Journal of Insect Biotechnology and Sericology 84, 17-28 (2015): Technical Report

INTRODUCTION

　Despite the fact that sericulture in India goes back thousands of years, possibly even preceding that of China (Cloudsley-Thompson, 1976), surprisingly little informa-tion is available on traditional sericultural practices in In-dia. Passed down within a society, a tradition is a belief with special significance and origins in the past. The rear-ing of sericigenous insects (for review, cf. Yokoyama, 1963), is an age-old tradition especially for the people of North-East India, with Assam being the only state in India that uses all four of the silk-producing species. According to Unni et al. (2009) the species are known locally as pat (Bombyx mori), muga (Antheraea assama = assamensis), tasar (also known us tussah) (Antheraea mylitta, A. pernyi and A. paphia) and eri (Philosomia ricini). Remarkably muga and eri silkworms are found almost entirely in the Brahmaputra valley of Assam (Borthakur, 2003), parts of Nagaland (Meyer-Rochow and Changkija, 1997) and at the foot hills of Meghalaya (Chakravorty et al., 2010).　Physical and chemical differences between the fibres of muga, tasar and eri silks have been reviewed by Babu (2012), who has shown that the three wild types of silk not only differ considerably from the domesticated mul-berry-based Bombyx mori silk in terms of optical proper-ties like lower birefringence and possessing much more

alanine and proline, yet far less glycine than mulberry silk, but that also amongst the three types of wild silk based fabrics considerable differences exist (Table 7.2: Babu, 2012). Lowest tenacities given as g/denier, for ex-ample, are 2.3 for eri, 3.2 for muga and 3.74 for tasar silk fibres, while highest tryptophan and lowest serine contents of all silk types analysed and compared by Babu (2012) appear to be special characteristics of muga silk.　Assam is a uniquely suitable place for muga culture due to its favourable climatic conditions and is renowned for its golden-coloured muga silk yarn (Unni et al., 2009; Saikia, 2012). Our survey revealed the many uses that this type of silk has: cloths made out of muga silk are UV-protective, colour stable (everlasting) and comfortable to wear in both the summer and winter seasons. The threads of silk are used in surgical sutures as well as in regular clothing and muga yarns are incorporated into aircraft tyres, bulletproof jackets and parachute ropes (Nath, 2013). Muga silk is therefore of considerable socio-economic value as it contributes significantly to the economy of the country. Although the name of this moth, i.e., Antheraea assama = assamensis indicates the insect’s origin is As-sam, the precise origins of muga culture in Assam are still a mystery. However, according to Cloudsley-Thompson (1976) “...references in Sanskrit literature suggest that a silk industry may have existed in India at about 1,000 BC, or possibly even as early as 4,000 BC”. It is certain that muga sericulture was important during the era of the Ahom kings (1228-1828 A.D.), who took a special inter-est in it, but that it later fell into decline during the Brit-

　Assam is well known for the production of golden-coloured silk from muga (Antheraea assama = assamensis) silkworm. Muga culture has a long tradition amongst the rural community of North-East India and the people of the district of Dhemaji in Assam are no exception in this regard. The process of culturing muga involves three successive phases, which are distinguished as pre-rearing, rearing and post rearing. The traditional rearers fol-low a variety of indigenous practices that were passed on from generation to generation by word of mouth. In re-cent years, however, these age-old, religiously followed and highly respected practices involving every step and stage of muga culture are often no longer adhered to by the younger generation of culturists. This disregard and/or ignorance of the traditional ways can compromise the quality of the muga silk product. The present study has been undertaken to record and publicize the traditions associated with muga rearing still being followed by the rural inhabitants of the Dhemaji district of Assam.　Key words: Silk, silkworm culture, age-old practices, rearing methods, sericigenous insects, Saturniidae (Lepi-doptera)

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Cultural Attributes and Traditional Knowledge in Connection with the Rearing of Muga (Antheraea assama = assamensis)

in the Dhemaji District of Assam, North-East India

1 Biochemical Nutrition Laboratory, Department of Zoology, Rajiv Gandhi University, Itanagar, Arunachal Pradesh-791112, India2 Department of Biology, Oulu University, Oulu FIN 90140, Finland

3 Research Institute of Luminous Organisms, Hachijo Island, 2872 Nakanogo, Hachijojima, Tokyo 100-1623, Japan

(Received February 20, 2015; Accepted March 26, 2015)

