• Communications for Statistical Applications and Methods
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• v.22 no.6
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• pp.575-587
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• 2015

The development in data collection techniques results in high dimensional data sets, where discrimination is an important and commonly encountered problem that are crucial to resolve when high dimensional data is heterogeneous (non-common variance covariance structure for classes). An example of this is to classify microbial habitat preferences based on codon/bi-codon usage. Habitat preference is important to study for evolutionary genetic relationships and may help industry produce specific enzymes. Most classification procedures assume homogeneity (common variance covariance structure for all classes), which is not guaranteed in most high dimensional data sets. We have introduced regularized elimination in partial least square coupled with QDA (rePLS-QDA) for the parsimonious variable selection and classification of high dimensional heterogeneous data sets based on recently introduced regularized elimination for variable selection in partial least square (rePLS) and heterogeneous classification procedure quadratic discriminant analysis (QDA). A comparison of proposed and existing methods is conducted over the simulated data set; in addition, the proposed procedure is implemented to classify microbial habitat preferences by their codon/bi-codon usage. Five bacterial habitats (Aquatic, Host Associated, Multiple, Specialized and Terrestrial) are modeled. The classification accuracy of each habitat is satisfactory and ranges from 89.1% to 100% on test data. Interesting codon/bi-codons usage, their mutual interactions influential for respective habitat preference are identified. The proposed method also produced results that concurred with known biological characteristics that will help researchers better understand divergence of species.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.301-305
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• 2003

This study investigated the ecological characteristics of Frankliniella occidentalis on four horticultural crops. On red pepper leaves, larval developmental period and survival rate of F. occidentalis were 6.4 days and 67%, respectively. While adult female lived longer on cucumber leaves as long as 16 days, on Petal lived 8.1 days. F. occidentalis adult female preferred tomato to eggplant, cucumber and red pepper, and higher number of hatched larva were from leaves of middle part of egg-plant compared with those from other parts. F. occidentalis adult female fed preferably on petal compared with leaves and Petals of eggplant, and among petals of four tested plants, the most preference was those of red pepper.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.131-136
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• 2001

Cabbage butterfly, Pieris rapae was reared in a room to establish a year-round rearing system. The eggs oviposited by the parent fed on host plant showed 89.2% of hatchability and hatched in 3.9 days after oviposition. The larval period was 18.1 days under high temperature, long day condition ($25^{\circ}C$, 16L : 8D), showing 97.8% pupal ratio and emergence rate. However, under low temperature, short day condition ($21^{\circ}C$, 10L : 14D) the larval period extended to 23.6 days and the pupal ratio was 70%. All of those pupae went into diapause. The oviposition preference experiment on different hosts (Chinese cabbage, cabbage, tulip and kale) showed that hot-water extract was preferred over methanol extracts or squeezed raw juices. The host preference showed that Chinese cabbage was less preferred than the other three. The artificial ovipositing kit was constructed for the oviposition in a room. The 48-hours old eggs could be stored for 7 days at$ 5^{\circ}C$ and showed 70% of hatchability. Non-diapausing pupae could be stored for 30 days at 5 to $15^{\circ}C$, showing 85% of emergence rate. However, the pupae stored at $5^{\circ}C$ showed longer storage period and higher emergence rate. The systematic successive rearing method of cabbage butterfly in a room was completed, based on the above experiments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.359-369
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• 2007

