Aquatic ecosystem is composed of various organic and inorganic matters. Its health is essential for sustaining its members such as vegetations, mammals, birds, fishes and invertebrates. Samcheonpo stream is one of candidate streams in Sacheon area of ecological restoration. For this reason, this study conducted to build up a data base for future comparison. The results shows that biodiversity of Epilithic Diatoms and Invertebrates is below average which means that human impacts such as artificial structures and activities have been negatively related to stream health. Consequently, we suggest several key factors when ecological restoration is performed in the stream.
이 연구에서는 주요 가로수인 왕벚나무를 대상으로 구례지역의 조기낙엽 현황 진단을 위해 제주도와 낙엽비율 비교연구를 진행하였고, 구례군에서 수행가능한 주요 가로수 관리방법을 두 가지로 구분하여 관리방법별 조기낙엽 지연효과와 피해를 규명하여 최적관리방법을 도출하였다. 구례지역은 기상청 단풍시기와 낙엽시기가 유사한 제주도 지역보다 같은 시기 낙엽비율이 높았고, 약제처리, 약제와 관수처리를 진행했을 때 구멍병이 방제되어 낙엽 시기가 2주 지연되었다. 조기낙엽은 왕벚나무의 생장과 개화에 영향을 미쳤으며, 약제와 관수처리를 진행한 관리방 법에서 생장이 가장 높았고, 2년 뒤 개화량이 가장 높은 것으로 추정되었다. 따라서 왕벚나무 가로수의 조기낙엽을 지연시키기 위해 구멍병 방제가 중요하고, 조기낙엽이 수관의 발달과 개화량에 영향을 미칠 수 있으므로 약제와 관수처리를 함께 처리하는 관리방법을 도입하는 것이 필요할 것으로 생각된다.
번식기 유부도 일대의 조수 경계부에서는 검은머리물떼 새 (Haematopus ostralegus osculans) 성체와 미성체가 한데 모여 복족류 (서해비단고둥, Umbonium thomasi)와 이매패류를 섭식하는 것이 관찰된다. 본 연구는 성체와 미성체 간의 섭식 능력에 차이가 있는지 알아보고자 해당 먹이원을 섭식하는 개체들의 행동을 영상으로 녹화한 후 성체와 미성체로 구분하여 단위 시간당 걸음수, 먹이원 탐색시도횟수 및 탐색방법 구성비율, 섭식성공횟수, 조작시간, 머리 들어 올리기횟수를 비교하였다. 서해비단고둥을 섭식할 때 먹이원 탐색방법의 구성 비율, 이매패류를 섭식할 때 먹이원 탐색시도횟수와 머리 들어올리기횟수에서 유의한 차이를 나타냈으나, 단위 시간당 걸음수, 탐색시도횟수, 섭식성공횟수는 차이가 없었다. 결과적으로 번식기 유부도 일대에 서식 하는 검은머리물떼새 미성체가 성체에 비해 비록 열세이고, 먹이원의 위치를 파악하는 능력이 부족하지만, 전반적인 섭식 능력은 성체와 유사한 수준임을 의미한다. 월동기간 동안 고도의 섭식 능력을 갖추어야 섭식이 가능한 이매패류를 지속적으로 섭식한 것에 기인한 것으로 판단된다
이 연구에서는 한라산을 포함한 제주도 전역에서 높은 밀도로 자라고 있는 제주조릿대 (Sasa quelpaertensis Nakai) 가 서식지 고도와 수관부 개폐 여부에 따라서 나타나는 식물의 생태학적 특성과 소비자 군집 다양성 변화에 영향을 받는가를 알아보았다. 고도와 상부 식생의 유무에 따라 제주조릿대 군락 네 지점을 선정한 후각 지점에서 자라고 있는 제주조릿대 식물 특성 그리고 소비자 군집 다양성을 통하여 삼중영양 상호작용 (Tritrophic interaction)을 조사 하였다. 조사결과, 고도가 증가하면서 상부 식생이 없어지고 제주조릿대의 잎 면적, 수분함량, 질소함량은 감소하였으며, 밀도와 C/N함량은 증가하였다. 상부 식생이 존재할수록 제주조릿대의 생육특성은 더 좋아졌으며 이를 기주로 하는 초식곤충과 포식자가 증가하였다. 따라서 제주조릿대의 생육조건은 고도에 따른 주변 수관부 개폐와 밀접한 관련을 가지고 있으며 이러한 조건은 소비자 군집과도 밀접한 관련이 있는 것으로 생각한다.
