• Journal of Aquaculture
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• v.11 no.4
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• pp.521-528
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• 1998

The influence of starvation on survival, growth and feeding incidence of larval tiger puffer Takifugu rubripes was investigated for 16 days after let them hatched at the temperature of 16.5~18.5${\circ}C$. The effect by delayed initial feeding on larvace was also studied. Almost all larvae began to be fed from the stage of yolk absorption about 5 days after hatching, in which rearing trials revealed that their survival and growth were influenced by food availability. Survival of unfed larvae, which stated to decrease drastically since the oil globule was exhausted about 9 days after hatching, dropped to 50% and 0% respectively on the 11.5th and 16th day. the difference of growth between fed and unfed larvae came into sight on about 5th day after hatching when the initial feeding was started, and had reduced in proportion to the length of starvation period. The condition factors for the unfed larvae were lower than thost of the fed. Of the larvae which had starved less than 5 days, more than 80% could consume food upon feeding. No fish had the ability in having food after 10 days. It appeared that the turning point of recover for the starving larvae came on 7th or 8th day. Their taking-food ability seemed to be affected by the change in swimming activity which depended on the duration of starvation. For the seed production of tiger puffer, therefore, feeding should be initiated as soon as possible, so as to enhance the production and survival of healthy seeds.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.435-447
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• 2022

The soybean podborer, Matsumuraeses falcana (Lepidoptera: Tortricidae), is one of important pests in soybean crop. In the purpose of forecasting population dynamics of M. falcana, we investigated the effects of temperature on development of each life stage, adult longevity and fecundity of Matsumuraeses falcana at seven constant temperatures of 10, 13, 19, 22, 25, 28, and 31℃. Eggs hatched successfully at all temperature subjected. M. falcana developed from egg hatching to adult emergence at the tested temperatures except 10, 13, and 31℃. The developmental period of each life stage and adult longevity of M. falcana decreased as temperature increased. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of M. falcana were estimated by linear regression as 10.2℃ and 492.04DD, respectively. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. TL and TH from egg hatching to adult emergence using SSI model were 16.7℃ and 29.1℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of M. falcana was 12.4℃. We constructed the adult oviposition model of M. falcana using adult survivorship and fecundity. Temperature-dependent immature development and adult oviposition models will help constructing the population model of M. falcana and developing the strategies of integrated pest management in soybean fields.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.83-88
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• 2001

The effect of topical application with 200,400 and 600 $\mu$g/ml 2,4-dichlorophenoxyacetic acid (2,4-D) on the fifth larval stadium of the silkworm, B. mori, was analyzed. Larvae treated during fifth larval stadium enhanced larval, cocoon and adult parameters. The larval period was significantly decreased with increase in silk gland weight at 400 and 600 $\mu$g/ml, male cocoon weight and shel1 weight in all the treated groups and filament length and weight at 200 $\mu$g/ml treated group. Length of the ovariole, eggs per ovariole and hatching percentage increased significantly in all the treated groups when compared with those of the carrier control. This suggests that the plant growth regulator 2,4-D in addition to affecting silk production also affect reproductive performance.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.69-74
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• 2001

The effect of topical application with androstenedione on economic parameters was analyzed following treatment of last larval stadium. The treated larvae showed significantly increased larval weight along with other enhanced larval, cocoon and adult parameters. The larval period was significantly shortened in all the treated groups with increased cocooning percentages cocoon weight and its shell weight in female and filament length, weight and denier in all the treated groups. Hatching percentage increased significantly in dose dependent manner in all the treated groups when compared with the corresponding parameters of the carrier control group. This suggests that androstenedione can be used effectively for commercial silkworm rearing.

• Environmental Mutagens and Carcinogens
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• v.16 no.1
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• pp.30-34
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• 1996

This study was performed to examine the availability of using medaka (Oryzias latipes) in teratological test. Medaka embryos were collected within 2 hours post-fertilization and cultured in petri dishes containing buffered saline until hatching. The embryos were treated with 0.56 mg/l chlorpyrifos-methyl and 10 mM methyl methanesulfonate at 20 stages (about 35 hours post-fertilization). Eleven developmental features were selected and observed from 33 stages (about 9 days post-fertilization). Scoring system was developed and applicated for the measurement of potential teratological effects by the test compound. Chlorpyrifos-methyl did not induce teratological effect in medaka embryos. However, we found teratological test using medaka embryo reduced the cost, labors, period and space of experiment significantly compared with teratological study using rodents. Above findings strongly suggest that medaka embryo can be used as a lab animal model for teratogenicity test instead of rodents.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.195-197
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• 1996

