Cottonwood Dagger Moth

Uncommon in Alberta, but a widespread species. No reason for concern.

In Alberta adults have been collected from late May through July.

Throughout much of eastern North America and west across southern Canada to Vancouver Island and southward. In Alberta it has been collected across the southern half of the Boreal forest, in the foothills and along the wooded river valleys of the southern grasslands. To date (2002) it has not been collected in the Aspen parklands, where it also undoubtedly occurs.

"A medium-sized (4.0-5.0 cm wingspan) grey and white dagger-moth. The lines, except for the postmedian line, are obsolete and indicated only by dark blotches where they would meet the costa. The postmedian line is incomplete and marked by a series of darker spots or small crescents, with the 'dagger-mark" in the anal area prominent and enlarged. The area beyond the postmedian line is usually darker grey than the rest of the forewing, and there is a terminal line made up of black spots between the veins. The orbicular spot is a faint thin black oval, and the reniform is indicated by only a few dark scales. There is a thin but prominent black basal dash. The hind wing is white, with a series of black dots marking the terminal line. The females are larger and somewhat darker, especially on the hindwings. Antennae simple. The Cottonwood Dagger Moth can be separated from the similar Fingered Dagger Moth (A. dactylina) by the black basal dash (absent in dactylina), and the crisper dark markings (smudged in dacylina). A. vulpina is also similar, but is larger, has broad chalky grey-white wings and a short, thick basal dash. Alberta specimens have been treated by Bowman (1951) as subspecies lepusculina, felina, and canadensis."

Deciduous and mixedwood forest and edges; riparian woodlands on the plains.

The Cottonwood dagger moth is a solitary defoliator of poplars. The single annual brood each year overwinters as pupae.

No Alberta data; elsewhere in Canada recorded hosts include mainly poplars (Populus spp., including P. tremuloides, P. balsamifera, P. nigra, P. grandidentata, P. trichocarpa and P. acuminata) and occasionally willows (Salix sp.) and Paper birch (Betula papyrifera)(Prentice 1962)."