Bombyx Mori Life Cycle

The Bombyx Mori is the caterpillar of the white silk moth, and is native to northern China. Bombyx Mori is also known as the silkworm or mulberry silkworm. But the Bombyx Mori is not a worm; it is a caterpillar. The cocoon of the silkworm is harvested for silk.

  1. History

    • The Chinese have harvested silk for thousands of years from the cocoons of Bombyx Mori. The silkworm has been domesticated to the point where it can no longer survive in its natural habitat in the wild. Adult moths can no longer fly. Because of its fat bodies and small wings, it cannot lift its own body weight. The Chinese have commercial silkworm farms where the silk is harvested, processed and sold.

    Harvesting Silk

    • Silk comes from the cocoon of the silkworm. When the Bombyx Mori pupates (forms a cocoon or chrysalis), it secretes a single protein strand from two glands on the top of the head. This single protein strand is the silk, and it weaves this single strand into a complex cocoon to protect itself during the development from caterpillar to moth. Once the caterpillar has spun the cocoon, the cocoon is placed into boiling water. This kills the pupa (developing moth), and aids the process of unraveling the cocoon. The silk from each unraveled cocoon measures between 985 feet to 2,953 feet long.

    Larvae

    • Bombyx Mori larvae hatch from clutches of small black eggs. As the lavae grows, it eats large amounts of mulberry leaves. It continues to grow rapidly, shedding its skin several times and growing to almost 3 inches long.

    Pupa

    • Once it has reached around 3 inches long, the caterpillar begins to pupate, spinning a cocoon around itsel, which often takes more than three days. The intricate silk cocoon covers a hard brown pupa. It remains in this stage for around three weeks unless the cocoon is to be harvested for the silk. Just after the cocoon is spun is generally the time it is harvested.

    Moth

    • After three weeks in the pupa stage, the adult moth emerges from the cocoon. The life span of an adult silk moth is between four and six days. During this time the female lays 200 to 500 yellow eggs, which turn black as they mature and typically take 10 to 14 days to hatch.