• Journal of Sericultural and Entomological Science
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• v.8
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• pp.51-62
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• 1968

This study was carried out to investigate the life cycle and the damage of Tricholyga sorbillans Wiedmann to silkworms(Bombyx mori L.). The results are summarized as follows. 1. This insect has 5 or 6 generations per year in Suwon area. 2. The egg, larval, and pupal stage are about 2, 8 and 18 days respectively. 3. The weather conditions considerably affect the life cycle, that is, the 3 rd generation is the shortest of all, lasting for 21 days and l4 hours, and the 5th generation is the longest for about 40 days. 4. The larvae come out of silkworm bodies, burrowing into the ground 3.5cm to 10.5cm in depth before changing into the pupae. 5. This insect does not overwinter as pupa, but seems to do as larva, parasiting on the field insects. 6. The damage of Tricholyga sorbillans Wiedmann to silkworm was 27.9％, it is so high that the silk worms could not be reared outside without a reasonable control method. 7. When the full-grown silkworm is parasited by one egg of these insects, there is not only enough possibility of spinning. but also without any effects of their larvae on the cocoon quality. 8. The damage of Tricholyga sorbillans Wiedmann throughout the country covers 6.36％ in spring, 4.09％ in fall, and 5.25％ yearly mean.

• Journal of Aquaculture
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• v.18 no.2
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• pp.86-91
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• 2005

Three haptophyte algae, Isochrysis galbana, Prymnesium parvum and P. patelliferum were offered to the marine copepod Tigriopus japonicus as food. Growth rate of larvae, egg production, mortality and comsumption rates of T. japonicus were measured for each of the haptophyte species offered. The growth rate of larvae, egg production and algal ingestion of T. japonicus fed on P. parvum and P. patelliferum were much lower than those fed on I. galbana and corresponding high mortality rates were also observed during the experimental period. The harmful effects observed during the present study indicate that bloom-forming haptophyte algae, P. parvum and P. patelliferum are not suitable feed species for culture of copepod, T. japonicus.

• Journal of Aquaculture
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• v.13 no.1
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• pp.69-78
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• 2000

Bioactivity growth and survival rte of yolk sac larvae in cultured black seabream (Acanthopogrus schlegeli) red seabream (Pagrus major) and olive flounder (Paralichthys olivaceus) to 5 different concentration (0, 25, 50, 75 and 100%) of water soluble fraction (WSF) of Kuwait crude oil were studied. The 75% and 100% of WSF concentration influenced negatively on the length growth of larvae in each species so the growth rates of total length in the concentration of WSF were significantly lower than those of control. The high concentration (50%, 75%, and 100%) of WSF influenced negatively not only on the swimming frequency and speed but also on the morphological abnormality of larvae. Red seabream larvae showed the highest rate of abnormality by WSF among the tested fishes. The fish larvae exposed during pre-and post-hatch (egg and larval stages) and during post-hatch (larval stage only) to the WSF were significantly influenced on their survival rate. The larvae of red seabream were more sensitive to WSF than those of black seabream and olive flounder. The survival rates of larvae exposed to higher concentration (50%, 75%, and 100%) of WSF were significantly lower than those of the control but those of the 25% group were not.

• Journal of Aquaculture
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• v.16 no.2
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• pp.94-98
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• 2003

Effect of temperature (5, 10, 15, 18, 21$^{\circ}C$) on pre-and post-embryonic development of the sea urchin Strongylocentrotus intermedius was studied. The egg, which measured 122.5 ${\mu}{\textrm}{m}$, became globular. At 18$^{\circ}C$, it attained 4 celled stage at 3 hours after fertilization, hatched after 15 hours, 4-armed larval stage after 3 days and 8- armed larval stage after 20 days. The relationships between temperature (WT) and time (1, hour) required for each of the selected developmental stages are: Hatching: 1/t=0.0036WT+0.0088 Pyramid: 1/t=0.0014Wl-0.0016 4- armed: 1/t=0.0009WT-0.0020 6- armed: 1/t=0.0004WT-0.0005 8-armed : 1/t=0.0002WT+0.0002 Biological minimum temperature for the egg and larval development is calculated as 1.61$^{\circ}C$.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.117-122
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• 2000

