Medium sized light-brown moth

2009 May 2

This could possibly be one of the most boring, hard-to-identify moths in the world. [1]. Still, I want to be comprehensive in these pages, which means I can’t just skip the boring ones.
We found it on October 21, 2007. The wingspan as it rested was about 3 centimeters, so while it wasn’t a huge moth, it wasn’t tiny, either. It was on the window of the door leading from the kitchen to the entryway, which meant that I could turn on the kitchen lights and the entryway lights and get pictures of it from both sides.
Here is the top side:

and here is the underside:

And there I get stuck. There is very little pattern on the wings other than a dot in the center of each wing, and a faint wavy line running across the wings on the back. The wings are a bit on the translucent side, and not really very eye-catching at all [2]. And, of course, since this is about dull as the duller moths get, hardly anybody takes pictures of them, or identifies them, or puts them up on bug guide, so I got absolutely nowhere identifying it. It isn’t just me, either: I submitted them for ID, and so far nobody on bug guide wants to hazard a guess, not even to the family. And yet, this is more or less what the average moths look like that come swarming around the lights at night. There are probably more moth species that look more or less like this, than there are moths with identifiable patterns.

If I had to hazard a wild guess, I’d say it is probably a geometrid (inchworm) moth of some sort, because the other moths I’ve found that rested with their wings spread out flat like that tended to be geometrids. Of course, I could just as easily be completely wrong.

I would like to point out that it is really handy when an insect lands on a window, because it does give the opportunity to photograph both sides like this without disturbing it. This works best with moths, because they tend to land on the window and stay still, probably because they think it is an opaque surface that they are camouflaged on, not a transparent surface that they stand out like a sore thumb on. Other insects that one finds on windows, like flies and wasps, are harder because they will keep walking around all the time. Makes it very hard to focus.

Well, I guess that’s all I have to say about this one. You win some, you lose some. I’ll try to get something more identifiable for next week, now that the snow is finally gone[3] and the bugs are coming back out

[1] Then again, who knows? I thought the last two moths were pretty much unidentifiable, and then Carl Strang came through with an ID both times. How about this one, Carl? Any ideas?

[2] I feel kind of bad about being so dismissive just because of the dull-brown wings. After all, if this was, say, a wasp, I wouldn’t be talking about it being nondescript just because it had transparent wings, would I? But, the blunt fact of the matter is that the primary visible feature of butterflies and moths (Lepidoptera) is their wings. And so, that’s what pretty much everybody sees, to the exclusion of other interesting features like the coiled-up tongue or the googly eyes or the structures on the legs or what-have-you. I expect that the ID keys that the professionals use cover all these details and aren’t so wing-centric, but (a) I don’t have a good moth ID key yet, and (b) even if I did, I probably wouldn’t be able to make much sense of it without a lot of training.

[3] We had a blizzard about a week and a half ago, starting on April 20. This was about a week later than the April blizzard that we got last year. It dumped about two feet of snow on our property, with a 3-foot pile at the end of the driveway where the snowplow mounded it up. Gah, what a mess. On the bright side, it probably set back the mosquito population quite a bit, they were starting to get numerous just as the blizzard hit.

3 Responses
  1. May 4, 2009

    Yeah, this is a tough one. There are possibilities both in the Geometridae, as you suggest, and in the Noctuidae. When moths fade with loss of scales it gets really tough, though the specialists still often can succeed. What’s distinctive about this one, I think, is the limited number of lines: only the one strong one on the fore wing, none evident on the hind wing. One geometrid possibility is Lambdina pellucidaria, the yellow-headed looper moth. The attraction here is the yellow head and thorax, but the problem is that the species is supposed to have gray rather than tan wings, and something of a line on the hind wing (which conceivably is present in this individual in incomplete form, represented by the dark dot). The noctuid possibilities are close relatives of one another, a few species of Zanclognatha plus the morbid owlet Chytolita morbidalis. These are of interest because their larvae all eat dead leaves. The two with the weakest wing lines are the grayish zanclognatha, Z. pedipilalis, and Chytolita. But again the ground color should be more gray than tan.

    Moths are an acquired taste, but there often are intricate patterns on those brown and gray wings. Ecologically they are of extreme importance in the caterpillar stage, both as plant consumers and as food for birds. I had the good fortune to spend some time learning from George Godfrey, a former lepidopterist with the Illinois Natural History Survey who sadly lost his position in a downsizing and moved on to a university in Oklahoma. George demonstrated that moths are accessible, and from him I got a sense of the amount of variability to expect within a species. Charles Covell’s Field Guide to the Moths does a good job of helping us amateurs with most of the species we will encounter. Originally part of the Peterson Field Guides, it didn’t sell well enough to satisfy Houghton Mifflin, and went out of publication for several years. Happily it has been picked up by the Virginia Museum of Natural History and is back in print.

  2. May 5, 2009

    How can you say it’s boring? For all you know, it may be one of the most well-read and erudite moths around. Sheesh! It’s like you’re judging the Miss America pageant or something.

    Or maybe not.


  3. May 26, 2009

    OK, so I have a possible ID, although it is far from a sure thing: it could be a very faded Linden Looper, Erannis tiliaria. What pattern it has (the horizontal stripes, the spots in the middle of the wings, and the unpatterned hindwings) are about right, assuming that it faded a lot while beating around the lights and knocking scales off of the wings. And both the body shape and resting pose are very, very close.

    And, of course, I know for sure that it is a species that lives here, because I already have pictures of the Linden Looper caterpillar, which is much more distinctive than the adult.

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