Pacific Northwest Moths

Identification

Adults

Autographa rubidus is a medium-sized moth (FW 15 - 17 mm) that flies in forests in southern British Columbia during the summer. It has a mottled, slightly reddish-brown color and a curved sickle-shaped silver stigma on the mid-wing. The forewings have a somewhat pointed apex and a small flange at the anal angle. The color is mottled reddish gray-brown, with a slight violent tint on the lighter areas. The median area, especially the mid-portion near the stigma, is darker and more homogeneous dark brown, with rusty red-brown in the fold near the tip of the stigma.  The anterior half of the distal wing is darker gray, especially a shade preceding the subterminal line.  The thin, silvery-white stigma curves across most of the median area and is usually sharply bent to form a sickle-shape. A greasy sheen is apparent on the distal wing in the region of the fold. The basal, antemedial, and postmedial lines are dark brown, double and filled with a light shade of the ground color. The basal line is present on the anterior half of the wing and is associated with a small dark dot near the wing base. The antemedial line is strongly oblique toward the distal limb of the stigma on the costa, then offset to the proximal limb at the cubital vein, coursing in a smooth oblique curve toward the base. The postmedial line is faint on the anterior two-thirds of the wing, coursing obliquely from the costa to the fold where it is focally drawn toward the base and bent posteriorly, the posterior portion is slightly irregular and convex toward the outer margin. The subterminal line is is evident as the transition from dark lateral subterminal area to the lighter terminal area. It is irregular, approaching the outer margin below the apex and as a W-mark surrounding vein CuA1. The terminal line is dark brown medially and pale rosy gray laterally. The fringe is pale violet gray with faint to moderate dark gray checkering. The orbicular and reniform spots are thin and pale. The orbicular spot is barely visible anterior to the basal stigma. The reniform spot is hour-glass-shaped, often with a thin silver outline in the posterior portion. The hindwing is light gray-tan with darker gray discal bar, veins, postmedial line, and marginal band with an indistinct medial border. A thin, dark terminal line is present at the base of the fringe which is buff to pinkish off-white with ill-defined dark gray basal checkering. The head and thorax are mottled warm brown with thin gray margins on the collar, tegulae, and the tips of long tufts on the posterior median thorax. Additional tufts are present on several abdominal segments. The male antenna is filiform.

This species can be identified by the combination of a mottled reddish forewing, a thin looped stigma, and tan and gray hindwing. Other red-brown members of the subfamily Plusiinae have different-shaped stigmas or yellow and black hindwings. Autographa flagellum, another species that occurs in British Columbia, has a long looping stigma but is violet-gray and dark brown rather than red-brown like A. rubidus.

Larvae

Larva is smooth and has only two pairs of abdominal prolegs.  The color is green with three pairs of thin white lines on the back and a white or light-yellow lateral line. It is illustrated by Lafontaine & Poole (1991).

Habitat

This species is widely distributed across Canada in mixed hardwood-conifer forests.  It appears to be restricted to cool, boreal forests.

Distribution

Pacific Northwest

Autographa rubidus has only been collected in British Columbia in our region. Its range extends south to the edge of the Cariboo Plateau near Clinton.

Global

Found from eastern British Columbia east to Newfoundland in Canada. In the United States it occurs in the Great Lakes and New England.

Life History

Larvae

This species is probably a generalist feeding on a variety of herbaceous plants. Lafontaine & Poole (1991) indicate that the larva accepted dandelion (Taraxacum officinale L.) in the laboratory.

Adults

Adults fly from late June to mid July in British Columbia and Alberta.

Economic Importance

None.

Literature

Eichlin & Cunningham (1978)

Lafontaine & Poole (1991)

Moth Photographers Group

University of Alberta Strickland Museum