Domestic silk moth

Silk moths do not live in the wild.

They live with people, on silk farms and in classrooms. People give the silkworms fresh leaves to eat every day.

Silk moths do not live in the wild anymore. They live only where people keep them, on silk farms and in schools. Silkworms were first tamed in China, and today people raise them in many countries, such as China, India, Japan, Thailand, Cambodia and Brazil.

Silkworms are so used to living with people that they cannot hold on to the leaves of a plant by themselves. Farmers keep them in trays or boxes and bring them leaves to eat.

The domestic silk moth has no wild range. It survives only in sericulture, in classrooms and in laboratories. Butterfly House names Brazil, Cambodia, China, India, Japan and Thailand as examples of countries that raise silkworms for silk, and records that European settlers brought silkworms to Australia in the nineteenth century to try to start a silk industry, attempts that continue today.

The map on this page shows, by continent, where silkworms are kept by people; it is not a natural range. Animal Diversity Web notes that the species originally lived wild in Asia but is believed to no longer exist in the wild.

Silkworms eat mulberry leaves.

They munch and munch and grow very fast. The grown-up moth does not eat at all.

Silkworms are picky eaters. They eat the leaves of mulberry trees: white, black or red mulberry. Very young silkworms will only eat very young, soft leaves. On big silk farms, the leaves are sometimes ground up and mixed with flour to make silkworm food.

After all that eating as a caterpillar, the adult moth never eats again. Its mouthparts do not work, so it lives on the energy it stored up as a silkworm.

Larvae are fed on plants of the mulberry family (Moraceae): white mulberry (Morus alba), black mulberry, red mulberry and che (Cudrania tricuspidata). Young larvae accept only very young leaves. Commercial rearing often uses leaves ground and fortified with flour, a feed sometimes called silkworm chow; Butterfly House notes that caterpillars are reported to accept lettuce but decline spinach.

Adults have degenerate mouthparts and do not feed. As Butterfly House puts it, they are totally reliant on the nourishment taken in during the caterpillar stage, so almost all of the silk moth's eating, growth and silk-making happens before it ever becomes a moth.

Silk moths cannot fly.

A mother moth gives off a special smell. When a father moth smells it, he flutters his wings in a little dance. That helps them find each other.

Silk moths cannot fly, but they still need to find each other. A female gives off a special scent called a pheromone. When a male picks up the scent, he flutters his wings in a little dance. This helps the two moths find each other.

Silk moths were the very first animals in which scientists discovered and named pheromones, the scents animals use to send messages to others of their kind.

Silk moth courtship depends on chemistry. Females have a gland that releases a sex pheromone; males respond with a wing-fluttering "flutter dance" that helps the pair find each other. Animal Diversity Web notes that Bombyx mori is the animal in which pheromones were first discovered and named.

Adults cannot fly or feed, and a female dies after laying her eggs. The caterpillars, by contrast, spend their lives eating; domesticated larvae have lost the ability to hang on to plants at steep angles and rely completely on people to bring them food.

Silk moths are not in danger.

There are lots of them on silk farms. People take care of them and feed them every day.

The domestic silk moth is not endangered, because people raise huge numbers of them. But it cannot survive without people, since it no longer lives in the wild.

Silkworms are also helpful in science and schools. In Australia, silkworms are used in schools to teach children, and scientists study their genes to learn more about silk and about genetics.

As a domesticated species, Bombyx mori is not endangered or threatened, according to Animal Diversity Web, and its numbers depend on sericulture rather than on wild habitat. Silkworms are attacked by diseases and parasites, such as pebrine (caused by Nosema bombycis), viruses and the uzi fly, a parasitic fly.

The species is also a research and teaching animal. Animal Diversity Web notes that silkworms are used for education in Australian schools and that scientists are mapping their genes, both to improve silk and to learn about genetics more widely.