• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.377-383
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• 1997

The effects of embryo number and incubation volume on the development of mouse embryos were evaluated. The growth rate of two-cell mouse embryos to attached blastocyst stage and the growth rate of blastocysts to early somite stage were assessed after culture in different incubation volumes and embryo densities. Embryos were collected from ICR female mice superovulated with pregnant mare serum gonadotropin and human chorionic gonadotropin and mated by ICR males. In experiment 1, groups of one, five, ten, twenty 2-cell embryos were cultured in 10-, 50-, 500-, 1000-${\mu}l$ drops of BWW media under mineral oil at $37^{\circ}C$ in a humidified atmosphere of 5% $CO_{2}$ and 95% air. As the incubation volume decreased, significantly (p<0.05) higher rates of embryos reached morular and blastocyst stage on day 3 and 4 culture, respectively. In experiment 2, groups of one, five, ten, twenty blastocysts were cultured in 1- and 2-ml volumes of CMRL 1066 media under same condition as in experiment 1. However the reverse was the result. Decreasing the number of embryos incubated per volume from 1 to 20 significantly (p<0.05) increased the number of blastocysts reaching the late egg cylinder (LEC) and early somite (ES) stage on day 6 and 8 culture, respectively, regardless of incubation volume. Blastocysts cultured in 2ml had higher (p<0.05) development rates to LEC and ES stage on day 6 and 8 culture, respectively, than embryos cultured in 1ml. Our results suggest that the effects of embryo number and incubation volume on the development of mouse embryos are stage specific and the shifting point was between hatching and EEC stage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.43-55
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• 1976

Fertilization and early development of turbo cornutus was studied based on the samples which were collected in Yeosu area. Particular emphasis was paid on induction of artificial spawing, fertilization rate, preembryonic development, the growth of the early larva and larval survival to various salinity. Among the various methods for induction of artificial spawning which have been tested for the present study, drying by exposure to air is the. most efficient, and percentage fertilization rate was $83.8-96.4\%$. The diameter of fertilized eggs was $0.182{\pm}0.0028mm$; and the diameter of egg membrane was $0.245{\pm}0.093mm$. Under the temperature range of $20.6-25.4^{\circ}C$ the larvae hatched out after 11:05-11:15 hours of fertilization. After 3.0-3.5 days of fertilization the planktonic larvae begand to settle, and the settlement terminated within 5 days. During the period of 150 days of early culturing the diameter growth of shell(M) and the diameter of shell aperture(A) was formulated as follows: $$1972\;M=0.33e^{0.02070D}$$ $$A=0.19e^{0.02282D}$$ $$1973\;M=0.32e^{0.02282D}$$ $$A=0.16e^{0.02596D}$$ During the same period of early culturing the relative growth of shell diameter and the diameter of shell aperture was formulated as follows : 1972 A=0.6478 S-0.1575 1973 A=0.5897 S-0.0515 After 11 days of larval hatching $0.02-0.18\%$ of planktonic larvae settled. After 150 days of settlement the survival rate of the early shells was $7.4-21.6\%$. Under the temperature range of $21.0-22.7^{\circ}C$ the optimum salinity range for the development of egg and the planktonic larvae was $30-35\%_{\circ}$.

• Journal of Aquaculture
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• v.9 no.1
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• pp.25-42
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• 1996

