Tuesday, August 2, 2011

Parasitized Looper

Plant eating larvae are often difficult to find because of their habit of blending inconspicuously into the plant upon which they feed. Camouflage can be a detriment when the larva finds itself on the wrong part of the plant. I was investigating holes in the leaves of a Tuliptree when this twig mimicking looper fell from above and landed on a leaf. If it had refrained from moving, it probably would have passed as a small twig fallen from the tree. Its first reaction, though, was to strike out in search of a more secure location.

Some people refer to these moth larvae as inch-worms because their form of locomotion resembles a method of measuring by using a length of flexible material. I prefer to call them loopers because of the loop formed by the body each time the tail end scoots up to meet the head. Regardless of the name, they’re a fascinating animal to observe.

This one seems to be carrying a bit of an extra burden. On its back is a balloon-like cluster of parasitic larvae and below that seems to be a cluster of eggs. There also appears to be a scattering of eggs just behind the head. For those who haven’t yet gotten their bearings, the head is to the left.

It’s hard to tell just what stage of development the larger cluster is displaying. If those are larvae that will hatch to invade the looper’s body, there won’t be much room left inside for anything else. I’m not familiar with parasites that feed from the outside of the body. They could be larvae that have exited the body in order to pupate. It just seems to me that the looper doesn’t have enough body mass to accommodate all of the offspring that will exit those eggs.

In any event, I imagine that this guy has just about formed his last loop. It might be that he is already weakened and that contributed to his fall from the tree. It’s certain that he won’t live to transform into an adult moth. The question is whether or not he can survive long enough to nurture a couple broods of parasite larvae.


  1. Oh, my. Not happy for the looper....

  2. Pretty amazing. I've seen parasitic larvae on hornworms before, but never on loopers. Wonder what it is?

  3. Hi, Lois. Most loopers end up being eaten by something, so maybe by looper logic it's better to support a whole family of something small than be just a snack for something large.

    Hi, Karen. It would be nice to know what eventually hatches out. There are probably so many possibilities that it's not even worth guessing.