Samia ricini, or the Eri silkworm, is raised in India and parts of the Orient for its silk. They will be a couple of days behind all the way through their life cycle. Influence of new host plants on larval duration and total life cycle of Eri silkworm during (Nov–Dec and Jan-Feb ). 3. Influence of new host plants on. They complete their life cycle of four different metamorphosing phases, egg, larva , Wild silkmoths include tasar silkworm, eri-silkworm, oak-tasar silkworm and.
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In this article we will discuss about the life cycle of various silk moths: Tasar Silk Moth 2. Eri Silk Moth 3. Tasar silk is generated by the worm of the silk month Antheraea mylitta. It lkfe for 2.
Samia ricini, the eri silkworm
This silk moth is available in China, Sri Lanka in addition to India. The tasar silkworms are grown only in the wild. So they are cultivated in places where their host plants are available.
By piercing one end of the cocoon the adult moths come out.
Life Cycle of Various Silk Moths
Adults are very large with colourful wings spanning about 15 cm. Female has yellowish grey wings and males lifee yellowish red wings with prominent eye spots on each wing Fig.
The males mate the females just after emergence. The eggs hatch within days during summer and days in winter. Following hatching the larvae ctcle taking food leaves from the host plants. The worms are generally green in colour with hairs on cuticle [Fig. It moults 4 times during the whole larval silkwor that continues for days during summer and days during winter.
The mature larvae spin cocoons which are hard od different colours according to the types of plant leaves they fed. Some are light green, others are yellow, and some are grey and others almost white Fig. Unlike mulberry cocoons, the tasar cocoon has a stalk peduncle which helps in fixing the cocoon with the twig of host plant [Fig.
The tasar rearer collects the female moth from the wild and keeps it tied with the twig of host plant carefully. The males are then attracted by the pheromone secreted by the female and start copulation. After mating the female lays eggs which are collected by the farmers and are gummed on long strips of paper- or leaf-made cup which are then hung on suitable host trees, where they hatch quite naturally.
A barrier of some sort is coiled around silkwogm host tree trunks to prevent the caterpillars from wandering. The worms after hatching start feeding the leaves. On completion of the spinning, the cocoons are harvested like fruit. Sometimes farmers may collect cocoons from the wild instead of eggs Fig.
Tasar filaments show the greatest length among the non- mulberry silks, m. The spun yarn is generally coarse xilkworm a denier ofwhile the reeled yarn is fine and thin with a denier value of Tasar silk has natural shades of pale gold, pinkish honey, creamy copperish, etc. It eeri less lustrous but coarser than mulberry silk. The fabric is light, airy, and stiff, and has its own feel and appeal.
Erk finer variety of tasar silk is generated by the silkworm Antheraea proyeli and A. These moths feed on leaves of oak, are found in abundance in sub-Himalayan belt. The oak tasar is finer than the common tasar silk. The silk worms silkwlrm the silk moths Philosamia ricini and Attacus ricini generate a different kind of white silk, called eri silk. Ericulture eru a small scale industry. In fact, eri cocoon is considered as a palatable item to the local people of Assam.
Castor, the host plant of eri moth is mainly used in other parts of India for production of seed as a valuable material; but in N. It is found in East Asia. In India, it is cultivated mainly in the North-Eastern states including Assam. Eri worms are polyphagous having primary as well as secondary food plants hosts. Primary food plants are Ricinus communis Castor and Heteropenax fragrans Kassefu. Castor plants are of two varieties; the green leaved [Fig.
Both are equally suitable for feeding the eri silkworm. The secondary food plants are Manihot utilissima Tapioca. The eri silkworn is multivoltine in nature and can pass 6 life cyclee in a year. These worms are totally domesticated and are reared indoors. The wings are greyish brown in colour with prominent eye spot [Fig.
When the adult moth emerges from a cocoon it makes a hole to get out. Like other silk moths, eri moths also start mating activities following their emergence from pupal stage. Following mating, the female starts egg laying that may continue up to 3 days. Each female can lay about eggs [Fig. The hair like newly hatched larvae are yellow in colour [Fig. Initially they feed on soft castor leaves but at later stages, worms can feed on mature leaves.
After moulting for 4 times by 32 days [Figs. Caterpillars in their final stages start spinning the cocoons. The spinning is completed in days. The cocoons are open mouthed, tapering at one end and flat rounded at the open end. Eri cocoons are stalkless, flossy, white or brick red in colour [Fig. Disease-free seed cocoons are obtained from grainages or agencies and reared fully indoors. Healthy cocoons are spread on bamboo trays in cool dark room. On hatching, active males are separated from passive females and are then allowed to mate in quiet dark room.
Kharikas are then suspended from a string. Eggs are laid within 25 hours on Kharika and are normally selected for rearing. The eggs are white, oval and covered with a gummy substance, which makes them adhere to one another. Hatching takes place in the morning after ten days of incubation.
These larvae are brushed to rearing trays over which few tender food leaves are spread, and crowding is avoided. As the worms advance in age, older leaves can be given as food at 2-hour interval for four to five times. Bed cleaning is carried out at regular interval in the same way as for the mulberry silkworm. The growing worms undergo four moults and have five instar stages. Total larval period lasts for days. The 5th instar, mature larvae stop feeding and start searching for a proper place to spin the cocoon.
At this stage, the mature worms are picked up and transferred to mountages Chandri-kas. In wild, cocoons are spun between folds of leaves. Stifling is done by spreading and exposing the cocoons to the sun for 1 -2 days. For degumming, cocoons are tied in a cloth sac and dipped in boiling soda solution. After sufficient boiling, the cocoons are taken out washed with water several times to remove soda, squeezed to remove water and then spread on mats to dry.
So, the thread can only be spun and not reeled. Traditionally, spinning is done in wet condition on takli and in semidried condition on a charkha. Improved spinning machines like N. Das type charkha and Chaudhury type charkha are also available for spinning of silk from eri cocoons. The silk produced by eri moths is referred to as eri and endi or errandi silk by local people.
This silk is collected from pierced cocoons, so it is spun silk. The fibres in the cocoon are like a tiny bale of cotton, all wound together and tangled. So when eri silk is spun, it forms a lower grade of silk of unusual quality. Depending on how it is spun and woven it can give a very woolly result and as with poorly made wools, eri can feel like cheap acrylic. But it can also give a tight, strong fibre-like linen.
This is what makes eri textiles amazing — they can have the drape and weight of linen but are warm and insulating like cotton or wool Eri silk is less glossy and wrinkleless. Muga is produced from cocoons of Antheraea assamensis which is available only in Assam. The most expensive of silks, muga, is intrinsically woven into the off traditions of the people of Assam.
The vibrant Sualkuchi sarees and mekhla-chaddars are the traditional items made from muga silk. The specialty of this silk is its golden bright colour.
It is superior in every respect from the normal white silk available all over the world. The native place of this moth is Assam.
Its production was confined to Assam, border areas of neighboring north-eastern states and Cooch Bihar in West Bengal. Now it is reared in Nagaland, Meghalaya and Andhra Pradesh also. The muga worm feeds on aromatic leaves of Som [Fig.
It can also be reared on host plants similar to that of tasar worms. The moth is multivoltine the entire life cycle lasts for about 50 days in summer and days in winter.