Moth

An adult male pine processionary moth (Thaumetopoea pityocampa). This species is a serious forest pest when in its larval state. Notice the bristle springing from the underside of the hindwing (frenulum) and running forward to be held in a small catch of the forewing, whose function is to link the wings together.

Some moths, particularly their caterpillars, can be major agricultural pests in many parts of the world. Examples include corn borers and bollworms.[6] The caterpillar of the gypsy moth (Lymantria dispar) causes severe damage to forests in the northeastern United States, where it is an invasive species. In temperate climates, the codling moth causes extensive damage, especially to fruit farms. In tropical and subtropical climates, the diamondback moth (Plutella xylostella) is perhaps the most serious pest of brassicaceous crops. Also in sub-Saharan Africa, the African sugarcane borer is a major pest of sugarcane, maize, and sorghum.[7]

Several moths in the family Tineidae are commonly regarded as pests because their larvae eat fabric such as clothes and blankets made from natural proteinaceous fibers such as wool or silk.[8] They are less likely to eat mixed materials containing some artificial fibers. There are some reports that they may be repelled by the scent of wood from juniper and cedar, by lavender, or by other natural oils; however, many consider this unlikely to prevent infestation. Naphthalene (the chemical used in mothballs) is considered more effective, but there are concerns over its effects on human health.

Moth larvae may be killed by freezing the items which they infest for several days at a temperature below −8 °C (18 °F).[9]

While moths are notorious for eating clothing, most species do not, and some moth adults do not even eat at all. Some, like the Luna, Polyphemus, Atlas, Promethea, cecropia, and other large moths do not have mouth parts. This is possible because they live off the food stores from when they were a caterpillar, and only live a short time as an adult (roughly a week for some species).[10] Many species of adult moths do however eat: for instance, many will drink nectar.[8]

Some moths are farmed for their economic value. The most notable of these is the silkworm, the larva of the domesticated moth Bombyx mori. It is farmed for the silk with which it builds its cocoon. As of 2002, the silk industry produces more than 130 million kilograms of raw silk, worth about 250 million U.S. dollars, each year.[11][12][13]

Not all silk is produced by Bombyx mori. There are several species of Saturniidae that also are farmed for their silk, such as the ailanthus moth (Samia cynthia group of species), the Chinese oak silkmoth (Antheraea pernyi), the Assam silkmoth (Antheraea assamensis), and the Japanese silk moth (Antheraea yamamai).

The larvae of many species are used as food, particularly in Africa, where they are an important source of nutrition. The mopane worm, the caterpillar of Gonimbrasia belina, from the family Saturniidae, is a significant food resource in southern Africa. Another saturniid used as food is the cavorting emperor (Usta terpsichore). In one country alone, Congo, more than 30 species of moth larvae are harvested. Some are sold not only in the local village markets, but are shipped by the ton from one country to another.[14]

Tomato hornworm parasitized by braconid wasps

Nocturnal insectivores often feed on moths; these include some bats, some species of owls and other species of birds. Moths also are eaten by some species of lizards, amphibians, cats, dogs, rodents, and some bears. Moth larvae are vulnerable to being parasitized by Ichneumonidae.

Baculoviruses are parasite double-stranded DNA insect viruses that are used mostly as biological control agents. They are members of the Baculoviridae, a family that is restricted to insects. Most baculovirus isolates have been obtained from insects, in particular from Lepidoptera.

There is evidence that ultrasound in the range emitted by bats causes flying moths to make evasive maneuvers. Ultrasonic frequencies trigger a reflex action in the noctuid moth that causes it to drop a few centimeters or inches in its flight to evade attack,[15] and tiger moths can emit clicks to foil bats' echolocation.[16][17]

The fungus Ophiocordyceps sinensis infects the larvae of many different species of moths.[18]

Some studies indicate that certain species of moths, such as those belonging to the families Erebidae and Sphingidae, may be the key pollinators for some flowering plants in the Himalayan ecosystem.[19][20] A UK study published by The Royal Society in 2020 established that moths are important nocturnal pollinators of a wide range of plants.[21][22]

• Gypsy moth (Lymantria dispar), an invasive species pest of hardwood trees in North America
• Winter moth (Operophtera brumata), an invasive species pest of hardwood trees, cranberry and blueberry in northeastern North America
• Corn earworm or cotton bollworm (Helicoverpa zea), a major agricultural pest
• Indianmeal moth (Plodia interpunctella), a major pest of grain and flour
• Codling moth (Cydia pomonella), a pest mostly of apple, pear and walnut trees
• Light brown apple moth (Epiphyas postvittana), a highly polyphagous pest
• Silkworm (Bombyx mori), for its silk
• Wax moths (Galleria mellonella, Achroia grisella), pests of bee hives
• Duponchelia fovealis, a new invasive pest of vegetables and ornamental plants in the United States