Tuesday, October 01, 2013

Making a caterpillar hammock

Cabbage white butterflies go through several generations each year. In warm weather, a complete cycle takes from one to two months. Over the winter, though, the caterpillar goes dormant in his chrysalis, stuck to a leaf or twig. A three-point attachment is all that holds him, through rain, snow, wind, and ice storms. And through all the shaking and jerking about he goes through as he sheds his old skin. There's a spot of glue at the tip of his tail, and a fragile-looking thread glued to the leaf on either side, and strung over his back. That seems to be enough.

Day-old chrysalis. The thread is visible across his mid-section.

I've been wondering how the caterpillar manages to tie a thread behind his own back, and managed to catch my latest visitor demonstrating the technique.

First, he selects his leaf. He was eating nasturtiums, but moved to maple for the winter.

He bends over backwards, and turns to one side.

Glues a strand of silk to the leaf on his left,

Swings back, stretching at right angles to his leaf,

continues the swing

to the right side,

and glues the thread down.

He repeated this action about a dozen times, then returned to his upright position and started the transformation.

Here he is, on video, in real time. It's a painstakingly slow process.

If you watch this at full size, it's easy to see the thread stretching over his back.

But he says, in the immortal words of the Cat in the Hat, "That's not all I can do!" More tomorrow.

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