Cocoon Characterization of silk insects from North East India: An approach for sustainable economic development

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In the present study, nine species were examined to evaluate the arrangement of silk fibres in the different cocoon species to understand variations and to know their commercial importance. Scanning electron microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) analysis were done to observe the arrangement of silk fibres in the different cocoon species.. The morphometric characteristics of cocoons showed distinct and significant variations among the different silk insects. SEM analysis showed that in all the species, the cross-binding and bifurcation of filaments formed an intricate network and Y-shaped structures. The study successfully evaluated the sustainable importance of the different cocoons and silk fibres. Besides, the study and can also be considered as the first to report on the dyeability of silk fibres and handicrafts made from waste silk insect cocoons from this region. Animal Science Cocoon silk insects sustainable development economic development North-East India tensile strength Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Introduction The Northeastern region of India, comprising the states of Arunachal Pradesh, Assam, Meghalaya, Tripura, Mizoram, Nagaland, and Sikkim can be physio-graphically categorized as the Eastern Himalayas. The northeastern region holds a special place in the globe since it is the only place where all four species of silkworms—Eri, Muga, Tasar and Mulberry coexist(Boro & Borah, 2020). North-East India is one of the major and important hot spots among 35 biodiversity hotspots of the world, which is known for “Endemism” due to the unique climatic conditions. 29 species of silk insects have been collected and identified from different states of North East India. Out of these only Antheraea assamensis, A. mylitta, and Samia ricini are commercialized for obtaining silk in North-East India. In addition to the silkworm, many different types of silkworm host plants are native to this area. There are currently 31 species of Saturniidae and 9 species of Bombycidae known to exist in northeastern India (Kakatiya et al., 2009; Kalita & Dutta, 2014 ; Boro & Borah, 2020) . The process of producing raw silk by the rearing of caterpillars, or larvae, especially those of the domesticated silkworm (Bombyx mori), is known as Sericulture. Two procedures are typically involved in the manufacture of silk: [i] handling the silkworm from the egg stage until the cocoon is finished and [ii] creation of mulberry trees, which supply the worms with leaves to eat(Mahanta et al., 2023) . Silk production, or sericulture, has a long and illustrious history that dates back more than five thousand years. The sericulture industry, which starts with the cultivation of mulberry trees and their many applications, including the production of leaves for silkworm food, promotes employment, economic growth, and health. High-quality silk thread and high-protein food for both humans and animals are the products of sericulture(Altman & Farrell, 2022; Mahanta et al., 2023 ). Sericulture broadly comprises interlinked activities such as food plant cultivation and maintenance to feed the silkworms, silkworm rearing to produce the silk cocoons, reeling the cocoons for unwinding the silk filament, yarn making, weaving, and processing of fabric (Kalantzi et al., 2013) . Nature provides an enormous diversity of silk-producing insects ranging from well-known Bombyx mori to completely least concerned silk-producing insects (Kakati & Chutia, 2013). While mulberry sericulture deals with the rearing of the domesticated silkworm, non-mulberry sericulture, also known as ‘ Vanya silks ’ comes from the forest-based insects that are in general not reared in captivity. The majority of the non-mulberry silk moths belong to the family Sturnidae which constitute one of the largest groups of Lepidoptera comprising about 1200–1500 species all over the world (B. C. Chutia et al., 2022). Out of which only 80 species are known to produce silk of economic value. They constitute part of the ‘‘Charismatic megafauna’’ of the insect world which produces lustrous silk (B. C. Chutia et al., 2022). A cocoon is a natural silk composite with a non-woven structure made of continuous and non-continuous silk fibers conglutinated by a sericin bonding matrix. The cocoon characteristics like shell weight, filament length, and reeling characteristics such as denier and renditta have commercial importance as they reflect the silk quality. The fine structural character of the cocoon filament is one of the most important factors determining what kind of final product can be expected from the reeled silk or spun silk yarn (Akai; 2000). Production of quality cocoons and silk yarn depends on the altitudinal and geographical variation, length of the larval period, environmental changes in different seasons, variation among broods and races and is greatly affected by the foliar constituents of kinds of host plants that are used for feeding silkworms. Studies on cocoon and yarn characteristics of silk insects in India are mostly confined to commercially exploited silk species, viz. Antheraea mylitta, A. proylei, A assamensis, and Samia ricini, with only little effort has been made on other wild silk species (Kakati & Chutia, 2013; B. C. Chutia et al., 2022). Silk materials and their products have received significant attention throughout the world because of their attractive combinations of design, mechanical strength, and toughness. However, a gap of knowledge exists regarding studies on cocoon and silk characteristics of many silk species as most of the studies are confined only to commercially exploited silk species. Thus, to bridge the knowledge gap the study explores and compares the physical properties of different silk cocoons of Northeast India and their degummed protein fibers, to know their potential utilization for sustainable economic development. In the present study, nine species were characterized for the economic characteristics of cocoons to know their commercial importance. MATERIALS AND METHODS The experiment was carried out at the Zoology department, Cotton University; Guwahati; Assam, India. The live cocoon samples were collected based on available literature and consulting with the local people adopting the random sampling method. The survey covered the autumn and spring seasons, particularly during the year 2022–2023. During the sample collection minimum 5 km distance was maintained between the two sites of sample collection to prevent population overlapping. The sample collection sites are represented in [Fig. 1 ] The length and breadth of cocoons were recorded using Vernier Caliper and the whole cocoon weight and shell weight were measured by the electronic balance. The shell ratio was calculated using the following formula Sample sizes of 2 mm sizes were sliced from the cocoons of each sample. The samples were them washed out thoroughly for 4–5 times to remove the dirt particles and fixed in 3% glutaraldehyde. After fixation samples were washed in 0.1M Sodium cacodylate buffer for 3 changes, each for 15 minutes at 4 0 C. The samples were the processed for dehydration passing through 30–100% acetone, each for 15 minutes and 2 changes. Then the specimen were immersed in Tetra Methyl Silane for 5–10 minutes for two times at 4 0 C. These were brought to room temp (25-26 0 C) to dry. After drying the specimen were mounted on aluminium stubs and coating of 35 nanometre was carried out using gold in Fine Coat Ion Sputter JFC1100. The gold coated samples were then observed SEM (JEOL JSM 6360) connected to a voltage of 15KV, in 30X, 150X,500X and 2000X in SAIF, NEHU, Shillong, India. The sample pieces that were used for observation under SEM were used for EDX (Energy Dispersive X-Ray Analysis) also. The ISIS 300 EDX unit (Oxford instrument) was used to identify the crystals present on the fibres. The cocoons were boiled adding 0.3% soda solution (Sodium carbonate) and gently teased out. When cooled the brines were following the traditional method used for silk reeling and spinning by the village people. For the removal of crystals that make the cocoons hard, demineralization was carried out with 20% lemon juice and kolakhar (NaOH) treatment for 24 hours in a shaking incubator. The single cocoon filament length, yarn colour, degumming loss % (weight loss of silk after degumming), and yarn yield % (length of material in a specific weight) were measured followed by degumming. The tensile properties of silk filaments were measured by a Universal Testing Machine, interfaced with a PC (Instron 5542 instrument 500N load cell) at 65% relative humidity and 26℃ temperatures (Gheysens et al., 2011 a; Boulet-Audet et al., 2015 ). To check the dyeability of the silk fibres obtained from different species of silk insect cocoons, the fibres were dyed with natural dye extracted from Bixa orellena and Pomegranate (mordant) in a neutral medium. The reflectance values of dyed samples were measured using an X-rite Ci6xBT portable spectrophotometer. From the reflectance values (R) in the visible spectrum (400–700 nm) at the maximum absorption wavelength (λ max) for each dyed sample, the corresponding colour strength (K/S) values of the samples were calculated by using the Kubelka–Munk equation.