• The Korean Journal of Ecology
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• 제21권6호
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• pp.799-804
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• 1998

laboratory experiments were conducted to determine the effects of Dimilin, an insect growth regulator which acts to inhibit chitin synthesis, during the larval development of liocarcinus corrugatus Pennant. The larvae was exposed to control (10 ppb acetone sea water and untreated sea water solution) and five concentrations 0.1, 1.0, 5.0, 10.0 and 25.0 ppb of both TG and WP-25 formulations of Dimilin from the hatching to the megalopal stage, and the effect of Dimilin on development of the larvae were determined. Two formulations (TG and WP-25) had different effect on the different stages in L. corrugatus. and early stage larvae of L. corrugatus were more sensitive to TG than to WP-25. Concentrations of diflubenzuron >5.0 ppb are lethal to L. corrugatus larvae upon chronic exposure. Lethal concentrations are defined here as those in which less than 10% of the larvae survived to the megalopal stage. However, Dimilin (TG and WP-25) showed no significant effects on developmental time of L. corrugatus larvae.

• Parasites, Hosts and Diseases
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• 제54권1호
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• pp.103-107
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• 2016

The objective of this study was to evaluate the effects of several different commercial disinfectants on the embryogenic development of Ascaris suum eggs. A 1-ml aliquot of each disinfectant was mixed with approximately 40,000 decorticated or intact A. suum eggs in sterile tubes. After each treatment time (at 0.5, 1, 5, 10, 30, and 60 min), disinfectants were washed away, and egg suspensions were incubated at $25^{\circ}C$ in distilled water for development of larvae inside. At 3 weeks of incubation after exposure, ethanol, methanol, and chlorohexidin treatments did not affect the larval development of A. suum eggs, regardless of their concentration and treatment time. Among disinfectants tested in this study, 3% cresol, 0.2% sodium hypochlorite and 0.02% sodium hypochlorite delayed but not inactivated the embryonation of decorticated eggs at 3 weeks of incubation, because at 6 weeks of incubation, undeveloped eggs completed embryonation regardless of exposure time, except for 10% povidone iodine. When the albumin layer of A. suum eggs remained intact, however, even the 10% povidone iodine solution took at least 5 min to reasonably inactivate most eggs, but never completely kill them with even 60 min of exposure. This study demonstrated that the treatment of A. suum eggs with many commercially available disinfectants does not affect the embryonation. Although some disinfectants may delay or stop the embryonation of A. suum eggs, they can hardly kill them completely.

• Animal Systematics, Evolution and Diversity
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• 제18권1호
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• pp.35-48
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• 2002

유생의 형태발생이 미발표된 별따개비속의 하구별따개비는 조간대의 암석 기저부에 부탁하거나 가리비의 껍질에 부착하여 생활하는 따개비이다. 유생을 실험실에서 최초로 사육하여 유생발생단계를 형태적으로 도시 및 기재하였다. 노플리우스에서 어린 성체 직전까지 유생사육 기간은 20$\pm$0.5$^{\circ}C$에서 3주일이 소요되었다. 각 유생단계별로 유생의 크기 및 강모식을 설명하고 하구별따개비 유생의 유생기별 전장, 갑폭, 촉각 내지에 위치한 4적의 강모형태, 상순, 4-6기의 노플리우스 두순극의 형태 및 제 1촉각, 제 2촉각, 대악의 강모식이 본 따개비유생의 동정에 유용함을 설명하였다 위에서 언급한 형태학적 특징 뿐만 아니라 복부돌기에 있는 미세가슴가시의 형태와 미세가시수도 따개비유생의 종내 및 종간 동정에 매우 유용함을 구명하였다.

• 한국잠사곤충학회지
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• 제37권2호
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• pp.121-126
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• 1995

1000배로 희석한 "인세가"9주성분 : fenoxycarb)를 분무한 뽕잎을 일정기간 누에에 섭식시킨후 각 령의 경과일수, 5령 유충무게, 화용비율, 전견중 및 견층중 등에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1. fenoxycarb 첨식은 유충경과 일수를 연장시킨다. 특히 4령 3일 이후의 처리에서는 5령 경과일수가 20일 이상 길어지고 토사하지 못한채 모두 폐사하였다. 2. fenoxycarb 첨식은 5령 유충무게를 증가시킨다. 처리구의 유충무게 최대치는 대조구에 비해 2령 전기간 처리구에서 약 20%, 3령, 4령, 5령기의 전기간 처리구에서 각각 40%, 70%, 20% 정도 증가하였다. 3. 화용비율은 1령 처리구에서는 90% 이상으로 대조와 큰 차이는 없었으나 2~3령 처리구에서는 70~8-0%, 4령 후반기 이후 처리구에서는 0%였다. 4. 전견중 및 견층중은 1~3령 처리구에서 대체로 증가하였고 특히 전견중은 2령 전령 처리구에서 대조대비 47% 견층중은 3령 전기간 처리구에서 41% 증가하였다.41% 증가하였다.