Peking duck embryos incubated for 82 hrs after oviposition, stage 18 to 20(Hamberger and Hamilton, 1951) were transferred into the recipient eggshells and further incubated at $38.0^{\circ}C$ RH(relative humidity) 60 to 70%, with rotation at an angle of $30^{\circ}$ and the frequency of 4 times an hour. The survival rate was 100, 98, 82, 82, 70, 46, 21 and 16%, after the incubation period of 4, 8, 12, 16, 20, 24, 28 and 29 days, respectively. The present result clearly shows that the ex ova culture is possible for the Peking duck just as in the cases of the chicken or the quail. This culture technique could be useful for experimental manipulation of the embryos.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.47-52
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• 2000

The effect of supplementation with potassium nitrate on economic parameters was analysed following treatment of last larval stadium. The treated larvae showed a significant increase in larval weight at 500$\mu\textrm{g}$/ml and silk gland weight in all the treated groups along with other enhanced larval, cocoon and adult parameters. The larval period was significantly decreased in all the treated groups with increased female and male cocoon weights its shell weights filament lengths at 500$\mu\textrm{g}$/ml. The denier was significantly decreased in all the groups. The filament weight moth emergence percentaged length of the ovariole were unaffected. However, eggs per ovariole, fecundity and hatching percentage significantly decreased compared with the corresponding parameters of the carrier control.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.41-45
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• 2000

The effect of topical application with hydrocortisone on economic parameters was analysed following treatment of last larval stadium. The treated larvae showed a significant increase in larval weight at higher concentrations along with other enhanced larval, cocoon and adult parameters. This suggests that hydrocortisone can be used effectively for commercial silkworm rearing. The larvas period was significantly increased in all the treated groups with increased female cocoon weights, its shell weights and male cocoon shell weight at 20$\mu\textrm{g}$/ml treated group. Filament length, weight and denier were increased significantly in all the treated groups. Moth emergence percentage, length of the ovariole, eggs per ovariole, fecundity and rind hatching percentage were unaffected when compared with that of the carrier control group. This suggests that hydrocortisone in addition to affecting larval growths also affect silk crop.

• Korean Journal of Ichthyology
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• v.3 no.1
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• pp.1-10
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• 1991

Spawning behavior and development of eggs and larvae of Mugilogobius abei were observed in the laboratory at Pusan, Korea. The adult male of Mugilogobius abei was observed making nest-like spawning-bed to lay eggs and showing territorial and courtship behaviors. The eggs were transparent and spherical in shape, measuring 0.40~0.50 mm in diameter. They have a bundle of adhesive filaments at their basal end and a cluster of small oil globules. The eggs became ellipsoid shape after the insemination and measured about 0.93~0.96 mm on the long axis. Hatching began about 110 hours after fertilization at water temperature of $24.5{\sim}25.5^{\circ}C$. The newly hatched larvae were 2.04~2.10 mm in total length, with 24~25(8~9+16) myomeres. Many melanophore and guanophore are distributed on eye cups, gas bladder, optic vesicle and the caudal region. Four days after hatching the yolk and oil-globule were completely absorbed and the larvae attained a total length 2.20~2.35 mm. The larvae swam actively in the aquarium and start to practice feeding on the rotifer. Twelve days after hatching, the larvae averaged 3.20 mm in TL and the caudal notochord flex at $45^{\circ}$. Rudimental second dorsal, anal, caudal and ventral fins are also formed. The larvae attained 10.40~10.80 mm in TL, 35 days after hatching, are found to start the bottom-life after having completely formed first dorsal and ventral fins. The larvae reached the juvenile stage at 50~60 days after hatching and attained 15.37~20.25 mm in TL. At this period all scales appeared on the body.

• The Korean Journal of Pesticide Science
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• v.11 no.4
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• pp.254-260
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• 2007

In order to evaluate the toxic effects of butachlor, a herbicide widely used for control of weeds in paddy field, on medaka (Oryzias latipes), acute toxicity tests for five developmental stages and early life stage toxicity test of were conducted. As the results of acute toxicity test, $96h-LC_{50}s$ for 1 day, 1 week, 2 weeks, 2 months and 5 months after hatching of O. latipes were 0.68, 0.52, 0.38, 1.09 and $0.45\;mg\;L^{-1}$, respectively. This indicated that the most sensitive stage was 2 weeks after hatching. The early life stage toxicity test showed that no statistically significant hatching period and hatching success of embryo was observed at all concentrations of butaclor. However, 0.05 and $0.1\;mg\;L^{-1}$ of butachlor showed statistically significant post hatching survival with p<0.1. Abnormalities of larva were 2.1, 2.3 and 10% at 0.025, 0.05 and $0.1\;mg\;L^{-1}$ of concentration, respectively. They showed abnormal vertebral axis, craniofacial alteration and retarded yolk-sac resorption. The total length and weight were decreased depending on butachlor concentration the end of test. Weight of larva was showed more sensitive toxic indicator than total length. The toxicological responses of O. latipes to butachlor expressed as LOEC(lowest observed effect concentration), NOEC(no observed effect concentration) and MATC(maximum acceptable toxicant concentration) values were 0.025, 0.013 and $0.018\;mg\;L^{-1}$, respectively.