Social Caterpillars Thermoregulate

For more photographs of the caterpillars, see http://www.becauseoftime.org/ISD/PhotoVideoTRI2.html (gallery 6).

Imagine camping out with a few of your friends, naked, on a very chilly night.  What do you do to keep warm?  You cuddle, of course!

We witnessed a phenomenon at ISD late last week, something I'd certainly never seen before:  caterpillers in a large group, cuddling, young and old alike, thermoregulating.  

On Friday morning, when I arrived at school, the caterpillars were descending from the upper branches, in what I assume was a pheromone highway, gathering in a patch along the sun side of the trunk, as if to bask in the first morning light.

Later in the day, we learned that several critters had been harassing the poor caterpillars, from birds, to wasps, to a few misguided human children.  By the end of the day, the number of caterpillars had been much reduced, and, on Saturday morning, there was but a fraction of Thursday's morning's crowd.  We only hope that many fluttered away, rather than being nipped, injected, or smooshed.