The study has been conducted to know an appropriate feeding strategy and effects of the rearing density on larval growth of the rockfish, Sebastes schlegeli. The results obtained are as fellowed ; 1. Thirty-day-old larvae reached at $25.25{\pm}3.76$ mm in total length and $0.23{\pm}0.07$ g in body weight in experiment A, at which rotifer was provided from the beginning to the end of 30-day experiment, Anemia from 3th to 18th day, and artificial feed from 13th to 30th day after hatching. When rotifer was provided for 30 days, Artemia from 6th to 18th day, and artificial feed from 18th to 30th day after hatching (experiment B), these larvae grew up to $27.52{\pm}2.50$ mm in total length and $0.26{\pm}0.06$ g in body weight. On the other hand, when rotifer and artificial feed were supplied with the same time schedule as shown in experiment B, and Artemia was feed from 6th to 30th day after hatching (experiment C), the total length and body weight of those larvae were $23.22{\pm}3.44$ mm and $0.15{\pm}0.05$ g, respectively. The best result for larval growth was obtained from experiment B. The survival rates estimated were $57.6\%$ in experiment A, $66.4\%$ in experiment B, and $44.4\%$ in experiment C. 2. The growth in total length of the larvae according to their rearing days could be represented by the following equations : Experiment A : Y=4.350+0.116X+$1.887X^2$ (r=0.993) Experiment B : Y=4.500+8.931X+$2.221X^2$ (r=0.994) Experiment C : Y=4.478+5.734X+$1.881X^2$(r=0.990) The average number of Artemia nauplius intaken by the larvae was rapidly increased between 15th and 20th day afer hatching, and 9, 212, 242, 750, and 1,171 nauplius were found in the different sizes of larvae, whose total length were 5.65, 6.81, 9.45, 14.96, and 24.52 mm, respectively. 3. Larval growth in total length and body weight reared at four different densites (A: 1.8 $kg/m^3$, B; 4.0 $kg/m^3$, C; 5.0 $kg/m^3$, D; 6.2 $kg/m^3$) indicated that the best growth was found in experiment A, at which the larval were reared at the lower density and the final survival rates extimated were $92.9\%$ in exp. A, $99.5\%$ in exp. C, $89.0\%$ in exp. B, and $88.2\%$ in exp. D. The amount of production per cubic meter turned out to be 30.45 kg in exp. D, 25.89 kg in exp. C, 20.75 kg in exp. B and 10.48 kg in exp. A. therefore, considering both larval growth and survival rate, higher yields seemed to be attainable at the relatively high-rearing density.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.243-250
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• 2020

Two meridic diets, N4 and N6, containing pinto bean, wheat germ, soybean, whole milk and sucrose as main nutrients were developed for rearing Spodoptera frugiperda (Noctuidae) larvae. Six larval instars were observed when neonate larvae were individually raised on these diets in small petri-dishes (ø 50 × 10 mm, 19.6 ㎤) at 25℃ and 15:9 h (light:dark) photoperiod. The average pupation rate of 97.8% on the N4 diet was significantly higher than the rate of 85.6% on N6 diet. The emergence rates were 92.0% on N4 diet and 93.5% on N6 diet, with a non-significant difference. The larval periods were 17.9 and 17.7 days for females, and 18.7 and 18.5 days for males, for N4 and N6 diets, respectively, with non-significant differences between diets and sexes. The pupal periods on both diets were identical (11.1 days for females and 12.8 days for males), despite differences between sexes. The pupal weights of both sexes on N4 diet were identical with a value of 257 mg, whereas those on N6 diet were 256 and 263 mg for females and males, respectively, with a non-significant difference. The longevity of female adults that emerged on N6 diet was 13.8 days and longer than 8.6 days on N4 diet. The pre-oviposition periods were 5.0 and 4.2 days on the N4 and N6 diets, respectively, with a non-significant difference, however, the oviposition period of 6.5 days on N6 diet was longer than the period of 3.9 days on N4 diet. The effective fecundity on N6 diet was 1,392 eggs (maximum 1,776) and was higher than that of 942 eggs (maximum 1,694) on N4 diet, with a non-significant difference. The egg hatching rates on N4 and N6 diets were 79.2 and 79.8%, and egg periods were 3.0 and 2.9 days, respectively, with non-significant differences.

• Korean Journal of Animal Reproduction
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• v.16 no.1
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• pp.63-76
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• 1992