Amoebophrya is an obligate endoparasitic eukaryotic dinoflagellate infecting host species and eventually killing them within a short period. Because of its host specificity and significant impacts on population dynamics of host species, it has long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). For several decades, the difficulties of culturing host - parasite systems have been a great obstacle to further research on the biology of Amoebophrya but recent success of several culture systems reactivates this research field. In this study, as a preliminary work for understanding the impacts of Amoebophrya on the population dynamics of host species, semimonthly occurrence of infected host dinoflagellates by Amoebophrya spp. had been observed in Jinhae Bay for two years and with a host - parasite system cultivated, host specificity of Amoebophrya spp. on several dinoflagellates was tested. Amoebophrya spp. were observed in the cellular organelle and cytoplasm of several species including Akashiwo sanguinea, Ceratium fusus, Dinophysis acuminata, Heterocapsa triquetra, Oblea sp., Prorocentrum minimum, P. triestinum, Scrippsiella spinifera, and S. trochoidea. Among them two host - parasite systems for an athecate dinoflagellate, A. sanguinea, and for a thecate dinoflagellate, H. triquetra, had been able to be successfully established as laboratary cultures. Cross-infection tests for 6 species of dinoflagellates in which Amoebophrya was observed or had been reported to exist confirmed high preference for host species of the parasite. Through the continuous research on Amoebophrya occurring in Korean coastal waters, we need to maintain various host - parasite culture systems, which will be very helpful for understanding its ecological role in marine food webs and for applying the species to biologically control harmful algal blooms.

• Korean Journal of Environment and Ecology
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• v.33 no.2
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• pp.202-215
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• 2019

This study was conducted to investigate the spawning preference of the Acheilognathinae fishes in relation to the shell size of host mussels after identifying the species of eggs and fries in the host mussel using our recently developed RFLP (Restriction Fragment Length Polymorphism) molecular marker at four sites [Hongcheon Naechoncheon (HN) and Deokchicheon (HD) from the North Han River basin and Jeongseon Goljicheon (JG) and Joyanggang (JJ) from the South Han River] in South Korea during May in each year between 2015 and 2018. The Acheilognathinae fish observed in the studied sites included one species (Acheilognathus signifer) in HN and JG, three species (Rhodeus uyekii, A. signifer, and Acheilognathus yamatsutae) in HD, and two species (A. signifer and Acheilognathus yamatsutae) in JJ, and we collected 982 host mussels (Unio douglasiae sinuolatus) that inhabited in all four sites. Using the RFLP molecular marker, we confirmed 46 eggs and fry of the Acheilognathinae fish (454 A. signifer, 43 Acheilognathus yamatsutae, and 149 Acheilognathus yamatsutae) in Unio douglasiae sinuolatus (N=163; 16.6%). We compare the average shell length, shell height, and shell width of mussels with [presence] eggs/fry and mussels without [absence] eggs/fry to examine the spawning preference according to the size of host mussels in each site. The results show that the shell length (1.98 mm), shell height (0.85 mm), and shell width (0.73 mm) of mussels with the eggs/fry were significantly larger (Mann-Whitney U test, P=0.002; difference=1.98 mm) than those of mussel without eggs/fry in HD where three species cohabitated. Although the shell length, shell height, and shell width of mussels with the eggs/fry were larger also in the other three sites, the difference was not statistically significant. In addition, we analyzed the mean number of spawned eggs and fry of each species and found $9.31{\pm}5.94$ R. uyekii, $2.86{\pm}2.45$ A.signifer, and $2.50{\pm}1.32$ A. yamatsutae. R. uyekii spawned 6.45-6.81 more eggs than A.signifer and A. yamatsutae on average per mussel, and it was statistically significant (Kruskal-Wallis test, P < 0.001). These findings indicate that the three species of Acheilognathinae fish tend to prefer larger mussels as their spawning hosts, and this tendency increases when the number of cohabitating bitterling fish species increases. Moreover, A.signifer and A. yamatsutae spawned a smaller number of eggs evenly in more host mussels while R. uyekii spawned many eggs on relatively fewer mussels. We found mussels (N=4) having the eggs/fry of two coexisting species, A. signifier and A. yamatsutae in HD and JJ where more than two bitterling fish species occurred. It suggests the interspecific competition taking place between the Acheilognathinae fishes for utilizing the same resource of mussels for spawning when two or more species cohabitate. This study is expected help to understand better the spawning patterns and reproductive ecology of the Acheilognathinae fishes, which will provide insightful information for advancing our understanding of their ecological relationships - mutualism or host-parasitism - with host mussels.