• Animal cells and systems
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• 제13권1호
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• pp.59-69
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• 2009

This paper documents the defining morphological characteristics of the larval stages of Chionoecetes tanneri Rathbun, 1893, the grooved Tanner crab, from specimens reared in the laboratory. Chionoecetes tanneri larval stages include two zoeae and one megalopa. The first zoea is characterized by: six setae on the posterior margin of the carapace; postero-lateral spines on abdominal somites 3 and 4, extending beyond the posterior margin of adjacent somites and bearing 9-10 spinnules; 12 plumose setae and one stout distal plumose seta present on the margin of the scaphognathite of the maxilla; and one fused lateral spine and one articulated dorso-medial spine on each fork of the telson. The second zoea is characterized by: 9 setae on the postero-lateral margin of the carapace; a serrated mandible molar; a mandibular palp bud; 25-26 plumose setae on the margin of the scaphognathite of the maxilla; pereiopods with well-developed gills and buds; and four pairs of stout setae on the posterior margin of the telson. For the megalopal stage, the distinguishing characteristics include: a rostral spine equal in length to the supraorbital spine; six setae on the exopod of the uropod; and a single spine on the ischium of the second pereiopod. This study allows C. tanneri larvae to be distinguished from the larvae of known sympatric congeners. This information provides a basic taxonomic tool for researchers in fisheries management and zooplankton ecology who are addressing issues related to trophic interactions, metapopulation dynamics and ecosystem impacts in the evolving marine resource management strategies in the North Pacific, and those related to Chionoecetes species in particular.

• Ocean Science Journal
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• 제40권3호
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• pp.177-182
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• 2005

The process of embryogenesis and larval development of the asteroid sea star Asterias amurensis $(U{\ddot{u}}tken)$ was observed, with special attention paid to morphological change and larval duration. In reproductive season, mature sea stars were collected under floating net cages, located in Tongyeong, southern Korea. The mature eggs are $138\;{\mu}m$ in average diameter, semi-translucent and orange in color, sperms in good condition appear light cream to white-gray in color. Embryos develop through the holoblastic equal cleavage stage and a wrinkled blastula stage that lasts about 9 hours after fertilization. Gastrulae bearing an expanded archenteron hatch from the fertilization envelope 22 hours after fertilization. At the end of gastrulation, rudiments of the left and right coelom are formed. By day 2, larvae possess complete alimentary canal and begin to feed. At this stage, the larva is called early bipinnaria. In 6-day-old larvae, the pre- and post- oral ciliated bands form complete circuits and the bipinnarial processes start to develop. By day 12, the lateral and anterior projection of the larval wall processes along the ciliated bands begins to thicken and curl, and the ciliated bands become more prominent. By day 32, early brachiolaria are presented with three pairs of brachiolar arms. Advanced brachiolaria with a well-developed brachiolar complex (three pairs of brachia and central adhesive disc) occur 6 weeks after fertilization. In the field, spawning of the sea star was observed in April to May, settlement form larvae and just settlements seem to occur from June to July, and early juveniles occur from August to September. Although we had not described the end of brachiolaria stage, it can be tentatively estimated that the duration of the pelagic stage of A. amurensis is 40 to 50 days.

• 한국환경농학회지
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• 제35권4호
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• pp.241-246
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• 2016

BACKGROUND: Recently, the widespread distribution of pesticides in the hive has been of concern about pesticide exposure on honeybee (Apis mellifera L.) health. Larval toxicity was adapted to assess the synergistic and antagonistic interaction of cumulative mortality to the honeybee larvae of the four most common pesticides detected in pollen. METHODS AND RESULTS: Acetamiprid($3.0{\mu}l/L$), chlorothalonil ($803.0{\mu}l/L$), coumaphos ($128.0{\mu}l/L$), and tau-fluvalinate ($123.0{\mu}l/L$) were tested in combination; binary, ternary and four component mixture. Larvae were exposed to four pesticides mixed in diet at the average levels detected in pollen. As a result, synthetic toxicity was observed in the binary mixture of acetamiprid with coumaphos. The binary and ternary component mixtures of tested pesticides have mostly demonstrated additive effect in larval bees. The significant antagonistic effects were found in four parings of mixtures including chlorothalonil added to acetamiprid/tau-fluvalinate or acetamiprid/coumaphos/tau-fluvalinate, and tau-fluvalinate added to acetamiprid/chlorothalonil or acetamiprid/coumaphos/chlorothalonil. CONCLUSION: Interactions between combinations of four pesticides showed mostly additive or antagonistic effects in larval bees. Therefore, predicting the larval mortality of pesticides mixtures on the basis of the results of single pesticide may actually overestimate the risk. We suggest that pesticide mixture in pollen be evaluated by adding their toxicity together for complete data on interactions.

