• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.82-83
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• 1987

The number of chromosomes of the wild mulberry silkworm, Bombyx mandarina, collected in Suwon area in the middle part of Korean peninsula was investigated. The chromosomes were examined after smearing and squashing the testis of the last instar larvae which were at spining stage and the microscopic observation showed that the number of chromosomes of the wild mulberry silkworm was 27.

• Journal of Sericultural and Entomological Science
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• v.34 no.2
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• pp.26-31
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• 1992

Flacherie virus (FV) and Densonucleosis virus (DNV) of the silkworm, Bombyx mori, which give the most severest damage to the silk production in korea, were fed on the mulberry wild silkworm, Bombyx mori mandarina, the mulberry pyralid, Gryphodes phyloalis, and the American fall webworm, Hypantria cunea, to investigate cross infectivity by serological and histopathological at observation. By the Ouchterlony's double difusion test the mulberry wild silkworm was infected with both FV and DNV type 1 (DNV-1) and the mulberry pyralid with DNV-1, so those were confirmed the cross infection. But the American fall webworm was not recognized the cross infection by the same method. The infection and multiplication of the FV in the mulberry wild silkworm was observed in the cytoplasm of the goblet cell with the appearance of the virus-specific vesicle. In DNV-1 infection to the mulberry wild silkworm and the mulberry pyralid, the nuclei of columnar cell in the midgut of both insects was hypertrophied and the nuclei of midgut cell of the mulberry pyralid positively stained with the feulgen stain. Multiplication of DNV-1 in the midgut cell of the mulberry wild silkworm was replicated in two different patterens as linear arrays and large masses, while that of DNV-1 in the muberry pyralid was multiplied as virus masses in several portion of the nuclei of the midgut cell.

• Korean journal of applied entomology
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• v.31 no.1
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• pp.33-36
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• 1992

To establish the succeeding generations of wild silkworms, Bombyx mandarina Moore, massrearing was made in the laboratory. The rearing result was good under high humidity and moderately warm condition. Larval periods were 15 to 25 days and the most of larval period was around 17 days. The pupation rate and the pupal period of most of males and females were 40% and 13 to 25 days, respectively. There were two emergence peaks of males and females, and males emergence peak occurred two or three days faster than females.

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.155-164
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• 2009

The most important factors in environment that influence the physiology of insects are temperature and humidity. Insects display a remarkable range of adaptations to changing environments and maintain their internal temperature (thermoregulation) and water content within tolerable limits, despite wide fluctuations in their surroundings. Adaptation is a complex and dynamic state that widely differs in species. Surviving under changing environment in insects depends on dispersal, habitat selection, habitat modification, relationship with ice and water, resistance to cold, diapause and developmental rate, sensitivity to environmental signals and syntheses of variety of cryoprotectant molecules. The mulberry silkworm (Bombyx mori) is very delicate and sensitive to environmental fluctuations and unable to survive naturally because of their domestication since ancient times. Thus, the adaptability to environmental conditions in the silkworm is quite different from those of wild insects. Temperature, humidity, air circulation, gases and photoperiod etc. shows a significant interaction in their effect on the physiology of silkworm depending upon the combination of factors and developmental stage affecting growth, development, productivity and quality of silk. An attempt has been made in this article to briefly discuss adaptation in insects with special emphasis on the role of environmental factors and their fluctuations and its significance in the physiology of mulberry silkworm, B. mori.

• The Korean Journal of Ecology
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• v.27 no.1
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• pp.1-7
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• 2004

With the emergence and development of ecological engineering in China, and also the research and demonstration of Chinese Ecological Agriculture (CEA), in recent 10 years many types of ecological engineering have been appeared in Southern China, they could be classified into 4 typical patterns. These typical patterns are; 1. Ecological Building (EB), such as ecological public toilet, ecological garden, ecological integrated building, farmers' ecological household, the combine of ecological building and CEA; 2. Ecological Engineering in Paddy Field (EEPF), like rice-fish system, water caltrop-wild ricestem-fish system, mulberry-silkworm-pig-fish system; 3. Ecological Engineering of Agroforestry Systems (EEAF), as tea-food crops intercropping system, rubber-tea-chicken system, bamboo-chicken system, fruit tree-chicken system, metasequoia-fish-duck system; 4. Ecological Engineering Linked with Biogas (EELB), such as animal (pig)-biogas-fish system, animal (pig)-biogas-fruit tree system, animal-biogas-food crops system. Some case studies were presented in the paper. It is showed that these typical patterns have better ecological, social and economic benefits, now they are deeply been extending in southern China.

• Journal of Sericultural and Entomological Science
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• v.25 no.1
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• pp.1-20
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• 1983

It has been known that the insect molting hormone and its analogues exist also in plant kingdom and their concentration has been found to be about 0.1~2.0% of dry matter, which is equivalent to $10^3{\sim}10^5$ times of those in insects. This study was carried out; 1) to isolate the phytoecdysones from Korean Achyranthes radix and characterize their physico-chemical properties. 2) to investigate the biological activity of this phytoecdysone on Bombyx mori larvae. The resuls were summarized as follows; 1. The extraction method of phytoecdysones was optimized by three consecutive reflux for 1hr using 200g of dried and milled radix per 1l methanol. 2. The purification from the crude extract was made by a series of steps such as precipitation of gum-type polymer with n-Butyl acetate, adsorption on technical grade silica and chromatography with neutral alumina. The conditions of each step were optimized and the resulting crude crystal was about 500mg per kg dry radix. 3. The crude crystal from the cultivated Achyranthes(Achyranthes japonia) contained ecdysterone (20-hydroxyecdysone) and inokosterone in the proportion of one to one. In order to separate these, a series of processes such as acetylation, separation by alumina column chromatography deacetylation by alcoholysis, deionization and crystallization were introduced and optimized 125mg of ecdysterone and 18mg of inokosterone per kg dry radix were thus obtained. 4. The wild Achyranthes (Achyranthes obtusifolia) radix was found to contain the ecdysterone only. A 285mg of ecdysterone was crystallized per kg dry radix. 5. Isolated ecdysterone, inodosterone and acetylated compounds were characterized by IR., UV., NMR spectroscopy, mp, TLC and densitometry. 6. Ligation experiment was undertaken to confirm the biological activity of the purified ecdysterone; the ecdysterone could induce larval-pupal metamorphosis in the ligated abdomen of 4th instar larvae injecting 0.5~1.0${\mu}g$. 7. By ecdysterone feeding experiment using artificial diet, it was elucidated that the critical time of feeding would be the first half of each instar resulting in increased weight of silk layer. 8. The ecdysterone was fed to 5th instar silkworm at the level of 1, 2, 3, 5ppm of dry feed of artificial diet containing 5% mulberry leaves for 72hrs. At 2ppm of the concentration. body weight and silk layer weight were arrived at maximum. But at higher concentrations body weight and silk layer weight decreased than the control group. At 2ppm of the concentration, body weight was increased by 12.5%. 9. Feeding 2ppm of ecdysterone at the later half of 5th instar, the duration of larvae was shortened.