This study was carried out to investigate the appearance time of the second polar body for producing Gynogenesis or Triploid which could be obtained by arresting the second polar body by cold shock, and then blastoderm was used to measure fertility that revealed the nature of oogenesis, the effects of water temperature on fertility, hatchability, abnormality, viability and growth rate, and the water temperature and the breeding methods to prevent early death of larvae in Korean loach(Misgurnus anguillicaudatus) ; the results obtained in this study were summarized as follows. The second polar body was observed ont he surface of plasma disc close to micropyle within 10~40 min after fertilization at 29$^{\circ}C$. Artificial inseminatin had to be done immediately after the egg spawning because the spermatozoa of loach their mobility within 2 minutes when they were exposed to water. The amount of time needed to reach at blastoderm stage was 12 hours if fertilized eggs were incubated at 16$^{\circ}C$, 8 hours at 19$^{\circ}C$, 6 hours at 21$^{\circ}C$, 5 hours at 23$^{\circ}C$, 4 hours at 26$^{\circ}C$ and 3 hours 30 min at 29$^{\circ}C$ showing the shorter time for development of eggs at higher temperature. Fertilization rates in water temperatures of 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$, and 26$^{\circ}C$ were higher than those of water temperatures, 16$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 19$^{\circ}C$, 21$^{\circ}C$, and 23$^{\circ}C$ showed higher hatching rates that those of 16$^{\circ}C$, 26$^{\circ}C$, and 29$^{\circ}C$, while abnormal rates in 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$ and 23$^{\circ}C$ were lower than that of 26$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$ and 26$^{\circ}C$ respectively, were more different than 29$^{\circ}C$ in survival rates. The embryos were hatched at 72 hours after fertilization in 16$^{\circ}C$ water temperature, 48 hours in 19$^{\circ}C$, 40 hours in 21$^{\circ}C$, 32 hours in 23$^{\circ}C$, 25 hours in 26$^{\circ}C$, and 16 hours in 29$^{\circ}C$. Within three days after hatched out, the larvage grew 3mm in total length, the yolk granules were entirely consumed and the head and the trunk became thicker. Within 45 days after hatched out, the larva grew 25mm at 29$^{\circ}C$, 21mm at 26$^{\circ}C$, 16mm at 23$^{\circ}C$, 15mm at 21$^{\circ}C$, 12mm at 16$^{\circ}C$ in a 30 litreglass aquarium.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.277-286
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• 2006

Population ecology of Cobitis tetralineata was examined at Churyeong Stream, Seomjin River, Korea. C. tetralineata inhabited on the sand bottoms with $10{\sim}20cm/see$ in current velocity, and $30{\sim}150cm$ in water depth. This species was active on the sand during the daylight hours from March to October, but they hibernated in the inside of the sand during the winter season. Sex ratio of female to male was 1:0.57, and female was $20{\sim}30mm$ (TL) larger than male. The age group of C. tetralineata (female) population showed that the $20{\sim}40mm$ group is 0+ years old, the $45{\sim}65mm$ group 1+ years old, the $65{\sim}90mm$ group 2+ years old, and the group longer than 90 mm over 3 years old. Males $13{\sim}14$ months old after hatching had lamina circularis at the base of its pectoral fin as a secondary sexual character. And in its spawning season, lateral color pattern of male was changed as a sexual dimorphism. The spawning season may be from late June to middle July, $22{\sim}26^{\circ}C$ water temperature. The average number of mature eggs in ovary was about $1,288{\pm}583(474{\sim}2,976)$, egg diameter was about $0.98{\pm}0.1mm$. C. tetralineata fed mainly on Chironomidae, Arcellidae, Branchioda and Algae. The feeding rate was the highest in April and September, but they did not fed in the winter.

• The Korean Journal of Zoology
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• v.8 no.2
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• pp.89-127
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• 1965

1. This report is on the outcome of observation made up the breeding process of Narcissus flycatcher, Muscicapa narcissina zanthopygia, using 15 ness-boxes at Seoul and Kwang Nung Experimental forest in 1964, and the relevant feeding habit was studied by the collar method of wrapping the necks of thenestlings for 50-60 minutes or more in some cases from 1963 to 1964. 2. The Narcissus flycatcheris a common summer resident throughout Korea arriving at the end of April. The earliest data of arrival of this species in Seoul, is April 26, 1964. They migrate southward from the later part of September to early part of October. 3. In a week after their arrival , they start to build nest after a brief courtship. Male and female prepare their nest ina nestboxes in 4 or 5 days. Nests are usually found in the moss, which provide definite frame-work. The inner side of the nest is usually composed of roots of Gramineae or leaves of pine, oak or other broad leave tree. 4. The laying period is generally from the later part of April to the middle of June : and the number of eggs laid is from 3 to 8 , therefore 5 in average : eggs are pink with traces of milky yellow blending of light auburn and orange red spots and chicken-egg-like in shape. 5.The incubation takes place for 7-12 days from the middle part of May to the middle of June, in the order of male and female . The hatching rate tends to increase in proportion to clutch size. 6. The feeding period usually lasts 15 days in average from the early part of June to the middle of July and the feeding urge tends to increase in proportion to brood size. 7. The animals invading into their nest-boxes are red ants, chipmunks, bees , barkbeetles and philippine red-tailed shirkes, etc. 8. On the basis of analysis covering 714 birds in 31 nests, the food they consumed during the nesting period of nestlings were mostly of animal matters composing of : insect larvae form-39. 88% insect adult form 36.26%, insect pupae-0.19%, spider-17.75% and other animal matters 5.92% , Besides a small amount of plant pieces were found . As to the insect larvae, Lepidoptera was the largest in the content followed by Hymenoptera , Orthoptera and Coleoptera. As to the insect adult, Diptera was the largest in the content followed by Coleoptera, and Hymenoptera. In view of forest protection, noxious insect was of 69.38%, useful insect 4.39%, and spider 17.75%. 9. The rich assortment of its food, the ability of acquiring various insect (adults as well as larvae), its destruction of great numbers of harmful insects , and its quick assimilation artificial nesting with the nest-boxes of 2.5-3cm entrance hole employed, allow us to conclude that the flycatcher may be successfully employed in the elimination of fores pests. The above results are only that part obtained near Seoul in the middle of Korea, however, if we would extend the scheme to other broad areas using similar techniques, the nest-boxes could not only be well used by the birds, but also it would help to prevent the increase of harmful. insects.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.97-107
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• 2007

