• 한국동물학회:학술대회논문집
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• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
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• pp.91.2-91
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• 1997

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• 한국수산과학회지
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• 제44권5호
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• pp.516-523
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• 2011

To compare four populations of sea squirt Halocynthia roretzi adults, their egg quality and larval development were investigated in the hatchery. The populations were: south sea wild (SSW), south sea cultured (SSC), east sea wild (ESW) and Iwate Japan cultured (IJC). Egg quality and larval development were compared using 13 factors (fertilization rate and diameter, proximate composition, amino acid and fatty acid contents of eggs, hatching rate and various sizes of tadpole larvae) which were obtained from each population. Fertilized egg diameter, hatching rate and size of tadpole larvae were significantly different among the four populations (P<0.05). Eggs were produced with higher crude protein ($5.20{\pm}0.00%$ SSW, $4.71{\pm}0.01%$ ESW, $4.66{\pm}0.01%$ SSC and $3.96{\pm}0.01%$ IJC) and lipid ($1.22{\pm}0.01%$ ESW, $1.01{\pm}0.00%$ SSW, $0.77{\pm}0.01%$ SSC and $0.69{\pm}0.00%$ IJC,) contents from domestic wild populations than from Japanese or cultured populations. Also amino acid and fatty acid contents were different. The extent of similarity between domestic and Japanese populations (30.5% IJC:SSW, 34.3% IJC:SSC and 40.7% IJC:ESW) was relatively low but was very high between SSW and SSC (73.9%). These results may have been due to differences in the abundance of food types and environmental conditions in the four localities and consequent differences in the diets of the sea squirts.

• 한국양식학회지
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• 제8권1호
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• pp.69-76
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• 1995

넙치(Paralichthys olivaceus) 암컷과 범가자미(Verasper variegatus) 수컷간의 잡종을 유도하여 넙치, 범가자미 및 잡종을 대상으로 변태기 전인 부화후 25일째까지 자어의 생존율 및 성장을 비교 조사하였다. 실험 종료시 잡종의 생존율과 성장은 양친으로 사용된 두 종 중 넙치와 유사하였다(P>0.05). 부화자어의 형태에서 잡종은 난황의 길이 대 폭의 비에서 넙치와 좀 더 많이 닮았고, 수온 $17\pm1^{\circ}C$에서 유구가 완전히 소실되는 기간은 잡종이 18일, 넙치가 14일이었으며 범가자미에서는 유구가 관찰되지 않았다. 조사 결과 변태기전까지의 잡종은 그의 생존율 및 성장에서 범가자미 보다 넙치와 더 유사한 경향을 나타내었다(P>0.05).

• 생명과학회지
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• 제10권1호
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• pp.1-6
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• 2000

Larval development, adult longevity and oviposition of the beet armyworm, Spodoptera exigua H bner was studied at 16, 20, 25 and 3$0^{\circ}C$ with a 16L: 8D photoperiod. Egg hatchability of S. exigua was the highest at 3$0^{\circ}C$ and reduced with decreasing temperature. Egg period was the shortest at 3$0^{\circ}C$ and prolonged with decreasing temperature. Percent pupation was became higher at higher temperature form 23.2% to 94.0%. Developmental period of larva was the shortest at 3$0^{\circ}C$, but extended with decreasing temperature. Adult emergence ratio was the highest at 3$0^{\circ}C$ and reduced with decreasing temperature. The mean pupal period was 35.2, 14.4, 7.8 and 5.0 days at 16, 20, 25 and 3$0^{\circ}C$, respectively. Relationships between constant temperature and the developmental velocity of egg, larva and pupa were linear. Developmental threshold temperature seems to be 13.3 8$^{\circ}C$ for egg, 14.02$^{\circ}C$ for larva, 14.09$^{\circ}C$ for pupa, and 13.84$^{\circ}C$ for egg the adult. Estimated value of the total effective temperature for completing each stage was 36.89 day-degree for egg, 155.72 day-degree for larva, 79.20 day-degree for pupa, and 273.41 day-degree for egg to adult. Female longevity varied to temperature from 11.4 days at 16$^{\circ}C$ to 5.8 days at 3$0^{\circ}C$, and male longevity was longer than that of female. Preoviposition period was the shortest at 3$0^{\circ}C$, but prolonged with decreasing temperature. It was about 2.7 times longer at 16$^{\circ}C$ than that at 3$0^{\circ}C$. Number of eggs per female was the highest at $25^{\circ}C$, followed by 20, 30 and 16$^{\circ}C$.

