Ento-musings from the University of Kentucky Department of Entomology

Monday, July 23, 2012

Moth 1: National Moth Week

Blake Newton, UK Extension Entomology

This week is National Moth Week. To help celebrate, I am posting an image of a moth each day this week and discussing its identification and other details. Since I want to learn something along the way, I will be featuring moths that I did not know very much about prior to this week. This will force me to learn all about them!

Today's image was emailed to me a few days ago by Bob Sanders in Anderson County, KY, who kindly gave us permission to use the photo. Because I'm not a moth expert, I was not immediately sure which kind it was. There are a couple of clues regarding its identity, though. For one thing, it was photographed during the day, flying from one flower to another. This is important because most moths fly at night. Another clue: the ink-black wings. Many moths are gray and/or brown, but only a handful of U.S. species are black.

When I see a black moth, the first thing I usually think of are the "ctenuchids." Ctenuchid is a name sometimes used for a group of moths in the Ctenuchina group of the Tiger Moth family. But when I looked up the ctenuchids, they didn't look right. For one thing, none of them that I could find pictures of had any prominent spots. They are also a little sleeker than the moth pictured above. (You can see some pictures of typical ctenuchid moths here.)

So the next thing I investigated were the "foresters." There are several forester moths in the U.S., and they are known for their black wings and white spots. I have seen them a few times before, and the picture above reminded me of them. After looking at a couple of pictures on Google images (using the search phrase "forester moth") it seemed like a good match. Bingo! 

But upon reading about the foresters, one of the web pages that I was reading mentioned the Grape Leaf-roller Moth, which is also a black moth with white spots, and which is often confused for forester moths. Upon looking at it, I remembered why I'm not a moth guy. To me--at first glance--it looks almost exactly like a forester.

After doing some comparisons, though, I quickly ruled out the leaf-roller. The leaf-roller has very slender wings and doesn't have the white "shoulder pads" seen on the image above. So I went back to the foresters.

And then I found a picture of something called the White-spotted Sable, which is a moth that I'd never heard of before. This thing really looks like my picture! Its got the shoulder pads, the spots look right, and it flies during the day. But it's missing one important thing. See the orange tufts on the legs of the image above? The sable doesn't have those. But foresters do!

Finally, after looking at several foresters, I came to the conclusion that Bob Sander's moth is probably Alypia octomaculata, the Eight-Spotted Forester. This moth fits. It's got eight spots, its common in Kentucky, it flies during the day, and it is active in early summer. Other candidates included the Six-Spotted Forester and Wittfeld's Forester Moth, but neither was quite right.  

So... am I sure of my identification? No. As I have said before, I am not a moth expert. More importantly, I am working from a picture instead of a specimen. Accurate identification--of any insect--is not truly possible from an image alone. But I'm pretty sure! The moth looks right and all the evidence matches. On top of that, I learned a bunch of stuff, and not just about the eight-spotted forester, but about the grape leaf-roller, the white-spotted sable, and several other moths as well.

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