Jharna Chakravorty1, Mallika Gogoi1 and V. Benno Meyer-Rochow2, 3,＊

Chakravorty et al.18

ish period due to a lack of proper support (Mahan, 2012).　The muga insect (Antheraea assama = assamensis) is a semi-domesticated variety of polyphagous silkworm moth that does not, however, feed on mulberry as a larva. Its principal host plants are: som (Persea = Machilus bomby-cina) and the sualu trees (Litsea monopetela, L. polyan-tha). Secondary host plants are mejankori (Litsea cubeba), and dighlati (Litsea salicifolia). Traditional rearers usually preferred the som tree for the production of good quality silk yarn, but the sualu tree was favoured for seed cocoon production due to the resultant variation in colour and compactness of silk yarn. However, when produced by us-ing the host plant som, the cocoon is brighter and shinier than that of the sualu plant.　The colour of the silk yarn furthermore varies with re-gard to the seasonal variation. Muga culture is an outdoor practice, which is strongly affected by climatic and other environmental conditions. The larvae are prone to disease caused by seasonally varying kinds of pathogens and the larvae are at risk of attack by numerous pest insects, pred-atory animals and parasites. Yet, Muga culture remains an activity in the rural landscape, because traditional meth-ods developed by local culturists have been capable to hold back the losses of Muga silkworms at low stage. These methods, passed down from generation to genera-tion only by word of mouth, may or may not have a scien-tific background, but they represent indigenous knowledge that may be crucial for muga sericulture and thus has to be worth recording.　Traditional rearers believe that muga silkworms are holy and that the rearing depends on the blessings of the gods. With regard to sericulture in Upper Assam, a num-ber of proverbs exist, of which this may serve as an ex-ample: “Ahu kheti ahu kal muga kheti kopal val hali kheti korilei pai”. In English this means that ‘cultivation of rice depends on the season, but the rearing of muga depends on the fate of the rearer”. Therefore, even today, muga rearers in the rural areas implement traditional knowledge at each and every step of the entire rearing and spinning process-es. Although some aspects of the indigenous practices re-lated to muga culture have been recorded (Borthakur, 2003; Phukan and Chowdhury, 2006; Unni et al., 2009; Chakravorty et al., 2010; Sarmah et al., 2010; Nath, 2013) the available information is fragmentary and incom-plete. The present study was undertaken to remedy this situation and to provide a record of the traditional wisdom before it may be eliminated from the society.

MATERIALS AND METHODS

Collection of data　For the collection of primary data extensive field sur-veys were conducted in thirteen different villages of the

Dhemaji district in the North-Eastern region of Assam, i.e. Gohain gaon, Bakal gaon, Jamuguri, Nahoroni, Khojua, Saru ajuha, Kolakota, Bormer, Puwa saikia, Ghuguha, Bo-rajan, Deogharia and Pukia. The surveys were based on interviews. A total number of 15 villagers between 45-75 years of age (10 male and 5 female) from each of the vil-lages surveyed were interviewed to reveal information about their muga silkworm rearing techniques.

Area of study　The Dhemaji District lies between 94°12′18″E and 95°41′32″E longitude and 27°05′27″N and 27°57′16″ N latitudes. The district covers an area of 3237 km2 and basi-cally represents an extensive plain with diverse bio-ecolo-gy of tropical to temperate characteristics at an altitude of 104 m above the MSL. Temperature extremes are 5.9°C in winter and 39.9°C in summer, while relative humidity an-nual precipitation range from 73-90% and 2600-3200 mm, respectively. The soil type is alluvial and laterite (i.e., rich in iron oxides) with abundant humus and pH-values local-ly varying between 4.9 and 7.95. Physiographically the region is swathed by mountains and dominated by the plains of the Brahmaputra. The Dhemaji District, which has a population of close to 700,000 is one of the border districts of Assam to Arunachal Pradesh.

RESULTS AND DISCUSSION

1. Traditional muga culture　Muga culture traditionally distinguishes pre-rearing, rearing and post rearing phases. Each of these phases is connected with different traditional methods that come into use at successive steps. The numbering of the subsec-tions is designed to make navigating through the paper easier.

1.1. Pre-rearing procedures (Figure 2 a-q)　Before initiating the rearing of muga silkworm the local people take great care in first choosing the most suitable site to grow the silkworm’s host plants, principally Persea bombycina. The criteria for choosing a place that can be turned into a muga rearing farm, locally termed somoni, are primarily based on the health of the plants growing there. Young plants with heights of around 2 m and an abundance of fresh leaves, away from the roadside in ar-eas where the plants are exposed to direct sunlight are preferred to older plants closer to the road.

1.1.1. Rules to be followed for maintaining the farm　The traditional rearers strictly obey the following rules: 1. To protect the farm from intruders, the rearers prepare a bamboo fence around the somoni. 2. Dry and damaged

Traditional muga silk culture in Northeast Assam 19

branches, unwanted trees, shrubs, weeds, grasses and herbs, which could harbour pests and spread disease-caus-ing microorganisms, are burned in the somoni. 3. To re-move ants from the plant, rearers may place a dead fish, frog or a lizard of the genus Australolacerta, locally known as naipia, near the base of the tree to first attract the ants in large number and then to burn them off. 4. To drive the cattle away from grazing the host plants, clumps of cowdung are deposited around the base of the trees. 5. To control diseases (e.g., grey blight) affecting the host plant’s leaves, the rearers regularly plough the soil of the somoni. 6. To treat stem borer attacks, the rearer applies mud on the trunk of the affected trees or closes the holes made by stem borers with mud.

1.1.2. Selection of ideal host plant　The rearers know that the success of rearing muga de-pends mainly on the quality of the host plant som (i.e., Persea bombycina). Rearers classify individual som plants according to the shapes of their leaves. For example, they are called aampotia if their leaves resemble those of man-go trees (Mangifera indica); jampotia if they resemble those of blackberry shrubs (Syzygium cumini); belpotia if they look like those of the wood-apple tree (Aegle marme-los) and nahorpotia if they are similar to those of the In-dian iron wood (Mesua ferrea). Given the variety of leaf shapes, som plants classified as nahorpotia are the most preferred. However, not only leaf shapes, but also the taste of the leaves is important. Nahorpotia leaves are said to possess either bitter or sweetish tastes and that the

sweetest ones are indicative of a superior quality, i.e. may represent leaves that are neither too young nor too old and can thus be easily digested by the muga larvae. Older leaves are believed to be more fibrous and more difficult to handle by the larvae.

