|scientific name Digrammia neptaria |
common name Dark-bordered Granite
Occurs in dry open jack pine and other forest; possibly also other xeric wooded habitats.
Mid June to late September; double brooded in the south.
Ground colour light grey with some dark grey speckling, particularly on the hindwing. Nearly straight two-toned AM and PM lines, the AM line usually less distinct. Faint median line and a well-defined discal spot. Similar to the faintly-marked form of D. rippertaria, but rippertaria has a two-toned, less sinuous PM line. D. mellistrigata is smaller overall, and the PM line has a sharp break near the costa and angles back toward the wing base. The occasional specimen may lack the wing markings altogether.
The immature stages are described by McGuffin (1972). Pupae of the second generation hatch in about 12 days. Adults come to light. Although the larval hosts are widespread, this is an uncommon and local insect in Alberta, and is apparently absent from much of the central forested regions. Given this species supposed larval host preference for such widespread plants as poplars and willows, the distribution and occurrence of neptaria is enigmatic: it ranges throughout most of Canada, yet in Alberta it appears to be absent (or at least very localized) throughout most of the central part of the province, having been recorded from Medicine Hat and Crowsnest Pass in the south, then again near the Richardson River Dunes in the extreme northeast. The extreme northern records may in fact be isolated populations in the xeric habitat of the Athabasca sand dunes and Peace River grasslands in Alberta, and the Atlin area in NW BC. Forbes (1948) also commented on neptaria's rarity in New England, and suggested it may be restricted to sand dune habitats. Occurs on pine barrens in Nova Scotia (Ferguson 1954).
No obvious concerns.
Larvae feed on willows (Salix) and poplars (Populus) (McGuffin 1972).
Yukon and southwestern NWT to Newfoundland, south to California and New Hampshire (McGuffin 1972).
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