The chemosterilizing effects of 4 benzoylphenylureas (BPUs), were tested on the adult house fly at different developmental stages. The male and female flies before insemination (I-day-old) or with fully developed ovaries (5-day-old) were exposed to the flask surface coated with BPUs solution (300 ppm) for 24 hrs. None of the eggs layed by the 5-day-old flies on the next day of exposure to either flufenoxuron or teflubenzuron hatched to larvae. The eggs layed by the 5-day-old flies exposed to either triflumuron or diflubenzuron also showed a significantly reduced hatchability of 23%. The first egg batches layed by 1-day-old flies exposed to flufenoxuron showed hatchability of only 1%. These results indicate that the BPUs applied were effective in egg sterilization irrespective of developmental stage of house fly. The effect of flufenoxuron was the most pronounced and lasted for 5 days after exposure.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.193-197
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• 2000

Wolbachia, vertically transmitted bacterial endosymbionts, is known to induce cytoplasmic incompatibility (CI), parthenogenesis, or feminization in some insect species. The Wolbachia found to exist symbiotically as a non-virulent form in Drosophila melanogaster, however popcorn is a lethal strain of Wolbachia, which causes tissue degeneration and early death of its adult host. Popcorn-infected flies showed the delayed duration of an egg and larvae, and their pupal period and life span reduced. The oviposition and egg-hatching rate of popcorn-infected flies were decreased 15% and 80%, respectiv~ly, compared to those of the normal Wolbachia-infected flies. The pupation and emergence rates of popcorn-infected flies were 67% and 65%, respectively. When popcorn-infected flies were crossed with Wolba-chia-infected flies, and vice versa, both crosses resulted in a significant reduction in egg production, egg¬hatching, pupation, and emergence rate, and their progeny revealed the popcorn syndrome. When popcorn-infected male flies were crossed with uninfected females, popcorn was not detected in their progeny. Popcorn also maternally transmitted in flies, but it did not induce CI and affected on its host life cycle as a virulence.

• Development and Reproduction
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• v.11 no.2
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• pp.127-135
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• 2007

In order to monitor the developmental features of embryos, larvae, and juveniles of Konoshiro Gizzard Shad Konosirus punctatus, the fertilized eggs were gotton using artificial insemination. Konosirus punctatus were caught in Mankyung-myeon, Kimjae, Jeollabuk-do at June of 2004, and experiments were carried out in Ichthyology laboratory in Chonnam National University. Konosirus punctatus spawned draft egg from March to June. The fertilized eggs were cultured in $19.0{\sim}23.0^{\circ}C$(mean, $21.2^{\circ}C)$. The eggs had spherical shape and the diameter is $1.14{\sim}1.34\;mm$(mean, 1.21 mm). The lens began to appear from 35 hr 53 min after fertilization. At the moment, the movement of larvae was more active, and the tail was separated completely from yolk, the heart had forms, and melanophore appeared. Hatching was observed from 37 hr 10 min after fertilization. The total length of the hatched larvae was $4.26{\sim}5.30\;mm$(mean, 4.96 mm), but the mouth and anus were not opened at the time when the larva had yolk sack, and had $22{\sim}27$ myometium, and the anus located just abdominal front of the tail fin, and melanophore accumulated in the eye. Post-larvae used yolk completely after 2 day of hatching, and the total length was $4.96{\sim}5.74\;mm$(mean, 5.24 mm). From 16 days after hatching, the tail had curved tail end, and appeared the stems for pectoral, dorsal, and caudal fins. At 53 days after hatching, the total length of post-larvae was $27.11{\sim}34.09\;mm$(mean, 30.11 mm), and the frontal part of head developed like an adult one. At this time, fins and body are transferred to those of adult Konosirus punctatus. Fishes have a different shape and location of melanophore even in the same family. This research was tried to elucidate the early developmental features of Konosirus punctatus, together with species-specific pattern of melanophore.