1.2. Selection of seed cocoon, known as sanch1.2.1. Variety of muga silkworm breed　The rearers select the seeds or sanch according to the sizes of the larvae and the cocoons. Larvae and cocoons of larger sizes are believed to indicate a greater propensi-ty for adaptiveness than smaller ones do. The rearers term the smaller larvae kukurbahi and the larger ones as kami-ni. The cocoons formed by male larvae are smaller and smoother than those made by female larvae. It is notewor-thy that the superior seed cocoons produce a more audible sound than inferior ones when they are kept in chokori pera (a kind of bamboo cage) (Figure 2 c, d) after collec-tion. The sound indicates that a pupa is getting ready to enclose and turn into an adult moth, which then has to be collected by the rearer for further processing.

1.2.2. Strategy for seed collection　In addition to the most suitable food tree (see above), the success of muga culture also depends on the quality of the seed cocoons. There is a proverb regarding the se-lection and collection of seeds: “Namonir sanch ujanir goch” which means in English that seeds (= cocoons of Antheraea assama = assamensis) collected from high alti-tude regions of Assam ensure a superior harvest to when

Fig. 1. The map shows the northern-most tip of Assam with the study area of Dhemaji indicated by the rectangle. The inset depicts India as whole and the state of Assam in the Northeast of the country.

Chakravorty et al.20

they are collected from lower altitude sites. Therefore the rearers collect the seeds from various hilly areas of As-sam, Arunachal Pradesh, and Meghalaya etc. It is com-monly believed that the wild silkworms present in the hilly areas are healthier and more productive than silk-worms from the plains. However, collecting seed from the same altitude at which the farm is located is not uncom-mon when need arises, but rearers believe this compro-mises the quality of muga.　The rearers also believe that the seed cocoons should be transported along the river and not by road and there-fore they usually use the Brahmaputra waterway in As-sam. Along with this the rearers also believe that the seed cocoons should be protected from strong sunlight, from

sudden jerks, vibrations or agitations and also from rain, which can damage the cocoons. One of the precautions that traditional rearers usually follow in order to prevent the cocoons from being exposed to sunlight is to carry the seed cocoons at night. Rearers can identify male and fe-male cocoons by examining them by eye as male and fe-male larvae usually form smooth/small and rough/large cocoons respectively (Figure 2 a).

1.2.3. Additional Criteria for Seed Collection　Selection of seed cocoons, apart from their places of origin, also depends on the physical examination of the silkworms and this includes the following aspects:

Traditional muga silk culture in Northeast Assam 21

(1) Farm visit　Prior to the seed collection, the rearer usually visits the somoni to examine the health of the larvae reared there. Only when the rearer is convinced of the high quality of the larvae that he sees on a particular farm, he may choose that farm (out of several farms in the same locali-ty) for collecting his seed cocoons.

(2) Larval coloration(2a) Body colour: The Body colour of a healthy muga

silkworm is bright green, a colour referred to as “muga green”. The bright green colour is thought to be indicative of the best quality silkworm larvae for rearing. But some-times other colours appear in silkworms, e.g., “kachupo-tia” (dull green), which resembles the colour of Alocasia indica leaves; “krishnaboronia” (light bluish black), remi-niscent of the body colour of lord Krishna and “kuhiapo-tia” (dark green), a colour similar to that of Saccharum officinarum leaves. Silkworms with these colourations are believed to be of lower quality and are rejected.

Fig. 2. The stages of culturing muga silk from muga (Antheraea assama = assamensis) silkworm adopting traditional knowledge followed in the Dhemaji district, Assam, (NE India). Pre-rearing stages (a-d); Rearing stages (e-q); Post-rearing stages (r-z): a- Female and male cocoons; b: Excreta of muga silkworm; c: Muga seed cage or chokori pera hanging above the kitchen with muga seeds; d: Evenly distributed muga seed cocoons in chokori pera; e: Kharika with Mating moths; f: Set of Kharikas with adult male and female hanged on a rope; g: Female moth with eggs on the kharika; h: Kharikas with eggs hanged on chak; i- Rearer performing a ritual in the farm or somoni during khorika logua; j: Kharikas hanging on the host plant; k: A girdle or jori bandh of thatch grass on the trunk of host plant; l: Gir-dle or jori bandh of fresh pseudostem of banana tree; m: Muga silkworms on the chaloni; n: Rearer driving away the predators using a bow or dhenu and batolu guti; o: Rearer making muddy pallets or Batolu guti in the somoni or farm; p: Khurung or cage for keeping the muddy pallets or batolu guti; q: Kuki or cage for keeping the ripe muga larvae; r: Cocooning in jalies; s: Muga cocoons; t: Drying of muga cocoons above the kitchen fire; u: Boiling of muga cocoons; v: Preparation of alkali from rice straw or dhankhar; w: Plant resources (1. Grewia hirsuta, 2. Dilenia indica, 3. Hibiscus rosa chinensis) used in reeling of muga yarn; x: Spinning of muga yarn in Bhanguri y: Muga yarn on the Bhanguri mari or reeler after reeling; z: Drying of final muga yarn

Chakravorty et al.22

(2b) Colour of the mouth of larvae: Rearers believe that the silkworm’s mouth can be of three different colours, e.g., distinguishable as “mukhkula” or black in colour; “mohrukhia” or cupric brown and “pabharukhia” or white in colour. Of these three different colorations “mohrukhia” is the preferred one in collecting seed cocoons.

(2c) Colour of the tubercules and spines of larvae: The rearers distinguish two different colours of the tubercules in muga silkworm, namely reddish and yellowish. Only the reddish coloured tubercular silkworm larvae are used as seed cocoons.

(2d) Colour of the legs of larvae: The legs of muga silk-worms can be of two colours. They can be cupric red or blackish. Only the silkworms with cupric red legs are considered as seed cocoons; others are rejected.

(3) Behaviour and physiology of the larvae　In their assessment of the quality of the seed, the tradi-tional rearers also observe the behaviour and physiology of the larvae. The most significant traits the rearers focus on involve.

