• Animal cells and systems
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• 제14권4호
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• pp.291-296
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• 2010

Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients ($q_t$). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The $q_t$ for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the $q_t$ was taken into account. The mortality coefficient, survival rate, $q_t$ and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

• The Korean Journal of Ecology
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• 제18권4호
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• pp.463-470
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• 1995

Anoplocnemis dallasi Kiritchencho is a sap-sucker which feeds on tips of amorpha fruticosa Linne in Korea. A. Dallasi had one generation a year and overwintered as the young adult stage. Most overwintered survivors emerged in early-mid May to late May. Known host plants were reviewed, and new host records were added. Females mainly laid eggs in linear single chain masses on leaves of Miscanthus sinensis var. purpurascens. Nymphs (except the non-feeding first instars) fed on young shoots. First instar nymphs clustered on leaves or shoots where they hatched, and, if disturbed, reformed aggregations soon. The second to the fifth instar nymphs migrate to the upper part of the shoot and congreagate on a partly expanded leaf. New adults firstly appeared in late August, remained on A.fruticosa, host plant, and fed on until mid October. The duration and survivorship curve, in laboratory rearing, of the egg and each nymphal stadium was determined.

• The Korean Journal of Ecology
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• 제19권6호
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• pp.575-582
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• 1996

Molipteryx fuliginosa (Uhler, 1860) is a plant juice sucker which feeds on new tips of Rubus oldhami Miquel and Zelkowa serrata Makino, and it has a strong preference for teses two plants in Korea. M. fuliginosa has one generation a year and hibernates as a young adult. Most of the winter survivors emerge in early May. It is the first time their host plants were found and reported. Females mainly lay their eggs one by one separately on the leaves of R. oldhami, and even on the steel wire, the lid guaze and the ground in the laboratory. Nymphs do not gather, but stay on the hatching site, Nymphs except the non-feeding first instar feed on young shoots. From the second to the fifth instar nymphs migrate to the upper part of the shoot and congregate in part on an expanded leaf. The new adults first appeared on 11 August, and remained in the host plant, and fed on until mid October. The duration of the hatching and molting, and the survivorship curve based on the laboratory rearing were determined.

• 한국해양학회지:바다
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• 제3권2호
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• pp.94-102
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• 1998

본 조사는 인천지역 조간대 지역에 분포하는 연체동물 유해집단의 구조를 알아보기 위해 계절 분포, 밀도, 회분중량과 크기-빈도 분포, 생존곡선 등 정량적인 분석을 시도하고 또 현생 생물군집과 비교하였다. 조사 기간 중 복족류 16 종과 이매패류 12 종을 포함하여 총 28 종이 동정되었다. 유해집단을 구성하는 종들의 대부분이 조간대 지역에 서식하는 종으로 구성되었으며, 종 다양성은 이매패류보다 복족류에서 높게 나타났다. 계절별 회분중량의 변화는 동죽의 분포에 따라 좌우되었다. 천공성 복족류에 의한 천공은 주로 패각의 각정부분을 선호하고 있었다. 우점종인 접시조개류(Moerella rutila), 동죽, 왕좁쌀무늬고둥 등 3 종에 대한 크기-빈도 분포와 생존곡선에 관해 분석하였다. 접시조개류인 Moerella rutila는 각 연급군별 유사한 사망률이 나타나는 분포를 나타냈으며, 겨울철 어린 개체의 사망이 증가한 것으로 나타났고, 동죽과 왕좁쌀무늬고둥의 경우 연급군별 사망률이 다른 두 개의 굴곡을 가지는 분포를 나타냈다. 이들은 크기-빈도 분포에서도 이중모드(bimodality)를 나타냈는데, 이는 각 연급군의 가입과 계절적인 사망률의 변화에 기인한다. 유해집단을 대상으로 한 연구는 화석화 과정에서 발생하는 여러 문제들만 해결한다면 현생생물에서와 마찬가지로 개체군에 대한 유익한 정보를 제공할 수 있다.

• The Korean Journal of Ecology
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• 제14권1호
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• pp.9-13
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• 1991

The short-horned grasshoppers, Oxya sinuosa Mistshenko, were reared in the growth cabinet exposed alternately to 16 hours of artificial light (510${\pm}$240 lux) and 8 hours of darkness under the condition of constant temperature of 30${\circ}C$ and 65${\pm}$3% in relative humidity. The results obtained in this study are summarized as follows. Both female and male grasshoppers had seven instars. In the larval developmental stages of female and male, the third stage was shorter than the other stages, and the longest stage was the seventh. The total developmental period of females and males were approximately 80.17 and 63.5 days, respectively. The survivorship curve at the temperature of 30${\circ}C$ shows straight line.

