• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.252-261
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• 2021

The egg development and early life history of short barbel gudgeon Squalidus japonicus coreanus were investigated. For the experiments, the mature adults were collected at the stream Jicheon in Korea. The eggs from the females were obtain by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 1.12±0.03 mm (1.10~1.16 mm, n=30) in diameter. The embryo began to hatch about 49 hrs after fertilization under water temperature of 23±1℃. The newly-hatched larvae (Yolksac larva) were 3.7±0.1 mm (3.4~3.8 mm, n=16) in total length, and they haven't Melanophore. 5 days after hatching, the Preflexion larva were 5.3±0.2 mm (5.0~5.5 mm, n=16) in total length, and they began to eat a Rotifer. 19 days after hathing, the Flexion larva were 6.0±0.3 mm (5.4~6.5 mm, n=16) in total length, and they began to eat a Brine shrimp. 29 days after hatching, the Postflexion larva were 9.6±0.5 mm (8.3~10.5 mm, n=16) in total length, and dorsal fin rays are were formed. 44 days after hatching, the juvenile were 15.5±1.0 mm (13.5~17.0 mm, n=16) in total length, and all their fin-rays were formed.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.222-231
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• 2020

The egg development and early life history of Sharpbelly Hemiculter leucisculus were investigated. For the experiments, the mature adults were collected at the Lake Yedang in Korea. The eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 0.97±0.02 mm (0.9~1.0 mm n=30) in diameter. The embryo began to hatch about 32 hrs after fertilization under water temperature of 22±1℃. The newly-hatched larvae were 3.0±0.2 mm (2.6~3.4 mm, n=15) in total length, and they haven't Melanophore. Six days after hatching, the Preflexion larva were 5.7±0.1 mm (5.4~5.8 mm, n=15) in total length, and they began to eat a Rotifer. 17 days after hatching, the Flexion larva were 6.8±0.2 mm (6.5~7.0 mm, n=15) in total length, and a gas bladder develop above the intestine. 30 days after hatching, the Postflexion larva were 8.8±0.7 mm (7.9~10.3 mm, n=15) in total length, three dorsal fin rays began to develop in the membrane fins. 50 days after hatching, the Juvenile were 20.8±0.8 mm (18.8~24.6 mm, n=15) in total length, and all their fin-rays were formed.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.262-272
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• 2021

The egg development and early life history of Tribolodon hakonensis that collected from the Seomjin River were studied. The fertilized eggs of the T. hakonensis were slightly adhesive and separated with a yellow yolk and no oil globule. The size of the eggs was an average of 2.89 mm (2.79~2.96) in diameter. Fifty percents of the embryos were hatched in about 63 hrs after fertilization at water temperature of 20℃. The newly hatched larvae showed average 6.92 mm (6.09~7.60) in total length. At 8 days after hatching, they were 13.75±0.67 mm (n=10) in total length and their yolk sacs were completely absorbed, opening mouth and anus (postflexion larvae stage). At 40 days after hatching, they became juvenile and reached 26.99±1.82 mm (n=10) in total length and all their fin rays were formed. At 137 days after hatching, the young fish were 72.63±10.7 mm (n=10) in total length and their body shape, color and behavior were similar to those of adult fish. The size of eggs and the larva after hatching significantly affected the initial growth among groups of genus Tribolodon, and the hatching time of fertilized eggs and the growth rate of the early life history according to the water temperate were different.

• Korean journal of applied entomology
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• v.61 no.2
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• pp.349-356
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• 2022

Fall armyworm, Spodoptera frugiperda, is a invasive migratory pest of native to the tropical and sub-tropical regions that has recently invaded Korea with damage to cornfield. The study was conducted to investigate the development periods of S. frugiperda on artificial diet at six different temperatures. The developmental period from eggs to adult at 18, 21, 24, 27, 30 and 32℃ was 79.8, 54.2, 34.3, 28.4, 24.6 and 24.0 days, respectivery and decreased with increasing temperature. The pupal periods of females were shorter than males. Most of the larvae developed through six instar, but the ratio of 7 or more instar increased at low temperatures. The relationship between the development rate and temperature was fitted with by linear regression analysis. The lower development threshold for egg and larva development was 12.9℃ and 11.3℃, respectively, 12.6℃ for pupae and 11.8℃ for egg-to-adult development. The effective accumulative temperature for the development of the respective life cycle stages were 37.0 DD for eggs, 286.3 DD for larvae, 132.2 DD for pupae and 456.8 DD egg-to-adult development.

