• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.123-127
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• 2004

Normally, silkworms, Bombyx mori, generate offspring by sexual activity. As we known, the hybrids of the first generation of the silkworm have higher cocoon production than pure lines. During the sericulture production, many processes are related with sex control. For example, sex sorting in the egg grainages, rearing of only male silkworm to save the mulberry leaf consumption and increase silk output and quality. Therefore it is very interested in understanding the sex control of the silkworm in theory and practice. Chinese sericultural scientists have been being engaged in the researches in the fields of artificifial parthogenesis, dispermic androgenesis, sex-limited varieties, sex linkage balanced lethal strain and high temperature sensitive male stocks for several decades and gained substantial achievement. Some of the achievements have been used in the commercial production. In this review, the authors introduced that the methods for control of the silkworm sex, and regulate the silkworm sex ratio according to different producing aim in the world and especially in China.

• Mycobiology
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• v.38 no.3
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• pp.180-183
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• 2010

This study was conducted out to select a silkworm variety suitable for synnemata production of Isaria tenuipes. Four kinds of the mulberry silkworm varieties, Bombyx mori, were hybridized using a Japanese parental line and a Chinese parental line, and used to test for synemata formation in I. tenuipes. The larval period of normal silkworms was 22 hr longer than the silkworms inoculated with this fungus. Among the silkworm varieties tested, Hachojam had the shortest larval period with 23.02 days. The non-cocooning silkworm had a shorter larval period than the cocoon producing silkworms. The pupation rate of normal silkworms was about 9% higher than that of silkworms sprayed with I. tenuipes. Hachojam had the highest infection rate at 99.8%, but no significant difference was observed for the infection rate by silkworm variety. The production of synnemata was the best in JS171 $\times$ CS188 with an incidence rate of 99.3%, followed by Hachojam, and Chugangjam. The synnemata produced from Hachojam were the heaviest and showed white or milky-white in color.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.1
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• pp.1-4
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• 2003

Sericulture is a traditional agro-industry, which involves mulberry cultivation and silkworm rearing, has made great contributes to the human civilization. With the development of national economy and modem technology, mulberry and silkworm are being used to develop products with functionality besides the traditional cocoon production in China. In this paper, we brief the current developing situation of sericultural byproducts with functionality in the following aspects. (1) Functional products from silkworm larvae: silkworm powder, white muscardine silkworm, isolation and purification of anti-bacterial proteins from the larvae and production of medically valuable substances by Bombyx mori nuclear polyhedrosis virus (BmNPV) vector. (2) Utilization of silkworm feces: for pillow and for isolation of chlorophyll etc. (3) Production of valuable Chinese traditional medicine like Cordyceps sinensis with pupae, functional utilization of pupa protein and chitin. (4) Silk as additives to cosmetics, silk food and medical materials. (5) Functional utilization of mulberry: cultivation of edible fungus on mulberry shoots as medium, mulberry fruit drinks, mulberry tea, etc. The prospect of sericultural byproduct industry in China is also discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.1
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• pp.128-134
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• 2014

Nesolynx thymus Girault (Hymenoptera: Eulophidae) is one among 20 hymenopteran parasitoids reported to attack the uzi fly, Exorista bombycis, which in turn infests the silkworm, Bombyx mori accounting a cocoon yield loss of 10-20%. A host of factors viz., age and size of host, age and size of parasitoid, availability of host, temperature and quality of host are reported to influence the reproductive efficiency of the parasitoids. In the present study an attempt was made to record the influence of foraging parasitoid density on their reproductive performance. Three day-old uzi pupae were offered to varying numbers (1 - 10) of 2 day old Nesolynx thymus adults for parasitization. The progeny production per pupa (84.44 - 132.77) increased significantly with increase in the number of foraging parasitoid adults (1 - 10) however, progeny production per female decreased. The sex ratio (M : F) (1:25.49 - 1:1.53) decreased significantly with increase in foraging parasitoid adults. The morphometric parameters except female abdomen width of first generation parasitoid showed significant negative correlation with number of foraging adults. However, correlation between the parasitoid size in first generation and their reproductive performance was nonsignificant.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.1
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• pp.1-4
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• 2011

