Pacific Northwest Moths

Identification

Adults

Lasionycta frigida is a small (FW length 12–13 mm) gray noctuid moth with black-banded off-white hindwings that is likely to occur in northern British Columbia during June and July. The forewing is slightly mottled powdery medium-dark gray with white-filled basal, antemedial, and postmedial lines. These lines are double, black. The basal and antemedial lines contribute to the mottled appearance of the wing base, but the strongly dentate postmedial line is a distinct feature of the distal wing pattern. The sinuous subterminal line is pale, most evident as a transition between darker subterminal and lighter terminal areas. The fringe is strongly checkered white and black. The orbicular spot is the most prominent spot, round or slightly ovoid, black filled with the ground color. The claviform and reniform spots are variable. When visible the reniform spot is dark gray to black, filled with white peripherally and the ground color centrally. The subterminal line is preceded by a dark shade, loosely arranged into chevrons. The terminal line is thin, black. The hindwing is dull off-white with moderate suffusion of gray scales, elongate dark gray discal spot, thin but complete subterminal line, and wide dark gray marginal band. The hindwing fringe is white with a gray base. The ventral hindwing is similar in color to the dorsum, with thin incomplete postmedial band and weak marginal band. The head and thorax are similar to the forewing in color. The male antenna is biserrate. The eye is covered in thin hairs.

Several small Lasionycta species found near the Yukon-British Columbia border are closely similar. Lasionycta frigida has on off-white hindwing with a relatively thin postmedial line on the underside of the hindwing. Other species have a yellow hindwing (Lasionycta leucocycla albertensis and too a lesser extent Lasionycta illima), a ventral hindwing with a thick black postmedial line (L. illima), or a white hindwing with black basal suffusion (Lasionycta staudingeri). Lasionycta leucocycla and L. staudingeri are alpine species that fly above timberline, whereas L. frigida flies in boreal forest in southwestern Yukon. The habitat of L. illima is poorly known.

Lasionycta frigida and L. illima are known from very few specimens. It is possible that they represent extreme forms of the same species rather than two distinct species.

Larvae

Habitat

Lasionycta frigida flies in open forests in southwestern Yukon and subalpine forest in Alberta.

Distribution

Pacific Northwest

This species is known from western Alberta and southwestern Yukon Territory. Given this, it must also occur in intervening British Columbia but it has yet to be found there.

Global

Lasionycta frigida has a limited distribution. It was only known from the Rocky Mountains of Alberta near Cadomin and Nordegg until it was discovered in southwestern Yukon Territory in 2017.

Life History

Larvae

The early stages are unknown.

Adults

Adults fly during early to mid-summer. It has been collected in late June in Yukon and during July in Alberta. Adults are predominantly nocturnal and come to lights in regions where it is sufficiently dark to light trap, but occasionally fly during the day. A series of this moth was collected in malaise traps near Kluane Lake, Yukon Territory.

Economic Importance

None.

Literature

Crabo LG, Lafontaine JD. 2009. A revision of Lasionycta Aurivillius (Lepidoptera, Noctuidae) for North America and notes on Eurasian species, with descriptions of 17 new species, 6 new subspecies, a new genus, and two new species of Tricholita Grote. ZooKeys 30: 1–156.

Moth Photographers Group