The Forest Tent Caterpillar

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Species: Malacosoma disstria     

Chrissy Bowker of Texas asks, “What’s this animal?”

The caterpillar in the picture above is none other than the Forest Tent Caterpillar, Malacosoma disstriaThey are commonplace in the eastern regions of US and Canada. Down in Texas, populations are sure to be booming this spring due to the warmer than average winter.

3-21 egg mass
Photo credit: Steven Katovich, USDA Forest Service,

Adult females lay eggs on the branches of deciduous trees in masses of around 300, which are coated with a rubber cement like adhesive to protect them from predators and the environment.

When they hatch, they will strip the tree of leaves, moving about in a line fashion by following a pheromone trail laid by silk strand by their fellow caterpillars. They weave a silken mat between the branches which they lie in together during molt as they grow (up to 2 inches).

Tent Caterpillar nest Photo Credit: Jesse Varner, Flickr

Much like an owl pellet, you can dissect these masses (after they’ve been abandoned, of course) and peel through they layers to reveal molt casings and dropping indicative of growth stage, increasing in size as you move outwards.

Forest Tent Caterpillars have the potential to defoliate vast areas of forest when the conditions are right. Though this is more rare than common, it is part of the reason for their infamous reputation as a pest-defoliater. About 5 week after hatching, the caterpillars change to pupae and live inside of their individual cocoons for about 10 days. As adults, they are average sized, relatively non-descript, brown moths, living for only a few days. Just enough time to mate, and lay a new batch of eggs.

Photo Credit: Seabrooke Leckie, Flickr

Have a picture of an animal or plant and can’t seem to figure out what it is? Send it my way and I’ll identify it for you! Send submissions to or message ‘The Wild Life’ on Facebook.

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