SILKWORM.pptx

What is Silk Worm and its types?

1. Silkworm

2. Introduction silkworm ( Bombyx mori ) belong to family Bombycidae and order Lepidoptera. They produce silk by feeding on mulberry plants . The larvae of silkworms feed on mulberry leaves. They become pupae and form a silky cocoon on pupal body produced by the saliva from their mouth parts . When these cocoons are put in hot water and the threads of silk appear clearly. Those threads are rolled and used for commercial purpose . The silkworm industry is called as sericulture .

3. Larva Cacoon Adult

4. TYPES Silkworms can be categorized into three major groups: Univoltine Bivoltine Polyvoltine

5. Univoltine Single generation per year. This breed is generally linked with the geographical area within greater Europe. The eggs of this breed hibernate during winter due to the cold climate, and cross-fertilize only by spring,

6. Bivoltine Generally found in China, Japan, and Korea . The larval duration is short. The quality of the cocoons inferior to that of Univoltine races. The breeding process of this type takes place twice annually.

7. Polyvoltine Can only be found in the tropics. The eggs are laid by female moths and hatch within nine to 12 days. The larval duration is short . The filament is fine and clean with little lousiness; but with more lustrous . They produce more than 5-6 generations/year.

8. PROCESS OF SILK SYNTHESIS: Eggs take about 14 days to hatch into larvae, which eat continuously . They are covered with tiny black hairs. When the color of their heads turns darker, it indicates they are about to molt . After molting, the instar phase of the silkworms emerge white, naked, and with little horns on their backs.

9. After they have molted four times, their bodies become slightly yellow and the skin becomes tighter. larvae then prepare to enter the pupal phase of their lifecycle, and enclose themselves in a cocoon made up of raw silk produced by the salivary glands. The final molt from larva to pupa takes place within the cocoon. The moth – the adult phase of the lifecycle – is not capable of functional flight. Silk moths have a wingspan of 3–5 cm (1.2–2.0 in) and a white, hairy body. Females are about two to three times bulkier than males (for they are carrying many eggs), but are similarly colored. Adult Bombycidae have reduced mouth parts and do not feed, though a human caretaker can feed them.

10. COCOON Cocoon is made of a thread of raw silk from 300 to about 900 m (1,000 to 3,000 ft.) long . The fibers are very fine and lustrous, about 10 μm (0.0004 in) in diameter. About 2,000 to 3,000 cocoons are required to make a pound of silk (0.4 kg ). At least 70 million pounds of raw silk are produced each year, requiring nearly 10 billion cocoons.