Silkworms

The Silkworm (Bombyx mori, Latin: “silkworm of the mulberry tree”) is the larva or caterpillar of a moth that is very important economically as the producer of silk. A silkworm’s diet consists solely of mulberry leaves. It is native to northern China and Persia (current Iran).
Silkworms have a strong appetite, as do all lepidopteran larvae. They eat mulberry leaves day and night. Thus, they grow very fast. When the color of their heads turns darker, it means that it is time for them to moult. After they moult about four times, their bodies turn slightly yellow and their skin becomes tighter, which means they are going to enter an apparently resting state (the pupa or chrysalis), during which they transform themselves into moths. Before becoming a pupa, the silkworm encloses itself in a cocoon, for protection during the vulnerable, almost motionless pupal state. The silkworm is so called because it spins its cocoon from raw silk produced in its salivary glands.