• Korean Journal of Ichthyology
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• v.3 no.1
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• pp.11-23
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• 1991

To study the distribution of inhthyoplankton in the adjacent water of Wolsong, samples were collected using Bongo net from the surface water in November of 1989, and February, May and July of 1990. Fish eggs were divided into Engrualis japonicus, Callionymidae, Maurolicus muelleri, Konosirus punctatus, and others. The dominant species of fish eggs were Maurolicus muelleri and Callionymidae accounting for 60.1% and 13.7% of the total egg abundance, respectively. Total of 21 taxa of fish larvae occurred. The predominant species was Engraulis japonicas accounting for 61.2% of the total lavae, and bollowed by Callionymidae(11.9%). Other major species were Maurolicus muelleri, Gobiidae sp., Ammodytes personatus, Sebastes inermis, S. Pachycephalus, Scartella cristata, and Sebastiscus marmoratus. These 9 taxa constituted 96.5% of the total larvae collected. In this area, where upwelling occasionally occurs the distribution of fish eggs and larvae appeared to be affected by the transport of the surface water during the upwelling period.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.101-104
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• 1993

The life history and host plants of Locastra muscosalis (Walker) which is a defoliating pest of walnut trees were studied mainly in Chungchongbuk-do province. Juglans nigra Linne, J. mandshurica Mixim., Carya illinoensis koch and Pterocarya stenoptera DC. were found to be new host plants. Locasta muscosalis (Walker) had one generation per year and the adults emerged form late June to late July with a peak emergence around July 10th. Females oviposited a mean of 560 eggs on the top surfaces of leaves. The duration of the egg stage was from 7 to 12 days. Young larvae fed on the leaves within webs that bound the leaves beginning in the middle of July. In the middle of September the fully matured larvae entered the soil -a cm below the soil surface, and the pupal period lasted 16 days on average. The natural enemies observed and/or reared from larvae of pupae were 3 species of parasitoids, 6 species of predators and an unidentified virus.

• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.105-111
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• 2005

Most of the eggs and (or) pre-larvae of Acheilognathus signifer were observed from the gills of Unio douglasiae sinuolatus, 30~45 mm in the shell length, that is the host mussel of A. signifer. There was no selectivity in proportion to mussel size at the range observed. One to seven individual eggs and (or) pre-larvae were found in the mussels, with a mean of 2.5 individuals, and the rate of possessing one egg and (or) pre-larva was 50.0%. When the prelarva of A. signifer acquired swimming ability inside the mussel, it moved into the suprabranchial chamber. It was estimated that the growth period was 4~6 weeks. The minute tubercles of the pre-larvae were observed immediately after hatching. Absorption of the minute tubercles was observed starting the 7 th day, with most of tubercles absorbed 13 days after hatching and completed 20 days after the yolk was entirely absorbed.

• Korean journal of applied entomology
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• v.38 no.1
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• pp.29-33
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• 1999

Orius strgicollis Poppius is an endemic natural enemy of thrips recently found. To estimatethe optimum temperature for rearing in laboratory, development and oviposition of 0. strigicollis wasstudied at 15, 20, 25 and 30$^{\circ}$C with a 16L : 8D photoperiod and 60-80% RH. Cotton aphid, Aphisgossipyii, was supplied as prey. Total number of eggs laid per female ranged from 39.1 to 68.5 with thehighest at 25$^{\circ}$C. Adult longevity decreased as temperature increased, and the reverse was true for eggsurvivorship. Survivorship of larvae was 26.7,43.3, 76.7 and 46.7% at 15, 20, 25 and 30$^{\circ}$C, respectively.Duration of eggs and larvae at tested temperatures ranged from 3.4 days to 18.9 days and from 9.4 days to45.6 days, respectively. A linear regression model could describe development of the predator as afunction of temperature (R2=0.949-0.997). The lower developmental threshold temperatures for egg,larvae, and total immature stage were estimated to be 12.4, 11.4, and 11.6"C, respectively.6"C, respectively.vely.