• 한국수산과학회지
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• 제36권2호
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• pp.107-112
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• 2003

Effect of PCBs on the skin and gill development of olive flounder, Paralichthys olivaceus were investigated by histological methodology and morphometric data. The olive flounder were exposed to limit concentration of effulent of PCBs (3.0 ${\mu}g/L$) for 60 days. Skin development can be classified into four stages: SSEL (simple squamous epithelial layer), MCA (mucous cell appearance) & CCA (club cell appearance) DLA (dermal layer appearance), and SEL (startification of epidermal layer) stages. Gill development had five stages: GFA (gill filament appearance), IGFE (identification of early gill filament epithelial cell) MCA (mucous cell appearance), PCA (pillar cell appearance), and FGL (formation of gill lamella) stages. The periods of structural completion of skin and gill were 22-30 days and 23-30 days after hatching in the exposure group respectively. The process of development of skin and gill of the exposure group was very similar to that of the control group. Therefore, PCBs (3 ${\mu}g/L$) have no influence on the development of skin and gill in the larval stage of olive flounder.

• 한국응용곤충학회지
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• 제36권4호
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• pp.317-322
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• 1997

실내 인공사료육에 의한 뽕나무하늘소(Apriona germari Hope) 유충의 발육특성을 조사하기 위하여 야외 뽕밭에서 채집된 뽕나무하늘소 부화유충을 14L:10D 광조건의 $25^{\circ}C$ 항온기에서 애누에용 인공사료와 뽕나무 가지 분말을 동량비로 석은 인공사료에 의하여 실내사육한 결과, 유충의 1령에서 12령까지의 두폭 범위는 0.12~0.69 cm 내에 있었고 각 영기의 성장비는 1령과 2령간이 가장 컸다. 체중의 증가에 있어서 1령에 비해 8령의 경우는 약 176배, 12령의 경우와는 약 354배의 성장도 차이를 보였다. 각 영별 경과일구는 영이 진전될수록 경과일수가 길어졌으며 1령에서서 9령까지의 경과일수는 186.03일, 12령까지의 경과일수는 304.58일이었다. 인공사료육에 의한 1세대 유충 생존율은 3령기에 걸쳐 약 45%로 매우 낮았으나 그 이후 안정되어 8령까지의 유충 생존율은 40.8%이었다. 용화율은 32.4% 이었으며, 용화 시기는 7령에서부터 11령에 걸쳐 나타났지만, 8령과 9령째가 대부분이었다.

• 한국패류학회지
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• 제27권4호
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• pp.307-315
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• 2011

유생의 발달크기에 따라 미세조류 12종에 대하여 섭취 가능성을 조사한 결과 유생의 크기에 따라 섭취 가능한 미세조류는 많은 차이를 보였다. 전체 유생크기에서 I. galban, I. aff. galbana, P. lutheri, C. ellipsoidea, N. oculata는 94.2-99.7%의 섭취율를 보였고, C. calcitrans, C. gracilis, C. simplex는 평균 각장 $189.3{\pm}13.8{\mu}m$ 크기인 중형 각 정기 이후 90.0% 이상의 섭취율을 보였다. P. triconutum, D. tertiolecta, T. tetrathele는 평균 각장 $65.0-100.0{\mu}m$의 D형 유생은 섭취가 관찰되지 않았지만, 이후 유생에서는 각각 97.3-99.7%, 43.3-99.3%, 48.5-99.3% 섭취하였다. 그러나 T. weissflogii는 평균 각장 $306.2{\pm}14.7{\mu}m$ 이상에서 1.0-1.7%의 섭취율을 보였지만, 전체 유생기동안 그의 섭취가 되지 않았다. 이상의 결과를 이용해 전체 50.0% 이상 섭취 가능한 먹이생물의 세포크기를 조사한 결과, 평균 각장 $102.3{\mu}m$ 이하의 D형 단계는 장축과 단축 모두 $4.6{\mu}m$ 이하, $158.3{\mu}m$ 미만에서는 장축기준으로 $9.3{\mu}m$ 미만까지 섭취가 가능하고, $158.3{\mu}m$ 이상 크기는 단축 기준 $9.3{\mu}m$까지 섭취가 가능한 것으로 나타났다. 전제 유생기 동안 장축과 단축을 포함해서 $10.0{\mu}m$ 이상은 섭취가 되지 않았다.