• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.23-27
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• 2009

The feeding habits of Lateolabrax japonicus were studied based on an examination of the stomach contents of 344 specimens collected monthly from January to December, 2005 in coastal waters off Dolsan-do, Yeosu. The standard length (SL) of specimens ranged in 8.7~52.8 cm. L. japonicus is a piscivore that consumes mainly teleosts such as Engraulis japonicus, Trachurus japonicus, and Acanthogobius flavimanus. Its diet also includes Macrura, Amphipoda, Cephalopoda, Polychaeta, Mysidacea, and Branchyura. Small individuals (<25 cm SL) consume mainly Amphipoda and Macrura. The proportion of these prey items decreases with increasing fish size, and this decrease paralleled the increased fish consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.430-436
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• 2019

The diet of Glyptocephalus stelleri was studied using 475 specimens collected in the coastal waters of the East Sea of Korea. The specimens ranged from 6.8 to 43.4 cm in total length (TL). G. stelleri was a crustacean feeder that consumed mainly euphausiids [percent index of relative importance (%IRI)=63.7%]. Polychaetes were the second largest prey component. The diet also included small quantities of bivalves, copepods, amphipods and shrimps. Individuals smaller than 15 cm TL fed mainly on euphausiids. The proportion of euphausiids decreased as body size increased, whereas the consumption of polychaetes increased gradually.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.77-82
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• 2019

The feeding habits of pacific cod (Gadus macrocephalus) were studied by analyses of stomach contents. Specimens of G. macrocephalus (n=407) were collected from the western coastal waters of Korea, monthly from July 2017 to June 2018. The size of G. macrocephalus ranged from 30.4 to 86.0 cm in total length (TL). G. macrocephalus was consumed mainly Pisces (71.5%) and Caridea (24.2%) based on % IRI, whereas other prey items including, Paguroidea, Euphausiacea and Cephalopods showed a low contribution to the diet. The feeding ratio of Caridea decreased with increasing fish size. While this decrease paralleled the increased consumption of fish preys. The feeding ratios of Pisces were the highest during spring, autumn and winter, whereas the proportion of Caridea was higher in summer.

• Korean journal of applied entomology
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• v.37 no.1
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• pp.53-58
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• 1998

Comparative studies on some ecological characteristics of three phytoseiid mitespecies (one native; Arnblyseius womersleyi Schica, and two introduced species; A. fallacis Garmanand Typhlodromus occidentalis Nesbit) were carried out. The two-spotted spider mite (Tetranychusurticae Koch) was supplied as prey. Under four constant temperatures of 20, 23, 25 and 30f OS$^{\circ}$C,duration of growth from egg to adult for A. womer.vleyi was 11.5, 7.7, 6.7 and 5.6 days. While twoother species needed slightly shorter time but not significantly different. Critical temperature andeffective degree-days (DD) of A. womerslevi females were 83$^{\circ}$C and 1 1 1.6 DD, whereas those of A..fallacis were 10.7"C and 86.0 DD, and those of 7: occidentalis were 10.7"C and 94.1 DD. Also, thoseof males were similar to their females. Average longevity of females of A. womersleyi, A. fallucisand 7: occidentalis were 18.2 k 8.67, 19.6 3~7.18 and 13.0f5.66 days, total fecundity were 34.3 $-11.93, 39.8k 12.64 and 23.6k8.86, respectively. Under four constant temperatures of 20, 23, 25 and30-t0.S$^{\circ}$C, A. womersleyi consumed 9.1 f2.49, 9.7 k2.00, 9.7 f 2.61, and 10.3 k2.33 eggs of 7:urticae throughout their development. A. ,fizlluc~i.sc onsumed 10.2 k 2.52, 9.7 f2.29, 10.7 f 2.37 and10.1 k2.62 eggs, while, 7: occidentalis consumed 1 1.9 k3.43, 14.2 f4.50, 14.8 k 3.2 1 and 12.7 f2.95 eggs, respectively. Gravid females of A. womersleyi, A. f~zllacis and 7: occidentalis consumed11.4f1.59, 12.5k1.43 and 11.7k3.07 eggs, or consumed 11.9f 2.63, 12.4k3.82, and 12.5f 3.73protonymphs of 7: urticae in a day at 25-30$^{\circ}$C.e in a day at 25-30$^{\circ}$C.

