Monday, October 3, 2011

Apple #548B: White Caterpillars, part II

A couple of weeks ago, I posted an entry about some caterpillars I encountered in the woods. Since I do occasionally get things wrong, especially where plant and animal identification is concerned, I posted my photos along with my best guesses of what the caterpillars were and invited feedback.

I got no responses.

Nobody told me I had guessed right, but nobody said I'd got it wrong, either. So I'm going with my best guess.

Now allow me to officially introduce to you the caterpillar of the American dagger moth, and the caterpillar of the Hickory tussock moth, respectively.

American Dagger Moth

American dagger moth caterpillar
(Photo by the Apple Lady)

  • This is the caterpillar of the American dagger moth (Acronicta americana).
  • This caterpillar ranges in color from yellow to white.
  • All varieties have those dense fuzzy hairs (setae) all over the body and long spiky things (lashes) that stick up higher than the setae. On this caterpillar, the lashes are on segments 1, 3, and 8.
  • Most of the caterpillars that are very hairy or fuzzy-looking like this are in some way unpleasant or even painful to the touch. Touching the hairs (setae) of this one can give you a reaction from a minor irritation to an allergic rash.
  • These freddies live East of the Rockies, primarily in woodlands and forests, especially ones that are swampy.
  • They like to eat the leaves of deciduous trees of typical hardwoods like ash, elm, maple, oak, hickory, walnut, and willow
  • Caterpillars are out from June through October
  • They're in the cocoon during the winter.
  • In April, the moths come out and fly around until September.
  • The adult moths look far less exciting than their caterpillar, or larvae, version.

American dagger moth in its adult form
(Photo by Cindy Mead at Red Planet)

Now for white caterpillar number two.

Hickory Tussock Moth

Hickory tussock moth caterpillar
(Photo by the Apple Lady)

  • My best guess is that this is the caterpillar of the Hickory tussock moth. The reason I'm not 100% confident is that hickory tussock moth caterpillars have black or a mix of white and black lashes. This one has only white lashes.
  • But it does have the black bands across the top of its abdomen and the white fuzzy setae. So I'm going with Hickory tussock moth (Lophocampa caryae).
  • These are one of several types of tussock moths caterpillars. "Tussock" refers to the way the setae get clumped together in groups, or tussocks.
  • I find it interesting that the common name of the species refers to something distinctive about the caterpillar rather than the moth. I think that's because the caterpillars look way more exciting than the adult moths do.
  • Another type of tussock moth that you might be more familiar with is the gypsy moth.

Asian gypsy moth caterpillar -- another tussock moth caterpillar
(Photo from the Agricultural Experiment Station Archives at the Global Invasive Species Database)

  • Gypsy moths are native to Europe and Asia. They were introduced to the US in the 1860s and, without a natural predator, have been on a tear through our trees ever since.
  • In the Eastern part of the US alone, European gypsy moths (which have a shorter range than the Asian gypsy moths) defoliate an average of 4 million acres each year.
  • As a relative of the gypsy moth, the Hickory tussock moth can also defoliate entire trees, but they tend not to be quite as damaging in the long run.
  • This is probably because they're native to the states, so they have some natural predators: lizards, frogs, wasps, and some types of birds.
  • True to their name, the Hickory Tussock moth caterpillars like to feed on the leaves of hickory trees.
  • That's only in the south, though. In the north, they like to eat the leaves of beech and oak and other nut trees.
  • For reasons which entomologists can only guess, there are an especially high number of these out and about this year.
  • Caterpillars wander about in the fall, eating as much as they can and looking for a good spot to make their cocoon. The moths come out in July.

The adult hickory tussock moth. Doesn't look much like its caterpillar version, does it?
(Photo from What's That Bug?)

  • Some people have been passing around emails about VENOMOUS black and white caterpillars with all sorts of WARNINGS in the messages.
  • The caterpillars to which they're referring are these, the Hickory tussock moth caterpillars.
  • It's probably not as dire as those messages would have you believe, but it's true, touching one of these with your bare skin can be painful. That's because the hairs do contain a very small amount of venom. Most likely you'll get a stinging sensation and maybe you'll even develop a poison ivy-like rash.

Another view of the hickory tussock caterpillar. Noli me tangere!
(Photo from Old Dominion Wildlife)

  • It can be unpleasant enough, though, that entomologists say you don't even want to come in contact with the hairs that might have fallen off the caterpillar. They suggest wearing gloves while cleaning up dead leaves in your yard.
  • If you do get stung, wash thoroughly with soap and water to get rid of any lingering venom.
  • Spines might even get stuck in your skin. If that's the case, use a piece of Scotch tape to pull out some of the broken spines.
  • You may even want to use an ice pack because you may experience swelling.
  • If you're having allergic reactions that are especially severe, or if you've been stung in the eye, see a doctor immediately.

The caterpillar of another type of tussock moth, the White-Banded tussock moth. Crrrazy-looking, isn't it? This one is venomous, too.
(Photo from Henderson State University)

Related posts: White caterpillars, part I, Woolly Bear caterpillars

Bug Guide, Species Acronicta americana - American dagger moth
Paklinks, Science & Nature forum, Stinging Caterpillars: Cute, Fuzzy ... but Itchy
Diana Bowley, Entomologists: Beware of Hickory Tussock caterpillar,
Bangor Daily News, August 30, 2011
USGS, Caterpillars of Eastern Forests, Hickory Tussock moth (Lophocampa caryae)
Global Invasive Species Database, Lymantia dispar (Asian gypsy moth)
Ask the Exterminator, Hickory Tussock Moth
Butterflies and Moths of North America, Lophocampa caryae


  1. what part of the caterpillar is poison or is it all of it?

  2. The hairs. I should have specified that in the entry. I'll do that now. Thanks for asking!

  3. What part of the country does this caterpillar come from ?

  4. I saw the American Dagger Moth caterpillar and the Hickory Tussock Moth caterpillar both in Ohio. But they live in a much wider range than just one state.

    I'm guessing you're more interested in the Hickory Tussock Moth, and this fellow's range is as follows:

    Nova Scotia to North Carolina mountains, west to Ontario, Wisconsin, and Texas. Absent from much of midwestern part of range.

  5. I just took pictures of this caterpillar on my porch in GEORGIA


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