• Animal Systematics, Evolution and Diversity
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• v.28 no.4
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• pp.241-260
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• 2012

Adult chironomids were collected by various methods, such as light traps, sweeping on grasses, aspiration of light-attracted adults, and sweeping of swarming males with insect nets at various localities. All collected specimens were slide-mounted and identified. I report eight species new to science: Chironomus jangchungensis n. sp., Demicryptochironomus paracamptolabis n. sp., Demicryptochironomus wontongensis n. sp., Microtendipes paratamagouti n. sp., Polypedilum macrohemisphere n. sp., Eukiefferiella busanensis n. sp., Psectrocladius paratogaminimus n. sp., and Pseudosmittia seosania n. sp. I also report four species for the first time in Korea: Chironomus fujiprimus Sasa, Pentapedilum convexum Johannsen, Tanytarsus smolandicus Brundin, and Tanytarsus oyamai Sasa. All species are fully described with illustrations. This is the first report of the genera Eukiefferiella and Pseudosmittia in Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.399-403
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• 2004

생태 수리학적 측면에서 수질 개선에 기여하는 깔따구들이 흐름 구조에 따라서 어떻게 분포하는지를 파악하기 위해 수리 실험을 수행하였다. ADV로 유속을 측정하였으며, 자기 다른 유속 조건하에서 유기물질과 깔따구들을 투입하였다. 취득한 유속자료를 이용하여 흐름구조를 파악하였으며, 난류특성인 난류 전단응력을 분석하였다. 유기물질과 깔따구들은 상대적으로 유속이 느리고 전단응력이 작게 나타나는 지점에 분포하였다. 깔다구들이 굴을 파고 서식을 하였더라도 흐름에 의해 서식처가 옮겨짐을 확인 하였으며, 서식처 역할을 할 수 있는 반구 구조물 주위에 서식하였다. 유기물질의 퇴적 및 깔따구들의 서식은 주로 흐름 방향 유속 분포에 영향을 받으며, 이차류도 이것들의 분포에 중요한 역할을 하고 있다.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.20-30
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• 2022

The present study was carried out to investigate the food and feeding habits of Oreochromis niloticus in Lake Shala to manage this species in this high Soda Lake. Stomachs of 226 fish (65.9%) had different food items, while those of 117 fish (34.1%) were empty. Phytoplankton was the dominant food categories occurring in 90.3% of the stomachs estimated and contributed 75.5% of the total volume. Bacillariophyceae (Nitzschia, Anomoeoneis, Navicula and Melosira) were identified as the most desired phytoplankton item. The prey items of O. niloticus differed among size classes (ANOVA, p < 0.05). The main prey items were zooplankton by the smaller-size class, and phytoplankton in fish of the larger-size class. Seasonal variation in the diet composition was evident (t-test, p < 0.05) and zooplankton, chironomids, nematodes, fish scales and detritus were important during the wet season, while phytoplankton predominates during the dry season. This study concludes that O. niloticus had a phytoplanktivores feeding mainly on phytoplankton and their feeding habits influenced by season and fish size in Lake Shala.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.281-288
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• 2004

In order to extract and analyze complex features of the behavior of animals in response to external stimuli such as toxic chemicals, we implemented an adaptive computational method to characterize changes in the behavior of chironomids in response to treatment with the insecticide, diazinon. In this paper, we propose an energy minimization model to extract the features of response behavior of chironomids under toxic treatment, which is applied on the image of velocity vectors. It is based on the improved active contour model and the variations of the energy functional, which are produced by the evolving active contour. The movement tracks of individual chironomid larvae were continuously measured in 0.25 second intervals during the survey period of 4 days before and after the treatment. Velocity on each sample track at 0.25 second intervals was collected in 15-20 minute periods and was subsequently checked to effectively reveal behavioral states of the specimens tested. Active contour was formed around each collection of velocities to gradually evolve to find the optimal boundaries of velocity collections through processes of energy minimization. The active contour which is improved by T. Chan and L. Vese is used in this paper. The energy minimization model effectively revealed characteristic patterns of behavior for the treatment versus no treatment, and identified changes in behavioral states .is the time progressed.

• Journal of Ecology and Environment
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• v.32 no.3
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• pp.197-206
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• 2009

Benthic macroinvertebrate communities were collected from six different sites in the Dobong Stream in Seoul, Korea to investigate spatial and temporal changes in benthic macroinvertebrate communities in response to natural disturbances such as floods and droughts. We collected samples monthly or semimonthly with a Surber net ($30cm{\times}30cm$), and measured environmental factors, including stream temperature, discharge, width, conductivity, dissolved oxygen and pH at each sampling site. Benthic macro invertebrates were strongly affected by floods as well as droughts. In addition, benthic macroinvertebrate communities displayed different responses to the onset of the rainy season in summer 2006 and 2007, apparently due to differences in the intensity and amount of precipitation. Chironomids were particularly sensitive to heavy rain. Floods and droughts also affected the proportions of functional feeding groups during the survey period: the proportion of scrapers was high right after heavy rains, while the proportion of predators tended to increase in intermittent-type streams as the riffle zone decreased. Finally, although species richness and abundance were strongly influenced by heavy rain, they recovered to background levels for within one month, and varied consistently among stream types, indicating habitat stability.