(3a) Sensitivity of the larvae: The rearers test the sensitiv-ity of the larvae by touching the larvae with their fingers. Sensitive larvae show a good, i.e. immediate response. The rearers, moreover, believe that the larvae should be fast moving, which is an indicator of a strong breed. Lar-vae that behave in this way are believed to be suitable for further use as seed and are included for the final seed col-lection.

(3b) Presence of excreta in the larval hind gut (= hartho-ka): The traditional rearers know how to detect the pres-ence of excreta in the larval hind gut by gently touching the larva’s rear end. Larvae in which at that position two or three faecal pellets can be felt are preferred to larvae devoid of the same. Larvae in which no faecal pellets can be felt are discarded.　Even the shape of the excreta matters for the rearers in selecting the most suitable seed. Usually the pellets of the larval excreta are barrel-shaped with distinct 4-6 ridges (Figure 2 b). The colour of the excreta should be reddish brown and the texture should be somewhat moist. Expert rearers usually test the degree of moisture by crushing an excretory pellet between two fingers and if this results in a moist and muddy kind of spot the larva is chosen. Indi-vidual excretory pellets should be large in size and pos-sess visible ridges; small sized excreta with indistinct ridges indicate poor quality of the seed.

(3c) Feeding habits: Larvae that are fast eaters and whose

mandibular action when cutting the leaves (pat kota) can be heard, are examined to see if they cut mainly the leaves’ lower stem without eating properly. Leaf cutting behaviour, i.e. food uptake, is critically observed only in second stage larvae and it is said that the best breeds of muga silkworm show medium rates of “pat kota” and that those exhibiting very low or very high rates are rejected. Besides, larvae which start feeding on leaves from the top of the tree and then systematically move down the tree are preferred over those which feed in the opposite direc-tion or cut leaves in a patchy manner.

1.3. Traditional knowledge regarding rearing equipment (Figure 2 c-q)　During the entire process of muga culture various tradi-tional implements are used. All of the equipment is made of bamboo and carefully cleaned by the muga rearer prior to it being used. The equipment includes the following:

Chokori pera: A box made up of bamboo to keep the seed cocoons (Figure 2 c, d).

Kharika: A bundle of thatch grass of about 30 cm in length and 1 cm in diameter across, bent to resemble a hook in shape, and used to transfer larvae from hatching site to host plant (Figure 2 e-h).

Chak: A round device of bamboo for hanging kharika (Figure 2 h).

Chaloni: A triangular shaped apparatus made of strips of bamboo, which is used to transfer muga larvae from one plant to another (Figure 2 m).

Batolu guti: Hard mud balls about 1.5-2 cm in diameter, used with a bow instead of an arrow to drive away birds and other predators that feeds on larvae (Figure 2 n, o).

Dhenu (bow): Bow, made of bamboo, and required to protect the silkworms in the somoni against predatory birds and other animals (Figure 2 o).

Khurung: A basket made of strips of bamboo and to carry Batolu guti (Figure 2 p).

Kuki: A round basket made of strips of bamboo and used for carrying mature muga around in the somoni (= muga farm). It is also known as khora in some parts of Assam. (Figure 2 q).

　After each cycle of rearing, the equipment is thorough-ly washed to remove diseased silkworms or their saliva and the dry skins as well as the excretory material of

Traditional muga silk culture in Northeast Assam 23

healthy silkworms. The equipment is then dried over the kitchen fire. This is done to destroy any contamination of the equipment with micro-organisms and fungal spores (= pebbrine), as described by Jolly (1986).

2. Rearing Techniques　Successful rearing involves many phases. Starting with the selection of the breeds and giving them optimal con-ditions for metamorphosis, pairing and oviposition, the sericulturist then has to monitor the hatching process and look after the larval requirements until cocooning ends the cycle. Traditions and rituals accompany every step in these various tasks.

2.1. Selection of breeds for rearing　Following the selection of the seed (at the pre-rearing stage) the rearers use a variety of indigenous practices for rearing muga. The muga species under debate is multi-voltine, which means it breeds 5-6 breeds per year. Rear-ers usually will not harvest silk that often in one year and choose instead only two times per year, i.e., “jethua” (May-June) and “kotia” (October- November) for the rear-ing. This is believed to yield a larger quantity of quality silk for commercial purposes when compared with the other times of the year, i.e. “jarua” (December-January), ”sotua” (March- April), “aherua” (June-July), and “vodia” (August-September). If high quality silk production is the main aim, this favours May-June and October-November harvests, i.e. jethua and kotia breeds, but if the production of seed cocoons for the rearing of muga silkworms is the priority, then the other four breeds (aherua, vodia, jarua and sotua) can also be used.　Of these latter four breeds to obtain seed cocoons from, the “jarua” and “aherua” are considered to represent the lowest quality while the other two breeds “sotua” and “vodia” are treated as medium quality seed. The breeds also differ with regard to the length of time they require to complete their development and since development de-pends to a very large extent on the environmental temper-ature it is not surprising that jarua take 50-55 days, sotua 40-45 days, jethua 24-30 days, aherua 24-28 days, vodia 24-30 days and kotia 26-30 days.

