Tent caterpillars display social behaviors and cooperate on building shelters. The silk “tents” they make in branches provide protection from predators. There is new evidence that the tents may have a second role, especially for young caterpillars.
Fitzgerald and colleagues* compared the temperature inside and outside the tents of young Eastern Tent Caterpillars, Malacosoma americanum. They found that temperatures inside the nest could be significantly warmer than ambient temperatures, especially on cool sunny days of early spring. For example, on days when the ambient temperature is below 10 degrees C, the temperature inside the tent can be 20 degrees C or higher. The temperatures have a significant effect on the growth and development of the caterpillars. At temperatures below 10 Centigrade (about 50 F) activity slows to a crawl. This includes food processing in the caterpillar gut. By returning to the warmth of the tent after an early morning feeding, the caterpillars are able to process their food much faster and grow much faster than it would without the tent.
*Terrence D. Fitzgerald, Steven Miller & Michael Smith. Thermal properties of the tent of early instar colonies of the eastern tent caterpillar, Malacosoma americanum. J Thermal Biology. Volume 37, Issue 8, December 2012, Pages 615–624.