Friday Caterpillar Blogging: Eastern Tent Caterpillars, Malacosoma americanum

These are Eastern Tent Caterpillars, Malacosoma americanum (Click the pic to enlarge). I recently photographed these at a nearby park on a nice sunny day. These silk tents were abundant at the park which is why they came to my attention. Before today's reading I didn't really know too much about the natural history of these caterpillars, but here are a couple of good links, from Wikipedia, and the UK Entomology Department. The key identifying features of these larvae include a generally black body with a white stripe down the back. The sides of the insect will have blue spots located between two yellowish lines. I was curious about the thrashing of the anterior portion of the body, and made a brief video. This is described in the Wikipedia article: "Tent caterpillars, like many other species of social caterpillars, vigorously thrash the anterior part of their bodies when they detect predators and parasitoids. Such bouts of thrashing, which may be initiated by a single caterpillar, radiate rapidly though the colony and may result in group displays involving dozens of caterpillars. Such displays create a moving target for tachinid flies, wasps and other small parasitoids that lay their eggs on or in the body of the caterpillar. They also clearly deter stink bugs and other timid predators."

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