The name "inchworm" refers to the larva of any one of 35,000 species of moth worldwide. Nearly all eat some variety of fruits, leaves or vegetable matter, depending on what is found in their particular environment. One of the most common inchworm species, the cankerworm, feeds on the fruit and foliage of a variety of trees including apple, oak and sweetgum. An infestation of cankerworms can devastate an orchard.

All varieties of inchworm use a characteristic method of locomotion. Having legs only at the front and back ends of their bodies, inchworms move by drawing their hind end forward while gripping with their front legs, then by extending their front end to a new location. This "looping" motion gives the inchworm its name, since it seems to be measuring its journey. While most eat fruit and leaves, there are some varieties that eat flowers, pollen or lichen. A few even feed on other insects. Inchworms come in a variety of sizes and colors, but the majority are green or brown and not more than one inch long. Many inchworms, if disturbed or threatened, camouflage themselves by standing erect and motionless on their hind legs, emphasizing their resemblance to a stem or a twig.