Muga Silkworm and Muga Silkworm life cycle

Muga Silkworm

The Muga Silkworm has its natural habitat in the deep forests of the North East India. The species is also found in Nepal, Bhutan and Myanmar. The Muga Silkworm is cultivated mainly in Assam (North East India), but also in neighbouring Meghalaya, Arunachal, Manipur, Mizoram, Nagaland and part of West-Bengal.

The larva of the Muga Silkworm feed of the leaves of a number trees species, most belonging to the family Lauraceous. The most important host species in Upper Assam Som tree and Lower Assam the Suala tree.

 Muga Silkworm life cycle

The tiny, newly hatched larva move high up in the top of Som or Suala tree and commence chewing the tender leaves. Later, as the larva grow in size and become green they gradually descend in the tree canopy. During their 3th instars,  the larva frequently cut off the base of a leaf, which is a peculiarity of the Muga larva and regarded as a sign of a healthy brood. One brood my denude all the leaves of a tree.

Having reached the end of the 5th instars,  the 12-13 cm long larva moves down the stem of the tree and starts spinning its cocoon between dry leaves on the ground. The larva  forms a hammock by semi-circular movement of its two spinnerets located at the base of the mandibles.

The larva then turns several hundred times until the extrusion of silk is completed and a golden or darker yellow cocoon, with a seemingly regular ‘woven’ surface structure, is finally formed. The length of the cocoons varies between 45 and 60 mm.    The adults have a wings of 11-15 cm. The female Silkworm may lay 150-300 eggs.

Muga Silkworm Culture

Both host tree species- Som and Sualu- can be planted and are suitable for rearing after about 5-6 years of growth and can withstand regular pruning. The larva reared on Som leaves yield more Silk and the resulting female Silkworms lay more eggs than larva reared on other host tree species.

It is the privilege of some particular tribes to collect the basic seed cocoons, which are sold as soon as possible to breeders in the plains of Upper Assam. The rearing of seed cocoons is conducted mainly by tribes from the plains. The Garos, Khasi, Boro, Rava, Kachari, and other tribes of Lower Assam, while the Ahoms in Upper Assam rear autumn and spring broods which become reeling cocoons – the primary raw material for Silk.

Breeders place considerable importance on procuring disease- free seed cocoons, thus ensuring that the next generation brood will be healthy. Careful surveillance of the last phase of seed cocoons rearing is a common practice. There are some particular characteristics of healthy broods which the producer perceived and understand with keen acumen and strict observation.

For breeding purpose, middle stage cocoons are selected where males and females emerge is equal numbers. The emerged Silkworms mate and very often stray males are lured into mating by trying the female Silkworm and leaving her in a secluded place, preferable in the open air.

A fertilized female Silkworm securely tied to a twig deposits about 200-brown-greyish 2-3 mm large egg on a bunch of straw this call Kharika. 

A special type of water is sprinkled to sanctify the eggs or to cleanse them of disease. In the early hours of the morning, the Kharikas are then hung on the sunny part of a tree facing east. The eggs should be examined for the pebrine disease which, however is seldom done due to the 3-4 days required for this strenuous job, The eggs hatch after about 9-10 days.