American Dagger Moth (Acronicta americana)
Detailing the physical features, habits, territorial reach and other identifying qualities of the American Dagger Moth.
Updated: 1/30/2018; Authored By Staff Writer; Content ©www.InsectIdentification.org
The large adult American Dagger Moth may seem harmless, but its bristly, stinging caterpillar has a reputation for teaching small children not to touch everything they see.
The largest of the Dagger Moths at over 50 mm (2 inches) in length, the American Dagger Moth is found east of the Rocky Mountains. It is most active from spring to early autumn and can be found in areas with deciduous trees like parks, backyards, forests and woodlands.
The adult may be considered drab in appearance compared to its larval form, but definitely charming in its own way. Its wings and upper legs are covered in grayish-white hairs. Faint black lines zigzag up and down the forewings, and a thin, black ring is centered close to the edge of each wing. A white band scallops along the lower part of the forewings and the bottom edges of the wings have a black and white checkered fringe.
The caterpillar has a more remarkable appearance and size. Also about 50 mm (2 inches) long, it is completely covered in bright yellow/green bristles. Four long bunches of black bristles, like long eyelashes, extend from the body near the head and midsection. A fifth bunch of these extra-long, black bristles comes out near the rear of the caterpillar. The bristles break off and embed themselves into skin. Toxins stored inside the hairs have a stinging sensation if touched. Many curious children have unwittingly picked up these big, fuzzy, bright creatures and consequently experienced a burning, itching sensation on their skin which can develop into a rash. These irritating larvae feed on the leaves of a variety of popular neighborhood trees like oak, ash, elm, alder, willow and maple. They may be found on the ground near them. Since their food source can usually be found in close proximity to backyards and schoolyards, the likelihood of an encounter with people is high. The American Dagger caterpillar is a great reason why it is best to "Look it up before you pick it up"!