Bryotropha galbanella Zeller 1839

Bryotropha galbanella (Zeller, 1839)

(figs. 7, 8, 22, 23, 37, 45, 55, 76)

Gelechia galbanella Zeller, 1839: 200.

Gelechia angustella Heinemann, 1870: 217.

Gelechia ilmatariella Hoffmann, 1893: 138.

Gelechia galbanella var. (et ab.) griseella Caradja, 1920: 99. Gelechia galbanella var. haareki Strand, 1920: 64. Gelechia fusconigratella Palm, 1947: 40.

Diagnosis. Large grayish species with a whitish fascia and distinct blackish stigmata.

Description. Adult (figs. 7, 8). Wingspan 15–16 mm (male). Labial palpus without a brush underneath segment 2 and with segment 3 slightly shorter than segment 2; white, speckled fuscous on the inner side, fuscous brown on the outer side. Antenna fuscous indistinctly ringed with ochreous. Head with frons creamy white, head thorax and tegula concolorous with forewing. Forewing dark brownish gray, suffused with creamy white; base darkened at costa; second plical and discal stigmata very distinct, first plical less clear; first discal beyond second plical; costal and tornal patches whitish, fused to form a distinct, angulated fascia; termen lined with patches of blackish scales; cilia dark gray with one or several ciliary lines. Hindwing uniformly fuscous gray; cilia concolorous.

Variation. The color of the forewing can vary from pale gray (strong suffusion with creamy white scales) to dark gray (weak suffusion with creamy white scales). In the latter forms the stigmata are rather indistinct. In the Palaearctic dark forms of B. galbanella only occur in the extreme north.

Similar species. The grayish tone, which is apparent even in very dark forms (fig. 8), separates B. galbanella from B. gemella, which always has a clear brownish tone.

Male genitalia (figs. 22, 23, 37, 55). Uncus broad, subrectangular. Socius with 5 or more setae. Gnathos slender, clearly thickened at bend, base with microtrichia. Thornshield triangular, without spikes. Vinculum covered with microtrichia. Apex of aedeagus with a very short (<100 µm) whip (arrowhead in fig. 23). The aedeagus with its short whip immediately separates B. galbanella from B. gemella whose aedeagus has a much longer whip (>200 µm) (arrowhead in fig. 25).

Female genitalia (fig. 45) (based on Palaearctic material). Segment VIII with small triangular lamella postvaginalis and many long needle­shaped microtrichia. Distal end of the ventral groove marked by a bulbous structure extending slightly beyond the distal rim of segment VIII. Ventral groove very distinct, with undulating margins. Dorsal side of segment VIII weakly concave. Signum large and clearly elongate, with two transverse folds, and densely covered with spikes. Similar to B. gemella, q.v.

Biology. Description according to Heckford & Sterling (2003). Larva with head and prothoracic plate black, body reddish brown, anal plate dark brown. In Europe the host plants include Dicranum scoparium (Hedw.) (Dicranaceae) and Homalothecium lutescens (Hedw.) H. Rob (Brachytheciaceae). The pupa is yellowish brown within a flimsy cocoon.

Adults are often disturbed during the day. In Europe (Denmark) they are most common in Pinus and Larix forests with the ground extensively covered with moss. Adults were collected from late June to early July indicating one generation only.

Distribution (fig. 76). Only known from a few localities in Alaska and extreme north­western Canada. Elsewhere this species is found from Europe to Japan.

Material examined. 5 ɗ — CANADA, Yukon Territory: 1 ɗ: 31 km E Dawson City, marsh/Salix/Betula bush, 7.vii.1994, evening, L. Kaila leg. (ZMUH). — USA, Alaska: 2 ɗ: 4 mi. N. Cantwell, 2000–2200 ft., 27.vi.1979, P. Opler & J. Powell, gen. slide AR 0 721 (EME); 1 ɗ: Steese Hwy, 63 mi. NE Fox, 2.vii.1979, P. Opler & J. Powell, gen. slide AR 0 722 (EME); 1 ɗ: 10 mi. SE Houston, 26.vi.1979, P. Opler & J. Powell (EME).