Identification
Adult: forewing heavily mottled with black and brown; discal spot white or pale yellow; PM line with shallow sinus near midwing; outer margin scalloped
hindwing light gray with pale-bordered dark median line, row of small black terminal dots, and scalloped outer margin
Larva: an excellent twig mimic; body variably yellowish and brownish with dark middorsal stripe and scattered dark warts; head angular, dark brown, with light brown swollen lobes and light brown streak across front; inconspicuous pair of narrow meandering dark brown subdorsal stripes; spiracles dark brown; third abdominal segment with prominent spiracular swelling and large dark tubercle below
[adapted from description at forestpests.org]
Range
Newfoundland to British Columbia, and coast to coast in northern United States, south in the east to South Carolina, south in the west to California
Habitat
coniferous and mixedwood forests; adults are nocturnal and attracted to light
Season
adults fly from May to July
larvae from July to September; pupation occurs in September
Food
larvae feed on conifers [Balsam Fir (Abies balsamea) and other firs in the west, Douglas-fir (Pseudotsuga menziesii), hemlock, pine, spruce, tamarack] but have also been reported on broad-leaved trees and shrubs [alder, birch, buffaloberry, meadowsweet, poplar, willow]
Life Cycle
one generation per year; overwinters as a pupa in soil or debris
See Also
Hubner's Pero (
P. ancetaria) is similar but, in Canada, occurs only in Ontario and Quebec (
compare images of both species)
other species of
Pero are also similar but usually have less dark mottling, a wavier PM line, and/or less scalloped outer margins; ID best determined by genitalic examination or in some cases, geographic distribution (
compare adult images of several other species, and note their distribution in the last Internet Reference below)
Internet References
live adult images by various photographers (Moth Photographers Group)
adult images (Larry Line, Maryland)
description of adult plus habitat, food plants, flight season, biology, distribution (Strickland Entomological Museum, U. of Alberta)
live larva image plus description, food plants, seasonality, biology, life cycle (C.T. Maier et al, USDA Forest Service, forestpests.org)
live larva images plus description, food plants, seasonality, biology (Canadian Forest Service)
food plants; PDF doc plus flight season and life cycle (Macrolepidoptera of Mont Saint-Hilaire Region, McGill U., Quebec)
common name reference plus flight season and food plants (Ohio State U.)
presence in South Carolina; county map (John Snyder, Furman U., South Carolina)
presence in California; list (U. of California at Berkeley)
distribution in Canada list of provinces (CBIF)
Contributed by
Robin McLeod on 22 January, 2006 - 12:39pm
Last updated 22 January, 2006 - 4:43pm
