Plume Moth

2009 June 6

This week, I got a couple of actual, no-fooling insect nets[1], and Sam and I went out to see what we could catch. There wasn’t much (it has been kind of cold and a bit breezy of late, so flying insects big enough to see easily were pretty scarce). Then, I saw something grey, blurry and unidentifiable flying past, quickly took a swipe at it with the net – and got it! It turned out to be this:

It’s a “Plume Moth”, in the Tribe Platyptiliini. Based on the color and wing shape, I think it’s most likely in the genus Platyptilia, and it could be a somewhat faded specimen of Platyptilia carduidactyla, the Artichoke Plume Moth.

It’s posing on a piece of standard aluminum window screen, and each square is about 1.6 mm, so the wingspan is about 17 mm. I expect that these moths are really common, seeing how easily I caught this one. The long, thin wings are actually pretty good camouflage, it makes them look quite a bit like a piece of straw. The wings are actually a forewing and a hindwing, and roll up pretty thin when the moth is resting.


And it isn’t just the wings. The body is also quite elongated, and the legs have spikes on them that make it look very much like frayed grass stems



In fact, the camouflage of a grass stem is so good that I had to look closely in the net to make sure I actually had a moth and not just some random bit of trash.

There are a bunch of species of plume moths, but there isn’t a lot of information about most of them because the majority don’t have much economic impact. The Artichoke Plume Moth is an exception, because the larvae eat artichokes and are therefore a crop pest in areas where they are grown. Of course, nobody grows artichokes up here in northern Michigan, so the immediate question is, what is it doing here? Well, first off, it may not be an Artichoke Plume Moth, it could just be a relative. Or, if it is an Artichoke Plume Moth, its larvae would be eating thistles, which are actually its primary food plant.


Which brings us to the fine line between a beneficial insect and a pest. Thistles are considered a noxious weed, and we would mostly be perfectly happy to have something eat them. In that case, these moths would be beneficial. But, as it turns out, not all thistles are noxious weeds – Artichoke is a type of thistle![2] So now, all of a sudden the little moths are the bad guys, just because we had the poor judgement to go and domesticate their food plant. Sometimes you just can’t win.

[1] We got the nets from Bioquip. Ted MacRae had spoken well of their products in the past, and I’d heard references to them from other people over the years, so I figured on giving them a look. It turns out they sell very nice insect nets for as little as $12 – $15 (although you can, of course, spend a lot more on them if you so choose), which I thought was pretty decent. I got the 12 inch standard aerial net, and it is pretty rugged, handy, and easy to use, all things considered. I got the “student version” for Sam, which has a shorter handle and is a couple of dollars cheaper, but is otherwise identical to the standard one. I’d never used an insect net before, aside from one that my brother made out of a mop handle, coat hanger, and nylon stocking when I was a kid (and that never did work very well), and was surprised how well this one worked. In this case it really is worth it to get the real thing (at least when the real thing is not outrageously expensive), and not just struggle along with improvised stuff.

[2] This is something that I did not know. I suppose when you domesticate a spiny plant, one of the first things you do is breed it not to have spines, and I guess that artichokes do look a lot like spineless thistles. The same thing evidently happened with citrus trees: we got a small bonsai orange tree a couple of months ago, and were a bit surprised to see that it has well-developed thorns, even though I’d never heard of citrus trees having thorns before.

2 Responses
  1. June 20, 2009

    Tim, you’ve outdone yourself this time. Even if I didn’t think the insects were fascinating, I’d still be in awe of your technical prowess with the camera.

  2. K T Cat permalink
    May 16, 2010

    Do you have anymore facts?

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