Animal: Chauliognathus pensylvanicus marginatus

The people who used to live in this house had a small garden in back, which I've mentioned before, and in the garden they'd planted some cilantro, which I haven't mentioned before because I was under the impression that it was parsley. But it's not. (I have to say I'm a little disappointed in y'all for not saying something when I misidentified it as such earlier. You guys are supposed to catch stuff like that.)

Anyway. Something else we had when we moved in was a low spot in the back yard, which bothered the husband something awful. So we spent the last couple years throwing grass clippings there, and if I had potting soil from dead plants to dump out, I'd dump it there too, and then this spring the husband got a bunch of compost from the city (Iowa City), and filled it in the rest of the way, so now it's more or less level.

That spot also erupted in tomato and cilantro seedlings this spring, so I guess at some point the husband also moved some dirt from the garden to the low spot. I don't understand why he would do that, but one of us must have, because:


So far, everybody seems to be pretty happy about this. The cilantro grew fast enough that I haven't had to do a lot of weeding (and it's been a cool, wet summer so far, so it's not too terrible when I do try to weed), the husband doesn't object because it's that much less to mow, and it's pretty. But our appreciation is nothing compared to the appreciation of the insect world: the blooms are always covered in various flies and beetles and gnats, the most conspicuous of which is Chauliognathus pensylvanicus, or the goldenrod soldier beetle Chauliognathus marginatus, the margined leatherwing. [UPDATE: the insect in question was initially misidentified.]


I was worried when I first saw these; I figured them likely to be a pest of something or another, and didn't want to be sheltering something that was going to go next door and eat all the neighbors' cucumbers or something. But as far as I can tell, they're not -- the adults eat pollen, nectar, and small insects; the larvae eat other insects or insect eggs. In fact, it's deliberately encouraged near corn fields, says a book I have here (The Audubon Society Field Guide to North American Insects and Spiders, 3rd ed.), because they eat corn earworm (Heliothis zea) caterpillars. So I don't have to feel bad about that. [UPDATE: the Audobon Guide does not include an entry for C. marginatus, but the one for C. pensylvanicus says that "several species" of Chauliognatus are used for controlling corn earworms, so I'm guessing that the information remains essentially correct.]


There's a slight question in my mind about whether I have the ID right -- the coloration is a little lighter than most of the reference photos I found; they have darker and larger spots on the wings and head. I didn't see anything that looked like a better match, though.


There may still be problems with this at some point, but I'm all for plants that attract beneficial wildlife and require almost nothing from me, especially if they're going to be this pretty. (I'm aware that they'll be less pretty later on, but I don't think they're terrible-looking even then.) Weirdly, the last time I was at the ex-job, the cashier told the person in line ahead of me that she had really horrible luck trying to grow cilantro. Is that normal? I can't imagine how it could be difficult.