Tortricid Moth – Oak Leaf Tier?

2009 April 26

Here’s another little guy. Once again, it was found on the window, in mid-July of 2007.


The way the wings are held and the general shape makes me think it is a Tortricid moth. This one is a bit unusual, in that it actually has some lumps and bumps on its wings, giving it a more three-dimensional camouflage than most other moths have.


I’m not holding up a lot of hope for identifying this beyond “A Tortricid”, seeing as how the Moth Photographers’ Group has pages and pages of unidentified tortricids. I haven’t seen anything quite like it yet, but again, if somebody recognizes it, please let me know.

Update: Carl Strang has once again given a likely ID in the comments. It looks a fair bit like the Oak Leaf Tier (or Oak Leaf Shredder), Acleris semipurpurana (formerly Croesia semipurpurana). These are considered one of the major hardwood defoliators in the United States. The site I just linked to says that they lay eggs in June, but that is for Pennsylvania, and it is reasonable that they would take until July to lay eggs around here. Oddly, they actually don’t hatch out right away. The eggs stay dormant the rest of the summer, overwinter, and don’t hatch until the following spring. At this point they go after the oak leaves just as they are emerging from the bud. It sounds like they grow fast, and once the oak leaves reach full size the caterpillars rappel down to the leaf litter on silk threads, and pupate quickly under the leaves to emerge as adults in a couple of weeks. They can apparently really tear up the young leaves on oak trees, and when they get numerous they can kill the trees.

As a group, Tortricid moths are commonly referred to as leafroller moths, because a lot of them have caterpillars that roll up leaves into little tubes so they can eat them in peace. Not all of them, though. There are a lot of kinds of tortricids, and in addition to leaf-rollers, some of them have caterpillars that are gall-makers, root-borers, fruit-borers, seed-predators, flower-feeders, and tip-tiers.

I’ll probably be running across other kinds of tortricids, which include a lot of invasive species and crop pests. Although, apparently some of them are considered beneficial because they eat certain invasive weed plants. This brings up the question: if you have an invasive weed, and an insect that eats it also gets introduced, is the insect also considered invasive? Or is that only if it switches food plants and starts eating something that we want to keep?


2 Responses
  1. April 27, 2009

    Hi, Tim,
    Simple-mindedly checking my handy-dandy Covell, your moth resembles three at the bottom of plate 59. I’ve collected that Clepsis in NE Illinois, and it’s more cream than yellow in forewing color. As in the one you depict, I’m impressed by what strikes me as a resemblance to a shed bud scale or other plant part in these moths. How about Croesia semipurpurana? Though the dark area of your moth is smaller than in the one depicted, Covell emphasizes the bright yellow ground color, the brown blotch “dusted with metallic gray scales,” and mentions that the dark area can be smaller. Covell couldn’t include all species, of course, but if that ain’t it, I have to think it’s a close relative with that many similarities.

  2. April 28, 2009

    Hmm, that does look pretty close, thanks! I think I need to see about getting a copy of Covell.

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