• Korean Journal of Ichthyology
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• v.30 no.1
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• pp.27-35
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• 2018

The activity period and feeding ecology of the Iksookimia yongdokensis were investigated to obtain baseline data for its ecological characteristics in the Chuksan Stream and Gokgang Stream, Gyeongsangbuk-do, Korea from 2015 to 2016. I. yongdokensis were active on cobble, pebble and sand bottom from March to November when the water temperature exceeded $10^{\circ}C$, but tended to overwinter in cobble and pebble during the winter months (December~February) when the water temperature was lower than $10^{\circ}C$. During the day from 9 am to 15 pm, individuals of I. yongdokensis were highly active with a high rate of food consumption. I. yongdokensis activley fed on the surface of stone, pebble and sand as a filter feeder. Their main food sources analyzed with an index of relative importance (IRI) include Chironomidae (54.7%), Branchiopoda (10.1%), Rotatoria (8.7%), Arcellidae (8.6%), Chlorophyceae (6.5%) and Bacillariophyceae (5.1%). Juveniles of I. yongdokensis (total length 20~39 mm) fed on small-sized preys such as Rotatoria, Branchiopoda and Arcellidae, but they exhibited a transition in their prey-size markedly dominated by large-sized preys such as Chironomidae and Ephemeroptera as they grow.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.461-467
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• 2012

Developmental characteristics of Geocoris pallidipennis were investigated at a constant temperature ($20{\pm}1$, $25{\pm}1$, $30{\pm}1$, $35{\pm}1$, $37.5{\pm}1$ and $40{\pm}1^{\circ}C$), under long day illumination 16:8 (L:D) and constant relative humidity ($80{\pm}10%$). From egg to adulthood, the lower developmental threshold and the effective accumulative temperature were $14.8^{\circ}C$ and 399.1 day-degree, respectively. The experimental results at $35^{\circ}C$ were as follows. The egg period was 5.6 days (hatchability: 81.1%) and the nymphal period was 14.3 days (1st: 3.2, 2nd: 2.2, 3rd: 2.7, 4th: 2.7, 5th: 3.6). Female longevity was 33.8 days and the oviposition period was 29.2 days. Total egg production was 111.2 eggs and the maximum daily egg production was 14.8 eggs (in 7th days). However, although some eggs and nymphs developed at $37.5^{\circ}C$, G. pallidipennis could not develop at $40^{\circ}C$, The total egg production at $40^{\circ}C$ was only 22.1 eggs. When G. pallidipennis was fed on Bemisia tabaci pupae, daily prey consumption by nymphs (1st, 3rd and 5th) and adults was 1.9, 7.3, 18.7 and 29.5, respectively.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.421-428
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• 2008

With the comparison of native Orius strigicollis (Poppius) to European O. laevigatus (Fieber), we investigated biological characteristics such as developmental period, fecundity, life span, predation ability, and augmentation after release. Experiments were carried out at five temperature condition, $15^{\circ}C\;20^{\circ}C,\;25^{\circ}C\;30^{\circ}C$, and $35^{\circ}C$. In the case of O. strigicollis, egg period was $3.1{\sim}14.9$ days (hatchability: $46.7{\sim}88.2%$), and developmental period of nymphs was $9.4{\sim}42.8$ days (survival rate: $2.4{\sim}96.5%$). Fecundity at each temperature was 28.1, 107.9, 123.6, 127.3, and 18.1, respectively. Life span of adults was 63.4, 40.1, 22.1, 18.3, and 11.0 days, respectively. In the case of O. laevigatus, egg period was $3.1{\sim}13.5$ days (hatchability: $65.0{\sim}89.9%$), and developmental period of nymphs was $9.3{\sim}42.0$ (survival rate: $4.3{\sim}80.6%$) days. Fecundity at each temperature was 101.8, 218.6, 224.5, 219.5, and 15.7. Life span of adults was 70.6, 66.4, 32.6, 34.5, and 7.3 days, respectively. In long-day condition (16L:8D), fecundity of O. strigicollis and O. laevigatus was 105.8 $(18^{\circ}C){\sim}142.4(25^{\circ}C)$ and 109.5 $(18^{\circ}C){\sim}191.5(25^{\circ}C)$, respectively. In short-day condition (10L:14D), fecundity of them was 1.0 $(18^{\circ}C){\sim}31.8(25^{\circ}C)$ and 63.0 $(18^{\circ}C){\sim}198.8(25^{\circ}C)$, respectively. Daily prey consumption of second instar Frankliniella occidentalis was 14.3 and 10.9, respectively. In greenhouse, density of O. strigicollis begins to increase from mid May and peaked about early July (1.8 individual/flower), while that of O. laevigatus begins to increase from mid March and peaked about early June (6.6 individual/flower).