Keratin
Several species of moth feed on keratin, a protein found in hair, skin and wool. The most well-known of these moths, the clothing moth, frequently infests wool and chews large holes in clothing. Though the adults lay eggs and live in wool, it is actually the larvae of these moths that cause damage to clothing. Clothing moth caterpillars can eat several times their own weight in wool every day.
Detritus
Detritus is dead and decaying organic material. Some species of moths feed primarily on detritus. Though this dietary preference may seem strange, detritus feeders fill an important ecological niche by preventing waste buildup and disposing of dead animals. Some people believe that carpet moths, common household pests, feed on carpet fibers. These moths actually feed on tiny organic particles in carpet including dead skin, parts of insect bodies and hair.
Trees
Both moth larvae and adult moths of many species feed on trees. Gypsy moths are small- to medium-sized with spotted wings. Males have brown or yellow markings on their wings, while females typically have solid-colored white or beige wings. They are common tree parasites and frequently eat large segments of hardwood trunks.
Nectar and Plants
Many species of moths feed on plants and the nectar produced by plants. These moths play an important role in plant reproduction by spreading pollen and seeds. The sunset moth is a diurnal moth with large, brightly-colored wings with red, green, black and orange bands of color. Both larvae and adults eat flower nectar and a variety of plants. Because of their bright colors, they are frequently mistaken for butterflies.