Portraits of a Sedge Muncher

I haven’t been going for many walks with a camera lately. I spend so much time viewing the world through various lenses and screens that it’s refreshing to experience it through my own bleary eyes from time to time. But the other day I spotted a Calligrapha beetle on our mulberry tree, and it was sufficiently fancy that I had to dash inside to get my camera. Once I finished with the beetle and was already outside with my big old macro lens, I figured I might as well take a quick stroll through our woods and see what else I could find.

What I found was a furry Ctenucha virginica caterpillar munching on the tip of a sedge leaf (Cyperaceae: Carex). It was just small enough to fit comfortably within the 2-cm field of view of the MP-E 65mm.

I didn’t notice as I was taking the above photo that there are a few little green crumbs of sedge leaf on the left side of the caterpillar’s face. You can also see, in this photo and in the two below, the tiny barbs on each of its hairs, as well as the serrations on the margins of the sedge leaf that give it its rough texture. But what really caught my attention as I zoomed in was the structure of the caterpillar’s prolegs that grasped either side of the leaf.

The curved, translucent structure, I just learned, is called the “planta,” and the tiny gripping hooks that come out of it are called “crochets” (as in crochet hooks). Virtually all butterfly and moth larvae have these hooks, even leafminers that don’t have anything that looks like legs, and this is an important feature in distinguishing them from sawfly larvae.

Ctenucha virginica, by the way, grows up to be a kind of tiger moth (Erebidae: Arctiini) called (get this) the Virginia Ctenucha. Apparently I haven’t photographed one in well over a decade, but they are distinctive day-flying moths that visit flowers, so they’re not hard to find. Here’s one sipping some Queen Anne’s lace.