Orange-Brown Moth with Scalloped, Curved Wings – Maple Spanworm

2014 September 27

I turned on the porch light again on September 6, 2013, and this fairly striking orange-brown moth was one of the things that came.

It looks to me like the adult form of the Maple Spanworm, Ennomos magnaria[1] These are pretty much masters of camouflage throughout their lives: the adult would blend in very well with dead maple leaves, and the caterpillar is supposed to be one of the better twig mimics. The only reason I ever even saw this one, is that it was drawn out of its preferred hiding place by the light.

Unlike most moths and butterflies, it doesn’t hold its wings either flat, or folded over its back. Instead, it holds them at about a 45 degree angle, all the better to resemble a somewhat crinkled dry leaf.

I kind of wonder about the extent to which it sacrifices aerodynamic qualities in order to be a better leaf mimic.

Like a lot of moths that fly in the fall, these overwinter as eggs. The eggs are laid in a row on an appropriate food tree, which could be alder, ash, basswood, birch, elm, hickory, maple, oak, poplar, or related trees. Which actually reads about like an inventory of the trees on our property: the only one on that list that I don’t think we have is elm (we wouldn’t have hickory either, except that we have about eight trees that we planted on purpose), and the only significant omissions are apple, cherry, pine, and spruce.

[1] Not to be confused with the Large Maple Spanworm, Prochoerodes lineola,(like this somewhat tattered specimen that came to the light on the same night)

or the Lesser Maple Spanworm, Speranza pustularia (which I also photographed once, back in 2011),

Neither of these look much like it, or are particularly closely related to it, but have nevertheless been saddled with very similar common names just because they all have inchworm-type caterpillars and all include maple as one of their food plants.

One Response
  1. October 3, 2014

    I so miss having the free time to come over and see your lovely photography and learn more about insects. Great job, Tim.

    I stole one of your photos and … well, you’ll see. 🙂

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