2.2. Seeds in the “chokori pera”　After having collected seed cocoons from different places, the rearers generally keep the seed cocoons in the chokori pera (a box made of bamboo), spreading out the cocoons in it evenly for easy emergence of moths from the cocoons. The box with the seed cocoons is kept in the kitchen close to the wood fire at a certain height so that the cocoons can receive optimal heat for their metamor-phosis. An even distribution of seed cocoons in the bam-boo box is necessary as it facilitates emergence of the

moths from their cocoons and is a precaution against mi-crobial contamination. Traditional rearers usually spread tulsi or holy basil (Oscimum sanctum) and kochu (Alocasia indica) twigs over the cocoons to prevent infections (Fig-ure 2 d). The use of Alocasia indica is mandatory in this process to avoid “the evil eye”, which could cause the de-mise of the cocoon through illness. The rearers also spray the watery extract of Oscimum sanctum leaves on the floor of the room where the cage with the seed cocoons is kept.

2.3. Hatching and copulation of the moths (“aar-joa”)　After it has hatched, the female moth is tied with cot-ton threads onto a kharika. The kharikas, as mentioned earlier, consist of thatch grass of about 30 cm in length and 1 cm in diameter, bent into the shape of a hook at one end. The rearers hang the kharikas on a jori (i.e., a long rope made from strips of bamboo) inside a separate room of the house and allow the female to mate with a male. Copulation or aar-joa is permitted for about one day, after which the moths normally decouple, which is known as Aar-bhonga. Thereafter the rearer uses smoke out of burning rice straw, a process known as jumuthi, in the house for providing a mild heat to the decoupled fe-male moth. The traditional rearers believe that due to this heating all the female moths excrete excess urine at the same time and thereafter lay eggs collectively. A healthy female usually lays about 100-200 eggs over a period of 4-5 days (Figure 2 g). According to the rearers’ informa-tion, eggs laid up to the second day result in the best off-spring. Surprisingly, moths of the “jarua” breed copulate for more than one day, but to decouple them, rearers use the same procedure (i.e., smoking by burning rice straw) as with the other breeds.　Females which could not copulate due to lack of a male moth or some other reason are hung on a rope outside the house at dusk. To invite stray males the rearers sing a song, clapping their hands to the rhythm of the song. The song goes like this: “Chokori aais chokora aais chokori aase mura melai chokora aahe ga ghelai” and translates into “the female moths are waiting for you (male moths) and you are to come”. Another invitation song would be: “Chokori aais chokora aais chokori aase hune rupe cho-kora aahe bari chuke”, which translates into “the female moths are wearing their ornaments and you (male moths) are to come to see them”. The rearer would sing this song only when some other people are known to also rear muga silkworm nearby. In cases of a shortage of male moths, rearers even used to keep water in a dug out hole in the ground, believing that a male moth after copulation will go to the source of the water for bathing and then be ready to copulate a new with another female.

Chakravorty et al.24

2.4. Hatching of eggs　About one hour after copulation the female moth may start to lay her eggs. The rearers will take only the eggs which are laid on between one to two days after copula-tion, believing that these eggs are best for rearing. There-after the kharikas, bearing the eggs, are very carefully hung on the chak or chaloni (i.e., equipment made out of bamboo) (Figure 2 h) together with Alocasia indica twigs to protect the eggs from “evil eyes” (i.e., mukhloga).Tra-ditional rearers dip the egg-bearing kharikas in a dilute extract of Oscimum sanctum leaves to stimulate fast and uniform hatching of the eggs.

2.5. Transfer of newly hatched larvae to host plant (= kharika logua)　On the first day of hatching the muga rearers transfer the kharikas from their home to the host plant on the farm, the somoni. They do this with the utmost care and decide how many larvae should be put on each host plant at a time. Our enquiry revealed that the rearer’s decision usually depends on the quantity of younger leaves present and the height of the chosen host tree. To avoid an early death of the newly hatched larvae the rearer hangs the khorikas on those branches of a healthy som tree that are not exposed to strong sunlight. This process is known as “khorika logua” (= putting the khorikas on the tree) (Fig-ure 2 i, j). The khorikas are kept on the host plant for a week so that all the larvae can creep onto the host plant and start feeding on its leaves more or less simultaneously.　After stripping a tree bare due to their feeding activity, the larvae crawl down the trunk of this tree, but to pre-vent them from crawling down onto the soil and thereaf-ter be difficult to locate, rearers surround the trunk at about 1.0-1.2 m above ground with a girdle or jori bandh, which the larvae will not crawl over. The girdles are made of either thatched grass (Imperata cylindrica) (Figure 2 k) or a variety of dry leaves and fresh pseudo-stems of ba-nana plants (e.g., Musa balbisiana, Colla sp. (Figure 2 l), or sometimes with fresh leaves of kapau dhekia (Microso-rium punctatum) and tora (Alpinia allughas).The muga larvae never cross or even touch the girdle, which may be due to the presence of the chemicals in the plant material used in the girdle. Thereafter the rearers can pick up the larvae by hand and place them on the chaloni, the trian-gular bamboo support, and put them on another tree that still carries green leaves.

2.6. Rules to be followed during rearing process　During the rearing process rearers abide by the follow-ing customs: 1. In order to avoid mukhloga disease (the “evil eye”), other than the rearer no outsider is allowed to be near the culture. Recently, Sarmah et al. (2010) de-scribed “mukhloga” disease as flacherie, a bacterial or vi-

ral disease of muga and other silkworms, e.g. Bombyx mori (Yokoyama, 1973). 2. Women, not even those be-longing to the rearer’s family, are allowed near the culture during their menstrual periods. 3. People who are taking care of the rearing process in the farm are not allowed to use any cosmetics (body oil, hair shampoo, soap, powder or scented substances), trim their hair, shave their beards or cut their nails during the rearing period.　To protect the larvae from predatory birds and other an-imals in the somoni the rearers stay in the somoni for the entire rearing period. They construct a temporary hut or shelter with bamboo and thatch grass and call it somoni ghar (= farm house). In it they keep essential tools and equipment and also prepare the “batolu guti” by drying them over a fire or keeping in strong sunshine. They keep the jalies (= cocoon forming cages) in the house, where they also cook their food and from where they control ev-ery step of the rearing process.