• Parasites, Hosts and Diseases
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• v.48 no.1
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• pp.49-55
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• 2010

In vitro cultivation of trematodes would assist studies on the basic biology of the parasites and their hosts. This is the first study to use the yolk of unfertilized chicken eggs as a simple and successful method of ovocultivation and the first time to obtain the adult-stage of the trematode Cymatocarpus solearis Braun, 1899 (Digenea: Brachycoeliidae). Chicken eggs were inoculated with metacercariae from the muscle of the spiny lobster, Panulirus argus (Latreille, 1804). The metacercariae were excysted and incubated for 576 hr (24 days) at $38^{\circ}C$ to obtain the adult stage. Eggs in utero were normal in shape and light brown color. The metacercariae developed into mature parasites that have been identified as the adultstage found in marine turtles. The adult lobsters collected in Quintana Roo State, Mexico, showed the prevalence of 49.4% and the mean intensity of 26.0 per host (n=87). A statistical study was performed to determine that no parasitic preference was detected for male versus female parasitized lobsters. Morphometric measurements of the adult-stage of C. solearis obtained in our study have been deposited in the National Helminths Collection of the Institute of Biology of the National Autonomous University of Mexico. This study is significant because it is the first time that a digenean of the family Brachycoeliidae has been demonstrated to develop in vitro from metacercariae into adults capable of producing eggs using the yolk of unfertilized chicken eggs. Secondly, this technique allows to obtain the adult stage of C. solearis without the presence of its marine turtle host, allows us to describe the mature parasites, and thus contribute to our understanding of the biology of C. solearis.

• Parasites, Hosts and Diseases
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• v.54 no.3
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• pp.363-368
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• 2016

We describe here the mass death of predatory carp, Chanodichthys erythropterus, in Korea induced by plerocercoid larvae of Ligula intestinalis as a result of host manipulation. The carcasses of fish with ligulid larvae were first found in the river-edge areas of Chilgok-bo in Nakdong-gang (River), Korea at early February 2016. This ecological phenomena also occurred in the adjacent areas of 3 dams of Nakdong-gang, i.e., Gangjeong-bo, Dalseong-bo, and Hapcheon-Changnyeong-bo. Total 1,173 fish carcasses were collected from the 4 regions. To examine the cause of death, we captured 10 wondering carp in the river-edge areas of Hapcheon-Changnyeong-bo with a landing net. They were 24.0-28.5 cm in length and 147-257 g in weight, and had 2-11 plerocercoid larvae in the abdominal cavity. Their digestive organs were slender and empty, and reproductive organs were not observed at all. The plerocercoid larvae occupied almost all spaces of the abdominal cavity under the air bladders. The proportion of larvae per fish was 14.6-32.1% of body weight. The larvae were ivory-white, 21.5-63.0 cm long, and 6.0-13.8 g in weight. We suggest that the preference for the river-edge in infected fish during winter is a modified behavioral response by host manipulation of the tapeworm larvae. The life cycle of this tapeworm seems to be successfully continued as the infected fish can be easily eaten by avian definitive hosts.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.319-329
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• 2017

We investigated the host preference of Ricania app. at different developmental stages to select the effective control methods. Ricania spp. at different developmental stages preferred different host plants. During the nymphal period, individuals moved to the bottom due to environmental factors such as wind and rain, rather than inhabiting trees, and fed on various plants ranging from 1 year-old herbaceous plants to shrubs. Especially, at Palbong Mt. in Gonju, Ricania spp. nymphs preferred Symplocos chinensis f. pilosa, Celastrus orbiculatus, Euonymus alatus, Kalopanax septemlobus, Aralia elata, Styrax japonicas, Rubus parvifolius, Ru. coreanus, Ru. crataegifolius, Quercus acutissima, Cornus officinalis, Lespedeza bicolor, Albizia julibrissin, L. maximowiczii, Rhododendron schlippenbachii and Rh. indicum. At Yongbong Mt. in Hongseong, Ricania spp. adults preferred herbaceous plants, such as Helianthus annuus, Solanum nigrum, and Oenothera biennis rather than trees during the pre-oviposition stage. Subsequently, as the oviposition season began, Ricania spp. adults were rarely found in H. annuus, S. nigrum, or O. biennis and appeared to migrate to the perennial trees and shrubs hosts to lay eggs. At Palbong Mt., the main laying hosts of Ricania spp. adults were Weigela subsessilis, Ailanthus altissima, Q. aliena, Boehmeria platanifolia, Diospyros lotus, Ziziphus jujubae var. inermis, St. japonicus, Prunus mume, P. serrulata var. spontanea, Spiraea prunifolia f. simpliciflora, Ru. crataegifolius, Salix koreensis, Ru. yedoense f. poukhanense, and Co. controversa. The degree of egg laying, number of egg masses and adult Ricania spp. were significantly higher in sunlit areas than in shaded areas, in addition, the lower the altitude, the more adults were present. This study contributes toward the development of traps that can attract and control Ricania spp. and reduce the density of Ricania spp. that disturb the ecosystem.

