Pacific Northwest Moths

Identification

Adults

Schinia acutilinea is a common, small (FW length 11 - 15 mm) moth that flies in sage steppe during the fall. It has a forewing pattern of light tan or gray-tan and gray separated by wide white lines, and a white and gray hindwing. The median and terminal areas are tan, light gray-brown, or gray, whiter in the cell through the reniform spot to the postmedial line. The basal wing near the antemedial line and the subterminal area are darker gray, brown-gray, or, least commonly, dark tan. The wing base is lighter white on the mid-wing, with a diffuse dark dash below the cubital vein. The antemedial and postmedial lines are black with broad white components adjacent to the median area. The antemedial line is smooth, very strongly excurved toward the outer margin with apex on the mid-wing. The postmedial line is smooth or slightly scalloped, convex toward the outer margin opposite the cell with the apex close to or touching the subterminal line, then oblique toward the base to the trailing margin, usually slightly concave toward the base. The subterminal line is white, irregular on the medial side and smoother toward the outer margin, drawn toward the base opposite the cell and above the trailing margin. The fringe is pale gray to white, often weakly checkered with light gray. The orbicular spot is a small gray spot or absent. The reniform spot is weakly figure-eight-shaped, pale gray. Other lines and spots are absent. The hindwing is white with dark gray bar-like discal spot that is slightly wider posteriorly. The lateral margin is gray with a complete submarginal line and a lateral marginal band resulting in a pale area near the posterior margin. The head and thorax are light gray-tan. The male antenna is filiform.

Pacific Northwest specimens of S. acutilinea can be recognized by the pattern of wide white lines on the forewing separating gray-tan and gray areas and white hindwing with patchy gray marginal areas. The most similar fall-flying moth is Schinia walsinghami, but these species are readily distinguishable by color and pattern. It is a warm orange-brown color and lacks the patchy pattern on the distal hindwing of S. acutilinea.

Habitat

This species is widely distributed on dry rangelands throughout much of western North America.  In the Pacific Northwest, it is common to abundant on dry sagebrush steppe and in juniper and pine woodlands at low to middle elevations east of the Cascades.

Distribution

Pacific Northwest

Schinia acutilinea is found in the dry interior regions of the Northwest as far north as southern British Columbia. It is common in the Columbia Basin, southeastern Oregon, and southern Idaho.

Global

Schinia acutilinea is found throughout much of the West from southern British Columbia, Alberta, and Saskatchewan south to northern New Mexico, southern Utah, and southern California.

Life History

Larvae

This species is a foodplant specialist feeding on the flowers of big sagebrush (Artemisia tridentata) in the Asteraceae.

Adults

Adults fly late in the year and have been collected during August and September in the Northwest. They are predominantly nocturnal and are attracted to light, but adults are often found taking nectar at the flowers of rabbitbrush in late afternoon and evening.

Economic Importance

None.

Literature

BugGuide

Crumb (1956)

Hardwick (1996)

Moth Photographers Group

Powell & Opler (2009)