The Wolbachia bacterium, one of the most prevalent endosymbiotic bacteria, is known to induce reproductive anomalies in various invertebrate taxa. We investigated Wolbachia infection frequency in 203 Coleopteran insects collected from Korea. Among them 26 species (12.8%) across families proved to harbor Wolbachia. The phylogenetic trees of two Wolbachia specific genes imply that there have been complex horizontal gene transfers and recombination events within and between divergent Wolbachia subgroups. Interestingly, we also find that the infection frequency is noticeably low and incongruent at the family level when compared to other literature cases of Wolbachia infection in beetle species.
이 연구에서 채집된 아메리카동애등에의 성충은 원산지의 성충과 그 크기가 비슷했다. 체형에서 가장 큰 차이점을 보이는 부분은 더듬이 바깥쪽 (antenna 2) 길이이며, 그 다음으로는 머리넓이 (head width), 복부넓이 (abdomen width) 등의 순으로 나타났다. 이 연구결과는 유기물 분해와 분변토 생산의 우수개체를 선발하는데 기초자료가 될 것이다. 국내 51개 조사지역 중, 22개 지역에서 아메리카동애등에가 출현했으며 위경도 및 고도 등 지리적 특성보다는 유기물의 존재에 더 영향을 받는 것으로 생각된다. 이 곤충의 발생현황은 유기성 폐자원의 선순환 구조를 파악할 수 있는 지표로 사용될 수 있을 것이다.
에메리개미는 여왕개미와 수개미가 유전적으로 복제되어 번식한다고 알려져 있으며, 여왕개미의 날개형태가 장시형과 단시형으로 나타난다. 장시형은 정상적인 날개형태이고, 이보다 짧은 날개형태는 단시형이라고 한다. 장시형과 단시형 모두 한 종으로 취급되지만, 두 가지 점에서 종 지위에 대한 조사가 필요하다. 첫째, 자연 상태에서는 두 날개형이 함께 발견되지 않고, 둘째, 날개형이 육안으로 뚜렷하게 구분된다. 또한 복제되어 번식한 여왕개미가 단수체인지 배수체인지 조사가 필요하다. 따라서 우리는 본 연구에서 에메리개미 유전체 크기를 추정하여 두 날개형은 동종이며, 여왕개미는 배수체임을 확인하였다.
Haplodiploid sex determination is prevalent in nature comprising about 25% of higher taxa. Due to its uniqueness, selfish entity may relatively easily slip in the system. Here, I will introduce 3 different types of selfish entities. First, some microorganisms are known to distort sex ratio in favor of their own prosperity. Second, a genetic fragment, called paternal sex ratio chromosome, is classified as the extremely selfish element so far in haplodiploid. Finally, haploid genome itself can evolve selfishness. The first two result in skewed sex ratio, and the last in completely new genetic relatedness. I will also discuss their evolutionary significance and potential utilization in controlling pest populations.
During the breeding season, some Eurasian Oystercatchers (Haematopus ostralegus osculans) in Yubu Island foraged in the open mudflat area nearby the breeding ground, instead of the tide water line area, main feeding site throughout the year. We found significant differences in foraging behavior and prey species diversity between the two different feeding site types. Even though the birds took more steps for most probably searching preys, their feeding success was much lower in the open mudflat area than the tide water line area. The multiple peck and boring methods were more frequently adopted to catch polychaetes on the open mudflat area, whereas the single peck method was dominant and gastropods and bivalves were main preys in the tide water line area. This study suggests that the bird shows flexible foraging strategy of shifting feeding site, foraging behavior and preys for better reproductive success.
