Warren 2005), mid-May to mid-July in British Columbia (Threatful 1988; Guppy and Shepard 2001).

Diagnostic Characteristics
Best determined by a combination of wing fringes strongly checkered in buff and black, uppersurface and undersurface of forewing with subapical spots wider at costal margin forming a white wedge; undersurface of forewing and hindwing frosted with violet or gray on the apex or outer third.

Species Range
Montana Range Range Descriptions


Range Comments
British Columbia east across Canada to Gaspe Penensula and Nova Scotia, south to central California, northern New Mexico (avoiding desert southwest), northeast Texas, throughout east US to southern Florida (Opler and Wright 1999; Glassberg 2001); to 2400 m elevation in the Rocky Mountain states and Black Hills of South Dakota (Ferris and Brown 1981), 1829 m to 2743 m elevation in Colorado (Brown 1957; Scott and Scott 1978), near sea level to about 1341 m elevation in Oregon (Warren 2005), to 762 m elevation in southeastern British Columbia (Threatful 1988). In Montana, reported across the state from at least 22 counties (Kohler 1980; Stanford and Opler 1993; FLMNH Lepidopterists' Society database), to at least 1770 m elevation. Rare to locally uncommon in one brood areas (Glassberg 2001).

Observations in Montana Natural Heritage Program Database
Number of Observations: 12

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)


Woodland openings and edges, aspen meadows, grassy riparian areas, streambanks, forest roadsides (Scott 1986; Threatful 1988; Opler and Wright 1999; Glassberg 2001; Guppy and Shepard 2001; Pyle 2002). Habitat in Montana not described but probably similar.

Food Habits
Larval food plants are native and exotic grasses, including Agrostis, Avena, Bromus (multiple species), Cynodon, Elymus (multiple species), Phleum, Poa, Schizachne, and Uniola (Scott 1986, 1992; Layberry et al. 1998; Pyle 2002; Graves and Shapiro 2003; Warren 2005; James and Nunnallee 2011). Adults feed on flower nectar (including Apocynum, Astragalus, Fragaria, Geranium, Glecoma, Heterotheca, Jamesia, Lathyrus, Medicago, Mertensia, Oxytropis, Penstemon, Phlox, Rubus, Scutellaria, Taraxacum, Thermopsis, Trifolium, Verbena, Viola) and mud (Pyle 2002; Warren 2005; James and Nunnallee 2011; Scott 2014).

Reproductive Characteristics
Females lay eggs singly on the undersurface of host plant leaves, often < 50 cm above ground (Scott 1986, 1992). Eggs hatch in about 6 days (depending on temperature), develop rapidly from L1 instar to L5 instar in about 26 days, then take abut another 22 days to pupate. Adults eclose (emerge) from pupae in about 8-9 days (James and Nunnallee 2011). Larvae feed on host plant leaves mostly at night, L1-L4 instars live in silk-tied shelters of rolled leaves, L5 instar rests exposed or sheltered in partially rolled leaves; overwinter as L5 instar or possibly pupae (Scott 1979, 1986, 1992; Pyle 2002; James and Nunnallee 2011). Males perch throughout the day on or near ground in narrow and shrubby or wooded valley bottoms, forest openings, waiting for passing females (Scott 1975b, 1986; Warren 2005; James and Nunnallee 2011).

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Citation for data on this website:
Common Roadside-Skipper — Amblyscirtes vialis.  Montana Field Guide.  .  Retrieved on , from