White Geometrid Moth

2015 January 14

And here’s a second type of nearly pure-white moth that came to the lights on June 12, 2014. It wasn’t very big (just a bit larger than a thumbnail).

From the way it holds its wings when resting, it looks to be a geometrid moth.

There are several species of white geometrid moth that this could be. From the shape of the hindwings and the brown speckling on the forewings, and from the fact it was flying in June rather than July, it looks to be The Vestal, Cabera variolaria Although it could also be the very similar Virgin Moth, Protitame virginalis – to tell them apart, I’d apparently need to be able to see the color of the forelegs, and I didn’t quite get them in the pictures. Still, based on the exact shape of the wings and the way it holds the antennae when resting, I think The Vestal is most likely.

In either case, their caterpillars are little inchworms that eat the leaves of poplar and aspen (and in the case of The Vestal, also cherry, willow, and related trees). They overwinter as pupae, and apparently can have several generations per year (at least in the warmer parts of their range). So, we could potentially see the adults later in the summer as well. Since two of their food trees (Paper Birch and Aspen) have white bark, and these moths rest flat and pressed against the surface, I think that in this case the white color is almost certainly camouflage.

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