The multicolored Asian ladybird beetle (Harmonia axyridis) has been commonly used with biological control agents for control of several kinds of aphids in agroecosystems. Also, environment friendly agricultural materials have been commonly applied in crop fields because the government held down pesticide application and environment friendly agricultures are gradually increased with consumer's desires. The multicolored Asian ladybird beetles may be directly or indirectly under the influence of environment friendly agricultural materials In crop fields. The insecticidal environment friendly agricultural materials (IEFAMs) might be saff against each developmental stage of multicolored Asian ladybird beetle. Fungicidal environment friendly agricultural materials (FEFAMs) had a miner effect to each developmental stage of multicolored Asian ladybird beetle with the exception of FEFAM A. Environment friendly agricultural materials contained useful soil microorganisms (EFAMSMs) C and H might be down the hatching rate of eggs, and EFAMSM A and F had a killing effect to 1st instar of lady beetles. Environment friendly agricultural materials contained plant extracts (EFAMPEs) A and D might be suffered effect a deathblow of egg hatching with lady beetles. Otherwise, there was a miner effect to lady beetles with the rest of tested environment friendly agricultural materials.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.135-140
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• 2000

Development and reproduction of the cotton caterpillar, Palpita indica, were investigatedunder different temperatures (15 .O, 17.5, 20.0, 22.5, 25 .O, 27.5, 30.0, 32.5, and 35 .O$^{\circ}$C). Duration fromegg to pre-adult of the cotton caterpillar were ranged from 68.6 days at 175$^{\circ}$C to 19.7 days at 35.0% (3.5times shorter growth period compared with that at 17S$^{\circ}$C). At 15.0$^{\circ}$C, cotton caterpillar eggs developedto the last larval instar but were not able to go through the pupal stage. The lower developmentalthreshold temperatures and degree-days of egg, larva, pupa, and complete development were 13.4, 10.6,11.6, and 11.5"C and 55.3,251.5, 138.3, and 479.8 degree days, respectively. The hatching, pupation andemergence rates were higher at 25.0eC and 27.5"C compared with other temperatures. The survival ratefrom the hatched larva to adult was the highest at 27.5"C. The preoviposition and the adult longevity were11.5 and 30.6 days at 17.5"C and 1.5 and 9.2 days at 35.0$^{\circ}$C, respectively. The mean fecundity perfemales was greater at 25.0$^{\circ}$C and 27.5"C compared with other temperatures. Mean generation time indays (T) was shorter on higher temperature. Net reproductive rate per generation (R,) was the lowest atthe highest temperature as well as at the lowest, and it was 199.1 which was the highest at 27.5"C. Theintrinsic rate of natural increase (r,) was highest at 30.0$^{\circ}$C as 0.148. As a result, optimum ranges oftemperature for P. indica growth were between 25.0-32.5"C .emperature for P. indica growth were between 25.0-32.5"C .t;C .

• Korean journal of applied entomology
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• v.55 no.4
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• pp.421-429
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• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.