Sericulture

Sericulture definition, types of silk, equipments and methods used in sericulture...

1. Economic zoology

2. Name : mahpara nabeel class: 7 th sem Bs ( hons ) ZOOLOGY

3. SERICULTURE SILK has been under use by human beings for various purposes. It is known as “the queen of fibres ” High scale production of silk in world. Rearing, developing and looking of silk insects is termed as SERICULTURE

4. HISTORY Lotzu empress of kwang -Ti discovered the origin of silk worm in the form of thread. But its technique was kept in secret. The sericulture technique was known to only china, and one who tried to open it, hanged to death. Then this secrecy was opened when two spies from EUROPE were sent to CHINA.

5. Silk moth The silk producing machine is an insect called as SILK MOTH( resham ka kira ). Types of silk Mulberry silk T asar silk Eri silk Muga silk

6. Mulberry silk This is supposed to be the superior in quality to other types due to its shiny and creamy color. It is secreted by caterpillar of Bombyx mori which feed on mulberry leaves.

7. Tasar silk Antheraea paphia , common in India, china and sri lanka . Catterpillar feed on ber , oak, and fig plant. Cocoon is hard and hen’s egg size which produces brown colored silk.

8. Eri silk Produced by caterpillar of Attacus ricini which feed on castor leaves Color is creamy white like mulberry but less shiny.

9. Muga silk Antheraea assama Native place is assam , good source of cottage industry. Catterpillar feed on Machilus plant Semi domesticated

10. Life cycle of silk moth, Bombyx mori

11. Physical characteristics It is pale, cream or ashy white in color. 2.5 to 3 cm long and covered with small color. Body is divided into head thorax and abdomen. Head is big having large compound eyes and a pair of antennae. Thorax is strong muscular three segmented structure provided with spiracles 2 pair of wings(4-6cm long) and 3 pair of legs.

12. Physical characteristics Abdomen is covered with scales and highly extended in females whereas narrow in males. Sexes are seperate , sexual dimorphism exist. Males small in size than females Females live for 2-3 days but males sometimes die during copulation, once females copulate they lay eggs(all fertilized) till she dies. One moth lay eggs 400-500 eggs depending upon climatic conditions and nutrition.

13. Stages of life cycle Eggs eggs are rounded and white. With increase in time egg become darker day by day. Two types of eggs are present:- Diapause : eggs are laid by silk worm inhabiting in temperate regions, all vital activities are ceased. Non- diapause : silk worm belong to sub tropical region like india .

14. Eggs of bombyx mori

15. caterpillar Hatches from egg are 5-7mm in length ,body is rough, wrinkled and greyish in color. Have 12 segments , distinct into 3 parts i.e head, thorax, abdomen Head is mandibulate mouth parts ,feed on leaves. Thorax has 3 segments bear a pair of true jointed legs.

16. caterpillar Abdomen has 10 segments . Larva feed on mulberry leaves and grow very quickly. Stop feeding, become inactive after 4 to 5 days then 1 st molting occur. 2 nd stage larva is similar to 1 st one but slightly larger., eat for 7 days and 2 nd molt occur. And 3 rd larva formed. Larva repeats this process four times .

17. caterpillar Maturity is achieved in 45 days since time of hatching. And matured catterpillars are now 7-10cm. By this time formation of a pair of salivary gland is completed . Salivary glands secrete silk that are also called as silk glands.

18. caterpillar

19. pupa Fully formed instar larva undergo physiological changes and become restless. Due to intrinsic hormonal reasons. Moves its head in whirling position , constantly and rapidly rotates head at its axis & in mean time saliva comes out through a small pore known as SPINNERET . Located on tip of hypopharynx in mouth. There is continous flow of saliva through this pore.

20. pupa

21. cocoon White color bed of pupa whose outer thread are irregular and inner threads are regular. Thread’s length is 1000-1200m, in concentric manner . Binding of threads round cocoon is very quick i.e 65 times/min Now silk worm pupa is covered with thick, oval white or yellow silken cocoon.

22. emergence of imago Active metamorphic changes take place during pupation in which abdominal prolegs disappear, thorax develop two pairs of wings. Pupa is metamorphosed into young adult moth in 12-15 days called as IMAGO It secrets alkaline fluid that soften one end of cocoon and come out

23. emergence

24. sericulture This is multivoltine (having several broods within year) They are of domestic types and can b reared indoors Large and healthy cocoons are selected, kept in vantilated cages emerge after few days Males and females are distinguishable. Kept in pairs in coupling jar for 24 hours copulate females transferred to egg laying boxes made of cardboard Female lay 300-400 eggs.

