Most adult moths eat nectar or simply do not feed, and moth larvae feed on many types of foliage and clothing fibers. Adult male moths of the Calyptra genus are capable of feeding on blood.
Clothes moths are infamous household pests due to the ability of larvae to feed on keratinous materials, such as wool or fur. Over time, this causes serious damage to textiles. Damage occurs mostly beneath buttons, around seams and in pockets due to the moth's habit of seeking out dark, recessed spaces. Adult clothes moths lack mouth parts and do not eat at all.
Gypsy moths are a significant pest species in parts of North America. Larval gypsy moths cause extensive damage to the foliage of trees, sometimes resulting in tree death and deforestation. Like clothes moths, adult gypsy moths do not feed.
Adults of the aptly named hummingbird clearwing hover at flowers to sip nectar, like the eponymous bird species. Hummingbird clearwings belong to a larger family, the sphinx moths. While adults are harmless nectar feeders, the larvae of some species are garden pests.
Moths of the genus Calyptra, native to Malaysia and southern Europe, have the nickname of vampire moths. Adult males of this genus possess a proboscis capable of piercing flesh and drawing blood for nourishment. While this behavior causes a sore or itchy spot for the moths prey, Calyptra carry no diseases and are not harmful.