• Animal Systematics, Evolution and Diversity
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• v.38 no.2
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• pp.59-64
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• 2022

The family Chamaemyiidae is commonly referred to as aphid flies, as all larvae are predators of sternorrhynchous aphidoid or coccoid hemiptera, as well as a small group of acalyptratae flies found worldwide. Adults are small flies and typically found near their larval prey in grasslands and forests. They have a silver-gray body with dark gray or black markings on the abdominal tergites. This family is described for the first time in the Korean fauna, based on the discovery of two nominated species: Leucopis argentata and Leucopis glyphinivora. Diagnoses and figures about the firstly recorded species, and a key to the Korean species are provided herein.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.35-50
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• 2007

In this work, optimal harvesting policy for the predator-prey system of three species with age-dependent and diffusion is discussed. Existence and uniqueness of non-negative solution to the system are investigated by using the fixed point theorem. The existence of optimal control strategy is discussed and optimality conditions are obtained. Our results extend some known criteria.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.3
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• pp.139-151
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• 2008

We investigate a three species food chain system with Lotka-Volterra type functional response and impulsive perturbations. We find a condition for the local stability of prey or predator free periodic solutions by applying the Floquet theory and the comparison theorems and show the boundedness of this system. Furthermore, we illustrate some examples.

• Journal of the Chungcheong Mathematical Society
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• v.20 no.3
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• pp.231-243
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• 2007

In this paper, we study a Lotka-Volterra type simple food chain model. We investigate the positive coexistence of the steady states to the model and give some results for the extinction of species under certain assumptions which can be interpreted as Domino effect and Biological control. The methods of a decoupling operator and the fixed point index theory on a positive cone are used as well as the comparison argument. Numerical evidences for our results also are provided.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.1
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• pp.93-102
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• 2004

A model of three trophic level food chain with ratio dependence is considered. The existencem uniqueness and stability of its solutions are investigated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.160-167
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• 2014

The feeding habits of Tridentiger bifasciatus were studied using 733 individuals collected in the tidal creek at Sangnae-ri, Suncheon, Korea, using a push net, monthly, from April 2011 to March 2012. The standard length (SL) of the specimens ranged from 1.5 to 8.2 cm. The stomach content analysis indicated that T. bifasciatus consumed mainly amphipods, such as Corophium sp., while copepods, polychaetes, and shrimps were other important prey species. In addition T. bifasciatus ate small quantities of crab larvae, fish, gastropod larvae, and insects. T. bifasciatus is a generalist that feeds on various zoobenthos, including fish. T. bifasciatus underwent an ontogenetic dietary shift. Smaller individuals (1-2 cm SL) fed mainly on amphipods. The proportion of amphipods decreased as body size increased, whereas the consumption of polychaetes increased gradually. The seasonal variation in the diet composition of T. bifasciatus was significant. Insects were common prey during summer, while the amounts of other prey, including polychaetes, were similar during spring, autumn, and winter.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.665-672
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• 1998

Feeding habits of Conger myiaster collected from the eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. C. myiaster was a carnivore which consumed mainly fishes, shrimps and crabs. Its diets included small quantities of amphipods, gastropods, cephalopods, polychaetes, mysids, cumaceans and isopods. It showed ontogenetic changes in feeding habits. Small indinviduals preyed on shrimps, fishes, crabs, and gammarid amphipods in nearly equal proportions. While the portion of the stomach contents attributable to shrimps and gammarid amphipods decreased with increasing fish size, consumption of fishes increased progressively. C. myiaster showed very constant prey selection regardless of prey availability-Especially fishes were heavily selected by this species throughout the year, although availability of fishes was lower than any other prey organisms in the eelgrass bed.

• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.28-37
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• 2009

The diet of Pacific cod (Gadus macrocephalus) in the East Sea, Yellow Sea and Jinhae Bay was studied by analysis of stomach contents. In total, 518 individuals ranging from 15.5 to 77.0 cm standard length SL were analyzed. Prey organisms of the Pacific cod in the East Sea consistedof Caridea, Cephalopoda and Pisces, whereas In the Yellow Sea, the main food items of Pacific cod were similar to those of East Sea Pacific cod except for Cephalopoda. Interestingly, the stomach contents of Pacific cod in Jinhae Bay is mainly Pisces, which is in contrast to those of the two different coastal areas, the East Sea and the Yellow Sea. Although various species of food were eaten by smaller Pacific cod, both Caridea and Pisces were mainly taken by larger Pacific cod. Consequently, the diet of Pacific cod within acertain size is mainly influenced by prey abundance and prey-size spectrum in its habitat. Higher stomach emptiness of Pacific cod in Jinhae Bay might indicate that fully matured Pacific cod temporally stop feeding during their spawning period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.282-288
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• 2008

Feeding ecology of the white-spotted conger eel Conger myriaster in the Southern Sea of Korea was examined. Specimens were caught monthly from January 2004 to December 2006. Primary prey items of C. myriaster included fish, shrimp, and crabs. C. myriaster exhibited a nocturnal feeding strategy and preyed upon a wide range of pelagic fish groups(e.g., Engraulis japonicus, Glossanodon semifasciatus, and Maurolicus muelleri). This species was also an opportunistic feeder that exploited the available prey in each area(i.e., fish in the A area and shrimp in the B area). The composition of the diet of C. myriaster exhibited seasonal fluctuations that were related to food availability during each season. The observed ontogenetic shifts in diet were relatively clear, despite substantial overlap between the 10 cm and 20 cm groups of C. myriaster.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.401-405
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• 1999

Comprehensive collecting survey were performed fer study on ovipositioning habits and developmental process of Rana temporaria dybowskii from mid February 1998 to late May 1998 from Kyunggi-do, Kangwon-do and other areas in South Korea. Oviposition occurred in both running water and pool between late February and late May. In lotic habitat, they laid egg mass in irregularly ball shaped, and eggs were sticked to substrates such as stone or macrophytes. On contrary, in the pool, they laid an oval shaped egg mass not sticked to any other substrates. Every egg was hatched at day 7, and all developmental processes were completed at days 71 after oviposition. Developmental process of this species was relatively short, and this may increase predation activities during abundant prey season.