(Safi & Amirshahi, 2023 ) Statistical analysis was performed in RStudio software (version 2024.04.2 + 764) with packages ‘dplyr’ ‘ggplot2’ ‘ggeffects’, ‘emmeans’ ‘lme4’ ‘lmerTest’ ‘Matrix’ and using linear mixed models (lm),. Log likelihood ratio test (LRT) was used to investigate the significance of all explanatory variables on the response variables in all models and based on Chisq(χ2), Degrees of freedom (Df) and p-value the best model was selected and fitted. Modelling was done starting from the most complex model and then simplification was done using LRT to nested models. From the packages ‘ggeffects’ and ‘emmeans’; ggemmeans was used to calculate the estimates. The cocoons that are not fit for reeling were separated from double, stained, crushed, flimsy, malformed, fluffy, insect-damaged, and mold-attacked cocoons manually following the cocoon sorting table developed by Central Silk Board of India. These cocoons are thrown as waste or burnt leading to environmental hazards. Depending on the environmental conditions the number of defective cocoons increases which may result in economic loss to the farmers. The hard shells of the cocoons left after reeling are also considered waste. These cocoons were processed for disinfection, natural dyeing of cocoons, and making handicrafts as shown in [Fig. 3 ]. RESULTS AND DISCUSSION The morphometric characteristics of cocoons showed distinct and significant variations among the different silk insects [Table 1]. Out of the total nine species collected, Samia ricini is domesticated, Antheraea assamensis is semi-domesticated as well as wild, Antheraea proylei is semi-domesticated while Samia canningi, Antheraea frithi, Actias selne, Attacus atlas, and Criculatri fenetrata are wild in nature belonging to the order Lepidoptera and family Saturniidae. All the cocoons were oval or spindle-shaped and showed distinct variations in colour, size, and texture. The wild cocoons were found to be harder than the semi-domesticated and domesticated silk insect cocoon species. Criculatri fenestrata cocoons represented unique porous structure with bright golden colour. The cocoons of A. assamensis, A. proylei, Actias selene, and Attacus atlas were observed to have a thin, filament-like structure called a peduncle at its anterior end. The color of the peduncle was the same as the cocoon color. The wild stocks had more peduncle length than the semi-domestic stocks. Significant variations were recorded in cocoon size, whole cocoon weight, shell weight, and shell ratio of cocoons among the various species. The largest cocoon size was recorded for Antheraea assamensis (wild) (L = 6.41cm, B = 2.90cm) and the smallest for the species Criculatri fenestrate (L = 3.6cm, B = 1.5cm). The maximum shell weight was found for the A. atlas while the shell ratio was found maximum for A. assamensis (wild) [Fig. 4 ]. After degumming of silk cocoons, the morphometric study of silk fibres revealed the single cocoon filament length highest in A. assamensis followed by S. ricini, A. proylei, A. altus, C. trifenestrata, A. frithi, S. canningi, A. assamensis (wild) and A. selene as represented in [Fig. 5 ]. Scanning Electron Microscopic (SEM) study showed that in all the species, the cross-binding and bifurcation of filaments formed an intricate network and Y-shaped structures [Fig. 6 ]. Energy Dispersive X-ray Spectroscopy (EDX) indicated that the granular materials were composed predominantly of calcium, nitrogen, oxygen, carbon, potassium, chlorine, aluminium, and silicon [Fig. 7 ]. The filaments were more tightly packed in wild populations than the semi-domestic stocks. Many irregularly shaped crystals were noticed to deposit on the surface of the fibres. Dyeing of all the silk fibres at uniform conditions (Temperature = 45 0 C, Time = 60 min) in a neutral medium showed positive results except for Muga silk which did not take any colour. K/S value of different silk fibres revealed the highest value for Eri silk from S. ricini followed by tasar silk from A. proylei [Fig. 8 ]. To avoid economic loss for the farmers' different handicraft items were made in two categories-jewellery and home décor. Yarn loss percentage patterns [Fig. 9 (A)] over three years revealed that A. assamensis (semi-domesticated) has the highest percentage of yarn loss whereas for C. trifenestrata has the lowest percentage. Degumming loss percentage patterns [Fig. 9 (B)] revealed that A. assamensis (semi-domesticated) has the highest percentage while S. ricini has the lowest degumming loss percentage. Tensile strength assessment of the fibres [Fig. 10 ] and [Fig. 11 ] showed that A. assamensis has the highest tenacity, strain%, Young’s modulus, and toughness while the lowest was observed in S. ricini . The present study is focused on unveiling the economic characteristics of cocoons, fibre length and strength, yarn yield, and dyeability. ( Chutia & Kumar, 2014 )stated that the host plant plays an important role in the determination of cocoon colour which has a very close consortium with the present study. According to (Heisswolf et al., 2009) pupal weight is proportional to fecundity. In the present study, a similar observation was found for which, a smaller number of wild cocoons could be collected during the field survey. Although the semi-domestic and domestic stocks recorded larger shell weight, a fair amount of yarn yield was found from the wild stocks between 28-62.28%. The bifurcation of filaments forming an intricate network and Y-shaped structure observed in the present study has a close consortium with the findings of (Mondal, 2007 ) in hybrids of Bombyx mori cocoons. They also stated that voids in the cocoon filaments are important in the selection process of good quality of silk cocoons for silkworm breeding. The arrangement of silk fibres also showed a close relationship with the fibre length. The more the fibre length more compact the arrangement of fibres was observed. In the indoor cocoon shells, the filaments were loosely arranged and slightly visible with wider gap. The number of filaments in the outdoor cocoons was found to be more in indoor cocoons that outdoor ones. This observation is supported by (Shamitha & Rao, 2006 ). The quality of cocoons depends both on sericin and fibrin which are controlled by atmospheric conditions. The presence of more cementing substance (sericin) and less filament (fibrin) in the indoor cocoons suggests the role of environmental factors on the synthesis of these proteins by silk gland. The sericin content as being the deciding factor in the quality of the cocoon and raw silk reeled was reported by (Shamitha & Rao, 2006 ). However, filament length and quality of the shell are based on the fibroin content. This is corroborated by the findings of a reduction in filament length of outdoor cocoons as observed in the present investigation. The crystals observed were of calcium oxalate and the number of crystals determines the hardness of the cocoon shell (Kaur et al., 2015 ; Kalita & Dutta, 2020 ). Deposition of more crystals makes the cocoons harder and makes it difficult to reel (Gheysens et al., 2011 ). The presence of crystals on the silk fibre is common to other wild silk filaments, bearing a striking contrast with the very smooth appearance of B. mori silk, and is also responsible for the lower degree of lustre of textile products made by wild silk. In the present study, pre-treatment of cocoons with lemon juice (citric acid) and kolakhar revealed the complete removal of crystals and made the reeling process easy. It is reported in earlier studies that treatment with EDTA and citric acid can remove the Calcium oxalate crystals from the hard cocoon surface(Verplaetse et al., 1986 ; Kaur et al., 2015 ). Prior studies revealed that most fibres have a strain at break around 16% against the 18–38% observed in the present study. This may be due to fact that the samples taken from different layers in cocoons differ significantly, and even spatially close samples can be very different due to factors such as bending of the fibres in the motion the worm makes while spinning the cocoon (Devi et al., 2011 ; Yuan et al., 2024 ).Based on the tensile behaviour and microstructure of the filaments,(Chen et al., 2012 ) divided the silk insect cocoons into four types which has a very close similarity with the present study. ‘Lattice’ cocoons have only a loose scaffold structure made up of a few fused fibre bundles supporting the cocoon frame with large pores ( Cricula trifenestrata ). The fibres sustain the load when the cocoon is stretched. ‘Weak’ cocoons have high porosity and weak interlayer bonding as observed in Samia sp . ‘Brittle’ cocoons usually have low porosity and strong interlayer bonding or a single layer structure ( Antheraea assamensis ). ‘Tough’ cocoons can be grouped into fourth type, in which the cocoons have medium porosity and interlayer bonding ( Antheraea proylei ). Degumming loss % indicates that along with A. assamensis the wild cocoons may also be a good source of sericin for silk protein-based product development (Sarovart et al., 2003 )reported the use of sericin as an antioxidant and antimicrobial potential component. Except Muga silk as the other silk fibres have dyeability, they can be used for various product development with beautiful colours. The use of waste cocoons for handicraft making may be another breakthrough to prevent the economic loss of farmers due to the higher number of waste cocoons in adverse climatic conditions. Further awareness and strategies on the conservation of these silk insects in in-situ or ex-situ may revolutionize the Seri-industry of Northeast