Tuesday, May 7, 2013

Moths: Still a lot to learn

This is the rather clumsily named Beautiful Eutelia, Eutelia pulcherrimus. They sure got the beautiful part right, but blurt out EUTELIA! in polite company and they'll look at you as if you're daft. This thing looks like a Pablo Picasso artwork with wings, and it was a first for me.

I've got to apologize for the less than stellar photographic work. I made this image at about 5:45 am one day last week. There's a building that's brightly lit with nightlights not far from our 6 am rendezvous spot for fields trips for the New River Birding & Nature Festival, in southern West Virginia. I'd have about ten minutes or so to look through the Lepidopterans that had collected on the walls, then hightail it over to meet my group. Anyway, I now sorely regret not working with this moth a bit more, and trying to craft some better images.

Beautiful Eutelias are, supposedly, not very common. I had no idea what it was when I saw it, nor did the people that I was with. It wasn't hard to figure out, though, and once the basic necessity of identification is out of the way, I naturally wanted to know what its host plant(s) are. One should never just stop with learning a name; if you do, what have you accomplished? Not much, other than learning a name.


I checked several moth reference guides, and good online resources. All said the same thing - the host plant of the Beautiful Eutelia is Poison Sumac, Toxicodendron vernix. I knew something was amiss, or at least there was more to the story. I photographed this moth in Fayette County, in a region that I have come to know well. There's no Poison Sumac anywhere near where I was. Poison Sumac is actually a very habitat specific plant, and not common in West Virginia, Ohio, or other surrounding states. It grows primarily in bogs and fens, and those are not common habitats. The above map, courtesy the USDA Plants Database, shows in green the counties in which Poison Sumac has been documented. Fayette County is not one of them; in fact, it doesn't even abut one of the green counties.

So, I began to wonder if perhaps the moth's caterpillars noshed on Poison Ivy, which has essentially the same chemical properties that the rash-inducing sumac does. I grabbed David Wagner's outstanding Caterpillars of Eastern North America book from the shelf, thumbed to the Beautiful Eutelia account, and sure enough, Dave listed both Poison Sumac and Poison Ivy. Bravo!

But this confirmation of Poison Ivy as a host raises another question. Why are there not more of these beautiful moths flying around? Poison Ivy, Toxicodendron radicans, is one of our most abundant native plants. It is everywhere, in nearly every conceivable habitat. There's obviously more ingredients required to produce Beautiful Eutelias than meets the eye.

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1 comment:

DenPro said...

This is indeed a beautiful moth. Though it ranges from Canada to Florida, it really is not abundant. Northern Ohio records do correspond to known locations of Poison Sumac, but that leaves those from southern Ohio unexplained. Poison Ivy makes sense, but it's probably a secondary host not preferred by the insect. Definitely more than meets the eye going on here.