Question

Which stage of silkworm secretes silk?
A) Adult
B) Larva
C) Cocoon
D) Pupa

Answer 1

Hint: Silkworm is the larva of Bombyx mori moth. It makes silk which is used as fabric for clothes. It feeds on mulberry leaves.

Complete Answer:
- Silkworm is a native of China. It feeds on mulberry leaves. The total lifecycle of a silkworm is 6 to 8 weeks. The females have larger abdomen as compared to males.
- The female silkworm lays around 300 at a time on the mulberry leaves. The eggs hatch into larvae or caterpillars in about two weeks.
- The larva feed voraciously on the mulberry leaves. The larva weaves a net around itself. This net is made up of proteins and becomes silk fibres. This covering is known as a cocoon. The cocoon is in the colour of white, cream and yellow.
- It is made up of a single thread which can be around 1KM long. Once the pupa matures inside the cocoon, it breaks the cocoon and becomes an adult moth.
- The metamorphosis of pupa to moth in a cocoon takes around 10-14 days. The moth mates immediately after coming out from the cocoon.

Thus the correct answer is (B) Larva secretes silk.

Note: Metamorphosis is the process by which an animal undergoes rapid physical changes after birth to form an adult. For example in silkworm metamorphosis takes place in the stages like egg, larva, pupa, adult.