Underwing Moth – Yellow and Black

2012 February 25

Sam found this rather large moth (body about 3 cm long) on the wall of the front porch on August 14, 2011. Its forewings were pretty well camouflaged for resting on bark, making it look kind of nondescript.

But, when it was startled, it would briefly flash its hindwings at us, which were something else altogether:

Of course, since it was just briefly flashing them, I couldn’t actually get a good, solid picture (it was as bad as the average butterfly that way), but hopefully there is enough to actually see the pattern.

The underwing patterning was also visible from the bottom (this one is a little hazy because I was photographing through the side of the plastic container we had the moth in, and the container wasn’t perfectly transparent).

This is certainly an Underwing moth, genus Catocala. These are generally-large moths that have the characteristic trait of having drab forewings, and brightly-colored hindwings that they will flash when startled. The flash of color probably surprises predators enough that it gives the moth that extra couple of seconds to escape.

There are 110 underwing species known in North America, not all of which are on BugGuide. But, after plowing thorugh the ones they have, I think it looks most like the Yellow-Banded Underwing, Catocala cerogama (although there are some other possibles, too). The caterpillars of underwings eat foliage off of trees, and generally have a fringe of little fleshy protuberances running along their bellies that help to break up their outline, making them hard to see when they are stretched out along a branch. The Yellow-Banded Underwings are found in this area, and feed on basswood leaves, which is a tree that we have in some abundance.

2 Responses
  1. February 26, 2012

    Lovely photo. Looks like the moth has lots of image noise. I was going to try using Photoshop’s noise reduction on it today and see what a “cleaned up” moth would look like, but I got into other things. I’ll see if I can get to it later this week.

  2. February 27, 2012

    That would be cool, thanks! The free ImageJ software that I use for cropping and adjusting photos isn’t all that sophisticated (or, at least, my use of it isn’t), it would be interesting to see what a real photo editor can do with it.

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