• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.2
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• pp.81-86
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• 2006

Of all factors that govern productivity in sericulture, the role of silkworm egg is of prime importance. The production of silkworm seed involves a long chain of interdependent and highly specialized conditions. Female moths of Bombyx mori L. commence egg deposition immediately when the moths were decoupled. More than 60% of eggs are deposited within 4 hrs after decoupling i.e. 62.33% in CSR-3, 61.67% in CSR-6, 62.50% in CSR-16 and 63.28% in CSR-17. Almost 90% of eggs were laid in the first 12 hrs (93.13% in CSR-3, 90.81% in CSR-6, 89.71% in CSR-16 and 93.17% eggs in CSR-17) after decoupling. Almost 8 to 10% of more eggs were laid when oviposition period was prolonged upto 48 hrs instead of 24 hrs. The present investigation showed that a significant increase of 45 (8.34%), 50 (9.98%), 41 (8.26%) and 45 (8.30%) (P < 0.01) numbers of more eggs were found between 24 to 48 hrs (T6 to T9) in CSR-3, CSR-6, CSR-16 and CSR-17 races respectively. The findings of present investigation is very important for sericulture industry while producing layings to keep for different hibernation schedule especially for autumn/late autumn crop, female may be allowed for prolonged oviposition to get 8 -10% more eggs and farmer may fetch 8 -10 kg. more cocoon yield/l00 dfls with more income.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.1
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• pp.157-163
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• 2008

Infection of pathogenic microsporidia, Nosema bombycis and Nosema mylitta (Chakrabarti and Manna, 2006) decreased egg production, fecundity, hatching % and increased sterile eggs in heavily infected mulberry silkmoth, Bombyx mori L. On an average a disease free moth laid upto 442.67 eggs with high hatching % (99.53) and less sterile eggs ($0.47{\sim}2.00%$). While an infected moth laid less number of eggs ($7.00{\sim}412.00$) with low hatching % ($32.437{\sim}98.643$) and high sterile eggs ($2.143{\sim}129.571$). Fecundity of disease free laying was highest (468.714) during season-1 then gradually decreased during season- 2 (414.000) to season- 3 (404.285). But fecundity of an infected laying was highest during season-2 and hatched eggs were lowest during season-2. Higher inoculums concentration of N. mylitta infected to 5th stage larva of mulberry silkworm drastically decreased the fecundity in season - 3 and lower inoculums concentration of N. bombycis decreased the fecundity in season-1 and 3. Season-3 was most effective season to decrease the fecundity and increase sterile eggs when both temperature and humidity were fluctuated from the optimum level.

• Journal of Life Science
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• v.6 no.3
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• pp.171-177
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• 1996

It was carried out to find the carbohydrate metabolism for the glycogen utilization and the effects of low temperature(1$\circ$C, 5$\circ$C)on embryonic development of the silkworm, Bombyx mori L. The content of sorbitol and glycerol in the chillihg eggs stored at 5$\circ$C or 1$\circ$C on 24 hours after oviposition showed the highest level on the 50th day. After that, the corresponding value in the eggs stored at 5$\circ$C were decreased, and the value in the eggs stored at 1$\circ$C maintained the similar level. The trehalose level was rapidly increased on 50$\sim$60th day or thereabouts, and then, it was accumulated. When the eggs stored at low temperature were tranaferred and developed the embryo at 25$\circ$C, sorbitol and glycerol were respectively changed to glycogen. Futhemore, the content of trehalose and glucose showed specific of patterns with each embryonic stage at low temperature. With the aforementioned results, the intemediary metabolism of carbohydrate was discussed with regard to embryonic development of non-diapause eggs of silkworms.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.19-23
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• 1965

Author studied to investigate the form and character of silkworm, Bombyx mori L. which bred from double copulation. The results obtained are as follows. 1. Some eggs of silkworm were fertilized evenly 10 minutes copulation, but it was varried by the race of the worm. In silkworm eggs production, the male and female should be separated from the early stage of 5th instar in order to do not make non hybrid eggs. 2. It was very difficult to find the tendency of fertilization ratio between homo race copulation and hetero race copulation in crossing with mates of two different race for a female (double crossing).

• Journal of Sericultural and Entomological Science
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• v.28 no.2
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• pp.35-37
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• 1986

To reduce the number of rearing season required for preservation of multivoltine silkworms which do not produce diapause eggs, the optimal egg stage, temperature, and period of cold storage were examinede using hatchability as an indicator of viability. Multivoltine silkworm starains MR, SPT, and HM were used in the study. 1. The hatchability of multivoltine silkworm eggs (MR and STP) preserve at 5$^{\circ}C$ for 30 days was 80% for the eggs chilled from 2 days after oviposition but less 5% for those chilled from 7 days after ovipostion. 2. When 2 day-old eggs of multivoltine silkworm (HM) were preserved between -2.5$^{\circ}C$ to 7.5$^{\circ}C$ for 15 to 60 days, $0^{\circ}C$ and 2.5$^{\circ}C$ showed the highest hatchability with 91% at 30 days and 61% at 60 days storage, respectively. 3. From these results, it can be concluded that by preserving 2 day-old eggs at 2.5$^{\circ}C$ for 50 to 60 days, rearing seasons required for preservation of the multivoltine silkworm can be reduced to half per year.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.149-153
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• 2002

