Acronicta insita
Walker, 1856
Large Gray Dagger, Fingered Dagger
Acronicta insita, commonly known as the Large Gray Dagger or Fingered Dagger, is a noctuid found across North America from Newfoundland to the Pacific coast. The was first described by Francis Walker in 1856. Formerly, Acronicta hesperida and Acronicta dactylina were treated as separate species but are now recognized as synonyms. have a wingspan of 45–55 mm and fly from May to July.
Pronunciation
How to pronounce Acronicta insita: /ˌækrəˈnɪktə ɪnˈsiːtə/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
can be distinguished from other Acronicta by geographic range and period, though specific diagnostic features are not detailed in available sources. The larval stage is notable for its containing toxin—this trait is shared with some other dagger moths but the specific combination of plant use and geographic distribution helps separate it from similar species. Acronicta betulae (Birch Dagger) and Acronicta americana (American Dagger) are related species with different host associations and distributions.
Images
Habitat
Associated with deciduous forests and woodlands containing trees including alder, birch, poplar, hawthorn, and willow.
Distribution
North America: Newfoundland west to Pacific coast and Vancouver Island, British Columbia, including Haida Gwaii; south to North Carolina and Colorado.
Seasonality
active May to July in one per year, with timing varying by location.
Diet
Larvae feed on leaves of alder (Alnus), birch (Betula), poplar (Populus), hawthorn (Crataegus), and willow (Salix). feeding habits not documented.
Host Associations
- Alnus - larval food plantalder
- Betula - larval food plantbirch
- Populus - larval food plantpoplar
- Crataegus - larval food planthawthorn
- Salix - larval food plantwillow
Life Cycle
Complete with one per year. emerge May–July. Larval stage feeds on plant foliage. details not documented in sources.
Behavior
are and attracted to light. Larvae are solitary feeders on plant foliage.
Ecological Role
Larval herbivore on deciduous trees and shrubs. Specific ecological interactions beyond herbivory are not documented.
Human Relevance
Larvae pose a health hazard due to containing toxin; contact can cause skin rashes lasting up to a week. Some individuals react more severely than others. Not considered an agricultural pest.
Similar Taxa
- Acronicta betulaeBirch Dagger moth; similar appearance but associated primarily with birch and has more eastern distribution
- Acronicta americanaAmerican Dagger moth; larger with different larval coloration and range
- Acronicta radcliffeiRadcliffe's dagger moth; similar members with overlapping ranges but different associations
Misconceptions
Formerly treated as three separate (A. insita, A. hesperida, A. dactylina); these are now synonymized, which may cause confusion in older literature.
More Details
Taxonomic History
Grote described this in 1874, though Walker's 1856 description takes priority. The synonymy of A. hesperida and A. dactylina with A. insita reflects improved understanding of variation within this widespread species.
Venomous Larvae
The hollow, toxin-filled hairs of the caterpillar represent a defensive . Rashes can spread to other body areas through clothing contact or scratching, indicating the toxin can be transferred mechanically.