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Montana Field Guides

Sagebrush Checkerspot - Chlosyne acastus


Global Rank: G4G5
State Rank: S4

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General Description
[From Ferris and Brown 1981; Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002] Forewing 1.8-2.4 cm. Uppersurface checkered pale orange (males) to bright orange with black lines and smudges, postmedian bands on wings sometimes red-orange, sometimes orange bands alternate with yellow or red rows; undersurface of hindwing very light, banded with red-orange alternating with large oval spots flat white to pearly white, sharply crescent-edged in black, median band white, submarginal white band with 5 orange spots.

Phenology
One flight in Colorado, mid-May to mid-June; two flights in the north, June to August; three flights in the south, May to September (Scott 1986). March to May in the south with partial second flight August to October; elsewhere mid-May to mid-July (Glassberg 2001). Late May to late June in Colorado (Scott and Scott 1978); mid-April to mid-June in Oregon (Warren 2005); late April to late June in Oregon and Washington (Pyle 2002); early April to early July in Washington, mid-April to mid-June in Oregon (James and Nunnallee 2011).

Diagnostic Characteristics
Similar to Chlosyne whitneyi (Rockslide Checkerspot); best determined by combination of habitat, undersurface of hindwing very light, banded with red-orange alternating with large oval spots flat white to pearly white, sharply crescent-edged in black, median band white, submarginal white band with 5 orange spots.

Species Range
Montana Range

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Range Comments
Southern Alberta and southern Saskatchewan south through parts of the western Dakotas to the western half of Colorado and New Mexico, and extreme northern Mexico; also west through Arizona, Utah, Nevada to eastern California, with small populations in Idaho, Oregon, Washington (Scott 1986; Opler and Wright 1999; Glassberg 2001; Pyle 2002); 1860 m elevation to at least 2590 m in Colorado (Brown 1957; Scott and Scott 1978); 427 m elevation to 533 m in Washington (James and Nunnallee 2011); 30 m elevation to 1829 m in Oregon (Warren 2005). In Montana, reported across the state mostly east of the continental divide, Flathead County the exception (Kohler 1980; Stanford and Opler 1993). Mainly common, but locally rare in the northeastern part of range (Glassberg 2001).

Migration
Non-migratory.

Habitat
Aridlands, sagebrush steppe, sagebrush-juniper woodland, stream beds, oak or pinyon-juniper woodland (Ferris and Brown 1981; Opler and Wright 1999; Glassberg 2001; Pyle 2002). Pine woodland and canyons at lower elevations in Greater Yellowstone Ecosystem (Debinski and Pritchard 2002).

Food Habits
Larval food plants include Acamptopappus, Chrysothamnus, Erigeron, Eucephalus, Machaeranthera, and Symphyotrichum (Scott and Scott 1978; Scott 1986, 2006; James and Nunnallee 2011). Adults feed on flower nectar (many species, including Chrysothamnus, Erysimum, Prunus, Schoenocrambe) and mud (Warren 2005; Scott 2014).

Reproductive Characteristics
Females lay eggs in clusters on the undersides of host plant leaves, sometimes on flower buds, sometimes on inert surfaces nearby (Scott 1986, 2006; James and Nunnallee 2011). Eggs hatch in about 6 days (depending on temperature). L1 and L2 instars last about 6 days each, L3 instar leaves host plant and diapauses about 30 days post egg-hatch; L4 instar sometimes reached about 19 days post egg-hatch, molt to L5 in about 6 days, and diapause as L5 instar. Pupation by L5 instar occurs in about 11 days, adults eclose (emerge from pupae) in about 18 days. L1 and L2 instars gregarious, build only thin silk nest; postdiapause larvae solitary, feed during day, rest openly (James and Nunnallee 2011). Males territorial, perch and sometimes patrol throughout the day in dry washes, gullies, paths and trails, seeking females (Scott 1975; James and Nunnallee 2011).

References
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Citation for data on this website:
Sagebrush Checkerspot — Chlosyne acastus.  Montana Field Guide.  .  Retrieved on , from