Species Acronicta dactylina - Fingered Dagger - Hodges#9203

9203

Alder Dagger

western populations formerly considered a separate species (Acronicta hesperida) are now considered synonymous with A. dactylina (see Lafontaine and Troubridge, 1998)

DACTYLINA: from the Latin "dactylus" (a finger); the origin of the common name but it is not clear how that name applies to this species

uncommon, but widely distributed

wingspan 45-55 mm

Adult: most similar to American Dagger but forewing PM line is single (not double and white-filled, as in American Dagger), with greater amount of dark shading on distal side of PM line than in American Dagger

hindwing white in male; gray in female; lacks median line crossing the wing (present in American Dagger)

Larva: body covered with stiff orange or brown hair dorsally, and pale yellowish or white hair laterally, with several much longer black hairs and white hairs concentrated near the front and back (may also have three dense dorsal tufts of long black hair on abdominal segments 1, 3, and 8)

all of United States and southern Canada (Newfoundland to Florida, west through Texas to California, north to British Columbia)

deciduous and mixedwood forest

adults may be active from April to September but normally have a more restricted flight season (May to August, or just June and July, depending on location)

larvae present from July to October

larvae feed on alder, birch, poplar, hawthorn, willow

one generation per year; overwinters as a pupa in leaves or debris protected in tough oval cocoon of coarse silk and hair (1)

large, pale, poorly marked adults of western populations were until recently considered a separate species (Acronicta hesperida), and are still listed as such on a number of sites

American Dagger has dark line running across hindwing (absent in Fingered Dagger) and a double white-filled PM line, with less dark shading on the distal side of the PM line (compare images of both species)

pinned adult image (CBIF)

description plus habitat, biology, distribution, food plants, and citation of A. hesperida as a former species (Strickland Entomological Museum, U. of Alberta)

pinned adult image (James Adams, Dalton State College, Georgia)

pinned adult image (Insects of Cedar Creek, Minnesota)

live larva and adult images plus seasonality (Jeremy Tatum, Butterflies and Moths of Southern Vancouver Island)

live larva image labeled as A. hesperida, plus description, food plants, seasonality (Jeff Miller, Caterpillars of Pacific Northwest Forests and Woodlands; USGS)

common name reference [Fingered Dagger] plus larval food plants and flight season (Ohio State U.)

common name reference [Alder Dagger] (Entomological Society of Canada)

presence in Florida; list (Michael Thomas, Florida State Collection of Arthropods)

presence in Texas; list (Dale Clark, Moths of Dallas County, Texas)

presence in California; list plus the former A. hesperida (U. of California at Berkeley)