SEE | Biology | Unit-14: Invertebrates
Answer these questions.
a. What is sericulture? What kind of silk worms are reared in Nepal?
Ans: the lultivation of silk worm is called sericulture. These are two types of silk worm reared in Nepal, i.e. Eri-silkworm and seri-silkworm, etc.
b. Describe the structure of a silkworm with a diagram.
Ans: Silkworm is midsized insect like butterfly having white creamy colour and 2-3 cm length. It’s body is divided into three parts:- Head, thorax and abdomen. It has pair of antina, wings and three pair of legs.
c. In Which phase does the silkworm produce silk fibres?
Ans: In pupa stage the silkworm produce silk fibres.
d. How are eggs kept in safe way when mulberry leaves are not available?
Ans: When mulberry leaves are not available then eggs can be store to kept in safe.
e. What is an instar? How many times does a silkworm moult in its larval stage?
Ans: The hatched larva is called first instar. Five times silkworm moult in its larval stage.
f. What is cocoon? Why is it kept in hot water or air to obtain silk fibres?
Ans: The pupa stage is called cocoon. It is kept in hot water or air to obtain silk fibres because to kill pupa.
g. Explain the economic importance of silk worm.
Ans: The economic importance of silk worm are:-
- Silk is use to make clothes.
- It improves economic condition of farmers.
- Intestines of silk worms are extracted to make strings (gut), etc.
h. Mention the features of silk fibres.
Ans: The feature of silk fibres are:-
- Silk is a shining, light and durable fibre.
- It is longer and more elastic.
- It can be coloured easily, etc.
i. Draw the life cycle of silk worm.
j. How do eggs of silk worm get stuck with leaves?
Ans: Eggs of silk worm get stuck with leaves due to that they are covered by gelatinous seeration.
k. Mention systematic position of silk worm.
- Kingdom – Animalia
- Sub kingdom – Invertebrata
- Phylum – Arthopoda
- Class – Insecta
- Type – Silk worm