Question

In silkworm, silk is the product of.
a. Salivary gland of the larva
b. Salivary gland of the adult
c. Cuticle of the larva
d. Cuticle of the adult

Answer 1

Hint: The insect silkworm had grown domestically by the farmers for the production of silk. The scientific name of a silkworm is Bombyx mori and a family of silkworms is Bombycidae. The cultivation of silkworm for the production of silk is known as sericulture.

Complete answer:
Silk: It is the strongest protein fiber composed of fibroin. It is used to make fabric and cloth. The silk cloth is healthier for skin.
- There are 300 – 500 eggs laid by female silkworms and covered their eggs with white fibers.
- After 10 days of incubation, the second stage of larvae called caterpillars get hatched from the egg. They are grown and molted completely by eating mulberry leaves.
- When the caterpillar grows completely, it develops salivary glands in between the head and mouth region.
- Then it secretes a sticky fluid (silk) from the salivary gland through the hypopharynx of the larvae.
- The fluid which was secreted by larvae is sensitive to the environment. So, it develops a covering layer called cocoon.
- Then, these cocoons are taken away from the leaves and boiled by the farmers to kill the caterpillar which is present inside the covering layer.
- Then the silk is obtained from the cocoon and is ready to use for making fabrics.
- In silkworm, silk is the product of the salivary gland of the larva.

Hence, the correct answer is option (A).

Note: The salivary gland of larva, be used to obtain silk easily when it is compared to the salivary gland of adult silkworms. The cuticle of an adult and a larva, is the outer covering layer of the silk moth. It does not produce silk.