Pleromella opter Dyar, 1921
WA : Skamania Co.
SE Big Lava Bed, 2112 ft
May 12, 2005, L. G. Crabo.
Specimen courtesy of LGCC
Photograph copyright: Merrill A. Peterson
Pleromella opter is a spring-flying smooth gray medium-sized noctuid moth (FW length 16 - 17 mm) with markings limited to dark veins that flies in dry forests with manzanita or bearberry in western Oregon and Washington during the spring. The forewing apex is slightly pointed. The color is nearly uniform steel-gray, slightly darker gray in an oblique area near the apex. The veins are thin and dark, with a similar thin black basal dash. The transverse lines and spots are absent except for a series of dark marks on the veins on the posterior two-thirds of the postmedial line. The fringe is the same color as the rest of the wing. The hindwing is light whitish gray in males, light gray in females, with a slight during of gray near the margin and dark veins. The hindwing fringe is slightly lighter than the adjacent margin. The head and thorax are gray with a slight median line on the collar and anterior thorax. The male antenna is widely bipectinate and the female antenna is biserrate.
This species is not likely to be confused with other spring-flying moths. It resembles Pleromelloida cinerea, but this species flies in the fall and the two species do not occur together at the same time of year.
This species is widely distributed in dry brushlands and forests with manzanita along the West Coast. In the Pacific Northwest, it is particularly common in brushlands, oak woodlands, and mixed hardwood forests with manzanitas at low elevations in southwestern Oregon. It is also common in dry mixed hardwood-conifer forests along the west slope of the Cascades, and in open ponderosa pine forests with manzanitas along the east slope of the Cascades at middle elevations.
The Northwest range of this species appears to be limited to the Siskiyou Mountains of southwestern Oregon and the Cascade Range north to southern British Columbia.
Pleromella opter is also found in California to near the border with Mexico.
This species is a foodplant specialist feeding on manzanitas (Arctostaphylos spp.) in the Ericaceae.
Adults are on the wing in the spring, with most records in our region from May. It is nocturnal and comes to lights.
Miller & Hammond (2003)
Powell & Opler (2009)