25. Tools and materials Machana : proper place for rearing silk worm Rearing trays : for keeping laid eggs along mulberry leaves Spining tray : for keeping caterpillars at time of full grown stage ready for pupation. Dalas : for fetching mulberry leaves Chopping knife : cut mulberry leaves Baskets : distribute mulberry leaves Hygrometer, thermometer oven and freezers are also used.

26. Rearing of silk worm 5 stages for rearing Supply of eggs : quality of seeds is important, only those eggs are given that has been produced in a well recognised grainage ( where eggs are made) Incubation of eggs : incubation conditions should be optimum. For uni voltine eggs 73.5-77*F, 77*F for bi voltine and 80*F for multi voltine . Humidity 75-80% For incubation seeds are spread on piece of paper In rearing tree.

27. 3. Brushing of worms : to separate newly hatched worms from shells of their eggs by means of a feather The process of brushing is spreading finely chopped mulberry leaves on the egg sheet after 95% eggs are hatched. The newly emerged worms crawl on top of feed. & then transferred to rearing tray 4. Rearing of worms : it requires following Rearing room : ventilated, protect against direct sun rays, well disinfectant with 2% formalin.

28. Rearing appliances : wooden racks, chopping knifes, leaf storing basket, gunny cloth pieces, door curtain etc Leaves & their preservation : harvested by cutting and plucking of leaves, preserved by keeping in basket covered with gunny cloth. Feeding : feed with mulberry leaves at different intervals, different staged larvae need different amount of food.

29. Cleaning : cleaning of trees is necessary to remove excreta. Spacing: necessary to give proper spacing, avoiding over crowdedness & spread of disease providing high temp. at first two stages(80-85F) & in 3 rd 4 th stage 10 degree lower. With humidity 85-90%. Mounting & harvesting : when worm is fully grown & appitite fails become restless and start spining out of cocoon. Put in cocoonages

30. 5. Spinning of cocoon: period in which worm stop feeding and start secreting a pasty substance from silk gland. Worms picked up and put in spinning tray & kept in position of slope to the sun for short period. Within 3 days spinning is done Cocoon formed Last stage of rearing

31. 6. quality of cocoon : depend on raw silk, filament length ,reliability & splitting. Marketing of cocoon : price of cocoon is fixed by govt. Post cocoon processing : the method of obtaining silk from cocoon is called as post cocoon processing. It includes stifling & reeling Stifling: “killing of cocoon” 8-10 days cocoon selected. Dropped in hot water(helps in unwinding), sun exposure to 3 days

32. Reeling: process of removing threads from killed cocoon Threads are transferred to large wheel then to spools called as reeled silk. Waste outer layer & damaged cocoon & threads are separated and filaments are spun. This spuned silk is called as spun silk. Raw silk is further boiled, stretched and purified by acid or by fermentation carefully washed again & again.

33. Rearing of silk worm

34. Diseases and enemy of silk worm Grasserie disease : viral, formation of polyhedral bodies in body fluid, hypodermic infection. Control is difficult. Preventions include sterilization of tools, optimum temp., cleaning and proper spacing. Pebrine : most serious one, protozoan parasite( Nosema bombycis ), effect young larva by loss of appitite , irregular moulting and growth. Muscardine disease : fungal, lose of appitite , specks appear on skin, body become limp, elasiticity loose & movement stop, death, appearance of white spores.

35. predators Tricoliga bombycis : parasite fly lay eggs near body of catterpillar larva upon hatching feed on tissue of caterpillar that dies. Canthecona fincellatta & tanchid fly : have long rostrum with the help of which penetrate body of silk worm, hemolymph oozes out & worm die. Ants, hornets, bats, kites atc feed on it.

36. Properties of silk Pasty secretion of silk gland; modified salivary gland When contact with air become hard and form strong silk strand. Secretion form 2 cores of fibroin( 1) tough elastic insoluble protein cemented together with sericin (2) gelatinous easily soluble in warm water. Wax & carotenoids are also detected.

37. Uses of silk Silk clothes Synthetic fibers For military purposes Fishing fibers Parachutes Tyres of racing cars Insulation coils of telephones Medical dresses & suture material.