Lasionycta leucocycla

Lasionycta leucocycla (Staudinger)

Figs 19–29, 146, 147, 203. Map 6

Anarta leucocycla Staudinger, 1857: 296.

Lasiestra leucocycla; McDunnough 1938: 71.

Lasionycta leucocycla; Lafontaine et al. 1986: 257.

Anarta leucocycla var. moeschleri Staudinger, 1901; in Staudinger and Rebel 1901: 219. Anarta staudingeri ab. moeschleri; Hampson 1905: 38.

Anarta staudingeri moeschleri; Warren 1912: 252.

Anarta leucocycla moeschleri; McDunnough 1925: 308.

Lasiestra leucocycla moeschleri; McDunnough 1938: 71.

Lasionycta leucocycla moeschleri; Lafontaine et al. 1986: 257.

Anarta hampa Smith, 1908: 111.

Lasiestra leucocycla hampa; McDunnough 1938: 71.

Lasionycta leucocycla hampa; Lafontaine et al. 1986: 257.

Anarta leucocycla albertensis McDunnough, 1925: 307.

Lasiestra leucocycla albertensis; McDunnough 1938: 72.

Lasionycta leucocycla albertensis; Lafontaine et al. 1986: 257.

Lasionycta leucocycla magadanensis Kononenko and Lafontaine, 1986: 260. Extralimital.

Type material. Anarta leucocycla: two syntypes [ZMHB, not examined]. Type locality: Greenland. Anarta leucocycla var. moeschleri: holotype [ZMHB, not examined].Type locality: Labrador. Anarta hampa: lectotype ♁ [AMNH, examined]. Type locality: White Mountains, New Hampshire. Lectotype male designated by Todd (1982: 96). Anarta leucocycla albertensis: holotype ♁ [CNC, examined]. Type locality: Nordegg, Alberta.

Diagnosis. Lasionycta leucocycla is a small (forewing length 10–12 mm, males; 11–14 mm, females) widespread species from the arctic, subarctic, and northern Cordillera. It has a narrow biserrate male antenna, a dark-gray or gray-brown forewing with a pale ocellate orbicular spot, off-white to yellow hindwing, and the ventral hindwing postmedial line is faint or absent. The male and female genitalia of L. leucocycla are typical for the species group and are of limited use for diagnosis.

All L. leucocycla from east of Hudson Bay are distinguished from L. flanda, which occurs in Newfoundland and Labrador, by the white hindwings and ellipsoid eyes (hindwing yellow brown or whitish brown and eye rounded in L. flanda). Arctic L. leucocycla from west of Hudson Bay have white hindwings and are most likely to be confused with L. staudingeri, however L. staudingeri lacks an ocellus in the orbicu- lar spot and is easily distinguished by genitalia in both sexes as described in the L. leucocycla species-group key. Other western populations of L. leucocycla have yellow hindwings and are likely to be confused only with L. illima. Lasionycta illima and the other western species in the L. leucocycla sub-group with pale hindwings (L. poca and L. frigida) have narrowly bipectinate antennae. Th ese three species also have a dark ventral hindwing postmedial line, nearly absent in L. leucocycla.

Eight similar CO1 haplotypes were identified in L. leucocycla (Fig. 248). These differ by up to 1.15 % but overlap significantly with those of L. coracina, L. anthracina, L. frigida, and L. flanda. Th e CO1 sequences of all populations of L. leucocycla and L. poca differ by at least 2.2 %.

Distribution and biology. Lasionycta leucocycla is Holarctic (Lafontaine et al. 1986). In North America it occurs in the eastern arctic from Greenland southward to Labrador and northern Quebec, with a disjunct southern population in the White Mountains of New Hampshire. Its range extends westward across northern Nunavut and Northwest Territories to Yukon and Alaska, with southern extensions on the west coast of Hudson Bay and in the Rocky Mountains to the Beartooth Plateau on the Montana-Wyoming border. It flies over dry tundra. Most populations are strictly diurnal and have reduced eyes. Subspecies L. l. hampa from New England has slightly larger eyes but records suggest that it is diurnal. Lasionycta leucocycla has been collected from mid-June through August across its range.

Lasionycta leucocycla feeds on nectar at Silene acaulis, Mertensia paniculata (Ait.) G. Don (Boraginaceae), and a Senecio species, probably S. lugens Richardson (Asteraceae) (BC. Schmidt, pers. comm.).

The early stages were described by MacKay (1972). Lafontaine et al. (1986) compared the larvae of L. leucocycla and L. staudingeri.

Remarks. Lasionycta leucocycla magadanensis Kononenko and Lafontaine, which has a pale white hindwing and small eyes, is the only exclusively Eurasian taxon that belongs with L. leucocycla. Lasionycta dovrensis (Wocke) stat. rev. has large eyes and dark hindwing and flies near midnight, not during the day (Ahola and Silvonen 2008) suggesting strongly that it is a distinct species. The taxon altaica (Staudinger) was not examined but is probably best considered a subspecies of L. dovrensis based on similar size, habitus, and eyes.

Geographical variation. The North American populations of L. leucocycla are arranged in four subspecies.