Induction of non-diapause eggs and manifestation of quantitative characters were studied in different seasons by low temperature incubation of eggs of a low yielding diapause with coloured cocoons silkworm breed, RDI of Bombyx mori. Hundred percent of nandiapause eggs were induced when the egg incubation was carried out at 15$^{\circ}C$ followed by incubation initially at $25^{\circ}C$ and then at $15^{\circ}C$. The diapause-nondia-pause relation was found to be reversible. Analysis of variance study demonstrated significant variation in all the quantitative characters whereas significant variation due to different incubation treatments was observed for larval span, fifth instar larval span, cocoon yield/10,000 larvae by weight, cocoon weight, cocoon shell weight, and cocoon shell ratio. study on hybrid vigour skewed significant heterosis over mid parent value for four economic characters viz., cocoon weight, cocoon shell weight, cocoon shell ratio and filament length in a Fl hybrid between RD1 with diapause eggs and Japanese type bivoltine $NB_{4} D_{2}$.

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.57-58
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• 1969

Artificial silkworm eggs must do washing the acid completely after soaking HCl. Author experimented following deacidification times: 30 minutes, 1 hour, 2 hours, 6 hours soaking and 12 hours soaking eggs in the fresh water after artificial hatching, and incubated room temperature. There was no difference 1 hour's with control but more than 1 hour deacidification influenced badly in hatching ratio. Especially above than 6 hours deacidification was not only delaying 1 day in hatching date but also decreasing in practical hatching ratio.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.47-51
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• 2004

To evolve silkworm hybrids with higher survival and productivity and easy and effective seed cocoon production, three new evolved bivoltine hybrids of silkworm (Bombyx mori L.), created with participation of sex-limited lines at eggs and larva stage were evaluated with control Super$_1$${\times}$Hessa$_2$ hybrid at Plovdiv Agrarian University during 2000 - 2002. ANOVA analysis was employed and the performance of hybrids was observed in respect of main quantitative traits. The results obtained show significant superiority of new hybrids T$_{15}$ 4/${\times}$TBV$_{2}$24/, XT$_{215}$38/${\times}$TV$_{3}$2/, XT$_{215}$38/${\times}$B$_{2}$6/ and their reciprocal crosses over the control. They were characterized with 99% hatchability of eggs, 93-95% silkworm survival, 2.32- 2.42 g cocoon weight, 53.5-55.7 cg shell weight, 22.9-23.1% shell ratio, 1,307-1,326 m filament length, 3.08-3.17 denier, 95-96% reelability, 44.4-45.1% silk ratio, 569-593 number of normal eggs per lying and 347-364 mg weight of normal eggs per lying. Newly evolved hybrids were manifested high productivity, 41.0-43.6 kg cocoon yield and 7.33-7.78 kg raw silk yield per one box (20,000$\pm$200 viable eggs), which significant surpass the control Super$_1$${\times}$Hessa$_2$ hybrid with 7.6-14.4% and 10.8-17.6%, respectively. T$_{15}$ 4/${\times}$TBV$_{2}$24/ and XT$_{215}$38/${\times}$TV$_{3}$2/ were considered as highly productive hybrids to local conditions and found suitable to rear in spring season.n.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.87-94
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• 2005

Mating is an essential behavioural social event in the life cycle of silkworm, Bombyx mori (L.) for the perpetuation of population. A number of intrinsic and extrinsic factors and events of significant importance are involved in successful mating and egg deposition by an adult silk moth which besides biochemical, physiological and environmental factors also includes attraction of reproductively competent male and female moth for mating, duration and frequency of mating, age of moth at the time of mating, reuse of male moth in the production of eggs etc. An attempt has been made in this review article to elucidate briefly the behaviour of male towards female moth after eclosion, impact of duration and frequency of mating on egg deposition and oviposition, reuse of mated male moth in the production of quality and quantity eggs etc. in the silk-worm, B. mori and its significance in silkworm seed production.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.41-43
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• 2006

Lamerin breed of the silkworm Bombyx mori L. is the only mulberry silkworm breed which survives with an associated microsporidian $(Lb_{ms})$ infection from generations. This present comparative investigation has produced information on the influence of $Lb_{ms}$ on the growth and development of the breed. The $Lb_{ms}$ transmits tranovarially as well as perorally at low level. Larvae developed from the eggs laid by female, infected with $Lb_{ms}$ were as normal as larvae developed from the eggs laid by healthy female. In infected tissues early developmental stages and mature spores located intracellularly but did not show hypertrophy of cells of the host. The meronts and sporonts measures $0.46{\pm}0.25,\;1.11{\pm}0.05{\mu}m$ in length and $0.32{\pm}0.05,\;0.78{\pm}0.10{\mu}m$ in width respectively. The mature spore measures $4.36{\pm}0.06{\mu}m$ in length and $2.14{\pm}0.01{\mu}m$ in width.