2.7. Rituals as part of the rearing process　Muga culturists initiate rearing of the muga silkworm by performing certain religious rituals designed to assure the fruitful completion of the rearing process. Towards this end they put a burning lantern/lamp at the base of the som tree on which the very first kharikas with newly hatched larvae (locally known as chai muga/ ek ulua) are to be placed kharika logua (= placing the newly hatched larvae on the som tree) and offer tamul pan (= betel nut and betel leaves) together with some money (a coin) and khir (= a sweet dish of rice, milk and sugar) and then worship god under that tree. (Figure 2 i). Even at the stage of maiky ulua (= emergence of fourth instar larvae) banana and/or coconut is offered“as prasad” (offerings) to god. Finally the pre-cocooning stage is welcomed with either rice wine or other local wine varieties (alcoholic or non-alcoholic). This worshipping is supposed to make the gods happy, because the rearers believe that in the somoni there is a super natural power, on whom the success and prosperity of the rearer depends.

2.8. Larval stages　Muga silkworms, like other insects, go through five lar-val polu (= stages) in their life cycle. The second larval stage is called dui ulua, with dui meaning second. The third larval stage is called tini ulua, with tini meaning third, and the fourth larval stage is known as maiky ulua. This stage is very crucial in the life cycle of a silkworm, after this stage the silkworm larva turns into the fifth and last larval instar prior to pupation. The mature or ripe lar-vae can be identified by behavioural changes like ceasing to feed, becoming sluggish and unwilling to crawl (a be-haviour locally known as jholom dhora) and starting to release copious amounts of excreta. At night they crawl

Traditional muga silk culture in Northeast Assam 25

down the tree and this mass exodus of larvae crawling down the tree is known as bhor pok. The bhor pok varies with the season and, for example, during the summer lasts 5-6 days, but in winter 8-9 days. At night the rearers col-lect the mature, ripe muga larvae by hand and put them into the khurung (= a basket made of bamboo).

2.9. Cocooning in jalies　For further cocoon formation the rearers keep the ma-ture muga in jalies, (leaf mesh) which are bundles of dry leaves of various plant species like, for instance, nahor (Mesua ferrea sp.), hingori (Castanopsis sp.), azar (La-gerstroemia speciosa), bhomlati (Celastrus monospermus), and mango (Mangifera indica) (Figure 2 r). Among these leaves, hingori (Castanopsis sp.) leaves are the most fa-vored one. Before the leaves and twigs are used, they are properly dried in the sunlight and ants and other harmful invertebrates are carefully taken out. However, in winter before preparing jalies the dry leaves are kept above the fire at certain height on a bamboo plate for a while for worming it up. They test the temperature of the jali by putting in the hand in the jalies and due to this warming the larvae at once enters into the jalies for cocooning. While in summer the fresh leaves are likewise employed for setting up jalies. The moisture in the fresh leaves be-lieved to let down the temperature of jalies in summer thereby leads to easy cocooning. During our field study it was also been recorded that during the period of continu-ous rain the traditional rearers use fresh bamboo leaves of the bamboo (Bambusa balcooa) locally known as bhaluka bamboo as jalies instead of sun dried leaves. Bamboo leaves do not cleave to water and are not moist, thereby the cocoon quality never damages, but in such case, the cocoons should be collected within 3-4 days to avoid the damage from moisture of the leaves.

3. Post-rearing techniques　The post rearing techniques include drying of the co-coons, boiling or cooking of the cocoons and reeling off silk yarn from the cocoons.

3.1. Drying of cocoons　The muga rearers collect the cocoons of the silkworms from the jalies one week after cocoon forming has oc-curred, but damaged cocoons (infected with flies like Mascicera grandis, Tricolyga bombycis and Sturmia seri-cariae) are sorted out within 4-5 days to avoid further in-fections. Thorough drying for further processing precedes reeling (Figure 2 x). Out of the population of suitable co-coons, the rearers select the very best, keeping them aside as seed for their next breed. The remaining cocoons are dried under strong sunshine or by keeping them above the fire at certain height on a bamboo plate for 3 to 4 days.

This procedure not only dries the cocoon, but also kills the pupa inside it without damaging the cocoon. The rear-ers believe that drying by smoke is the best process. Dry-ing continues until the pupae inside the cocoons are all dried up. The sounds that the cocoons make when they are being touched and felt by the rearer’s fingers indicate to the rearer the degree of dehydration. Apparently smoke-dried cocoons give a better shine to the muga yarn than sun-dried ones do. Properly dried cocoons can be kept for longer times when kept in a bamboo basket near to the fire in the kitchen to prevent absorption of moisture until reeling commence.　Prior to the reeling process, the rearers gather together cocoons of identical sizes for easy reeling and good quali-ty thread. Cocoons of widely diverse size and mass create problems in the reeling process.

