Pacific Northwest Moths

Identification

Adults

Gluphisia severa is a spring-flying, hoary, gray and ochre to olive, medium-sized to large moth (FW length 17–21 mm) that flies in forests during the spring and early summer.  The forewing shape is relatively long and apically pointed for the genus.  Most specimens are hoary dark gray, occasionally nearly black, and the median area of many females is commonly darker than the rest of the wing.  Patches of ochre to olive are found at the base, in the posterior median area, and as filling of the postmedian line and discal spot.  The antemedial and postmedial lines are usually dark, black and heavy in many females.  The discal spot is present in about half of individuals.  It is evident as the pale filling and lacks a dark outline.  The hindwings are slightly lighter gray than the forewing with a slightly expanded anal angle.  It is marked with a dark postmedian line, darkest at the anal angle where it is double, but lacks a discal spot.  The head and thorax are hoary dark gray.  The male antenna is bipectinate.

This species can be identified by its spring flight period, hoary dark gray color with patches of olive or ochre on the forewing, and a diffuse dark discal spot filled with the color of the patches.  It is closest in appearance to Gluphisia avimacula, a rare species only known from southern British Columbia in our region.  However, in G. severa, the forewing antemedial line is bent in the cell and the discal spot lacks a dark outline.  The antemedial line is nearly straight anterior to a bend near the anal vein and the pale discal spot is rimmed with black in G. avimacula.  Gluphisia severa is larger than G. septentrionis and has dark markings on the hindwing.  The hindwing of G. septentrionis is uniformly gray.  Gluphisia septentrionis is a smaller moth that flies later in the season, usually not beginning until the end of the flight of G. severa and peaking later in the summer.  It has less well-developed markings and lacks a discernible discal spot.

Larvae

The larva is smooth, slender, and bluish-green, with a very thin yellow stripe along each side and many small yellow spots. It is depicted by Miller et al. (2018).

Habitat

This species is common in coastal rainforests, mixed hardwood forests west of the Cascades, high elevation montane conifer forests in both the Cascades and Rocky Mountain region extending to the Blue Mountains.

Distribution

Pacific Northwest

Gluphisia severa occurs in forests throughout the Pacific Northwest as far north as north-central British Columbia.  It is not found in arid steppe habitats and is absent from much of the Columbia Basin, southeastern Oregon except on the larger mountains, and southern Idaho.

Global

This species occurs in western North America.  The range includes western Alberta, the northern half of California, and Nevada outside of the Northwest.

Life History

Larvae

This species is a foodplant specialist on Salicaceae, including both willows (Salix spp.) and cottonwoods (Populus spp.).

Adults

Adults are single brooded and occur in the spring.  Pacific Northwest records are from early March through June.

Economic Importance

None.

Literature

BugGuide

Miller et al. (2018)

Moth Photographers Group

Powell & Opler (2009)