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SILKWORM

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1. Simran Neupane 2. Prenisha Upreti 3. Sadhwi Uprety 4. Pratikshya Awasthi 5. Suvangy Lohani 6. Neha Dangaura

Presentators:

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S.N. TOPICS SLIDE NO. 1. ACKNOWLEDGEMENT 4 2. INTRODUCTION 5 3. CLASSIFICATION 6 4. EXTERNAL STRUCTURE 7 5. LIFE CYCLE 8-15 6. HISTORY OF SILK 16 7. ECONOMIC IMPORTANCE 17 8. EDUCATIONAL VISIT 18-20 9. QUESTIONS 21 10. CONCLUSION 22

CONTENTS

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Acknowledgement

We would like to express our special thanks of gratitude to our science teacher Mr. Krishna Prasad Bhusal ,who gave us the golden opportunity to do this wonderful presentation on the topic ‘SILKWORM’ , which helped us in doing a lot of research and came to know about much more new things related to it. We would also like to thank our parents and friends who helped us a lot in finalizing this presentation within the limited time frame.

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INTRODUCTION

Silkworm is a very important insect to us. It forms a quality of fibre called silk obtained from the cocoons of a silkworm. Mainly , two kinds of silkworm are reared in our country. They are ERI SILKMOTH (Attacus ricinii) and SERI SILKMOTH (Bombyx mori). ERI feeds on caster leaves whereas SERI feeds on mulberry leaves.

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CLASSIFICATION OF SILKWORM

Kingdom : Animalia Sub-kingdom : Invertebrata Phylum : Arthropoda Class : Insecta Type :Silkworm / Silkmoth

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External structure

The silkworm is creamy white in colour. It is about 2-3 cm long and shining in nature. The body is divided into 3 parts namely head, thorax and abdomen. The body of the silk moth is wider than the male silkmoth due to large number of egg it contain.

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Life cycle of silkworm

Silkworms are unisexual. The male and female silkmoth mate in the tail to tail position and fertilization is internal. After mating, the male dies . The female survives for about 4-5 days only after mating. The life cycle of a silkworm completes in about 45 days. The life cycle of a silkworm has 4 phases. They are: EGG LARVA PUPA ADULT

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Larvae

Eggs

Larvae

Pupae

Eggs

Adult

Pupae

Adult

Eggs

Larvae

LIFE CYCLE

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EGGS

After mating, the female lays about 300-400 eggs in clusters upon mulberry leaves. The egg laying is completed in 1- 24 hours. When the eggs are placed at the temperature of about 18 to 25 Degree Celsius, the larvae emerge out from the eggs within 10-12 days.

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LARVA

A silkmoth passes through 5 stages during the larvae phase of its life . This 5 stages are called instars. After the 4 th moult, a pair of long sac like silk glands develop on the lateral side of the body of the 5 th instars .the silk glands secrete a kind of sticky fluid. When the secretion of the silk glands comes in contact with air , it becomes hard and fine thread. Then the larvae caterpillar gets enclosed in this fine thread, which actually forms a case around its body ,this is called cocoon. The cocoon is a white or yellow ,thick oval capsule made up of silk. It completes in about 25 to 32 days.

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Normal egg 3-4 days 7-8 days Fresh cocoon with live pupa harvesting Cocooning 1st instar 2nd instar 3rd instar 4th instar 5th instar, 5th instar, Diapause egg RATE OF LARVAL GROWTH 1 st days last days lx 20x 120x 730X 2,640x 10,000x 6-8 days Egg hatched Ant (newly hatched) 1st instar 3-4 days 1st molt 2nd instar 2-3 days 2nd molt 3rd instar 3-4 days 3rd molt 4th instar 3-4 days 4th molt 5th instar Matured or ripened silkworm

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Pupa

It is the inactive stage in which its body is protected in a cocoon and under goes very important active changes. Its completes in about 12-14 days . Silk fibre is obtained from the cocoon of the silkworms. They are kept in boiling water or in a hot oven to destroy the glue of the cocoons to obtain silk then the silk fibre is unwound from them .the length of thread used in the formation of one cocoon is about 1000 meter.

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Adult

After active metamorphosis the pupae changes into an adult silkworm. The imago breaks the cocoon to come out from it. It cannot fly immediately, thus it dries its wings and flies. It survives for about 5-7 days after its emergence from the cocoon. The adult female silk moth lays egg after its maturity. In this way silkworm completes its life cycle in 45-50 days.

Tail to tail mating in silk moths Female (bigger) Male (smaller)

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LIFE CYCLE OF SILKWORM SILKWORM LARVA ¯

me fez-nale moth many tiny eggs, A black caterpillar hatcheg out of its egg. Ne adult moths mate With each other. The pupa changes ADULT into a moth. of the Peo* born SILKWORM LIFE CYCLE PUPA The caterpillar eats mulberry leaves and grows bigger and bigger. It gæs through 4 rnoltg. LARVA The caterpillar spins a cocoon of silk threads around Inside the the caterpillar changes into a pupa.

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A Chinese tale of the discovery of the silkworm's silk was by an ancient empress Lei Zu, the wife of the Emperor. She was drinking tea under a tree when a silk fell into her tea and the hot tea loosened the long strand of silk. As she it out and started to wrap the silk thread around her finger, she slowly felt a warm sensation. When the silk ran out, she saw a small larva. She realized that this caterpillar larva was the source of the silk. She taught this to the people and it became widespread. Chinese Empress Drinking tea under a tree Silkworm cocoon falls Silk strand unravels and larva exposed

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Economic Importance: The silkworm industry bakes or boils the each COCcX)n is reeled. This is When one unwound from each cocoon, either by these strands are twisted together to Silk isa expensive product today . made up Of the enzyme secreted by Which then turns into fine threads Of about m Of silk . Silk isa one Of the most important people rear silkworms fora industries rear silkworms a income. The art Of rearing benefit is called overstated in its industry and fashio to kill the pupa, then continuous strand Of silk is hand orby a machine. 6-8 Of create one thread Of silk. The cocoons Of a silkmrms is the silk glands Of a silkworm silk . A single CCKOOn gives multimillion dollar business and exports from Asia. so many economical benefit . Nariy big are based on them for silkworm for commercial 'Sericulture' . It cannot be importance to commerce,

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Educational visit to K hopasi, P anauti

We students of grade 10 were taken to Khopasi silk farm , P anauti on 2076/02/09

We got a golden opportunity to learn about the different species of silk worm as well as the mulberry leaves. We got not only the theory knowledge of life cycle of silkworm but also the practucal knowledge about it. We also got to know about the different processes from where the silk is obtained.

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SERICULTURE DEVELOPMENT DIVISION KHOPASI , KAVRE

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Questions

In which phase does the larvae produce silk? What is crysalis? What is the condition for eggs to get hatched? What is the average number of eggs laid by female silk moth at a time? What is the average time period required by silkworm to complete one life cycle? Why are cocoons are kept in hot water? When there is scarcity of mulberry leaves ,what is done? Who discovered the silkworm silk for the first time in world? In which country silkworm pupae are usually used as bait to catch fish? How long does it take silk of cocoons to produce a single kimono?