University of Alberta Museums Search

A medium-size (3.0-3.5 cm wingspan) pale buff grey moth. They lack "dagger-marks" and there is no basal dash. The antemedian and the post median lines are doubled, and the area between the two is usually paler than the remainder of the wing. The postmedian line is dragged outward at each vein, giving it a saw-toothed appearance. The orbicular spot is a small open circle, and the reniform is a larger, darker incomplete spot. The forewings appear powdery and the markings are all somewhat blurred. The hindwings are shining white, with a bit of grey dusting toward the outer margin. The antennae are simple. The sexes are similar, with females being slightly darker, especially on the hindwings. The pale color and soft blurry pattern will separate it from the other Alberta dagger moths.

A solitary defoliator, with a single brood each year, which overwinters in the pupal stage. The adults are attracted to light. Acronicta sperata is one of the least common Alberta dagger-moths. They appear to be associated with riparian areas in the valleys in the dry prairie grassland region of the province, and absent (?) in the more mesic aspen parklands and southern boreal forests. Our paler western prairie populations have been named subspecies speratina.

No Alberta data; in adjacent Saskatchewan and Manitoba, willow (Salix sp.) is the most frequent host, with single (questionable) records of Manitoba maple (Acer negundo), Hazel (Corylus) and Cherry (Prunus) (Prentice 1962). Elsewhere poplar (Populus) and alder (Alnus) have been reported as larval hosts (Forbes 1954).

New Brunswick west to the Alberta foothills, south to DC, Missouri and in the mountains to Colorado. In Alberta, it has been found most often along the valleys in the southern grasslands region, but has also been collected north to Edmonton and west to Calgary.