India. Thus, the present study clearly showed that the wild silk insects may be a source of silk reeling, sericin extraction, dyeing, and weaving. Thus, the study effectively assessed the various cocoons' and silk fibres’ economic and sustainable significance. Additionally, the study is arguably the first to document the dyeability of silk fibres and handicrafts created from leftover silk insect cocoons from this area. We believe that the study will encourage the potential utilization of wild silk insects for further sustainable economic development of the region and sericulture industry. Declarations ACKNOWLEDGMENTS The authors are thankful to traditional silkworm rearers of North East India who extensively helped in sample collection. The authors are also thankful to Department of Zoology, Cotton University for providing necessary laboratory facilities. They also acknowledge Gauhati University, NEHU Shillong and CSB, Bangalore for allowing to avail the instrumentation facility there. A UTHOR CONTRIBUTION STATEMENT Tarali Kalita : Conceptualization,Visualization, Writing-Original Draft Preparation, Investigation, Project Administration, Supervision, Validation, Writing- Review and Editing. Aditya Shankar Kataki : Data Curation, Software, Formal Analysis and Writing- Review and Editing Alo Saha Das, Devajit Basumatari, Jayashree Deka, Hiren Gogoi, Mrigakshi Phookan, Priyanku Sarma : Methodology, Sample collection, Formal Analysis and Writing- Review and Editing FINANCIAL SUPPORT The research project was supported by the Cotton University, Guwahati, Assam; India In-House Research Project Scheme (Ref – CU/Dean/R&D/2019/05/1995) CONFLICT OF INTEREST The authors report there are no competing interests to declare References Altman, G. H., & Farrell, B. D. 2022. Sericulture as a sustainable agroindustry. Cleaner and Circular Bioeconomy, 2, 100011. Boro, P., & Borah, S. 2020. Biodiversity of sericigenous insects in north- eastern region of India- A review. Boulet-Audet, M., Vollrath, F., & Holland, C. 2015. Identification and classification of silks using infrared spectroscopy. Journal of Experimental Biology, 218(19), 3138–3149. Chen, F., Porter, D., & Vollrath, F. 2012. Silk cocoon (Bombyx mori): multi-layer structure and mechanical properties. Acta Biomaterialia, 8(7), 2620–2627. Chutia, B. C., Nath, C., Goswami, L. M., Borkataki, S., Borah, N., & Tamuly, C. 2022. Morphophysical and Spectroscopic Characteristics of Wild Silkworm Cocoons in North-East India. Proceedings of the National Academy of Sciences India Section B - Biological Sciences, 92(1), 171–183. Chutia, P., & Kumar, R. 2014. Host Plants Relationship in terms of Cocoon Colour and Compactness of Eri Silkworm (Samia ricini). Devi, D., Sarma, N. Sen, Talukdar, B., Chetri, P., Baruah, K. C., & Dass, N. N. 2011. Study of the structure of degummed Antheraea assamensis (muga) silk fibre. Journal of the Textile Institute, 102(6), 527–533. Gheysens, T., Collins, A., Raina, S., Vollrath, F., & Knight, D. P. 2011. Demineralization enables reeling of wild silk moth cocoons. Biomacromolecules, 12(6), 2257–2266. , Andersson, T., & Ruohomki, K. 2009. 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Studies on the filament of tasar silkworm, Antheraea mylitta D (Andhra local ecorace). Current Science. Verplaetse, H., Verbeeck, R. M. H., Verbaeys, A., & Oosterlinck, W. 1986. Solubility of calcium oxalate monohydrate and hydroxyapatite in EDTA solutions. The Journal of Urology, 135(3), 608–611. Yuan, Y., Nasri, M., Manayi, A., Zhang, J., Wu, C., Jeon, T. J., & Kang, L. 2024. Sericin coats of silk fibres, a degumming waste or future material? Materials Today Bio, 29, 101306. Table 1 Table 1 is not available with this version. Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6836179","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":467507898,"identity":"1ed886fb-d4be-4432-b228-94021c6613e6","order_by":0,"name":"Aditya Shankar Kataki","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Aditya","middleName":"Shankar","lastName":"Kataki","suffix":""},{"id":467507899,"identity":"34e2dc77-ad70-466a-b1dc-06b3ad1a7705","order_by":1,"name":"Alo Saha Das","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Alo","middleName":"Saha","lastName":"Das","suffix":""},{"id":467507968,"identity":"1246594b-ef85-4080-9274-68c4353f238e","order_by":2,"name":"Tarali","email":"data:image/png;base64,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","orcid":"","institution":"Kalita","correspondingAuthor":true,"prefix":"","firstName":"","middleName":"","lastName":"Tarali","suffix":""},{"id":467508576,"identity":"a1b4bec2-5f08-4e18-a6a9-f3f1a500bf71","order_by":3,"name":"Devajit Basumatari","email":"","orcid":"","institution":"Cotton University","correspondingAuthor":false,"prefix":"","firstName":"Devajit","middleName":"","lastName":"Basumatari","suffix":""},{"id":467508577,"identity":"cde6ae6c-bd98-4a44-968f-850dabcf30eb","order_by":4,"name":"Jayashree Deka","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Jayashree","middleName":"","lastName":"Deka","suffix":""},{"id":467508578,"identity":"58025cb7-cb17-43f9-9e60-11d2916effd1","order_by":5,"name":"Hiren Gogoi","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Hiren","middleName":"","lastName":"Gogoi","suffix":""},{"id":467508579,"identity":"3226c7df-6108-49e2-be78-929e74e514a9","order_by":6,"name":"Mrigakshi Phookan","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Mrigakshi","middleName":"","lastName":"Phookan","suffix":""},{"id":467508580,"identity":"4bb4b1e0-4b50-4354-bf13-17b4118601b1","order_by":7,"name":"Priyanku Sarma","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Priyanku","middleName":"","lastName":"Sarma","suffix":""}],"badges":[],"createdAt":"2025-06-06 10:32:37","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-6836179/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6836179/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":84275171,"identity":"e8b135f6-59fd-425c-8295-15ae5f3dc9c8","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":210153,"visible":true,"origin":"","legend":"\u003cp\u003eThe map was created using QGIS software (3.40 version). The map of Assam, India represents the different locations from where the sample collection was done and evaluated.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/214d9efda6586c80f019a714.png"},{"id":84275168,"identity":"91899a88-6149-47ae-a086-cf2d923a545c","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":406537,"visible":true,"origin":"","legend":"\u003cp\u003eCharacterization of Cocoon: [A] \u003cem\u003eActias selene\u003c/em\u003e [B] \u003cem\u003eAntheraea assamensis\u003c/em\u003e (Semi domesticated) [C] \u003cem\u003eAntheraea assamensis\u003c/em\u003e (Wild) [D] \u003cem\u003eAntheraea proylei\u003c/em\u003e[E] \u003cem\u003eAntheraea frithi\u003c/em\u003e [F] \u003cem\u003eCricula trifenestrata\u003c/em\u003e [G] \u003cem\u003eSamia canningi\u003c/em\u003e [H] \u003cem\u003eSamia ricini\u003c/em\u003e (White variety). The color, shape, texture, and nature of the floss of the cocoons of each species were observed and documented.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/a3b52914c2f5bcf6c1b9e448.png"},{"id":84276829,"identity":"d6cd252e-7bf7-47ec-89ce-d2e81c61a547","added_by":"auto","created_at":"2025-06-10 05:43:45","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":447060,"visible":true,"origin":"","legend":"\u003cp\u003eUnfit for reeling cocoons were manually sorted from double, stained, crushed, flimsy, deformed, fluffy, insect-damaged, and mold-attacked cocoons using a cocoon sorting table devised by the Central Silk Board of India. These cocoons were processed for sterilization, natural colouring of cocoons, and producing handicrafts.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/fae211d0c8e5457bee2419ff.png"},{"id":84275176,"identity":"c1d69aa5-2b1f-40e9-aa3e-bae06d0dbe1a","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":460705,"visible":true,"origin":"","legend":"\u003cp\u003eCocoon properties of different silk insect’s species [ 1: \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated), 2: \u003cem\u003eA. assamensis\u003c/em\u003e (wild) 3:\u003cem\u003eS.ricini\u003c/em\u003e 4:S\u003cem\u003e.canningi\u003c/em\u003e 5:\u003cem\u003e A. pralei\u003c/em\u003e 6:\u003cem\u003e A. frithi\u003c/em\u003e 7:\u003cem\u003e A. selene\u003c/em\u003e 8: \u003cem\u003eA. atlas\u003c/em\u003e 9:\u003cem\u003e C. trifenestrata\u003c/em\u003e] from North-East India. Graph [A] and graph [B] displaying the length and breadth patterns respectively of the cocoons from three years showing \u003cem\u003eA. assamensis\u003c/em\u003e (wild) had the largest cocoon size whereas \u003cem\u003eC. fenestrate \u003c/em\u003ehad the smallest. Length was found to be changing with respect to specimen [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 274.46, df = 8, p-value = \u0026lt; 2.2e-16 ***] and not year [Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 0.1434, df = 2, p-value = 0.074] whereas breadth was found to be changing according to both year [Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 7.244, df = 2, p-value = 0.02673 *] and specimen [Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 187.16, df = 8, p-value = \u0026lt; 2.2e-16 ***]. Graph [C] , graph [D] and graph [E] displaying the cocoon weight patterns, shell ratio patterns and shell weight patterns respectively over three years. The shell weight is found to be changing according to species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 382.94, df = 8, p-value = \u0026lt; 2.2e-16 ***] and not year[Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 0.4589, df = 2, p-value = 0.795]. Similarly; shell ratio is found to get influenced by species [Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 471.33, df = 8, p-value = \u0026lt; 2.2e-16 ***]and not year [Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 0.7733, df = 2, p-value = 0.5142]. Highest cocoon weight is observed in \u003cem\u003eA. proyeli\u003c/em\u003e and the lowest in \u003cem\u003eC. trifenestrata.