• The Korean Journal of Ecology
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• 제8권4호
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• pp.201-204
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• 1985

The author reared the bandwinged grasshoppers, Oedaleus infernalis infernalis in the growth cabinet controlled as temperature of 25。C and 30。C under the conditiion of photoperiod 16L:8D, light intensity 510$\pm$240lux, relative humidity 65$\pm$3%. The results are summarized as follows: The female has six instars and male five instars. The larva reared in the temperature of 25。C died at the second larva stage, and the development to the third instar was impossible. The developmental periods of the egg stage of both sexes in the 30。C are 24.06 days. In the larval development periods, the fourth statge (19.73 days) was longer than that of any stage, and the second stage has the shortest period (9.9 days) in female. In male, the developmental period (9.59 days). The total developmental periods of female and male from the egg to the fifth instar were approximately 95.02 and 95.04 days, respectively. The total developmental period of female was as long as the period (15.75 days) of sixth instar which is not in the male. The survivorship curve in the temperature of 30。C shows concave type.

• The Korean Journal of Ecology
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• 제14권4호
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• pp.449-455
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• 1991

The water striders, gerris paludum insularis larvae which were fed with the drosophila melanogaster cultured on the appli diet and artificial diet, were reared in the growth cabinet controlled as the two constant temperature regimes of 25 c and 30 c under the condition of photoperiod 16l : 8d, light intensity 510 240 lux, relative humidity 65 3%, and in the natural state. The effects of temperature and diet on the devolopment of g. paludum insularis were analyzed and the results were summarized as follows. 1. The total developmental period of the water strider larvae fed with the d. melanogaster reared on the apple diet at the natural stste was the longest 40 days, and the total devopmental periods at 25 c and 30 c were 35 days and 27 days respectively. The tolal developmental period of larvae fed with d. melanogaster reared on the artifical diet at 25 c was the longest 42 dats, and the total developmental periods at natural stste and 30 c were 32 days and 27 days, respectively. 2. In the larval developmental stages, the fifth stage was longer than that of any stage. The duration of egg stage which was not influenced by diet at 25 c was the longest. 3. The water strider larvae fed which the d. melanogaster reared on the artificial diet at 25 c did not complete their devolopment. 4. No significant difference was odserved in the developmentperiod for diet at 30 c. but, there were significant differences in developmental periods for diet at 25 c and natural state. 5. The rate of adult emergence on the apple diet was higher than that of the artificial diet was higher than of the artificial diet. 6. The shapes of the survivorship curve were convex-curve. 7. The development periods of the larval stages of water striders might be affected to temperature and diet dependently.

• The Korean Journal of Ecology
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• 제12권3호
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• pp.171-182
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• 1989

The structure, clonal grwoth, shoot modules dynamics and rhizome respiratory rate of the Phragmites longivalvis circular patch were studied in a 15-year-old reclaimed land on Mado of the western Korea for two growing seasons. Clonal growth by P. longivalvis resulted in subpopulations of shoot modules which may be separated into pioneer, mature and senile growth phase. The radial growth of circular patch was 208 cm per a year. The shoot phytomass, shoot height and spike frequency were the lowest in the senile phase, and were the highest in the mature phase. The maximum shoot phytomass of pioneer, mature and senile phase in August was 347, 536 and 195g/$\m^2$ for the first year, and 609, 748 and 248g/$\m^2$ for the second year, respectively. The birth rates of shoot modules were the highest during the early spring. Of all modules, the percemtage of spring cohort of pioneer, mature and senile growth phase were 52, 82 and 70% for the first year, and 83, 88 and 85% for the second year, respectively. The flowering shoots were only derived from spring cohorts. The death rates of shoot modules of the pioneer and mature phase were the highest in October. The module is an annual semelparous plant though the genet is a perennial iteroparous plant. Their survivorship curve was negatively (Deevey type I). The density of shoot modules of the pioneer, mature and senile growth phase increased as much as 4.0, 1.6 and 2.3 times for one year, respectively. The respiratory rate was the highest in the lowest in the senile growth phase.