Polyphemus moth caterpillar (September)

(Note: while the next several posts may not be exactly timely, I try to always post things in the order I found them.)

So we were hiking around during the 2011 summer/fall drought (meaning, bad for mushrooms), and my hiking pal came upon this bright bright BRIGHT green fat fat FAT caterpillar.


It was the caterpillar of a Polyphemus moth (Antheraea polyphemus)—a big elegant silkworm moth, many shades of brown with nice eyespots on the wings. The male moths have enormous feathery antennae (a pic of one I found, here), for detecting pheromones from the females.

It was really hard to get a good photo of this caterpillar, because it wouldn’t stop walking. Apparently, at this time of year, they won’t stop walking. If you pick them up, they just keep walking. You try putting it on your friend’s arm to get a better shot, and they just keep walking. You try blocking it with a leaf, and it won’t stop walking.

I read that when these silkworm moth caterpillars are getting ready to make their cocoon, they stop eating, and start walking—they’re called “wanderers.” They’re looking for the right place to park for the winter and make their cocoon.

If it tries to get around you and your leaf, and falls approximately 1” off a little rock, it might stop walking and curl up defensively.



This particular brand of (fat!) caterpillar has a tendency to withdraw their heads into their fat, translucent, luminous bodies when they’re not marching ever forward. Seems to be a characteristic pose they strike. I would probably do that too, if I had folds of beautiful, neon-green, floppy soft skin.


 

When he fell approximately 1”, thanks to my pestering him with a leaf, he grabbed onto a little clump of loose moss and leaf, and didn’t let go.



This gave me a chance to get a passable shot of his prolegs—something I never took any notice of, until a Flickr contact posted this exquisite macro shot of them. Since I saw that image, caterpillar prolegs have become one of my most favorite things in the world. The prolegs are the dark grey and brown crazy-shaped things (note the fifth pair at the very end). Of course you can see why I’m nuts about them. Ask my friends--they'll tell you! "Oh, don't get her started on prolegs..."

The prolegs are tipped with “crochets,” little hooklets all around the edge. (In my image you can’t actually see them--they're way too tiny--they’re on the very edge of the brown bits.) The number, size, and arrangement of the crochets are used in identification. Who knew! Not me!

The six pairs of legs near his head are true legs—with joints and everything, and little claws at the end. Prolegs aren’t jointed, and have limited musculature. One source said they operate via hydraulics.

*Warning: if your supposed caterpillar has more than five pairs of prolegs (counting the ones at the very end), it is not a moth or butterfly! Run!

Anyway, rather than going on about caterpillar proleg crochets that you can’t actually see in these images, I’ll wander back to an overview of the super-cool prolegs. Of all the caterpillars I’ve seen in all my years of seeing caterpillars, I never really noticed their prolegs, which are bizarre, stumpy and wonderful. I never tire of caterpillar prolegs.

There’s also the issue of this caterpillar’s gorgeous translucence.  He really did look like a bioluminescent water balloon creature. If you click on the images to see full-sized, you can see how the light is passing through it, making him glow.

I’ve found more than one of their cocoons. I’m pretty sure whose cocoon it is, since I found one right before it hatched, and saw who was inside. Here’s one with a portion of the pupa’s exuvia still inside.



Well, that’s about it, really.