\u003c/em\u003e\u0026nbsp;\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/2dc6fc63be4a36916161adda.png"},{"id":84275179,"identity":"14f86fa8-7dd0-4e49-907f-3bbcf5b5953f","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":595857,"visible":true,"origin":"","legend":"\u003cp\u003eCocoon filament length (mm) of different silk insect’s species [ 1: \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated), 2: \u003cem\u003eA. assamensis\u003c/em\u003e (wild) 3:\u003cem\u003eS.ricini\u003c/em\u003e 4:S\u003cem\u003e.canningi\u003c/em\u003e 5:\u003cem\u003e A. pralei\u003c/em\u003e 6:\u003cem\u003e A. frithi\u003c/em\u003e 7:\u003cem\u003e A. selene\u003c/em\u003e 8: \u003cem\u003eA. atlas\u003c/em\u003e 9:\u003cem\u003e C. trifenestrata\u003c/em\u003e] from North-East India. Highest cocoon filament length was observed in \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated) while the lowest observed in \u003cem\u003eA. selene\u003c/em\u003e. The cocoon filament length was found to be influenced both year [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 7.883, df = 8, p-value = 0.03743*] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =412.98, df = 8, p-value = \u0026lt; 2.2e-16 ***].\u0026nbsp;\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/1e00d7b5be93febf4eeccf06.png"},{"id":84275181,"identity":"1e2bc88f-83e9-4f25-83d9-34a64a5927ba","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1203611,"visible":true,"origin":"","legend":"\u003cp\u003eSEM analysis revealed that in all the species (The s 1[a] and [b] \u003cem\u003eAntheraea proylei\u003c/em\u003e; 2 [a] and [b] \u003cem\u003eAntheraea frithi\u003c/em\u003e; 3 [a] and [b] \u003cem\u003eSamia canningi\u003c/em\u003e; 4[a] and [b] \u003cem\u003eCricula trifenestrata\u003c/em\u003e;\u003cem\u003e \u003c/em\u003e5 [a] and [b] \u003cem\u003eActias selene\u003c/em\u003e; 6 [a] and [b] \u003cem\u003eAttacus atlas\u003c/em\u003e; 7 [a] and [b] \u003cem\u003eSamia \u003c/em\u003ericini) the cross-binding and bifurcation of filaments formed an intricate network and Y-shaped structures indicated by arrows. Many irregularly shaped crystals were noticed to deposit on the surface of the fibres.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/85ee0d3ccd734742c274965a.png"},{"id":84275184,"identity":"ace06d93-8df3-4298-86d7-19405fb022d0","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":185026,"visible":true,"origin":"","legend":"\u003cp\u003eGraph represents the weight Percentage of elements found on silk fibres from different silk insects species [ 1: \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated), 2: \u003cem\u003eA. assamensis\u003c/em\u003e (wild) 3:\u003cem\u003eS.ricini\u003c/em\u003e 4:S\u003cem\u003e.canningi\u003c/em\u003e 5:\u003cem\u003e A. pralei\u003c/em\u003e 6:\u003cem\u003e A. frithi\u003c/em\u003e 7:\u003cem\u003e A. selene\u003c/em\u003e 8: \u003cem\u003eA. atlas\u003c/em\u003e 9:\u003cem\u003e C. trifenestrata\u003c/em\u003e] upon EDX analysis. The carbon element is found to be present at high quantities among all the elements. It was found that the weight % of elements was influenced by species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =412.67, df = 7, p-value = \u0026lt; 2.2e-16 ***] and elements [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =325.16, df = 8, p-value = \u0026lt; 2.2e-16 ***] and not year [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =0.5632, df = 2, p-value = 0.9154].\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/1877000cc96413fd9f8addb8.png"},{"id":84276832,"identity":"c1df1c8d-0931-4da8-beb8-de8c03540169","added_by":"auto","created_at":"2025-06-10 05:43:45","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":124371,"visible":true,"origin":"","legend":"\u003cp\u003eThe graph represents the K/S ratio values of different silk fibres. It was found that the K/S value was influenced by both years [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =6.773, df = 8, p-value = 0.0423*] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =188.96, df = 8, p-value =\u0026lt; 2.2e-16 ***]. Highest value was observed for Eri silk from \u003cem\u003eS. ricini\u003c/em\u003e followed by tasar silk from \u003cem\u003eA. proylei\u003c/em\u003e.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/49eb39bd3e4ebb755ecf8dfc.png"},{"id":84275180,"identity":"543d0fae-9e4f-459a-adaa-abe5916d8007","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":382656,"visible":true,"origin":"","legend":"\u003cp\u003eGraph [A] represents the Yarn Loss % trend over three years of the silk insect species [ 1: \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated), 2: \u003cem\u003eA. assamensis\u003c/em\u003e (wild) 3:\u003cem\u003eS.ricini\u003c/em\u003e 4:S\u003cem\u003e.canningi\u003c/em\u003e 5:\u003cem\u003e A. pralei\u003c/em\u003e 6:\u003cem\u003e A. frithi\u003c/em\u003e 7:\u003cem\u003e A. selene\u003c/em\u003e 8: \u003cem\u003eA. atlas\u003c/em\u003e 9:\u003cem\u003e C. trifenestrata\u003c/em\u003e]. It was found that the yarn loss was influenced by species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =324.56, df = 8, p-value =\u0026lt; 2.2e-16 ***] and not by years [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =0.4567, df = 2, p-value = 0.8194].The yarn loss (%) is found to be highest for \u003cem\u003eA. assamensis\u003c/em\u003e (semi-domesticated) and the lowest for \u003cem\u003eC. trifenestrata.\u003c/em\u003e Graph [B] represents degumming loss percentage trend of different silk insects from North-East India Silk cocoon over three years. It was observed that degumming loss % was influenced by both years[ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =223.16, df = 8, p-value =\u0026lt; 2.2e-16 ***] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) =563.67, df = 7, p-value =\u0026lt; 2.2e-16 ***].The highest degumming loss (%) is observed for \u003cem\u003eA. assamensis\u003c/em\u003e (semi-domesticated) while the lowest is observed for \u003cem\u003eS. ricini\u003c/em\u003e.\u0026nbsp;\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/9d7d8e770bf51368b24eea9c.png"},{"id":84277583,"identity":"1f693359-99bf-48ed-8525-2306629f8649","added_by":"auto","created_at":"2025-06-10 06:02:45","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":235485,"visible":true,"origin":"","legend":"\u003cp\u003eGraph [A] represents the Young’s modulus. It was observed that the Young’s modulus was influenced by both years [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 5.783, df = 8, p-value = 0.0233*] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 334.67, df = 8, p-value = \u0026lt; 2.2e-16 *** ]. Graph [B] represents the toughness assessment of the fibres. It was found that the toughness of the silk fibres were affected through the years [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 7.793, df = 8, p-value = 0.0334*] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 563.21, df = 8, p-value = \u0026lt; 2.2e-16 ***]. All the data are represented for the silk insect species [ 1: \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated), 2: \u003cem\u003eA. assamensis\u003c/em\u003e (wild) 3:\u003cem\u003eS.ricini\u003c/em\u003e 4:S\u003cem\u003e.canningi\u003c/em\u003e 5:\u003cem\u003e A. pralei\u003c/em\u003e 6:\u003cem\u003e A. frithi\u003c/em\u003e 7:\u003cem\u003e A. selene\u003c/em\u003e 8: \u003cem\u003eA. atlas\u003c/em\u003e 9:\u003cem\u003e C. trifenestrata\u003c/em\u003e].\u0026nbsp;\u0026nbsp;\u003c/p\u003e","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/f737d99bc1041b655ed196bb.png"},{"id":84275175,"identity":"420592f5-b947-4996-b157-216d90f1db8b","added_by":"auto","created_at":"2025-06-10 05:35:45","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":265899,"visible":true,"origin":"","legend":"\u003cp\u003eThe graph [C]\u0026nbsp; represents the tensile strength assessment of the fibres. It was found that tenacity of the silk fibres were affected through the years [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 8.673, df = 8, p-value = 0.0334*] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 432.66, df = 8, p-value = \u0026lt; 2.2e-16 ***].The graph [D] represents the strain(%) over the years. It was found that the strain % was influenced through the years [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 6.556, df = 8, p-value = 0.0123*] and species [ Chisq (c\u003csup\u003e2\u003c/sup\u003e) = 312.23, df = 8, p-value = \u0026lt; 2.2e-16 ***]. All the data are represented for the silk insect species [ 1: \u003cem\u003eA. assamensis\u003c/em\u003e (semi domesticated), 2: \u003cem\u003eA. assamensis\u003c/em\u003e (wild) 3:\u003cem\u003eS.ricini\u003c/em\u003e 4:S\u003cem\u003e.canningi\u003c/em\u003e 5:\u003cem\u003e A. pralei\u003c/em\u003e 6:\u003cem\u003e A. frithi\u003c/em\u003e 7:\u003cem\u003e A. selene\u003c/em\u003e 8: \u003cem\u003eA. atlas\u003c/em\u003e 9:\u003cem\u003e C. trifenestrata\u003c/em\u003e]. It was observed that \u003cem\u003eA. assamensis\u003c/em\u003e has the highest strain percentage and tensile strength\u0026nbsp; while the lowest was observed in \u003cem\u003eS. ricini.