Invasion of the Unidentified Moths

OK, so it wasn't an invasion. It was actually just two. At different times. One made its way into the hall, the other way hanging out on the lamb's ear. And it turned out that I was right that one of them was a type of sphinx moth, but good grief! These were tricky!

Besma quercivoraria, "Oak Eater"

I'd like to introduce you to a male "oak eater." It's official name is Besma quercivoraria ... which translates to oak eater. To make life complicated, the Oak Besma (how it is referred to by people who know a thing or two about moths) eats other stuff besides oaks. Namely stuff like elm, white spruce, poplar, willow and paper birch (in addition to oak). To make life more complicated, the Oak Besma looks significantly different, depending on its sex. This is what is meant by sexual dimorphism--same organism, different appearance. The first Bug Guide link below will take you to some great photos of the Oak Besma, and you will see that the female of the species is much paler, and looks more banded. This first image is the one I took before I got hold of my flash, when I found it in the hallway.

Second image, with flash (bounced)

My normal method of figuring out moths is to go to the Discover Life ID guide and start isolating features. They are very kind at Discover Life, because they provide hotlinks for all the terms I am unfamiliar with so that I can answer the questions in a somewhat educated fashion. Still, you do end up with a lot of links to look through, and in the case of this particular moth, I struck out, at least in terms of finding something that looked exactly like the moth on my wall. Everything I found initially, was an image of the female of the species, which just wasn't exactly "right" compared to what my guy looked like. Bug Guide was the key, once I had narrowed the species down by the shape of the wings--one contributed photo looked like my male. Just image this guy on the bark of a tree. He's not that big--less than two inches across--and would blend right in to the variations of tone around him on a tree. The larval form is a twig mimic... I doubt I would have found him at all! Please note: I included a second link on the Oak Besma, and you will see it contains almost no information at all. Many of these research sites rely on contributed information (and photographs) from folks just like you and me, who take note of where they find a species, take pictures, and finally submit our info to these sites for experts to stamp with approval and provide as a resource for others. If you have any interest in contributing your images or documentation, please contact any that are of special interest to you.

Just to be clear, I did capture him and get him outside to go on doing what moths do.

Newly emerged Lettered Sphinx moth

Our second unidentified moth was found outside on a patch of Stachys. It was early morning, and this guy was very compliant--I figured because of the chilly temps. After FINALLY getting him identified, however, I think it was because he had just emerged, and wasn't all dry and ready to fly yet. I never, in fact, saw the hind wings at all. Silly me, I thought with a tail sticking up like that I'd have no trouble with the identification. One of these days I will learn better! I first searched for a sphinx moth, because with wings shaped like that, and with such a "heavy" body, I just figured it had to be. However, my initial search just came up with lots of other sphinx moths that didn't look like the one hanging out on my Stachys.

Deidamia inscriptum in early morning after emergence

It turns out that the Lettered Sphinx is one of the first sphinx moths to emerge, and this particular one is the only one of its genus north of Mexico. The larval form eats grape vine, sourwood and Virginia Creeper. In my yard, he probably ate either sourwood or Virginia Creeper. Given that he had emerged in the front yard, it could have been either. See why you need native plants? No Virginia Creeper or wild grapevine, no Lettered Sphinx moth! The caterpillars feed at night.

As a sphinx moth, Deidamia inscriptum is fairly small--it's wingspan is under three inches. Given the strongly arched abdomen, this specimen is likely male. In the links below, you will find the most information in the final link on sphinx moths--again, contributions of photos and other information are still largely gathered by amateur ecologists. If you find good things, take note of where, on what, etc., and contribute your findings to an online forum!


Bug Guide, Oak Besma; Discover Life Moth ID GuideOak BesmaLettered Sphinx, BAMONALettered Sphinx, Bug GuideSilkmoths-Deidamia Inscriptum

Mother Nature Will Win

Mother Nature Will Win

Spiral Herb Garden Project

Spiral Herb Garden Project