Though the Forest Tent Caterpillar does not sting or bite people, it can range from being a nuisance to an all-out pest in certain circumstances. This particular Tent caterpillar does not actually build tents of silk like its relatives. It does leave trails of silk between areas where it feeds, however these strands are not the tangled mass of silk tents that describe most in this genus.
The dark brown or black body of the caterpillar has light blue stripes with thin yellow lines on either side of the 'spine'. A white mark shaped like a shoe print sits on top of each segment. Fine white hairs stick out of the lower sides of the body, face, and rear end. It looks similar to the Eastern Tent Caterpillar, but lacks the solid cream line on the 'spine' seen in that species.
A variety of deciduous hardwood trees provide leafy food for the larva with exception to red maple. They are often seen in groups. Their droppings may fall on people and cars sitting under a host tree. They are difficult to remove from a tree or other surface, and smashing them can leave a slick stain that is hard to clean off.
In some areas, outbreaks of this caterpillar occur that can typically last one to three years. A large population of this species can defoliate swaths of forest land, leaving trees naked. Mature, healthy trees can tolerate the leaf loss at the expense of energy stores. This may cost the tree in sap and fruit yield, but survival is the primary goal. Young or stressed trees may die from the extensive annual feeding. Natural inhibitors like cold and wet weather, and predators like fungi and parasitic flies and wasps eventually bring the Forest Tent Caterpillar under control. Tolerating the natural cycle of outbreaks is the most common response. If they are infesting a tree near property, pruning branches that have the dark egg masses on them during winter can help reduce their number in the spring. Wrapping the affected tree trunk with a sticky band of insect tape can impede caterpillar movement up and down the trunk once they hatch. In early summer, using a stiff broom to brush off their fuzzy cocoons stuck on siding also helps remove them from a high-traffic area.
The Forest Tent Caterpillar Moth is the adult form of this species. It is a yellow-brown moth with two thin brown lines crossing the wings. The middle area between these lines may or may not be filled in with brown color. Antennae have comb-like teeth. One to two broods can be produced each year.
The map above showcases (in blue) the states and territories of North America where the Forest Tent Caterpillar may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.*NOTE: States/Territories shown above are a general indicator of areas inhabited by the Forest Tent Caterpillar. Insects generally go where they please, typically driven by diet, environmental changes, and / or mating habits.