\u003c/em\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage111.png","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/0292b2fac6e8e528c7375e52.png"},{"id":84277954,"identity":"cd1762b6-c24d-43ad-a23a-c6a1176e4358","added_by":"auto","created_at":"2025-06-10 06:03:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5046168,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6836179/v1/480b7962-9833-49ed-bb54-bdcab28279e6.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eCocoon Characterization of silk insects from North East India:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAn approach for sustainable economic development\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe Northeastern region of India, comprising the states of Arunachal Pradesh, Assam, Meghalaya, Tripura, Mizoram, Nagaland, and Sikkim can be physio-graphically categorized as the Eastern Himalayas. The northeastern region holds a special place in the globe since it is the only place where all four species of silkworms\u0026mdash;Eri, Muga, Tasar and Mulberry coexist(Boro \u0026amp; Borah, 2020).\u0026nbsp;North-East India is one of the major and important hot spots among 35 biodiversity hotspots of the world, which is known for \u0026ldquo;Endemism\u0026rdquo; due to the unique climatic conditions. 29 species of silk insects \u0026nbsp; have been collected and identified from different states of North East India. Out of these only \u003cem\u003eAntheraea assamensis, A. mylitta,\u003c/em\u003e and \u003cem\u003eSamia ricini\u003c/em\u003e are commercialized for obtaining silk in North-East India. In addition to the silkworm, many different types of silkworm host plants are native to this area. There are currently 31 species of Saturniidae and 9 species of Bombycidae known to exist in northeastern India\u0026nbsp;(Kakatiya et al., 2009; Kalita \u0026amp; Dutta, 2014\u003cspan lang=\"EN-US\"\u003e;\u0026nbsp;\u003c/span\u003eBoro \u0026amp; Borah, 2020)\u003cspan lang=\"EN-US\"\u003e.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eThe process of producing raw silk by the rearing of caterpillars, or larvae, especially those of the domesticated silkworm (Bombyx mori), is known as Sericulture. Two procedures are typically involved in the manufacture of silk: [i] handling the silkworm from the egg stage until the cocoon is finished and [ii] creation of mulberry trees, which supply the worms with leaves to eat(Mahanta et al., 2023)\u003cspan lang=\"EN-US\"\u003e.\u0026nbsp;\u003c/span\u003eSilk production, or sericulture, has a long and illustrious history that dates back more than five thousand years. The sericulture industry, which starts with the cultivation of mulberry trees and their many applications, including the production of leaves for silkworm food, promotes employment, economic growth, and health. High-quality silk thread and high-protein food for both humans and animals are the products of sericulture(Altman \u0026amp; Farrell, 2022; Mahanta et al., 2023\u003cspan lang=\"EN-US\"\u003e).\u003c/span\u003eSericulture broadly comprises interlinked activities such as food plant cultivation and maintenance to feed the silkworms, silkworm rearing to produce the silk cocoons, reeling the cocoons for unwinding the silk filament, yarn making, weaving, and processing of fabric\u0026nbsp;(Kalantzi et al., 2013)\u003cspan lang=\"EN-US\"\u003e.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003eNature provides an enormous diversity of silk-producing insects ranging from well-known \u003cem\u003eBombyx mori\u003c/em\u003e to completely least concerned silk-producing insects\u0026nbsp;(Kakati \u0026amp; Chutia, 2013).\u0026nbsp;While mulberry sericulture deals with the rearing of the domesticated silkworm, non-mulberry sericulture,\u0026nbsp;also known as \u0026lsquo;\u003cem\u003eVanya silks\u003c/em\u003e\u0026rsquo; comes from the forest-based insects that are in general not reared in captivity. The majority of the non-mulberry silk moths belong to the family Sturnidae which constitute one of the largest groups of Lepidoptera comprising about 1200\u0026ndash;1500 species all over the world (B. C. Chutia et al., 2022). Out of which only 80 species are known to produce silk of economic value. They constitute part of the \u0026lsquo;\u0026lsquo;Charismatic megafauna\u0026rsquo;\u0026rsquo; of the insect world which produces lustrous silk (B. C. Chutia et al., 2022).\u003c/p\u003e\n\u003cp\u003eA cocoon is a natural silk composite with a non-woven structure made of continuous and non-continuous silk fibers conglutinated by a sericin bonding matrix. The cocoon characteristics like shell weight, filament length, and reeling characteristics such as denier and renditta have commercial importance as they reflect the silk quality. The fine structural character of the cocoon filament is one of the most important factors determining what kind of final product can be expected from the reeled silk or spun silk yarn (Akai; 2000). Production of quality cocoons and silk yarn depends on the altitudinal and geographical variation, length of the larval period, environmental changes in different seasons, variation among broods and races and is greatly affected by the foliar constituents of kinds of host plants that are used for feeding silkworms. Studies on cocoon and yarn characteristics of silk insects in India are mostly confined to commercially exploited silk species, viz. \u003cem\u003eAntheraea mylitta, A. proylei, A assamensis,\u0026nbsp;\u003c/em\u003eand \u003cem\u003eSamia ricini,\u003c/em\u003e with only little effort has been made on other wild silk species (Kakati \u0026amp; Chutia, 2013; B. C. Chutia et al., 2022).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Silk materials and their products have received significant attention throughout the world because of their attractive combinations of design, mechanical strength, and toughness. However, a gap of knowledge exists regarding studies on cocoon and silk characteristics of many silk species as most of the studies are confined only to commercially exploited silk species. Thus, to bridge the knowledge gap the study explores and compares the physical properties of different silk cocoons of Northeast India and their degummed protein fibers, to know their potential utilization for sustainable economic development. In the present study, nine species were characterized for the economic characteristics of cocoons to know their commercial importance.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003eThe experiment was carried out at the Zoology department, Cotton University; Guwahati; Assam, India.\u003c/p\u003e\n\u003cp\u003eThe live cocoon samples were collected based on available literature and consulting with the local people adopting the random sampling method. The survey covered the autumn and spring seasons, particularly during the year 2022\u0026ndash;2023. During the sample collection minimum 5 km distance was maintained between the two sites of sample collection to prevent population overlapping. The sample collection sites are represented in [Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cstrong\u003e]\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe length and breadth of cocoons were recorded using Vernier Caliper and the whole cocoon weight and shell weight were measured by the electronic balance. The shell ratio was calculated using the following formula\u003c/p\u003e\n\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\u003cimg src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAU4AAAAsCAYAAAAKGFGMAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAA+0SURBVHhe7Z3bqxbVG8fH3312vOoiosNFIAhqKhVBF2WkSBBlmoigFFoEBR0oIqQyTUmIzhhEeEgtElEpBYWKKCsxUrroQEh5pZX+Azaftef7/p699lrzzjv73bb3fp8PLGZmnWfNu5551rPWmnfK+ZLCcRzHacz/qqPjOI7TEBecjuM4PeKC03Ecp0dccDrjkg8//LCYMmVKceedd1Y+Y8sPP/xQ3HjjjRe0zPEGbXDZZZeFNmhL/Nz6ked4xAWn0+H+++8PP3AcHUD89ttvwe+dd96pfIZ3CNI1gbivvPJKdVUPeT7zzDPV1dhy5syZ4rbbbis2bdpUHDt2rPIdPKZPn15s2bKlumpH/Nz6ked4xAWn0+GNN94orr322mLevHnDhOHBgwfD8fDhw+EIdIinn346xLVCtp9cfPHF1Vme1atXNxbGOb755pvi77//Lm655ZZwX59++mkVMnhMnTq1OmtP/Nz6ked4wwWn0+Hyyy8vFi1aVBw5cqTyGWLz5s3B/8CBA5XPEEePHi2WL19eXXWHlW9PPvlkddUfvv322+qsPcePH6/OHKcZLjidYdx8881B+2IoDgxjuX7kkUdG+CNIb7/99nANhGm4zzD+2WefrUKGNMN4qE58bGH4WxfbGIl33XXXdcIoG7BJfvfdd8VTTz3VSZvC1gtHOt0H2vK6devCufJP8eWXX3ZsoMpD7N+/f1gYZamOwDltIdMGR2nphNE2CuM+Yw2+Ln/uQ2lte9p2ionLtPURxFFe1EntBXH6+H4HAReczjDuuuuucPzss8/CkWE62ibD2EsvvbT4+uuvO/50GLRUcc8994TOhGaJQHvrrbc6HfLNN98MRwvxr7nmmhD/119/DWYC7GN2qPzLL78UO3fuDMd9+/aFejG0BrRNTAXr168PeeT2cqhep0+fDg4hhE2Tzs49YHIA0qeG6dh4Fy5cWKxcuTLE+eKLL8L9KWz+/PmdMO4D98ADD4RwePXVV8NLhjSUf8cddxQnT54MYc8991y4D8JI/8QTTxSLFy8Oghq65S+TCdBOW7duDXZa2umjjz4K/jH4U5+ff/455EkbqD6CepEXZf31118hb6E6k577+eeff4LfQFE2nOMMoxSU50uB1DkvBVbnHKdz+QPn/JzKjlT5nD+/atWqTnwgvBRy1dXQdSmEqqvzIUzlAtezZs2qroaI8yC+vY5J1Ytz/LZv3x6uSc91jlKYj6iHSIWpzFLodMqybSVyYeRH20G3/CFVf9Lk2uXtt98+X74EO/dv4XmQl20v2ljPJVVn8iE/Qbn2OSrPyYRrnM4I0MbQWNDI0EykheLPNf5oSPIH2QmvuOKKMHzDoXGijeRAw3z99ddDfrh33303aKAWq9G2QfWy+eg81rJyfP/999l6pMI0GXLq1Knip59+CuepCZJcGPmhaUK3/HPk6gsPPfRQ0FI13E5NruXSq85owXrOaMiYcQYJF5zOCGS3ZPjFME7gTwdh6FlqkpXvEFdddVU4li/jYa5uhvr9998Pghhhi2MI+8ILL1Sh/UH1QjALnU+bNi0cuxELcwthNm84d+5cON5www3FlVdeGc5TKEzxBfnNnDkznHfLvy1M0jEEZ6kQNl671KwO1RlzRfysBwkXnM4I6KzlUC9ojLfeemvlO+SPlrh27drivvvuq3yHQKhiA0WLoaPj6IzxpIPlscceK/bs2dPpeNhBraZz9uzZEUIjxaFDh8KRsqWpCdWLl4DqxTn3MWfOnCpWPUuWLAkauLU76oVCGNq3BA9hzz//fHixcC+0WTls7WjWoHZRGPFVb8LIT+3bLf8clEX7pWDSR8+FNkDrVFwJ5Vy7q848O9WZySs7EUhe2KSF8lT8SUH5g3WcEWBb4+dhbV2A7S22uQnsXoSRDpuXtbGRDn/csWPHgh92MPnJkR7bHXYz+cneh72Ua/JWHpTJNS5lswPiql448lF6jqTFvxSmwS8F96J41FvpgXJJq7pRX9tuxNW9Em7bhXi6Lxz1jG2edfnb+pMP2LZOtQnPVmmUjvxSbYE9NM6LeLbOtj7Esf6pPCcD/lk55z+B5S3MFDOUl+aEloM2dO+99/Z9vafj9JNWQ3XUfIzC/MjbonV5Gv70I88LCZ0co7odoowWhn/kmRsmTSYY+mIv/eOPPyqfoYkH/GSXdJzxSlZw0nntIlcEnWbf6OCluh/O26K1eKIfefYK95WaUeyGNCM6+EsvvVT5DgeBqnazi4cF6WW3Erw82K5G2GQXnitWrAiTQczU00447GasY7QTUo7TlDpFxm4OQKal4mGrlULHUXbgFFnByQJbZt20SHbRokVhh4Zoso+4jpRhe7R55sAoTWP0C9qG4WSug9PgLCM5ffp0EAQswLbogbAsJAY/8n744Ycrn8kJz5/JIH5j/L5wLKpOtYnj1IFQZFMD8iklQ1BCeEEzscXvjAlJJjit0sTIlyVWL774Yojz4IMPDtuIMIIyUhKCYiM1Rl4RL3JtA2XULYDuF9xHza32BPW17ZACo7idALBlY0QnPUbzHMSJ28ZxnJEwkajJLWSH7XdCE1aawALS2Mkq+mw86Uk/xT9FVuMsMw3LHuyQEe0gBmkv9TYeYhKGVlanHjfF2kBtmXoj8PawajZxgHRLly4N54ThiIsZQueCusfmiVhd37ZtW9ehJBruTTfdVF0NB02SxcdslcuBNoaGT1l1aOhR54jjOBMF9Uuc+p76Y9wXAS0S/7qlWZ9//nlYXmfjzJgxI2wnFawnxnRkmT17dnYJVVZwfvzxx8FQf/311weBl7K51e0jhrq9y72CsCrfKJ0yX3vttbA+T2F8qYeyGR7Dyy+/HI6EoZoD9cAxY5vaO609uNSVePG+YaCBr7766uoqDQ/zq6++qq7+D/mQN/Y9CT2GGKmHw4OlLnUwI617yrm6BeiOM96gX5ZaXlDctBEDAVZqjV0Vlhz0r5xgVd9GiKaG+ci0FFnBiUaEIEI72rFjRxCg8XgfwaXJEW2/0xY3DK1URjtBECbc+O7du8N1W1Qm5aEB8/EJhLHeOjg0xbqtfil4MSDY16xZE+oK2Nt4U1nNj3vKaZOCtmNRNnkyAYTA55xPsLFb5r333uvYWxCcGzdurFIOByE7Vuit7s7df+1iEJ70O5QLNFD6TVuh2Y2LLrqoOksj5SwmKzgBIYR2hpZHxflCjCUnxaHN3uUmpMpEKKEV08gIotxboo4m+4abogkO7n3Dhg3h6z0IS4YCCHqEKjtCgCNabBtGM1SPNVN37v4rl4KPaqOk0PdGKzQvueSSICNSyGSGgEzttELbTZEUnGiWCCALHbyXjfxt9i63hW1jlMebiuEtGl6vNNk3LOI4KTSM1tYz9gPn9mFbW0sv+FDdmaxgNsPcRv9DIRoNzKgzerPC8/fffw9arUCpiRUY+m7c90VW46QgrTOkQIar2B1Et33E3fYuK61dAB3vcW2KFTwI/VwehDFplJqkYuiMwK3bNwy0Qa9fDGeHDB9TyGno9gFacv6OM5lBZqAJMnLj3wcYqcZrnlMgUxCIMfZ7BYAcQA5hlhPLli0LfV3yifIwBTIfkaTUSkbAtD37WZmuJwqO6XstoYn3owLhXJcV7MRjGVDZ+Tv+dqmA8lb8VJ6WunDtqyYv9tZSDteci1IoBj+O3B95KD/VF3/dB466x0uySJeqXw7qQJkW0lMOUPdUfqTppRzHmQyo/+m3b/u97c8W+oqVVfRb+pWFfqw4HFN5ITeQIcqjbjlgUnA6ebSO064Jy1FqwuEhcbSQNhbkFq4JG5R1nOoc8QtmrIhfkKOhH3Xnxa0O60wMaieHnJEwuYPBmMmebjD8x2ygWXrBkF32SY7xEF7fu6SssYKhiCaQYhsSqxJig7zWyLK8rAlMSuUmpmIo60Jut2XnF8u9SgE6zPzUhn7UnWHpZPwL3cmMC84W8F8su3bt6thD+gl5YqRmVnEswX6EcAa7phUbMDbj2FDOMqpSKwpbcMeCJtttaZumwjgHdjBWXbCkjBdWG5t6TD+2Cqe+EO+MX1xwtkAaI3+9MJrdUDFofuSZ0kLHAgzioF1WsHPnziBQWUFh/U+cOBG0q6b14h5w/eTHH3+sztqjZWeOMyqGRuzOICJbqjWUYxTHJpvytzZX0mLAl20OmyF+kLL7KT7+sQMM88TH3icjvrX/agLQupQNmPTWfkm9Nfln85aLUThHQTtwn0J1UZxudYe6egH3gr/FpqH8eMLDQlmE63lw5DkozD4r6qgwQfnUiXAc58JO8uLss4Zu+eu5006agLH1m4i44Bxw6OA4QGCqw9A5cKBJLgudgbh0Ghx54CdsvhDHJ2/bOelQlCHhQGels9lVDRJQdZAHZakczumknIMEVEroAvEIt51aQsPWhWvl2aTuTetlURrgGdQJG8qmnsQjT9qXegF5KAx4EVCW2kB560Vp60IY5wrjmrxSzzaXP3DN/ciP+lHmRMUF54CjH7nO1fk51w/b+gMdkzRWMNChbUeIBSfn6sgQCwrC6HwWwm0azusEpwSWhBGorhI4Ktd26hj70kDrQzBwbQWjBBp0q3sv9RKpNKpHjPKyz0Pkwqiv7kFCN0UqTHVDUDbJH4hjn6XymKi4jXPAmTt3bjjybYFPPvmks9gff9k5WYRsFwK3+YtYVhbw97/aXMCfl5UaSDgXo7Xr9uOvgOHuu+8O32dgIgmb74IFC8LuE/zggw8+GPHd0Lq6t6lXL1uWc9uFoclW4rH4+2Obf4qJPhnmgnPAYSkMAmzv3r1hhll7d+WP4AC7pKrNX8Rquyl5IgQQAHyBq5/046+AQTtNDh48GAQHH5TBr9SwwguGuqudmtCmXr1sWe7HXxDnIMzWG5SX/fvjJluVJxMuOJ0wi442E3+PkGu+lM2WUQudqRwy1/5FbAxrU/mqthUAVvh028Irjhw5EuKxNCleDma31hEH1+tfAQPaEisIWOVghUs5/CweffTR8LUeS9Ptx3X1kuBReypNbsuyRc9jNH9BzBItff2MeFrH2+3viZvkn0L3q/pOOMofsTPgyN4U26mwv+Fv7WwiniXGnqV4SofDPgrYt+QnVwqOUKaNL7uY8sZuqtlnbGqkwd/aXC3Exb6m/MhH6UHpbb4p1Caa8ABr9xVN615XL47ExZ/6CeqgNIRbG2EMeWD/TcXludhnRZ7xsya+6kA+qhtwj7bd7LOGbvkTX2Hkm7vfiYT/PbAz5qBVsHAdW6nVMtGm0FL6vd7TccYaH6o7Yw4TCAzd/vzzz8pnaMiHY6jnOBMN1zidCwL/7cSsOhMsUA7Rgp3s8ccfz87oOs54xQWn4zhOj/hQ3XEcp0dccDqO4/REUfwL+6fszuKKxwIAAAAASUVORK5CYII=\"\u003e\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003eSample sizes of 2 mm sizes were sliced from the cocoons of each sample. The samples were them washed out thoroughly for 4\u0026ndash;5 times to remove the dirt particles and fixed in 3% glutaraldehyde. After fixation samples were washed in 0.1M Sodium cacodylate buffer for 3 changes, each for 15 minutes at 4\u003csup\u003e0\u003c/sup\u003eC. The samples were the processed for dehydration passing through 30\u0026ndash;100% acetone, each for 15 minutes and 2 changes. Then the specimen were immersed in Tetra Methyl Silane for 5\u0026ndash;10 minutes for two times at 4\u003csup\u003e0\u003c/sup\u003eC. These were brought to room temp (25-26\u003csup\u003e0\u003c/sup\u003eC) to dry. After drying the specimen were mounted on aluminium stubs and coating of 35 nanometre was carried out using gold in Fine Coat Ion Sputter JFC1100. The gold coated samples were then observed SEM (JEOL JSM 6360) connected to a voltage of 15KV, in 30X, 150X,500X and 2000X in SAIF, NEHU, Shillong, India. The sample pieces that were used for observation under SEM were used for EDX (Energy Dispersive X-Ray Analysis) also. The ISIS 300 EDX unit (Oxford instrument) was used to identify the crystals present on the fibres.\u003c/p\u003e\n\u003cp\u003eThe cocoons were boiled adding 0.3% soda solution (Sodium carbonate) and gently teased out. When cooled the brines were following the traditional method used for silk reeling and spinning by the village people. For the removal of crystals that make the cocoons hard, demineralization was carried out with 20% lemon juice and kolakhar (NaOH) treatment for 24 hours in a shaking incubator. The single cocoon filament length, yarn colour, degumming loss % (weight loss of silk after degumming), and yarn yield % (length of material in a specific weight) were measured followed by degumming. The tensile properties of silk filaments were measured by a Universal Testing Machine, interfaced with a PC (Instron 5542 instrument 500N load cell) at 65% relative humidity and 26℃ temperatures (Gheysens et al., \u003cspan class=\"CitationRef\"\u003e2011\u003c/span\u003ea; Boulet-Audet et al., \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eTo check the dyeability of the silk fibres obtained from different species of silk insect cocoons, the fibres were dyed with natural dye extracted from \u003cem\u003eBixa orellena and\u003c/em\u003e Pomegranate \u003cem\u003e(mordant)\u003c/em\u003e in a neutral medium. The reflectance values of dyed samples were measured using an X-rite Ci6xBT portable spectrophotometer. From the reflectance values (R) in the visible spectrum (400\u0026ndash;700 nm) at the maximum absorption wavelength (\u0026lambda; max) for each dyed sample, the corresponding colour strength (K/S) values of the samples were calculated by using the Kubelka\u0026ndash;Munk equation.(Safi \u0026amp; Amirshahi, \u003cspan class=\"CitationRef\"\u003e2023\u003c/span\u003e)\u003c/p\u003e\n\u003cp\u003eStatistical analysis was performed in RStudio software (version 2024.04.2\u0026thinsp;+\u0026thinsp;764) with packages \u0026lsquo;dplyr\u0026rsquo; \u0026lsquo;ggplot2\u0026rsquo; \u0026lsquo;ggeffects\u0026rsquo;, \u0026lsquo;emmeans\u0026rsquo; \u0026lsquo;lme4\u0026rsquo; \u0026lsquo;lmerTest\u0026rsquo; \u0026lsquo;Matrix\u0026rsquo; and using linear mixed models (lm),. Log likelihood ratio test (LRT) was used to investigate the significance of all explanatory variables on the response variables in all models and based on Chisq(\u0026chi;2), Degrees of freedom (Df) and p-value the best model was selected and fitted. Modelling was done starting from the most complex model and then simplification was done using LRT to nested models. From the packages \u0026lsquo;ggeffects\u0026rsquo; and \u0026lsquo;emmeans\u0026rsquo;; ggemmeans was used to calculate the estimates.\u003c/p\u003e\n\u003cp\u003eThe cocoons that are not fit for reeling were separated from double, stained, crushed, flimsy, malformed, fluffy, insect-damaged, and mold-attacked cocoons manually following the cocoon sorting table developed by Central Silk Board of India. These cocoons are thrown as waste or burnt leading to environmental hazards. Depending on the environmental conditions the number of defective cocoons increases which may result in economic loss to the farmers. The hard shells of the cocoons left after reeling are also considered waste. These cocoons were processed for disinfection, natural dyeing of cocoons, and making handicrafts as shown in [Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e"},{"header":"RESULTS AND DISCUSSION","content":"\u003cp\u003eThe morphometric characteristics of cocoons showed distinct and significant variations among the different silk insects [Table\u0026nbsp;1]. Out of the total nine species collected, \u003cem\u003eSamia ricini\u003c/em\u003e is domesticated, \u003cem\u003eAntheraea assamensis\u003c/em\u003e is semi-domesticated as well as wild, \u003cem\u003eAntheraea proylei\u003c/em\u003e is semi-domesticated while \u003cem\u003eSamia canningi, Antheraea frithi, Actias selne, Attacus atlas, and Criculatri fenetrata\u003c/em\u003e are wild in nature belonging to the order Lepidoptera and family Saturniidae. All the cocoons were oval or spindle-shaped and showed distinct variations in colour, size, and texture. The wild cocoons were found to be harder than the semi-domesticated and domesticated silk insect cocoon species. \u003cem\u003eCriculatri fenestrata\u003c/em\u003e cocoons represented unique porous structure with bright golden colour. The cocoons of \u003cem\u003eA. assamensis, A. proylei, Actias selene, and Attacus atlas\u003c/em\u003e were observed to have a thin, filament-like structure called a peduncle at its anterior end. The color of the peduncle was the same as the cocoon color. The wild stocks had more peduncle length than the semi-domestic stocks. Significant variations were recorded in cocoon size, whole cocoon weight, shell weight, and shell ratio of cocoons among the various species.