• Korean journal of applied entomology
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• v.30 no.2
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• pp.101-105
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• 1991

The host finding, ovipostition of Anagrus incarnafus Haliday and the sex ratio of its offsprings was determined. Both male and female mate immediately after emergence and the female parasitoid search for host eggs by drumming with antenna immediately after release on the rice seedings. Time required for the host searching, drumming with antenna, tapping and inserting with ovipositor, and ovipositing of A. incarnaws takes 188.5, 17.5, 72.4 and 206.7 seconds, respectively. The time required for mating takes 16-21 seconds. The sex ratio of offsprings between female and male was about 3: 1 in mated females and all the offsprings emerged from the eggs of unmated females were males. So, A. incarnafus can reproduce zygogenetically and parthenogenetically and the mode of parthenogenetic reproduction was an arrhenotokous parasitoid.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.159-166
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• 2004

The effects of polychlorinated biphenyls (PCBs) on the reproduction of the oily bitterling, Acheilognathus koreensis were investigated using histological methods. The experimental fishes were exposed to 0. 3.4, 9.3 and 25.8 ${\mu}g\; L^{-1}$ PCBs fey 8 weeks. Dead fishes and abnormal behavior were not observed in control and PCBs exposure group. In compared with control group, PCBs exposure fishes showed differences of gonadal development, gonadosomatic index (GSI), hepatosomatic index (BSI), nuptial color index (NCI) and ovipositor length index (OLI). These results showed that PCBs could disrupt reproductive process in the fish.

• Korean journal of applied entomology
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• v.29 no.1
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• pp.25-30
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• 1990

Physiological and morphological differences in larvae and female adults of Thecodiplosis Japonensis from Haenam, Chullanamdo, and Chunsung, Kangweondo, were studied by means of electrophoretic technique and scanning electron microscope (SEM). On zymograms of whole body, third instar larvae of T. japonensis showed geographic differences in the band patterns of esterase and MDH iszymes, but patterns and the staining density of general proteins were similar in tow populations. In female adults, the populations revealed geographic differences in general proteins and esterase isozymens. In external ultrastructures, especially in genital segments, each population had distinctive structures in the 2nd segment of ovipositor.

• Korean journal of applied entomology
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• v.30 no.4
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• pp.233-240
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• 1991

A female Brachymeria lasus (Walker) was exposed to one or four pupae of host Hyphantria cunea Drury for 20 minutes within a petri dish $(1.5\times9cm)$ to learn factors influencing the host discrimination by the parasitoid. It rejected the parasitized host with its rejection ratio 73.3% for the one pupal exposure vs 100% for the four pupal exposure scheme. The parasitoid could discriminate the parasitized host by its antennal drumming and ovipositor probing due to a pheromone-like external marking which is effective only for a certain peiod of time, and a host quality associated with the parasitoid development, respectively.

• The Korean Journal of Zoology
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• v.32 no.1
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• pp.22-33
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• 1989

Comparison of morphological characters and development of eggs and larvae of two bitterlings, Acheilognathus limbata and A. signifer from Korea were observed and discussed taxonomically. A. signifer differs from A. limbata by the color pattern of dorsal and anal fin ray of male, egg form and the length of ovipositor of female. Although two species are overlapping each other in some morphometric characters, there is a great difference between the two in the multivariate analysis of 15 morphological characters of five comparative populations. These results indicate that A. limbata and A. signifer are two independent allopatric sibling species in Korea.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.87-96
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• 2006

Reproduction and organ system of the oily bitterling, Acheilognathus koreensis in Isa stream were investigated by means of histological methods. Sex ratio was observed 1 : 1 in female to male. The gonadosomatic index (GSI) of the female showed two peak in December and April. The ovipositor length index (OLI) represented irregular change. From the histological analysis of the organ system, epidermal atrophy and hyperplasia of pigment cell were observed in the skin. Epithelial layer lifting of the lamella and bifurcation of the filament were observed in the gill. Also histological changes as congestion, cytoplasmic degeneration of hepatic cell, glomerular dilatation, hyaline droplet degeneration of renal tubule epithelium and pycnosis of interstitial cell were identified in the liver and kidney, respectively.

