• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.744-750
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• 2010

This study examined the different polyphenism of larval salamander Hynobius ieechii according to two habitats, pond and stream. We collected salamander's eggs from three regions including Mountain Inwang, Surak and Gwangju. Eggs were treated by four different conditions according to predation level and habitat: high risk - which had a predation risk three times a day; low risk - which had no predation risk, pond and stream habitat. Predation risk was conducted by using chemical cue from Chinese minnows. The chemical cue treatment started from the day of collection and ended one week after the hatching. After the treatment phase, we measured the head width at the level of the eyes(HWE) and the largest head width(LHW) and snout-vent length of the each larva. We calculated the ratio of the head size by dividing HWE by LHW and made a comparison with each of the average ratio of head size according to the predation risk. The results showed that there was a significant difference in the ratio of the head size and snout-vent length according to the predation risk and habitat. From these results we found that predation risk and habitat condition can cause the different polyphenism to the larval salamander and these morphological changes could be affect their mortality.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.342-347
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• 2012

This study was conducted to demonstrate the relationship between experience of cannibalism and difference of phenotype in the Korean salamander Hynobius leechii from March to April 2011. We examined whether the different polyphenism of larval salamander is induced as a result of indirect cannibalism in early life cycle. We divided into two groups(one group continuously exposed to the indirect cannibalism and the other group never exposed to the cannibalism). We measured the head width at the level of eyes(HWE), the largest head width(LHW) and snout-vent length(SVL) of the each larva then calculated the ratio of the head size by dividing HWE by LHW. We found that exposure of indirect cannibalism in early life cycle cause the different polyphenism. Our result means the larval salamander responded to the chemical cue from conspecific.

• The Korean Journal of Zoology
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• v.36 no.1
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• pp.84-96
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• 1993

한국산 도롱뇽(Hynobius leechii) 유생의 다리 발생 과정을 관찰하고 잠재적 돌연변이 유발물질인 제-methyl-N'-nitro-N-nitrosoguanidine(MNNG)과 잠재적 기형 유발물질인 retinol palmitate가 다리 발생에 미치는 영향을 알아보았다. 정상적인 개체에서 됫다리의 발생 단계는 외부와 내부의 형태적 특징을 기준으로 하여 7단계로 나누어 볼 수 있었으며 전연골세포의 밀집에 따른 골격형성은 다리 발생아의 근위부에서 시작하여 원위부로 진행됨을 확인할 수 있었다. 도롱뇽 유생을 MNNG(10 rpm)나 retinol palmitate(37.5 lpm)로 처리한 경우, 공통적으로 다리 원위부의 골격 형성이 억제되었으며, 특히 이러한 골격 형성 억제 현상은 처리시기가 이를수록 보다 심하게 나타났다. 이러한 결과는 발생을 저해하는 물질에 대한 미분화 상태의 세포들의 반응성이 발생과정 중 특정 단계에 국한됨을 시사하는 것으로 해석된다.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.666-672
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• 2011

This study examined the different growth rate of larval salamander Hynobius leechii by the predation risk. We collected salamander's eggs from Mountain Inwang. Eggs were treated by two different conditions: (1) cue - which had a predation risk three times a day; (2) no cue - which had no predation risk. Predation risk was conducted by using chemical cue from Chinese minnows. The chemical cue treatment started from the next day after the collection and ended one week after the hatching. Between the first week and the second week after the hatching we fed salamander larvae with tubifex ad. libitium. After the treatment phase, we measured snout - vent length of the each larva on the first week and the second week after the hatching. The results showed that there was a significant difference in the growth rate by the predation risk. From these results we found that predation risk can cause the different growth rate to the larval salamander and these changes could be affect their mortality.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.485-491
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• 2013

This study examined the cannibalistic polyphenism of larval salamander Hynobius leechii by the level of predation risk. Salamander eggs were collected from three regions (Mountain Inwang, Mountain Surak and Gwangju). Eggs were treated by three different risk conditions: (1) high risk, predation risk three times a day; (2) medium risk, predation risk once a day; and (3) low risk, no predation risk. Predation risk was conducted using a chemical cue from Chinese minnows. The chemical cue treatment started from the day of collection and ended one week after hatching. Post-treatment measurements were head width at the level of the eyes (HWE), largest head width (LHW), and Snout-vent length of the each larva. To compare the morphological change according to the predation risk, we modified the two head size, HWE and LHW, to HWE/LHW. A significant difference in HWE/LHW and snout-vent length was evident according to the level of predation risk. And larval mortality was increase by the predation risk. The results indicate that predation risk can cause cannibalistic polyphenism of larval salamander and this morphological change could influence larval mortality.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.865-872
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• 2015

Body size is one of the important factors that determine mating success in various animal taxa. Nevertheless, only few related studies have been conducted on Korean salamanders. In this study, we have investigated whether large male Gori salamander (Hynobius yangi), which is a Korean endemic species and is unknown for its mating behaviors, is dominant in the mating competition than small males. Thirteen sets of mating trials composed of one large male, one small male, and one female per each group were analyzed in the categories of courtship display towards females, male competition and egg fertilizing behavior. The results show that the mating behaviors between large and small males towards females or with each other did not significantly differ. These results may have been caused by a small size variation among males and the presence of plenty of oviposition locations in breeding sites. This is the first report on Gori salamander's mating behaviors.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.121.3-122
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• 2000

• Proceedings of the Zoological Society Korea Conference
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• 1996.04a
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• pp.54.2-54
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• 1996

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.557-569
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• 2023

Amphibians are the world's most threatened group of animals, with approximately 41% facing extinction. Contrary to this global trend, the number of amphibian species in Korea has increased by approximately 53.3% over the past 20 years. In particular, salamanders within the genus Hynobius showed even greater diversity, with the number increasing three-fold from two species to seven. However, morphological and ecological traits required for the clear differentiation of these animals are yet to be determined, leading to much confusion. In this study, we investigated the validity of using size traits for species identification, as this method is currently considered a rule of thumb when differentiating Geoje salamanders (Hynobius geojeensis), cryptic Uiryeong salamanders (H. perplicatus), and Korean small salamanders (H. unisacculus). Our study revealed that sex, study period, and habitat were all factors associated with significant differences in snout-vent length, head width, and body weight. Differences in these size traits were evident both between and within species. Our results show that body size traits applied in the recent classification of the three new salamander species could not be seen as a suitable criterion. Such identification methods based solely on body size not only cause great confusion in the field but will also limit future research on Korean Hynobius salamanders.

• The Korean Journal of Zoology
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• v.33 no.3
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• pp.322-329
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• 1990

The effects of retinoic acid (RA) on the regenerating limbs of Korean newt (Hynobius leechii) larvae have been studied. Intraperitoneal injection of RA at 4 days post-amputation caused the proximalization of regenerate structures in the proximodistal (PD) axis of the limbs amputated through either the distal zeugopodium or the distal stylopodium. The mean level of proximalization (MLP) increased as a dose-dependent manner, and the MLP was also dependent on the level of amputation at a given dose of RA. At the dose of 150 $\mu$ g/g body wt., MLP's in either amputation level reached close to a peak value, and an increasing number of inhibition of regeneration or duplication in the transverse plane occurred at the dose of 200 $\mu$ g/ g body wt. and above. The changes induced by RA treatment suggest that positional values in the cells of the regenerating limbs have been modified in the three cardinal axes including PD and transverse axes in a graded mode. Furthermore, from the comparison of data in two different amputation levels, it can be speculated that the sensitivity of cells to RA effect along the PD axis might not be linear.