외래생물인 아메리카동애등에는 뛰어난 유기물분해능으로 주목받아왔다. 이에 우리는 한국내 분포상과 유전적 다양성을 알아보기 위해 전국적으로 채집하여 미토콘드리아의 사이토크롬 C 산화효소 1 (CO1) 유전자를 이용해 집단유전학분석을 실시하였다. 그 결과 이 곤충은 한국에 성공적으로 정착한 것으로 보이며 10개의 미토콘드리아 유전자형이 있었고 개체군 간 분화가 뚜렷했다. 이 결과는 국내정착한 아메리카동애등에가 특정 유전자형의 모계만이 도입된 후 지역 간 분산이 제한적임을 나타내는 것으로, 이는 이들의 단거리 비행 경향에 기인한 것으로 추정된다.
By definition, endosymbionts reside in the hosts' cells and are maternally inheritted to offspring as the mitochondriondoes. Recent progresses reveal that some endosymbionts have evolved their manipulabilities of hosts' reproduction. Inthis nature, once an endosymbiont shares its host with others, their association may last long unless their evolutionaryinterest or hosts' fitness is undermined.We tested whether the association existed among the endosymbionts; Wolbachia, Spiroplasma, Cardinium and Rickettsia.The results show that there are some multiple infection cases but there is no obvious pattern in their association.
We surveyed the habitat use and food materials of the endangered Swan Goose (Anser cygnoides) during the wintering period at the Seocheon tidal flat. The bird wintered about six months from October 2014 to early April 2015 at the flat. They showed a remarkable change in choosing their feeding habitat and prey. They stayed entirely at sedge grass patches on Songrim tidal flat during the early wintering period (October), while after November they gradually moved to Janggu bay and used rice paddy fields as well as sedge patches on the tidal flats as their feeding site. The dietary analysis showed the sedge grass (Bolboschoenus sp., Cyperaceae) was the main dietary source during the entire wintering period. Interestingly, the proportion of Cyperaceae on feces decreased slightly over wintering time, while the proportion of Fabaceae increased relatively since November. These results suggest that the Swan Geese switched their habitat and food sources in response to the change of food availability. The Seocheon tidal flat area is the important wintering site for Swan Geese and sedge grass patches in the area need to be managed as the main feeding area for the wintering Swan Geese.
Vollenhovia emeryi (Formicidae: Myrmicinae) is divided into two morphs based on the wing length of the queen caste: the long-winged with a normal wing and the short-winged with the aberrant short wing. The phylogenetic analysis shows that the short-winged is derived from the long-winged. In Korea, only the long-winged morph is infected with Wolbachia while the short-winged is devoid of the bacterium suggesting that the short-winged evolved the resistance to the bacterial infection. Intriguingly, some Japanese short-winged colonies proved to still be infected with the bacterium.
We hypothesized that the infected Japanese short-winged is the intermediate form in the process to complete cure. However, the data of the MLST and the measurement of Wolbachia density did not support our hypothesis. Our further experiment using microsatellite markers shows that the infected Japanese short-winged shows the similar genetic background to the long-winged. In this presentation we will discuss the potential resistance evolution in the Korean short-winged and future research direction at the genome level.
In every summer, cicadas emerge and become numerically and ecologically dominant in Korean penninsula. Especially, cicada emergence is affected by the environmental factors. In order to evaluate the effect of environmental factors in cicada species, we analyzed the temporal changes in cicada exuviae based on meteorological and non-meteorological factors such as artificial light intensity and habitat characters on urban park area surrounded by residential houses. Combined multivariate analyses with a cluster analysis and a principal component analysis (PCA) were conducted. Samples were classified into 3 different cluster based on differences of meteorological factors such as temperature and humidity. Moreover, Random Forest model (RF) showed a high predictability of daily mean temperature on species peak abundance. These results provide a strong evidence that meteorological factors have significant effects on cicada emergences. Regarding the non-meteorological factors, we found no relationship in cicada emergence.
