Ctenucha virginica caterpillar

2008 August 9

Last year I had a picture of an adult Ctenucha virginica, a striking black-and-orange tiger moth with an unpronounceable name. Well, this spring (on May 10), I found the caterpillar of the same species, climbing up a grass stem.

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As seems to be typical for tiger moths, they overwinter as nearly-mature, very hairy caterpillars, eat a bit in the spring, and then pupate to emerge as adult moths early in the summer. So, when I found this one, it was probably on its way for its early spring eating binge – tiger moth caterpillars frequently eat grass. Aside from the characteristic pattern of yellow and black tufts of hair, they also have orange prolegs, so I’m pretty sure this one is identified properly.

Their main defense against being eaten is those hairs: they are pretty stiff, and I imagine that eating something covered with those is pretty unpleasant.  I certainly don’t plan to eat one. It seems to work, because caterpillars like this are always crawling around, and never seem to get molested by anything.

If they are disturbed at all, they immediately curl up in to a ball, with the hairs all pointing out. That made it really difficult to get good pictures, because every time I tried to shift it for a better viewing angle, it immediately rolled up, and stayed rolled for about ten minutes. So, I got an awful lot of pictures of it like this:

Overall, these are harmless (unless you either rub the hairs into your skin, or try to eat them, in which case I understand the hairs are pretty irritating). They also aren’t a crop pest to speak of, because they aren’t that prolific, and in any case they eat grass. GRASS! Grass is everywhere! Who’s going to miss a bit of grass? Nobody, that’s who! They might be a problem if they built up to plague numbers like gypsy moths or forest tent caterpillars, but since they don’t, they are generally considered to be just another one of those innocuous caterpillars that one sees around from time to time.

10 Responses leave one →
  1. August 12, 2008

    My word, chomping down on that would be like eating a toilet brush.

    As usual, breathtaking photography and enlightening prose. Thanks!

  2. Dammit Woman permalink
    August 12, 2008

    WOW! Beautiful pix. Thanks for sharing.

  3. August 12, 2008

    What a great looking caterpillar!

  4. August 14, 2008

    Thanks! This fellow gave me a surprising amount of trouble while photographing (between the curling up, the high contrast, and the depth-of-field problems), it’s good to see that it wasn’t for nothing.

  5. Paul Gregory permalink
    July 16, 2009

    The C is silent so the name is pronounced as “Tea nucha”

  6. Bonnie permalink
    May 17, 2010

    Thank-you for confirming this ctenucha virginica is not considered a pest. Everyone wanted us to kill it like cut worms or tent caterpillars. It was ready to pupate as soon as we found it and I was worried it was dying since it lost all of its fur-we found it forming a cocoon with it and now we’re waiting to see it emerge. Thanks to you we know what to expect and when to expect it to happen.

  7. May 18, 2010

    Bonnie: you are welcome. Incidentally, the vast majority of insects are not pests, and in general any wooly caterpillars that are found crawling around (like this one) are most likely to be one of the many species of tiger moths (which mostly eat things like grass and lichen). There are a few pest caterpillars with hair (like tent caterpillars and tussock moths), but they are generally not nearly as fuzzy as this.

  8. Bernard L Schwartz permalink
    March 30, 2011

    I am writing a book and need a photograph of a Ctenucha virginica caterpillar. Can I use you photo

  9. Dylan Fruh permalink
    May 18, 2014

    I am thinking about getting this caterpillar is their any advice I should know, like what kind of grass or what they like??

  10. May 19, 2014

    Dylan:

    So far, all the ones I’ve found in spring haven’t eaten much, they just went straight to making a cocoon. I find them in the lawn pretty frequently, and I think they just eat normal grass, nothing exotic.

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