The Eating Habits of Caterpillars

Killers

• In 2005 scientists announced the discovery of meat-eating caterpillars in Hawaii. A type of inchworm, this carnivorous caterpillar carries a silk casing used to immobilize its favored viand, the snail. In fact, this caterpillar is the only butterfly or moth larva know to eat shelled prey. The caterpillar also uses camouflage and speed to capture more mobile insects. Disguising itself as a twig, it awaits; then it strikes rapidly, using its long, spiny legs to grab its victim. This caterpillar will not eat plant material, even if it is starving.

  According to the Live Science, the Hawaiian meat-eating inchworm is one of only 200 species of butterflies and moths, out of more than 150,000, that eat flesh. Others include a Danish caterpillar that lives with ants, who feed it even as it supplements its diet with their eggs.

Textile Workers

• One of the most luxurious fabrics is produced by a caterpillar that no longer occurs in the wild. The silkworm caterpillar, native to China, has been domesticated to such an extent that it no longer is found in nature. It lives solely on the leaves of the mulberry tree. When this caterpillar is ready to turn itself into a moth, it spins a cocoon out of a single strand of silk up to 3,000 feet long, according to the New World Encyclopedia. Unfortunately, after all this work, the silkworm is not allowed to fulfill its destiny: if it emerges from its cocoon, the silk is ruined, so the case is dropped into boiling water. This process kills the caterpillar and enables the silk to be unwound in a single strand. The worm sometimes is eaten, used for fertilizer or fish food.

Harmless Beauties

• Some caterpillars are beautiful, seeming to augur their future on the wing. The luna moth is an example. The plump green caterpillar metamorphoses into a large, exquisite green moth that is nocturnal and rarely observed. While adults do not have mouths and thus cannot eat, caterpillars dine on the leaves of hardwood trees, particularly birch, persimmon, sweet gum and walnut. Populations are not numerous enough for them to be destructive, according to Butterflies and Moths of North America.

  The popular, pulchritudinous monarch butterfly also has a beautiful larval form, a fat, black-white-and-yellow striped caterpillar that hints at the orange-and-black lepidopteran to come. These butterflies migrate annually from their wintering site in Mexico to the United States. The monarch caterpillar is harmless, primarily feasting on milkweed before beginning its transfiguration into resplendent, winged adulthood.

Destroyers

• Many caterpillars are pests. Two of the most notorious are the gypsy moth and the tent caterpillars, which strip the leaves from deciduous trees. While the tent caterpillar is native to the United States, the gypsy moth caterpillar was introduced -- always a bad idea -- in 1869 in an attempt to breed it with the silkworm. Instead, the gypsy moth thrived on the leaves of hardwood trees and "since 1980, has defoliated a million or more forested acres per year," according to the U.S. Department of Agriculture.

  Tent caterpillars build large nests of silk in the crotch of hardwood trees, where they set about devouring all the leaves on their host. According to the University of Kentucky, trees usually are able to recover after being defoliated, but the bare branches, laden with enormous caterpillar tents, are an eyesore. Populations of these pests fluctuate, with occasional years of plague-like proportions, when millions of the caterpillars can be seen crawling across roads and sidewalks.