• Fisheries and Aquatic Sciences
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• 제24권11호
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• pp.375-382
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• 2021

In this study, the reproductive behavior and embryonic and larval development of the short ninespine stickleback Pungitius kaibarae was described and illustrated based on observations during spawning, hatching, and larval rearing trials. Adult P. kaibarae were collected downstream in Jinhae during the reproductive season (April-May). Males had nuptial coloration on their entire black bodies, with blue dorsal spines and yellow eyes, whereas females had a brown spotted pattern on their bodies. Males built nests on the stems of water weeds and attracted females. Fertilization occurred in the nest immediately after spawning, and males guarded the eggs until hatching. The fertilized eggs of P. kaibarae were spherical, demersal, adhesive, and transparent, and each egg measured 1.43 ± 0.07 mm in diameter. The morula, blastula, and gastrula stages, as well as hatching began at 5, 18.5, 21.5, and 96 post fertilization (HPF), respectively, at 20.0 ± 0.5℃. The newly hatched larvae had a total length (TL) of 5.67 ± 0.50 mm, with a yolk volume of 0.583 ± 0.059 mm³. Their mouths and anuses had not yet opened. At 2 days posthatching (days post hatching, DPH), the yolk was completely absorbed and the larvae began to feed exogenously. Pigmentation was observed in freshly hatched larvae 4 h after hatching, with the presence of eight areas with a dotted pattern on the dorsal surface of the larvae and dispersed spots on the head and yolk sac. At 30 DPH, the TL of the juveniles was 21.34 ± 1.70 mm. The nest area and number of eggs were 259.56 ± 101.39 mm² (75.18-506.04) and 155.33 ± 114.12 (0-437), respectively.

• International Journal of Industrial Entomology and Biomaterials
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• 제10권2호
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• pp.137-141
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• 2005

Though many insecticides are commercially available, development of resistance, pest resurgence and effects on non-target organisms led to the search for alternate insect pest management (IPM) strategy based on larval growth and reproductive fitness. Reproductive potential of insects depends on its acquiring of vitellogenic competence which is under hormonal control. Exogenous application of analogues of JR (JHAs) and ecdysterone could derail normal development and reproduction in insects by manipulating an array of physiological processes. In the rice pest, brown planthopper, Nilaparvata lugens, JHA, hydroprene induced metathetely from the fifth (final) instar nymphs in an age-dependent manner. Day 0 of the final instar showed highest sensitivity to induce this abnormal development. Adults emerged from treated day 3 nymphs looked normal. Both the morphotypes were reproductively incompetent and showed partial to complete sterility. Pre-adult exposure of the ovarian tissue to hydroprene suppressed mitotic division of germinal cells and induced abnormalities in the later s1ages of growth and differentiation of ovary in N. lugens. More over the nymphal exposure to hydroprene inhibited patency changes of follicular epithelium and affected competence of the follicles for yolk sequestration. In the absence of ovarian growth and oocyte differentiation, germarium found disintegrated, trophic core regressed and terminal oocytes resorbed. Hydroprene exposure to newly ecdysed brachypterous females did not affect ovarian development and egg production. Proper larval-adult transition appeared as a. prerequisite for vitellogenic competence in N. lugens for which the ovarian tissues must be exposed to ecdysterone in the internal milieu devoid of JH.

• 한국양식학회지
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• 제10권1호
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• pp.17-24
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• 1997

한국산 갯지렁이류 중에서 산업적으로 가장 중요한 청충의 양식기법 개발에 관한 기초자료를 얻기 위하여, 실내에서 인공사육한 청충의 생식과 발생에 관하여 조사한 결과는 다음과 같다. 1. 0.4~2.4 g의 청충을 자연수온 및 $20.0\pm1.0^\{\circ}C$와 $25.0\pm1$의 가온구에서 사육한 결과, 생식형의 체중(Wt)과 산란량(NS)과의 관계는 NS=48635.5897Wt 상(1.3044) (r=0.8572)의 식으로 나타났다. 2. Atokous segment 는 암컷이 23~28(평균24.8$\pm1$), 수컷은 22~29(평균24.6$\pm2$)개로 같았고, 체색에 의한 암수의 차이는 없었다. 3. 수정란의 난경은 $220\mu m$으로, 수정 21.0~$23.0^{\circ}C$에서 수정후 56시간 만에 부화하였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제38권2호
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• pp.31-37
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• 2019

Silkworm larval mortality specifically during spinning stage leading to non-spinning with specific morphological symptoms was frequently complained by sericulturists in Karnataka, India during 2015. Survey was conducted and information collected through questionnaire from the identified farmers who faced the problem of non-spinning in both traditional and non-traditional areas of Karnataka. Survey results indicate that the problem is specific to the silkworm crop of those farmers' who shifted from other crops of agriculture/ horticulture/olericulture/ floriculture to Sericulture. Silkworm rearing performance of the batches fed with these leaves confirmed that the pesticide sprayed to the crops previous to mulberry, remain in the soil and when mulberry plantation is taken up in these gardens, the pesticide is absorbed by the roots of mulberry plants and transported to the leaves. Silkworms that feed on these mulberry leaves, grow and ripen normally but during spinning stage, larvae die with external symptoms like regurgitation, body shrinkage, rectal protrusion later become hook shaped leading to non-spinning or partial metamorphosis into pupa and death or spin flimsy cocoons. Larval mortality ranged from a minimum of twenty five percent to a maximum of hundred percent. The problem was noticed from the first harvest of leaves and lasted for a maximum period of 36 months. Cocoon crop loss depends on the concentration, duration and type of pesticides used previously for other crops.