This study was conducted to test the use of colored cocoon silkworm, Golden Silk, as a host for the fruiting body production of Cordyceps mushroom. Golden Silk variety had a shorter larval period than Yangwonjam at $25.3^{\circ}C$ and 78.5% RH: The average larval period of the Golden Silk was 24 days and 7 hr, and that of the Yangwonjam was 24 days and 15 hr. In the infection test of I. tenuipes on silkworm, the larval period of normal silkworms was longer than the silkworms inoculated with I. tenuipes in both Golden Silk and Yangwonjam. The pupae survival percentage of Golden Silk was 94.4%, whereas it was 91.9% in Yangwonjam. Golden Silk had a higher pupation rate than Yangwonjam. The pupation rate of normal silkworms was about 5% higher than that of silkworms inoculated with I. tenuipes. Infection rate of I. tenuipes into larvae of 5th instar newly exuviated silkworm was 93.8% in Golden Silk, and 96.9% in Yangwonjam. Synnemata production of I. tenuipes was better in Yangwonjam with an incidence rate of 99.8% than Golden Silk with 98.6%. The average synnemata weight of Golden Silk was 1.12 g and that of Yangwonjam 1.29 g. Golden Silk had a lower synnemata weight than Yangwonjam. But no significant difference was observed in synnemata weight varieties. The synnemata of I. tenuipes produced on pupae were white or milky-white in color, and similar in shape and color to wild synnemata collected in Korea.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.107-113
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• 2011

Infection effect of $Nosema$ $bombyics$ on the midgut of silkworm $Bombyx$ $mori$ and subsequent appearance of spores and the performance of larvae was studied. Autopsy of larvae showed white pustules on the surface of midgut at 5 days of post infection (pi). At later stage, important organs like midgut, silk gland and gonads reduced in size and all these organs showed white pustules. Light microscope observation of pustules revealed enormous spores. Spore multiplication was at a faster rate in young larvae. Infection of the adult larvae resulted in pebrinized pupa and moths. Larval weight, cocoon weight and cocoon shell ratio reduced as the post infection period increased. Transverse sections of midgut showed $N.$ $bombycis$ infection limited to a few columnar cells at 3-5 days of pi. At 7 days pi, cell volume increased, cells were swollen and elongated. Heavily infected cells looked like sacks filled with parasite and the apical region of certain cells were bulging into the gut lumen. Later at 8-9 days of pi, spores or its developing stages leaked into the lumen either freely or enclosed within the globules of host cytoplasm. Besides columnar cells, development of $N.$ $bombycis$ was observed in the regenerative cells and rarely in goblet cells. Development of $N.$ $bombycis$ was also observed in both longitudinal and circular muscles at the late pi period. The histopathological changes, deformities and spore production time in the host were all influenced by the spore dosage and age of the host.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.243-264
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• 2013

Antheraea mylitta Drury is a commercial silk producing forest insect in India and Xanthopimpla pedator Fabricius is its larval-pupal endoparasitoid, which causes pupal mortality that affects seed production. Effects of host plants, rearing season and their interactions on parasitic behaviour of X. pedator were studied here, as influence of these factors on biological success of X. pedator is not known. Seven forest tree species were tested as food plants for A. mylitta, and rate of pupal parasitization in both the rearing seasons were recorded and analysed. Results showed that rearing season and host plants significantly affected the rate of pupal parasitization in both the sexes. Pupal mortality was found significantly higher (14.52%) in second rearing season than the first (2.89%). Likewise, host plants and rearing seasons significantly affected length, diameter, and shell thickness of cocoons in both sexes. Out of all infested pupae, 85.59% were found male, which indicated that X. pedator chooses male spinning larva of A. mylitta for oviposition, but we could not answer satisfactorily the why and how aspect of this sex specific parasitic behaviour of X. pedator. Multiple regression analysis indicated that length and shell thickness of male cocoons are potential predictors for pupal parasitization rate of X. pedator. Based on highest cocoon productivity and lowest pupal mortality, Terminalia alata, T. tomentosa, and T. arjuna were found to be the most suitable host plants for forest based commercial rearing of A. mylitta in tropical forest areas of Uttarakhand state, where it has never been reared earlier. Sex and season specific interaction of X. pedator with its larval-pupal host, A. mylitta is a novel entomological study to find out explanations for some of the unresolved research questions on parasitic behaviour of X. predator that opens a new area for specialised study on male specific parasitization in Ichneumonidae.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.25-32
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• 2014

