Question

A dorsal horn is present on the _________ of the mulberry silkworm (caterpillar).
A. Head
B. 8th abdominal segment
C. 5th abdominal segment
D. 2nd thoracic segment

Answer 1

Hint: The scientific name of the mulberry silkworm is Bombyx mori. It is also known as the Chinese silkworm. Mulberry silkworm belongs to the class Insecta, subclass Pterygota, and order Lepidoptera. This silkworm is famous for having the highest quality of silk. The main food of this silkworm is the leaves of the mulberry tree. Thus it is known as the mulberry silkworm.

Complete answer: The body of the silkworm is divided into the head, thorax, and abdomen. Head bears mouthparts. The mouthparts of the adult silkworm are reduced. That’s why they are not able to eat. The dorsal horn is not present in the head. So the option is incorrect.
There are 11 segments found in mulberry silkworm. Caudal horn is located on the eighth segment of the abdomen on the dorsal surface of the body. The maximum length of the caudal horn is 75mm. Mulberry silkworm uses the caudal horn to protect itself from environmental hazards. So it is the correct answer.
The thorax of the mulberry silkworm functions as the joining point of the body. It is responsible for the joining of legs and the wings which are used for the locomotory purpose. It does not comprise the caudal horn.
So, the correct answer is “Option B”.

Note: Silk which is collected from the silkworm is a natural protein. Silk has great commercial value in the market as an animal fiber. The process by which silk is obtained from the moth is known as sericulture. There are four types of silkworms found in India. These are mulberry silkworm, Tasar silkworm, Muga silkworm, and the Eri silkworm.