Large Underwing Caterpillar and Adult

2012 November 3

I almost stepped on this one while pushing my bike up the hill on May 29, 2012. It was sitting on the road pavement, and looked so much like a mouldy bit of rotting stick that I nearly didn’t stop to pick it up.

It was something of a huge caterpillar, as we can see when we compare it to a penny.

The belly was more colorful, pink with a number of elongated black spots. It was pretty lethargic even for a caterpillar, and let me roll it around and photograph it quite a bit.

Based on the black spots on the pink belly, I’m inclined to think this is an Ilia Underwing caterpillar, Catocala ilia.

The face looks right for the Ilia Underwing, too.

We had it in a bowl, and it was so lethargic that I thought that it was probably going to pupate right there on the spot. So I didn’t put a cover on the bowl. Big mistake. Because a few hours later, I looked in on it again, and it was gone. I couldn’t find it anywhere, and figured it had probably crawled off under the stove or behind the cabinets.

But then, almost exactly a month later (June 30, 2012), I came home and Sandy presented me with a jar containing this big moth that she had caught in the kitchen. I suppose it is possible that this is a completely unconnected moth that just happened to get into the kitchen, but the circumstantial evidence here is pretty darned strong.

And, the bit of hindwing that we can see is consistent with the color and pattern of the Ilia Underwing adult photos on BugGuide, so there we go.

This is evidently one of the most common underwings in this area, so it’s no surprise that I found one. Aside from the fact that the caterpillars are practically invisible, and the adults apparently aren’t as drawn to lights as many other moths are, so it is a bit unlikely to actually see one. The only reason the caterpillar was out where I could spot it, was because it was crawling around looking for a place to pupate. They eat oak leaves, so it probably dropped out of one of the oak trees that grow next to the road where I found it.

6 Responses leave one →
  1. November 3, 2012

    That’s too cool. And I’m psyched for the moth that your home was a safe place to pupate, so it could go out and meet fellow (and lady) moths, thus fulfilling its destiny. =) Good work!

  2. Carole permalink
    November 3, 2012

    I laughed out loud when I read of your wife’s discovery. Good piece of writing and a nice discovery.

  3. November 4, 2012

    What an amazing, fascinating, horrifically beautiful face! You make me want to catch some caterpillars next spring. Maybe I’ll know enough from reading your blog by then to be able to assure myself that I won’t kill them.

  4. November 4, 2012

    Underwing moths are gorgeous. I remember seeing them when I lived in Georgia, but I didn’t realize we had them up here!

  5. November 5, 2012

    I wasn’t sure if it was going to pull off the pupation or not, and was glad to see that it did. I guess the warm, dark area under the stove is pretty suitable for them, at least in the summer when the air isn’t too dry.

    Cindy: Go for it! Caterpillars are actually surprisingly easy to raise a lot of the time.

    Rebecca: We certainly do have underwings, although I mostly find them by rearing caterpillars, the species around here don’t seem to be as strongly drawn to lights as a lot of other moths are.

  6. November 6, 2012

    Cindy: They have enormously varied faces, too. The book Owlet Caterpillars of North America has several pages worth of pictures of underwing caterpillar faces.

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