• Journal of Ecology and Environment
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• v.44 no.2
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• pp.106-114
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• 2020

Background: Determining patterns of habitat use is key to understanding of animal ecology. Approximately 1% of bird species use brood parasitism for their breeding strategy, in which they exploit other species' (hosts) parental care by laying eggs in their nests. Brood parasitism may complicate the habitat requirement of brood parasites because they need habitats that support both their host and their own conditions for breeding. Brood parasitism, through changes in reproductive roles of sex or individual, may further diversify habitat use patterns among individuals. However, patterns of habitat use in avian brood parasites have rarely been characterized. In this study, we categorized the habitat preference of a population of brood parasitic lesser cuckoos (Cuculus poliocephalus) breeding on Jeju Island, Korea. By using compositional analyses together with radio-tracking and land cover data, we determined patterns of habitat use and their sexual and diurnal differences. Results: We found that the lesser cuckoo had a relatively large home range and its overall habitat composition (the second-order selection) was similar to those of the study area; open areas such as the field and grassland habitats accounted for 80% of the home range. Nonetheless, their habitat, comprised of 2.54 different habitats per hectare, could be characterized as a mosaic. We also found sexual differences in habitat composition and selection in the core-use area of home ranges (third-order selection). In particular, the forest habitat was preferentially utilized by females, while underutilized by males. However, there was no diurnal change in the pattern of habitat use. Both sexes preferred field habitats at the second-order selection. At the third-order selection, males preferred field habitats followed by grasslands and females preferred grasslands followed by forest habitats. Conclusions: We suggest that the field and grassland habitats represent the two most important areas for the lesser cuckoo on Jeju Island. Nevertheless, this study shows that habitat preference may differ between sexes, likely due to differences in sex roles, sex-based energy demands, and potential sexual conflict.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.4 no.3
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• pp.104-114
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• 2023

In this study, the distribution, bait preference, hosts, symbionts, habitat status, and cytochrome c oxidase subunit-I sequences of the ant Linepithema humile were analyzed. This species habitat comprised approximately 1.5 km along stone crevices, flower gardens, roadsides, and container yards in the vicinity of Busan station, Korea. Feeding activity of this species was confirmed in 9 species of 7 families of plants. Which was approximately 14% of total flora (63 species of 37 families) in the studied area. Particularly, it was observed that Dendranthema indicum and Camellia japonica were the most frequently visited. Further, we verified that they interacted with four species of aphids. We identified 22 species of ants (17 genera, 4 subfamilies) inhabiting the Busan station area, including L. humile, Tetramorium tsushimae, Nylanderia flavipes and the alien species Paratrechina longicornis. In areas where L. humile was the dominant species, the habitat of local native ants was reduced by approximately 30%. Bait preference was ranked in the following order: jelly, water with glucose (25%), and yogurt, with the highest preference for baits containing sugar and protein. The 630-bp cytochrome c oxidase subunit-I sequences of the local L. humile populations were 99% identical to those of L. humile in the National Center for Biotechnology Information database, and the Argentine ants that invaded Korea had a sequence identical to that of other invasive populations from China, Japan, and New Zealand. As L. humile rapidly increases due to domestic adaptation, continuous monitoring and control strategy for eradication are needed to protect domestic biodiversity.