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe largest cocoon size was recorded for \u003cem\u003eAntheraea assamensis\u003c/em\u003e (wild) (L\u0026thinsp;=\u0026thinsp;6.41cm, B\u0026thinsp;=\u0026thinsp;2.90cm) and the smallest for the species \u003cem\u003eCriculatri fenestrate\u003c/em\u003e (L\u0026thinsp;=\u0026thinsp;3.6cm, B\u0026thinsp;=\u0026thinsp;1.5cm). The maximum shell weight was found for the \u003cem\u003eA. atlas\u003c/em\u003e while the shell ratio was found maximum for \u003cem\u003eA. assamensis\u003c/em\u003e (wild) [Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e]. After degumming of silk cocoons, the morphometric study of silk fibres revealed the single cocoon filament length highest in \u003cem\u003eA. assamensis\u003c/em\u003e followed by \u003cem\u003eS. ricini, A. proylei, A. altus, C. trifenestrata, A. frithi, S. canningi, A. assamensis\u003c/em\u003e (wild) and \u003cem\u003eA. selene\u003c/em\u003e as represented in [Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eScanning Electron Microscopic (SEM) study showed that in all the species, the cross-binding and bifurcation of filaments formed an intricate network and Y-shaped structures [Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e]. Energy Dispersive X-ray Spectroscopy (EDX) indicated that the granular materials were composed predominantly of calcium, nitrogen, oxygen, carbon, potassium, chlorine, aluminium, and silicon [Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e]. The filaments were more tightly packed in wild populations than the semi-domestic stocks. Many irregularly shaped crystals were noticed to deposit on the surface of the fibres.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eDyeing of all the silk fibres at uniform conditions (Temperature\u0026thinsp;=\u0026thinsp;45\u003csup\u003e0\u003c/sup\u003eC, Time\u0026thinsp;=\u0026thinsp;60 min) in a neutral medium showed positive results except for Muga silk which did not take any colour. K/S value of different silk fibres revealed the highest value for Eri silk from S. ricini followed by tasar silk from A. proylei [Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e]. To avoid economic loss for the farmers' different handicraft items were made in two categories-jewellery and home d\u0026eacute;cor.\u003c/p\u003e \u003cp\u003eYarn loss percentage patterns [Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e(A)] over three years revealed that \u003cem\u003eA. assamensis\u003c/em\u003e (semi-domesticated) has the highest percentage of yarn loss whereas for \u003cem\u003eC. trifenestrata\u003c/em\u003e has the lowest percentage. Degumming loss percentage patterns [Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e(B)] revealed that \u003cem\u003eA. assamensis\u003c/em\u003e (semi-domesticated) has the highest percentage while \u003cem\u003eS. ricini\u003c/em\u003e has the lowest degumming loss percentage. Tensile strength assessment of the fibres [Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e] and [Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e] showed that \u003cem\u003eA. assamensis\u003c/em\u003e has the highest tenacity, strain%, Young\u0026rsquo;s modulus, and toughness while the lowest was observed in \u003cem\u003eS. ricini\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eThe present study is focused on unveiling the economic characteristics of cocoons, fibre length and strength, yarn yield, and dyeability. ( Chutia \u0026amp; Kumar, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2014\u003c/span\u003e)stated that the host plant plays an important role in the determination of cocoon colour which has a very close consortium with the present study. According to (Heisswolf et al., 2009) pupal weight is proportional to fecundity. In the present study, a similar observation was found for which, a smaller number of wild cocoons could be collected during the field survey. Although the semi-domestic and domestic stocks recorded larger shell weight, a fair amount of yarn yield was found from the wild stocks between 28-62.28%. The bifurcation of filaments forming an intricate network and Y-shaped structure observed in the present study has a close consortium with the findings of (Mondal, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) in hybrids of \u003cem\u003eBombyx mori\u003c/em\u003e cocoons. They also stated that voids in the cocoon filaments are important in the selection process of good quality of silk cocoons for silkworm breeding. The arrangement of silk fibres also showed a close relationship with the fibre length. The more the fibre length more compact the arrangement of fibres was observed. In the indoor cocoon shells, the filaments were loosely arranged and slightly visible with wider gap. The number of filaments in the outdoor cocoons was found to be more in indoor cocoons that outdoor ones. This observation is supported by (Shamitha \u0026amp; Rao, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). The quality of cocoons depends both on sericin and fibrin which are controlled by atmospheric conditions. The presence of more cementing substance (sericin) and less filament (fibrin) in the indoor cocoons suggests the role of environmental factors on the synthesis of these proteins by silk gland. The sericin content as being the deciding factor in the quality of the cocoon and raw silk reeled was reported by (Shamitha \u0026amp; Rao, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHowever, filament length and quality of the shell are based on the fibroin content. This is corroborated by the findings of a reduction in filament length of outdoor cocoons as observed in the present investigation. The crystals observed were of calcium oxalate and the number of crystals determines the hardness of the cocoon shell (Kaur et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Kalita \u0026amp; Dutta, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Deposition of more crystals makes the cocoons harder and makes it difficult to reel (Gheysens et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The presence of crystals on the silk fibre is common to other wild silk filaments, bearing a striking contrast with the very smooth appearance of \u003cem\u003eB. mori\u003c/em\u003e silk, and is also responsible for the lower degree of lustre of textile products made by wild silk. In the present study, pre-treatment of cocoons with lemon juice (citric acid) and kolakhar revealed the complete removal of crystals and made the reeling process easy. It is reported in earlier studies that treatment with EDTA and citric acid can remove the Calcium oxalate crystals from the hard cocoon surface(Verplaetse et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e1986\u003c/span\u003e; Kaur et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePrior studies revealed that most fibres have a strain at break around 16% against the 18\u0026ndash;38% observed in the present study. This may be due to fact that the samples taken from different layers in cocoons differ significantly, and even spatially close samples can be very different due to factors such as bending of the fibres in the motion the worm makes while spinning the cocoon (Devi et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Yuan et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).Based on the tensile behaviour and microstructure of the filaments,(Chen et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2012\u003c/span\u003e) divided the silk insect cocoons into four types which has a very close similarity with the present study. \u0026lsquo;Lattice\u0026rsquo; cocoons have only a loose scaffold structure made up of a few fused fibre bundles supporting the cocoon frame with large pores (\u003cem\u003eCricula trifenestrata\u003c/em\u003e). The fibres sustain the load when the cocoon is stretched. \u0026lsquo;Weak\u0026rsquo; cocoons have high porosity and weak interlayer bonding as observed in \u003cem\u003eSamia sp\u003c/em\u003e. \u0026lsquo;Brittle\u0026rsquo; cocoons usually have low porosity and strong interlayer bonding or a single layer structure (\u003cem\u003eAntheraea assamensis\u003c/em\u003e). \u0026lsquo;Tough\u0026rsquo; cocoons can be grouped into fourth type, in which the cocoons have medium porosity and interlayer bonding (\u003cem\u003eAntheraea proylei\u003c/em\u003e).\u003c/p\u003e \u003cp\u003eDegumming loss % indicates that along with \u003cem\u003eA. assamensis\u003c/em\u003e the wild cocoons may also be a good source of sericin for silk protein-based product development (Sarovart et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2003\u003c/span\u003e)reported the use of sericin as an antioxidant and antimicrobial potential component. Except Muga silk as the other silk fibres have dyeability, they can be used for various product development with beautiful colours. The use of waste cocoons for handicraft making may be another breakthrough to prevent the economic loss of farmers due to the higher number of waste cocoons in adverse climatic conditions. Further awareness and strategies on the conservation of these silk insects in \u003cem\u003ein-situ\u003c/em\u003e or \u003cem\u003eex-situ\u003c/em\u003e may revolutionize the Seri-industry of Northeast India. Thus, the present study clearly showed that the wild silk insects may be a source of silk reeling, sericin extraction, dyeing, and weaving.