We produced the transgenic silkworm that expressed the enhanced blue fluorescent protein (EBFP) in the cocoon of silkworms. The EBFP fusion protein, each with N- and C-terminal sequences of the fibroin H-chain, was designed to be secreted into the lumen of the posterior silk glands. The expression of the EBFP/H-chain fusion gene was regulated by the fibroin H-chain promoter. The use of the $3{\times}P3$-driven DsRed2 cDNA as a marker allowed us to rapidly distinguish transgenic silkworm. A mixture of the donor and helper vector was micro-injected into 300 eggs of silkworms, Baegokjam. We obtained 5 broods. The cocoon displayed blue fluorescence, proving that the fusion protein was present in the cocoon. Also, the presence of fusion proteins in cocoons was demonstrated by SDS-PAGE and western blot analysis. Accordingly, we suggest that the EBFP fluorescence silk will enable the production of the silk-based biomaterials.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.76-81
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• 2012

Silk protein has been explored to be used for biomedical applications for several decades. However, it has not been used in this field cause to their irreversible crystallization after dissolving in water. The existing methods of silk protein hydrolysis using silkworm cocoon were used with harmful solvents and through a very complicated process. Therefore, we have developed novel methods for the production of water-soluble hydrolysate using silkworm gland. We manufactured two types of silkworm gland-derived hydrolysate (water-soluble SGH, SSGH; total SGH, TSGH) and compared the characteristics with commercial cocoon-derived sericin hydrolysate (CSH). The molecular weight of SGH ranged from 7 to 50 kDa (SSGH) and 5 to 15 kDa (TSGH) within glycine, alanine, and aspartic acid as a main amino acid composition. In contrast, CSH ranged from 15 to 50 kDa within serine and aspartic acid. The results of FTIR implied that SGH was more soluble form than CSH, as shown by the decrease in the ${\beta}$-sheet structure at $1630cm^{-1}$ on amide I peak. In comparison with 10% fetal bovine serum, 0.1% (1 mg/ml) SSGH had equivalent effect on the proliferation of human dermal fibroblasts and mesenchymal stem cells. All results of the SSGH made by novel manufacturing process indicate the SSGH is more preferable as a culture medium supplement than cocoon-derived sericin.

• Journal of Sericultural and Entomological Science
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• v.49 no.1
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• pp.14-17
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• 2007

A new silkworm variety Golden silk for spring rearing season is $F_1$ hybrid between Jam311, a Japanese race bred from introduction breeding and Jam312, a Chinese race from introduction breeding. In the local adaptability test performed at 8 local areas in spring of 2006, "Golden silk" was showed 7 percent higher in hatchability than authorized silk-worm races laval. "Golden silk" was receded higher 1.7 percent, 2.2 percent in pupation rate, best cocoon rate respectively than Chunsujam. The larval period shortened for 1.12 day even though low record to the several items including productivity than Chunsujam. "Golden silk" was showed 1,031 m, 2.97 denier in length of cocoon filament, weight of cocoon filament respectively. The concentration of Deoxynojirimycin(DNJ) was measured 4.34 mg in "Golden silk", high then to "Chunsujam"(3.81 mg). In the Paecilomyces tenuipes production ability test, the pupal weight of "Golden silk" was 1.20g.