Tent Worm, photo by sisterKRS10.

This year tent worms aka Eastern Tent Caterpillars seem to be a little thicker than normal in northern Michigan. I think the pictured caterpillar is actually a forest tent caterpillar. Both are tent caterpillars, about which Wikipedia says:

Tent caterpillars are readily recognized because they are social, colorful, diurnal and build conspicuous silk tents in the branches of host trees. Some species, such as the eastern tent caterpillar, Malacosoma americanum, build a single large tent which is typically occupied through the whole of the larval stage while others build a series of small tents that are sequentially abandoned. The forest tent caterpillar, Malacosoma disstrium, is exceptional in that the larvae build no tent at all, aggregating instead on silken mats that they spin on the leaves or bark of trees. Tents facilitate aggregation and serve as focal sites of thermal regulatory behavior. They also serve as communication centers where caterpillars are alerted to the discovery of new food finds…

The MSU Horticultural Research Station in Leelanau County has a really cool look at the Forest tent caterpillar in Northern Michigan that explained something I saw this weekend – tent worms leaving a tree on strands of web.

Here’s a PDF that looks at Gypsy Moth Caterpillars, Forest Tent Caterpillars and Eastern Tent Caterpillars and here’s more about Forest Tent Caterpillars and Eastern Tent Caterpillars. Most of what I read says that tent worm infestations are typically not life-threatening for trees. However, if you’re creeped out by these crawlies, eHow has advice for how to get rid of tent caterpillars.

Check this out bigger and in Kristin’s Mother Nature Up Close set (slideshow).