\u003c/p\u003e \u003cp\u003eThus, the study effectively assessed the various cocoons' and silk fibres\u0026rsquo; economic and sustainable significance. Additionally, the study is arguably the first to document the dyeability of silk fibres and handicrafts created from leftover silk insect cocoons from this area. We believe that the study will encourage the potential utilization of wild silk insects for further sustainable economic development of the region and sericulture industry.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eACKNOWLEDGMENTS\u003c/strong\u003e\u003c/p\u003e\n\n\u003cp\u003eThe authors are thankful to traditional silkworm rearers of North East India who extensively helped in sample collection. The authors are also thankful to Department of Zoology, Cotton University for providing necessary laboratory facilities. They also acknowledge Gauhati University, NEHU Shillong and CSB, Bangalore for allowing to avail the instrumentation facility there. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\n\n\n\u003cp\u003e\u003cstrong\u003eA\u003c/strong\u003e\u003cstrong\u003eUTHOR CONTRIBUTION STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eTarali Kalita\u003c/strong\u003e: Conceptualization,Visualization, Writing-Original Draft Preparation,\u0026nbsp;Investigation, Project Administration, Supervision, Validation, Writing- Review and Editing.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAditya Shankar Kataki\u003c/strong\u003e: Data Curation, Software, Formal Analysis\u0026nbsp;and Writing- Review and Editing\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAlo Saha Das, Devajit Basumatari, Jayashree Deka, Hiren Gogoi, Mrigakshi Phookan, Priyanku Sarma\u003c/strong\u003e : Methodology, Sample collection, Formal Analysis and Writing- Review and Editing\u003c/p\u003e\n\n\n\u003cp\u003e\u003cstrong\u003eFINANCIAL SUPPORT\u003c/strong\u003e\u003c/p\u003e\n\n\u003cp\u003eThe research project was supported by the Cotton University, Guwahati, Assam; India \u0026nbsp; In-House Research Project Scheme (Ref \u0026ndash; CU/Dean/R\u0026amp;D/2019/05/1995)\u003c/p\u003e\n\n\n\u003cp\u003e\u003cstrong\u003eCONFLICT OF INTEREST\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors report there are no competing interests to declare\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAltman, G. H., \u0026amp; Farrell, B. D. 2022. Sericulture as a sustainable agroindustry. Cleaner and Circular Bioeconomy, 2, 100011.\u003c/li\u003e\n \u003cli\u003eBoro, P., \u0026amp; Borah, S. 2020. Biodiversity of sericigenous insects in north- eastern region of India- A review.\u003c/li\u003e\n \u003cli\u003eBoulet-Audet, M., Vollrath, F., \u0026amp; Holland, C. 2015. Identification and classification of silks using infrared spectroscopy. Journal of Experimental Biology, 218(19), 3138\u0026ndash;3149.\u003c/li\u003e\n \u003cli\u003eChen, F., Porter, D., \u0026amp; Vollrath, F. 2012. Silk cocoon (Bombyx mori): multi-layer structure and mechanical properties. Acta Biomaterialia, 8(7), 2620\u0026ndash;2627.\u003c/li\u003e\n \u003cli\u003eChutia, B. C., Nath, C., Goswami, L. M., Borkataki, S., Borah, N., \u0026amp; Tamuly, C. 2022. Morphophysical and Spectroscopic Characteristics of Wild Silkworm Cocoons in North-East India. Proceedings of the National Academy of Sciences India Section B - Biological Sciences, 92(1), 171\u0026ndash;183.\u003c/li\u003e\n \u003cli\u003eChutia, P., \u0026amp; Kumar, R. 2014. Host Plants Relationship in terms of Cocoon Colour and Compactness of Eri Silkworm (Samia ricini).\u003c/li\u003e\n \u003cli\u003eDevi, D., Sarma, N. Sen, Talukdar, B., Chetri, P., Baruah, K. C., \u0026amp; Dass, N. N. 2011. Study of the structure of degummed Antheraea assamensis (muga) silk fibre. Journal of the Textile Institute, 102(6), 527\u0026ndash;533.\u003c/li\u003e\n \u003cli\u003eGheysens, T., Collins, A., Raina, S., Vollrath, F., \u0026amp; Knight, D. P. 2011. Demineralization enables reeling of wild silk moth cocoons. Biomacromolecules, 12(6), 2257\u0026ndash;2266.\u003c/li\u003e\n \u003cli\u003e, Andersson, T., \u0026amp; Ruohomki, K. 2009. Shifting body weight-fecundity relationship in a capital breeder: maternal effects on egg numbers of the autumnal moth under field conditions. Bulletin of Entomological Research, 99(1), 73\u0026ndash;81.\u003c/li\u003e\n \u003cli\u003eKakati, L. N., Chutia, B. C., \u0026amp; Rawat, G. 2009. Diversity and ecology of wild sericigenous insects in Nagaland, India. Tropical Ecology.\u003c/li\u003e\n \u003cli\u003eKakati, L. N., \u0026amp; Chutia, B. C. 2013. Cocoon and Yarn Diversity of Wild Silkmoths in Nagaland, India. International Journal of Wild Silkmoth and Silk, 17, 1\u0026ndash;9.\u003c/li\u003e\n \u003cli\u003eKalantzi, S., Mamma, D., Kekos, D., Kalantzi, S., Mamma, D., \u0026amp; Kekos, D. 2013. Physichochemical and Low Stress Mechanical Properties of Silk Fabrics Degummed by Enzymes. Eco-Friendly Textile Dyeing and Finishing.\u003c/li\u003e\n \u003cli\u003eKalita, T., \u0026amp; Dutta, K. 2014. Biodiversity of Sericigenous insects in Assam and their role in employment generation.\u003c/li\u003e\n \u003cli\u003eKalita, T., \u0026amp; Dutta, K. 2020. Characterisation of cocoon of different population of Antheraea assamensis (Lepidoptera: Saturniidae). Oriental Insects, 54(4), 574\u0026ndash;590.\u003c/li\u003e\n \u003cli\u003eKaur, J., Rajkhowa, R., Tsuzuki, T., \u0026amp; Wang, X. 2015. Crystals in Antheraea assamensis silkworm cocoon: Their removal, recovery and roles. Materials \u0026amp; Design, 88, 236\u0026ndash;244.\u003c/li\u003e\n \u003cli\u003eMahanta, D. K., Komal, J., Samal, I., Bhoi, T. K., Dubey, V. K., Pradhan, K., Nekkanti, A., Gouda, M. N. R., Saini, V., Negi, N., Bhateja, S., Jat, H. K., \u0026amp; Jeengar, D. 2023. Nutritional aspects and dietary benefits of \u0026ldquo;Silkworms\u0026rdquo;: Current scenario and future outlook. Frontiers in Nutrition, 10.\u003c/li\u003e\n \u003cli\u003eMondal, M. (2007). The silk proteins , sericin and fibroin in silkworm , Bombyx mori.\u003c/li\u003e\n \u003cli\u003eSafi, M., \u0026amp; Amirshahi, S. H. 2023. Estimation of dye concentration by using Kubelka\u0026ndash;Munk and Allen\u0026ndash;Goldfinger reflective models: comparing the performance. Scientific Reports 2023 13:1, 13(1), 1\u0026ndash;11.\u003c/li\u003e\n \u003cli\u003eSarovart, S., Sudatis, B., Meesilpa, P., Grady, B. P., \u0026amp; Magaraphan, R. 2003. The use of sericin as an antioxidant and antimicrobial for polluted air treatment. In Rev.Adv.Mater.Sci (Vol. 5).\u003c/li\u003e\n \u003cli\u003eShamitha, G., \u0026amp; Rao, A. 2006. Studies on the filament of tasar silkworm, Antheraea mylitta D (Andhra local ecorace). Current Science.\u003c/li\u003e\n \u003cli\u003eVerplaetse, H., Verbeeck, R. M. H., Verbaeys, A., \u0026amp; Oosterlinck, W. 1986. Solubility of calcium oxalate monohydrate and hydroxyapatite in EDTA solutions. The Journal of Urology, 135(3), 608\u0026ndash;611.\u003c/li\u003e\n \u003cli\u003eYuan, Y., Nasri, M., Manayi, A., Zhang, J., Wu, C., Jeon, T. J., \u0026amp; Kang, L. 2024. Sericin coats of silk fibres, a degumming waste or future material? Materials Today Bio, 29, 101306.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table 1","content":"\u003cp\u003eTable 1 is not available with this version.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"cotton university, guwahati","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Cocoon, silk insects, sustainable development, economic development, North-East India, tensile strength","lastPublishedDoi":"10.21203/rs.3.rs-6836179/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6836179/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSilk materials have received significant attention throughout the world because of their invaluable properties. In the present study, nine species were examined to evaluate the arrangement of silk fibres in the different cocoon species to understand variations and to know their commercial importance. Scanning electron microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) analysis were done to observe the arrangement of silk fibres in the different cocoon species.. The morphometric characteristics of cocoons showed distinct and significant variations among the different silk insects. SEM analysis showed that in all the species, the cross-binding and bifurcation of filaments formed an intricate network and Y-shaped structures. The study successfully evaluated the sustainable importance of the different cocoons and silk fibres. Besides, the study and can also be considered as the first to report on the dyeability of silk fibres and handicrafts made from waste silk insect cocoons from this region.\u003c/p\u003e","manuscriptTitle":"Cocoon Characterization of silk insects from North East India:\nAn approach for sustainable economic development","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-10 05:35:40","doi":"10.21203/rs.3.rs-6836179/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c75e63a4-c59e-48d0-bb70-50a510f7f987","owner":[],"postedDate":"June 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":49639442,"name":"Animal Science"}],"tags":[],"updatedAt":"2025-06-10T05:35:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-10 05:35:40","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6836179","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6836179","identity":"rs-6836179","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}