Can Caterpillars Eat Any Kinds of Leaves?

Butterflies and Moths

• Caterpillars' adult forms, butterflies and moths, don't eat leaves. While many butterflies and moths feed on the nectar from plants, others feed on rotting fruit, dung and even carrion. The red-spotted purple butterfly feeds on carrion, dung and even tree sap. Many moths only fly at night and visit flowers that bloom after sundown, such as the evening primrose.

Caterpillar Lifecycle

• Adult butterflies taste with their feet. When they land on a plant, they immediately know if it is the right food source for their eggs. The eggs, which come in many sizes, shapes, colors and textures, are generally laid on leaves. Once the eggs hatch, the caterpillars begin feeding. Some caterpillars, such as that of the gypsy moth, are voracious feeders and harmful pests. As they grow, caterpillars shed their old skin and grow a larger one. Once they reach maturity, they attach to a branch and form a chrysalis or cocoon from which they emerge as adults.

General Feeders

• Some caterpillars, such as the fall webworm, are not picky eaters. Fall webworms feed on any broadleaf, deciduous tree. While many caterpillars chew large holes in leaves, some, like the apple and thorn skeletonizer, eat the chlorophyll layer off leaves, turning them brown and causing them to drop. These caterpillars eat birch, crab apple, willow and mountain ash trees. Some caterpillars eat conifer foliage. The Douglas fir tussock moth larvae feed on a variety of conifers, often defoliating the tree's top third.

Specific Tastes

• There are caterpillars that only feed on particular host plants. Monarchs are an example, feeding only on milkweed. Toxins in the milkweed sap make the caterpillar and adult butterfly poisonous to predators. Other examples include the hackberry butterfly, which only feeds on hackberries, and the great spangled fritillary, which only eats violets.