Clostera brucei (Hy. Edwards, 1885)
WA : Okanogan Co.
Tiffany Mdws., 6381 ft
August 07, 1993, L. & A. Crabo.
Specimen courtesy of LGCC
Photograph copyright: Merrill A. Peterson
Clostera brucei is a small (FW length 12–14 mm) mottled dark blue-gray Clostera that is widely distributed in the Northwest but is sporadic and rarely collected. Like other members of the genus it has pale transverse lines, and the postmedial line forms a white mark at the costa that abuts a red-brown spot in the postmedial area. The head and thorax are black and the rest of the body is dark gray. The antennae are bipectinate and the tip of the male abdomen is tufted.
This species can be distinguished from our other gray Clostera species by the orientation of the pale lines in the median area. The antemedial and median lines do not touch in C. brucei. In Clostera apicalis and Clostera strigosa the lines are partially fused producing and oblique line from the medial third of the costa to the distal third of the posterior margin.
This is primarily a Rocky Mountain species that appears to be most common in Colorado in quaking aspen forests. It occurs rarely in conifer forests at low to middle elevations in the Northwest.
In the Pacific Northwest Clostera brucei is found most commonly in central and southern British Columbia as well as in adjacent northern Washington and Idaho. Scattered records from west of the Cascades extend south to west-central Oregon. This moth has also been found in southeastern Idaho.
This moth occupies a large portion of North America. It is found from Maine to New Jersey in the east, extending west to the West Coast. The range includes Colorado in the Rocky Mountains as well as California.
No specific foodplants records are available. It probably eats woody plants in the family Salicaceae, and may prefer quaking aspen (Populus tremuloides) based upon the habitat association in Colorado.
Adults have been found from late spring to summer in our region, with most records from June and July. The moth is nocturnal and comes to light.