Sphinx vashti Strecker, 1878

MONA 7803

Vashti Sphinx Moth

Identification

Adults

Sphinx vashti is a common very large moth (FW length 32–37 mm) that flies in a variety of habitats during the spring and early summer. The forewing is long and pointed as in most sphinx moths. It is usually dark gray in the Pacific Northwest, lighter gray in the Great Plains, with lighter gray anterior base, apex, and terminal area and nearly sooty blackish gray posterior base. A series of longitudinal black dashes located between the veins extend obliquely from the lower median area to the apex. The subterminal line is black bordered laterally by whitish grays and is smoothly convex or weakly scalloped. The hindwings are small and ovoid. They are stribed obliquely with whitish gray and black, usually with a thin light area between the broad black marginal band and the fringe. No spots are evident on either wing. The fringes of both wings are gray, sometimes checkered lighter gray on the hindwing. The thorax is variable, usually dark gray but occasionally lighter gray. The tegulae are black and dark gray medially, only evident in light specimens, and light gray adjacent to the wing bases. The dorsal abdomen is gray with a black median stripe, and the dorsolaterally portion is striped with black and silvery white on each segment. The antenna is whitish gray, club-like.

This species can be associated with the genus sphinx by its very large size, typical wing-shape, clubbed antenna, and pattern of gray, white, and black. It is most likely to be confused with Sphinx perelegans, but it lacks the smooth component of the subterminal line of S. vashti. Sphinx vashti is larger than Sphinx sequoiae, a species that occurs near junipers in Oregon. It is most readily distinguished from S. vashti by its solid gray hindwing.

The synonym Sphinx mordecai McDunnough was described from Penticton, British Columbia.

Habitat

This species is common to abundant in all habitats throughout the Pacific Northwest including coastal rainforests and mixed hardwood forests at low elevations west of the Cascades, montane coniferous forests at high elevations in the Cascades and Rocky Mountain regions, and in both juniper woodlands and sagebrush rangelands east of the Cascades at middle to low elevations. 

Distribution

Pacific Northwest

This common sphinx moth is found throughout the Pacific Northwest as far north as south-central British Columbia.  It does not occur in the most arid steppe habitats but is abundant in adjacent foothills and riparian areas.  It is uncommon in western Washington.

Global

The range of this species extends east from the Northwest and central Alberta to Lake Michigan. The southern limits of its range are Oklahoma, northern Arizona, and southern California.

Life History

Larvae

This species appears to be a foodplant specialist feeding on snowberry (Symphoricarpos spp.) in the Caprifoliaceae.

Adults

Adults have been collected from April through July in our area.  This species is nocturnal and comes to light.

Economic Importance

None.

Literature

BugGuide

Moth Photographers Group

Powell & Opler (2009)

Tuttle (2007)