• Journal of Aquaculture
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• v.20 no.2
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• pp.96-105
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• 2007

A pair of maroon clownfishes with an indonesian native, reared in recirculation culture system to develope its aquaculture techniques. Courtship, spawning behavior, egg developments and rearing of the maroon clownfish larvae were documented. The larval development were described with illustrative figures. The spawning was occurred 8 times between Feburary and August 2004. The gravid female spawned during 15:00-20:00. The male mainly took care of the eggs supplying oxygen by water currents using their pectoral fins, anal fin and mouth. The fertilized eggs were separative-adhesive and oval in shape, and $1.99{\pm}0.03\;mm$ in longer diameter and $0.88{\pm}0.03\;mm$ in shorter diameter. The fertilized eggs were in deep-orange color. Cleavage occurred in 30 minutes after fertilization, and the egg reached 2 cells stage in 1 hour 10 minutes after fertilization at $27.0^{\circ}{\pm}0.5^{\circ}C$. The embryo was formed in 23 hours 40 minutes after fertilization. Hatching began in between $120{\pm}2$ hours and $150{\pm}12$ hours after fertilization at $27.0^{\circ}C$ in the incubator. Total length (TL) of the newly hatched larvae was 3.22 mm with mouth and anus opened. Ten days after hatching, mean TL of the larvae were 6.21 mm with 28 dorsal fin rays, 17 anal fin rays and 28 caudal fin rays. Nineteen days after hatching, mean TL of the larvae were 9.34 mm. At this stage the larva had three white bands on the body, and they began to feed on commercial diet.

• Parasites, Hosts and Diseases
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• v.36 no.1
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• pp.15-22
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• 1998

An in uitro culture technique was established for harvesting Strongwloides venezuelensis free-living infective larvae using a nutrient broth medium as a substitute for rat-feces in polyvinyl culture bags ($10{\;}{\times}{\;}12{\;}cm$). The egg hatch rate V) in sterile saline at different incubation temperatures (X) was expressed as the quadratic function, Y = $-0.192X^2$ + 8.673x - 19.550 (r = 0.901). The highest (100%) egghatch rate was observed at $25^{\circ}C$. A significant difference (p<0.05) in development rate W) of free-living infective larvae was observed between different concentrations of nutrient broth (X) which was highest (20.6%1 in 0.12% nutrient broth concentrations, incubated at $20^{\circ}C$ for 5 days [Y = $-864.032X^2$ + 245.995X- 0.560 (r = 0.875)]. Yields (Y) of infective larvae were observed relatively high when the culture medium was incubated at higher temperatures (X) which peaked at $25^{\circ}C$ (20.0%) than at lower temperatures. $15^{\circ}C$M (10.9%) and $20^{\circ}C$ (18.1%) [Y = $-0.189X^2$ + 8.387x- 72.795 (r = 0.981)]. The period W) required for the development of infective larvae decreased with higher incubation temperatures (X) [Y = $0.035X^2$ - 2.025X + 32.375 (r = 0.995)] The highest yield (19.2%) of infective larvae was obtained from culture bag inoculated with 15.000 eggs than with below and over 15,000 eggs in 0.12% nutrient broth and incubated at $25^{\circ}C$ for 4 days. The newly adapted culture method (from egg to third-stage larva) may be useful as a bio-bar/bioassay system for screening new chemical products, anthelmintics and pesticides, as well as for parasito immunological studies with Strongwloides species.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.74-84
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• 2001

The early developmental stages, growth and morphological changes of the Korean bullhead, Pseudobagrus fulvidraco, were studied from a series of reared specimens. Details of the early developmental stages are illustrated with special reference to morphological transformations. Egg and sperm of Korean bullhead were obtained from mature adults under hormonal treatment, fertilized artificially, and incubated in the aquarium. The incubation period of fertilized eggs was 55 to 66 hours at a temperature of 24.9${\pm}$0.34$^{\circ}$. Larvae were fed successively with Artemia salina and Daphnia magna for 2 to 15 days and artificial food after 20 days. Fertilized eggs were adhesive and spherical with a diameter of 2.04mm(n = 100). The mean total length of newly hatched larvae was about 4.92${\pm}$0.33 mm. Mouth opening occurred on one-day-old yolk-sac larvae, and initial feeding was observed on the third day after hatching. The morphological transitions from larvae to juvenile and juvenile to young stages occurred when the fish reached about 17 mm in total length (about 13days after hatching) and about 32 mm in total length (about 30 days after hatching), respectively. Many changes in proportion of body parts to total length were observed at about 7~8 mm and 30~32 mm, corresponding to the transformations from larvae to juvenile and from juvenile to young, respectively. In comparing relative growth of each body part against total length, those characteristics related to head parts showed positive growth in the pre-larval stages, while those concerning mobile abilities showed positive growth in the post-larval stage.