• Environmental Analysis Health and Toxicology
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• v.24 no.2
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• pp.107-117
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• 2009

Metal pollution of aquatic ecosystems is a problem of economic and health importance. Information regarding molecular responses to metal exposure is sorely needed in order to identify potential biomarkers. To determine the effects of heavy metals on chironomids, the full-length cDNA of alcohol dehydrogenase (ADH3) from Chironomus riparius was determined through molecular cloning and rapid amplification of cDNA ends (RACE). The expression of ADH3 was analyzed under various cadmium and copper concentrations. A comparative and phylogenetic study among different orders of insects and vertebrates was carried out through analysis of sequence databases. The complete cDNA sequence of the ADH3 gene was 1134 bp in length. The sequence of C. riparius ADH3 shows a low degree of amino acid identity (around 70%) with homologous sequences in other insects. After exposure of C. riparius to various concentrations of copper, ADH3 gene expression significantly decreased within 1 hour. The ADH3 gene expression was also suppressed in C. riparius after cadmium exposure for 24 hour. However, the effect of cadmium on ADH3 gene expression was transient in C. riparius. The results show that the suppression of ADH3 gene by copper exposure could be used as a possible biomarker in aquatic environmental monitoring and imply differential toxicity to copper and cadmium in C. riparius larvae.

• Animal Systematics, Evolution and Diversity
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• v.26 no.3
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• pp.203-216
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• 2010

Adult chironomids were collected at Dangsan-ri, Muju-eup, Muju-gun, Jeollabuk-do on 5 September 2008, 22 May 2009 and 28 August 2009. A total of 221 specimens belong to the genus Polypedilum Kieffer from 1,113 adult midges collected were morphologically examined, and 16 Polypedilum species were identified. One species is new (Polypedilum dangsanensis Ree et Jeong sp. nov.) and eight species are newly recorded in Korea (P. asakawasense, P. convictum, P. decematogutatus, P. japonicum, P. kamotertium, P. pullum, P. serugense, and P. unifascium). These nine species are described with illustrations. Polypedilum nubifer was the most frequently collected species, consisting of 25.8% of the Polypedilum samples.

• Journal of Ecology and Environment
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• v.32 no.1
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• pp.19-25
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• 2009

An arthropod community in a rice ecosystem was surveyed to determine the impact of two insecticides frequently used in Korean rice ecosystems: carbofuran 3GR, which targets the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) in the early season and fenobucarb EC, which targets the brown planthopper, Nilaparvata lugens ($St{\aa}l$) (Hemiptera: Delphacidae) in the mid- and late seasons, respectively. Overall, the application of the insecticides reduced density of total arthropods by 48.4% compared to the untreated field, but their impact on each functional group were different. Carbofuran GR treatment on 1 June reduced the L. oryzophilus population significantly until mid-season. The population of filterfeeding chironomids was also reduced by 50%, whereas the spider population was less disturbed. Fenobucarb EC treatment on 16 August significantly reduced N. lugens and detrivorous entomobryid populations until the late season. Both web-building and wandering spiders were also significantly disturbed by fenobucarb EC although the impact differed according to their behavioral differences. While the population of web-building spiders significantly decreased over time, that of wandering spiders recovered from the disturbance a few weeks later.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.404-408
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• 2004

인공순환수로 실험구간에 반구구조물을 설치하지 않은 경우와 설치할 경우의 흐름특성을 분석하기 위하여 수치모의를 수행하였다. 수치모의는 FLUNET가 제공하는 RNG $k-\varepsilon$ 모형과 Reynolds Stress 모형을 사용하였으며 음파유속계(ADV)를 이용하여 측정한 결과와 비교분석 하였다. 수치모의와 실험결과의 상관성을 분석한 길과, RNG $k-\varepsilon$과 Reynolds Stress 모형의 계산결과와 실측값의 상관계수는 반구구조물을 설치하지 않은 경우 0.60 - 0.63, 반구구조물을 설치한 경우 0.75 - 0.78로 큰 차이가 없었다. 그러나 계산반복회수의 경우 RNG $k-\varepsilon$ 모형이 Reynolds Stress 모형에 비하여 2 - 5배 정도 빠르다. 두 모형의 걸과가 크게 차이가 나지 않으므로 순환수로 내의 흐름특성을 분석하기 위한 모형으로 수렴속도가 빠른 RNG $k-\varepsilon$ 모형을 선정하였다. 수치모의 결과와 "흐름 메카니즘에 의한 깔따구의 분포(I)- 실험"의 깔따구 분포경향을 비교한 결과 깔따구는 전반적으로 유속과 난류강도가 작은 곳에 분포하였으며 실험구간에 반구구조물이 있는 경우에는 구조물의 상${\cdot}$하류에 깔따구가 분포하였다. 이차류 또한 깔따구의 분포에 영향을 미친다. 향후 흐름특성에 따른 저서생물의 분포경향을 분석을 위하여 전산유체역학의 기법들을 적용하면 깔따구 등의 저서성 대형무척추 동물의 분포와 흐름특성의 관계를 저렴한 비용으로 분석할 수 있을 것이다.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.29-37
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• 2006

We investigated the feeding habits of Rhynchocypris kumgangensis in Hongcheon River of Saenggokri, Seoseokmyeon, Hongcheongun, Gangwon-do, Korea from April 2002 to March 2003. The fish is korean endemic species upper streams in Korea. It was asscertained that R. kumgangensis is a carnivore and consumes mainly Ephemeroptera, Diptera, Terrestrial insects and Trichoptera. The most important prey was chironomids: Chironomus sp. Their feeding habits changed according to growth. Small fish fed mainly on small prey organisms such as Diptera, while larger fish fed much more on Ephemeroptera and Terrestrial insects. There were also seasonal changes in the relative proportion of their food items.