3.2. Boiling or cooking of cocoons　Before reeling can commence the cocoons are cleaned by removing their outer most cover, known as floss, which is loosely bonded to muga yarns and cannot be reeled off. Once the cleaning has been done, the cocoons are boiled (Figure 2 u). During boiling various traditional degumming and other facilitatory reeling reagents are used. These include the kolakhar and dhankhar (Figure 2 v), and—for easy reeling of the thread—slippery substances like owtenga, simalu, joba pat, Kukurhuta leaves depend-ing upon their availability (Figure 2 w1,w2,w3). However, dhankhar is considered to be superior to kolakhar as alka-li agent and simalu, as slippery agent during reeling pro-cess is used rarely due to the difficulty with which it can be extracted.　Kolakhar: The dried banana peel or pseudostem of Musa balbisiana (Musaceae) is charred and steaped over-night in water. The aqueous extract is used as khar (= al-kali) for easy boiling and degumming of the cocoon. There are no specific instructions as to the proportion of alkali extract to be added to the boiling cocoon, but we found that the muga breeder determines the quantity of al-kali extract needed to be added by tasting a little water from the boiling vessel. If the water has a bitter taste then either more water needs to be added or additional cocoons are required.　Dhankhar: This term describes ‘alkali’ derived from an extract of rice straw ashes. Ashes obtained by burning the rice straw are kept in a vessel and a certain amount of wa-ter is poured through it slowly and clear filtrate is collect-ed carefully or sometimes the ashes are loosely wrapped in cotton cloth and held back in a certain amount of water for one daytime. The filtered aqueous extract is then used while boiling the cocoons and the method to determine the amount of filtrate to be used involves tasting of the water and is identical to the process described for kolakhar. At

Chakravorty et al.26

this point, it is believed that any remaining of the dhankhar after their use should not be discarded before completion of reeling as it helps in easy reeling process.　Owtenga: The slippery core of the owtenga plant (Dile-nia indica Linn.) is in use as a degumming agent by mix-ing it with filtered water and then adding it to the boiling cocoon.　Simalu: This is the bark of the simalu tree (Bombax malabaricum) and after grinding it up, it is used in the same way as the core of the owtenga. Throughout the procedure the cocoons are covered by a cotton cloth. Joba pat describes the leaf of the China rose (Hibiscus rosa-shinensis) and is regarded a good lubricating substance. Fresh leaves are plucked and washed properly with water and then chopped into small pieces and used in the reel-ing water after casing the cocoons with a cloth. Kukurhu-ta leaves (Grewia hirsuta) may also be used as slippery agents in the reeling process.　To prevent that remnants of the added substances can stick to the cocoons and interfere with the quality of the silk, these additional substances are introduced only after the cocoons, wrapped in cloth, have already been placed into the boiling water.

3.3. Reeling of silk yarn from muga cocoons　After they have been boiled, the cocoons are kept in water devoid of the alkali additions and reeled onto bhan-guri, bhowri or bhir (= spinners) made of wood. Two per-sons are required for this process, one for spinning out the thread from the boiled cocoons and the other for reeling it on the bhanguri (Figure 2 x). Several cocoons may be taken together depending on the width of the thread to be reeled. Inner filaments are pulled one by one and at least 4-5 filaments from the cocoons are put together to form a final thread which is called hir diya or (= compiling of yarns) and reeled onto the bhanguri and subsequently yarns are rolled out from spinner and dried in sun to give a final Muga thread (Figure 2 y, z). It is said that about 1000 kotia cocoons of the October-November breed can give about 200-270 g of yarn and that the same amount of jethua cocoons of the May-June breed may yield 200-250 g of yarn.In comparing to these two breeds similar numbers of cocoons of the other muga breeds (jarua, sotua, ahrua and vodia) usually give around 150-190 g of silk thread.

3.4. Precautions of reeling　Adherence to certain precautions is considered essential for successful reeling. 1. It is necessary to provide filtered water to the threads on the bhanguri to clean the threads. 2. The water in which the cocoons are kept for reeling is to be changed from time to time to keep the threads clean. 3. Under no circumstances are even traces of table salt al-lowed to contaminate the water during the reeling process

as this can damage the threads. 4. The reelers draw a small mark on the bhir or bhanguri with calcium carbon-ate (= chun) before the reeling commences to avoid any “evil eye” by envious people.

CONCLUSION

　Given that the traditional ways of muga culture are be-ing increasingly ignored in modern, non-traditional seri-culture enterprises, we have to ask ourselves whether it makes sense to discard practices, which for centuries have been accepted as common knowledge and are based on the collective experience of many individuals (Erren et al., 2013). Towards this end we shall now summarize the disadvantages and advantages of the traditional sericultur-al practices in Northern Assam.

Disadvantages of the traditional method　Muga culture is an age-old customary activity of the people of Assam (Phukan, 2012). Although the entire pro-cess of culturing muga silkworm relies heavily on the in-digenous knowledge and expertise of local culturists, hanging on to traditions can be a hindrance when it comes to accepting new ideas and modifying established meth-ods. Modernization, changing attitudes and life styles of the younger generation as well as the aim to get quicker returns from muga yarn production has led to a situation, in which traditional indigenous practices are now no lon-ger followed by the majority of Assamese sericulturists. The only areas in which the traditions still persist are re-mote country areas. However, even there they are in dan-ger of being abandoned.　Instead of collecting the seed from higher altitudes and transporting them at night via the river route, modern cul-turists can contact a muga egg retailer or rearer and ob-tain the seed cocoons from host plants in that person’s home garden. The traditional river transport of the seed at night is seen by modern sericulturists as unnecessarily cumbersome and dangerous and they therefore prefer to take the seed during the day by car or motor cycle. Visit-ing the muga egg retailer is faster and less strenuous than searching for seed, having to decide on its presumed qual-ity and needing to observe certain religious rituals, dictat-ed by tradition but apparently not scientific necessity.　Assessing a plant’s quality and position for a particular strain of silkworm in relation to the farm’s location re-quires years of experience. Relying on the commercial rearer in these matters, the modern sericulturist no longer has to be an expert on all aspects of silkworm biology and can, instead, focus on marketing and other business as well as family matters. Thus, responsibility for the success or failure of the sericulture outcome is shared between muga egg vendor and the sericulturist; which makes life a