• Development and Reproduction
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• v.23 no.4
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• pp.323-331
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• 2019

In this study, an experiment was conducted to investigate the annual reproductive cycle of a Korean flat bittering, Acheilognathus rhombeus, from Ogok-myeon located in Seomjin River. The reproductive cycle was examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), and developmental characteristics of female and male gonads. The maximum GSI was found to be 3.50±0.53 and 1.36±0.14 for females and males, respectively, when the water temperature and day light was 16.9℃ and 11.3 hours, respectively in October 2018. On the other hand, the minimum GSI was found to be 0.16±0.09 and 0.69±0.15 for males and females in December 2018 and February 2019, respectively. The ovipositor of females appeared from August to November 2018. We compared and calculated the stages of germ cell developmental characteristics in the testis and ovaries to determine the reproductive cycle. According to the result, we classified the female A. rhombeus reproductive cycle into four phases, which are ripe and spawning phase (October), degenerative phase (November to December), growing phase (January to March) and mature phase (April to September). The annual reproductive cycle of male A. rhombeus was categorized into four phases: mature phase (June to October), degenerative phase (November to March), resting phase (April) and growing phase (May). The Korean flat bittering is an autumn-spawner as the main spawning season in October. In male, testicular spermatogonia appeared all year-round, and the ripe and releasing phase, which is characteristics of the spawning season in other fish, did not appear.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.11-19
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• 2009

This study was performed to investigate the seasonal occurrence, developmental characteristics of each nymphal stages with different temperatures (20, 25, $30^{\circ}C$), longevity and fecundity of ussur brown katydid, Paratlanticus ussuriensis, damaging by outbreaks in the orchard areas of Bitan-ri, Yeongdong, Chungbuk. Paratlanticus ussuriensis occurred from late-March to late-August with peak of mid-May. Newly emerged nymphs appeared from March and do damaged fruit orchards with peak of mid-May when P. ussuriensis existed as 4th and 5th nymphal stages. P. ussuriensis adult occurred from early-June to mid-Aug. with peak of mid-July. Total density of P. ussuriensis was showed highest in mid-May. Paratlanticus ussuriensis goes through nymphal stages to 7th nymph, the ovipositor began exposed to outside from the 4th instar and the body weight increased heavily from this stage and the wings were observed from 6th instar. Developmental period was longer as increased the nymphal stages. Sex ratio of collected insect was showed as 0.57; females more than males. As increased the temperature, developmental period was to be short. Preoviposition was also to be short as 5.0, 4.3, and 3.4 days at 20, 25, $30^{\circ}C$, respectively, and fecundity increased as 69.0, 87.1, and 104.3 at 20, 25, $30^{\circ}C$, respectively. Longevity of male and female at $25^{\circ}C$ was showed the longest with 35.7, and 32.9 days and showed the shortest with 30.1 and 28.1 days at $30^{\circ}C$, respectively. The difference of developmental period in male and female were showed longer in female without relation of temperature. The eggs laid were frequently distributed 3 to 4 cm from soil surface, and showed the behavior laying eggs intensively when early oviposition period.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.423-429
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• 2009

Characteristics of habitat alteration and post-embryonic development of Paratlanticus ussuriensis were investigated in the mountain region of Bitanri, Yeongdong county, Chungcheongbuk-do from 2007 to 2009. Overwintered eggs under the ground in the hillside were hatched from late March to early April. The soil temperature during this season was $7{\sim}14^{\circ}C$. Young nymphs lived mainly at the hillside by eating oak tree leaves but the 3rd or 4th instars switched their habitat to orchards near the hillside in early May, which is the time for sprouting of peach leaves. Old nymphs developed into the adult stage at the orchards in late May and moved back to the hillside in late June. Duration of post-embryonic development from the first instar nymph to adult was 49.2 days after 7 moltings at $25^{\circ}C$. Female adults collected from the field had long ovipositor (26.2 mm) and were slightly longer in the body length, hind femur, tegmen and pronotum than those of males.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.381-389
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• 2014

We investigated the host fruit, seasonal occurrence, and oviposition habits of the eurytomid wasp, Eurytoma maslovskii that cause Japanese apricot fruit drops. This eurytomid wasp was found to occur in Gyeonggi-do, Chungcheongbuk-do, Chungcheongnam-do, Jeollanam-do, and Jeollabuk-do in Korea, and it attacked seeds of Japanese apricot, apricot, and peach. Overwintered larvae were observed until mid April, inside the stone of Japanese apricots. Pupation took place between late March and late April. More than 90% of the adult wasps emerged between late April and early May. The female wasps laid eggs just under the seed coat before endocarp hardening. The length of the wasp ovipositor was at least 5 mm, and hence, the diameters of fruits for oviposition would not exceed 2 cm. We observed up to five eggs per fruit, and the egg stage did not last for more than two days. Newly hatched larvae moved to the embryo, which is the first part that forms in a seed, and feeds on this. Larval competition occurs during this time; in this study, only one larva survived and matured. Thus, from the larva cycle of the wasp, most of the damaged fruits would have fallen by early June, before the harvest period.