• 한국어류학회지
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• 제1권1_2호
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• pp.73-82
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• 1989

전남(全南) 영암군(靈岩郡) 덕진면(德津面) 덕진리(德津里) 영암천(靈岩川)에서 채포(採捕)한 친어(親魚)를 사육(飼育)하던 중 1989년(年) 4월(月)과 6월(月)에 걸쳐 5차례 인공수정(人工受精)시켜 난발생(卵發生), 자어발육(仔魚發育) 및 자어(仔魚)의 표피상돌기(表皮上突起)를 관찰(觀察)한 결과(結果)는 다음과 같다. 성숙란(成熟卵)은 타원형으로 난경(卵徑)은 $1.89{\sim}2.01{\times}1.56{\sim}1.64mm$이며 란황(卵黃)은 담황색(淡黃色)이고 유구(油球)는 없다. 사육수온(飼育水溫) $22{\pm}1^{\circ}C$에서 수정후(受精後) 44시간(時間)만에 대부분(大部分)의 란(卵)이 부화(孵化)한다. 부화직후(孵化直後)의 자어(仔魚)는 전장(全長) 3.04mm로 란황(卵黃)은 크며 두부(頭部)는 낮고 그 앞끝은 란황(卵黃) 전단부(前端部)보다 훨씬 뒷쪽에 위치(位置)한다. 부화(孵化) 몇 시간후(時間後)의 자어(仔魚)는 3.64mm로 24~29개(個)의 근절(筋節)이 형성(形成)되고, 안포(眼胞)와 이포(耳胞)의 원기(原期)가 나타난다. 부화후(孵化後) 8일(日)째 전장(全長) 5.98mm자어(仔魚)는 심장(心臟)이 분화(分化)하여 박동하기 시작(始作)하고, 척색말단(脊索末端)은 위로 굽어진다. 13일(日)째 전장(全長) 6.86mm 자어(仔魚)에서 처음으로 한쌍의 비공(鼻孔)이 분화(分化)하며 흑색소포(黑色素胞)는 체측(體側)과 미부(尾部)의 등쪽과 배쪽정중선(正中線)에 나타난다. 부화후(孵化後) 17일(日)째의 전장(全長) 7.25mm인 자어(仔魚)에서 지느러미 중 처음으로 꼬리지느러미 줄기가 정수(定數)에 달(達)하고, 자유유영(自由游泳)을 하는 21일째 전장(全長) 8.30mm의 자어(仔魚)에서 2실(室)의 부레가 분화(分化)한다. 부화후(孵化後) 27일(日)째의 전장(全長) 8.47mm인 자어(仔魚)에서 가슴지느러미 줄기와 배지느러미 원기(原期)가 분화(分化)하며, 등지느러미와 뒷지느러미 줄기는 정수(定數)에 달(達)하고, 34일(日)째 전장(全長) 11.84mm의 자어(仔魚)는 모든 막지느러미가 소실(消失)하고, 배지느러미 줄기가 분화(分化)하기 시작(始作)한다. 자어(仔魚)의 표피상돌기(表皮上突起)는 부화직후(孵化直後)의 자어(仔魚)에서 $5{\sim}10{\mu}m$ 정도(程度)의 사면형(斜面型) 인상돌기(鱗狀突起)가 나타나고, 부화(孵化) 2일(日)째의 자어(仔魚)에서는 $20{\sim}40{\mu}m$정도(程度)로 높아진다. 부화후(孵化後) 15일(日)째부터 돌기(突起)의 크기는 작아지고 17일이후(日以後)가 되면 거의 모든 개체(個體)의 표피상돌기(表皮上突起)가 소실(消失)한다. 산란기(産卵期)는 4월 하순에서 6월 상순으로 한 개체(個體)가 다회(多回) 산란종(産卵鍾)이고, 1회(回)에 평균(平均) 195개(個)의 란(卵)을 산란(産卵)한다.

• International Journal of Industrial Entomology and Biomaterials
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• 제12권2호
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• pp.87-93
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• 2006

Multiplication and spore production of three microsporidia viz., Nosema bombycis, Nosema sp. 1 and Nosema sp. 2 in fifth instar larval tissues of silkworm, Bombyx mori L. in two seasons with distinct temperature regimes were studied. Nosema sp. 2 produced significantly (P < 0.01) higher number of spores in various tissues. Among the tissues, spore production was highest in silk gland, followed by fat body and gut. Spore production was significantly (P < 0.01) higher in season-II (Average temperature $29.4{\pm}1.1^{\circ}C$). Maximum spore production was observed 25 days post inoculation (p. i.) in season-I (Average temperature $18.9{\pm}1.1^{\circ}C$), whereas in season-II, it was 14 days p. i. In season-I, spore production was low up to 21 days p. i., then increased sharply. In season-II, there was a steady increase in spore production. The results indicate that the microsporidian multiplication is tissue specific and extremely sensitive to temperature at which the host is reared. It also reveals that, silk gland, fat body and gut are the most appropriate tissues for microscopic identification of microsporidia in the larval stage.