Vollenhovia emeryi (Hymenoptera: Myrmicinae) is dimorphic in its wing morphology of alate females: the long-winged and the short-winged. In our previous study, we found that the long-winged is ancestral and the short-winged is derived. Intriguingly, the former is infected with the intracellular symbiotic Wolbachia bacterium and the derived is void of the bacterium indicating that the latter somehow evolved resistance to the bacterium.
This may be one of few cases in which transition from susceptibility to the bacterium can be traceable via the divergence estimation. As a consequence, we inferred that the two morphs diverged approximately quarter million years ago; a remarkably recent event in evolutionary perspective.
In this presentation, we will further discuss genetic orchestration in the host insect and future research directions.
The Wolbachia bacterium is one of the best studied reproductive manipulators found in variuos invertebrate taxa. Theoretically it infects two thirds of invertebrates. It is thought to have a huge impact on its hosts’ evolution.
The ant is a very successful organism in terrestrial ecosystems especially with its charicteristic sociality. However, the influence of Wolbachia on the animal remains to be paid more attention.
This study is to examine Wolbachia infection frequency in some ant species in Korea. The result shows that 9 out of 12 ant species harbor the bacterium. Furthermore, at least two species show polymorphism in their infection status at the colony level.
This will be used as a foundation of further study on the interactions between the bacterium and ant species.
The study was to examine the variation and pattern of colony components of Vollenhovia emeryi. The total of 38 colonies was collected from 10 locations, including 35 colonies from 9 locations in South Korea and 3 colonies from 1 location in USA. To know colony components variation, we studied the approximate colony size, the approximate number of reproductives: queens, gyne and male, the approximate number of brood during 7 months. The observation period was from September 2012 to March 2013 over the breeding season from July to August. As a result, the study has found that colony components of the 38 colonies are not constant. This also indicates that gynes and males appear during non-breeding season at least in the laboratory condition. There are 4 types of gynes and males emergence: both(31.6%), only gynes(2.6%), only males(28.9%), absence(28.9%). The number of gynes and males of each colony also shows variance. It indicates that Vollenhovia emeryi may show colony components continuum. In this species, fertilized eggs become worker females and males; worker females are diploid but males are haplid because of maternal genomic elimination. Unfertilized eggs become queens which are diploid by clonal reproduction. Therefore, each individual of the sex can exceptionally transfer its own genes. This unique haplodiploid sex determination may create the conflict between queen and male and cause colony components continuum.
The phylogenetic analysis the queen polymorphic Vollenhovia emeryi ant reveals derivation of the Wolbachia- free short-winged from the Wolbachia-infected long-winged. However, intriguingly, some Japanese short-winged colonies harbor Wolbachia. Wolbachia specific bacteriophage (WO) is also detected in more than half of the infected colonies with no clear distribution pattern across the host insect lineage. We hypothesized that 1) the infected Japanese short-winged is in the intermediate stage to complete loss of Wolbachia and 2) the phage invaded the host after the host insect diverged. To test the hypotheses, we studied the strain diversity using the multi-locus sequence typing (MLST) of five ant colonies; three longwinged colonies from Korea and one long-winged colony and one short-winged colony from Japan. Both Korean and Japanese V. emeryi colonies show unexpectedly high level of Wolbachia strain diversity. However, the diversity is not significantly different between the long-winged and the short-winged against our first hypothesis. Phylogenies of Wolbachia show Korean strains and Japanese strains are largely monophyletic indicating prior infection before the host divergence. The strain diversity of the phage is also surprisingly high. Phylogenies of orf2 and orf7 genes are incongruent to that of Wolbachia and geographically distinct. This indicates that the phage is spatially static and the current infection pattern may be the consequence of local repeated gain and loss of the phage.