Traditional muga silk culture in Northeast Assam 27

great deal easier for the latter and allows him to branch out and, for instance, to develop skills in advertising his product, establishing business connections, attending meet-ings etc.　For final cocoon processing and yarn collection, mod-ern culturists have started using chemicals like caustic soda instead of using conventional alkali obtained, for in-stance, from extracts of kal khar, dhan khar or Hibiscus rosa-sinensis leaves to render the boiled cocoons slippery. Modern culturists can rely on the vendor’s recommenda-tion of the most suitable products and need not them-selves possess knowledge of the properties of local plant extracts. They also no longer follow the rules or specific rituals practised by the traditional rural rearers (described in this paper), because such practices are time-consuming and seen by the more affluent silk traders as outdated, in-effective and primitive. Their slogan “time is money” fell on fertile grounds with the young people and as they no-ticed they could (at least for now) achieve bigger returns for less labour, they began to discard the traditional ways.

Advantages of the traditional method　Despite the obvious advantages in time saving, greater output and productivity of the modern ways, the tradition-al ways have their own advantages. The aspect of conti-nuity, of a connection with the past is something that is of considerable value in an ethnic group that wishes to main-tain an identity; that possesses a certain pride and likes to be distinguished from others. However, on a more practi-cal basis, traditions that foster close relationships of a people with their environment, plants and fauna, serve as a protective element for the people against habitat disrup-tion. The traditionalist is keenly aware of the importance of the various plant species, the soils, the location of the hills, streams and the impact of the weather in the local ecosystem. Traditionalists see themselves as a part of the greater whole. This is reflected in their rituals and reli-gious practices. Silkworms and their product, the silk, are then more than just a commercial item. They are an ex-pression of Nature; a gift of Nature that needs to be nur-tured and appreciated.　By not relying on the seed and food plant recommenda-tions of the traders, but trusting their forefathers’ experi-ences and selecting seed from the wild, traditionalists are more likely to protect rare and only locally available pop-ulations of silkworm strains that are of no or little interest to the commercial rearers, who focus on the fastest grow-ing, easiest to keep and least specific strains. Traditional methods therefore almost certainly help maintaining silk-worm genetic diversity to a far greater extent than modern enterprises do and they also give the traditional vis-à-vis modern sericulturist greater independence, since the for-mer is self-reliant and controls every step of the process

himself without the need to involve other experts.　When it comes to value for money, the traditional seri-culturists may ultimately be the ones “who laugh last”, for it has happened in other industries that as more and more commercially available products depress the market price of a product, the genuine (or what is considered ‘genuine’) product, in this case “wild silk”, may well be-gin to fetch a higher price as it becomes an increasingly rare item. This is a further reason, why the few remaining traditional sericulturists should be encouraged to continue the age-old practices and, in marketing their products, should stress that the latter have been obtained with silk-worms from the wild, reared and processed by genuine traditional methods free of artificial chemicals; methods that stood the test of time.　As a by-product, muga rearers also obtain nutritious pupae, rich in fats, protein and vitamins; these can be sold or used to augment the farmer’s own food supply (Meyer-Rochow, 2005). In fact, according to Suzuki (cited in Nunome, 1988) silkworm domestication and the use of silk by humans may be rooted in entomophagy, i.e., the con-sumption of silkworm pupae as food. Although silkworm production as food is not restricted to traditional methods, it is certainly more important to traditional than modern sericulturists, given that nutritional shortcomings often ex-ist in exactly those remote areas, where traditional meth-ods still persist. This aspect of an additional benefit of the traditional ways of rearing muga silkworm is considered worth mentioning.

In summary　Assam silk yarn has been world famous for its lustrous beauty and has been used in the garment industry world-wide. However, muga silk has numerous additional uses and therefore muga culture has to be seen as being of considerable socio-economic importance. Tradtional rear-ers are not only the guardians of age-old practices, they are also responsible for keeping local populations of silk-worm strains alive that are specifically adapted to particu-lar regions. One ought therefore to expect an interest in safe-guarding the traditional methods of silk production in Assam. Yet, the traditional ways are nowadays persisting only in remote rural communities, where, nevertheless, they continue to fulfil a need.　The changes that were adopted by modern sericultur-ists, albeit at the expense of traditional practices, have un-doubtedly led to a greater efficiency in silk production and consequently the quantity of silk reaching the market is likely to increase. However, as the supply increases, re-turns in monetary terms are likely to fall. More important-ly, by focusing on only a few silkworm strains the yarns available will be less diverse and the reputation of Assa-mese silk, famous for catering to many specific uses and

Chakravorty et al.28

tastes on account of its wide spectrum in texture, fibre strength, colour etc., could deteriorate. Keeping traditional methods alive would be one way to forestall such a devel-opment and at the same time protect the biodiversity of different silkworm populations.

ACKNOWLEDGMENTS

　The authors are thankful to the Department of Science and Technology (DST) New Delhi, India for the financial support through a research grant to Dr. J. Chakravorty. Thanks are also extended to Rajiv Gandhi University, Arunachal Pradesh, India, and Jacobs University, Bremen, Germany, for providing facilities to complete this study. The Robert Bosch Foundation is acknowledged for the fi-nancial support extended to Prof. Dr. V. B. Meyer-Rochow’s recent visit to North East India. Thanks are also due to village informers in general and the muga rearer Mukut Phukan and Bhuban Buragohain at Dhemaji Dis-trict, Assam, India, for sharing their valuable knowledge with us. Dr. Sampat Ghosh (currently Andong University, South Korea) provided valuable hints regarding relevant and recent literature.

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