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Taxonomy and ecology of parasites on zooplankton, in particular, copepods

浮游动物，特别是桡足类寄生虫的分类学和生态学

基本信息

批准号：
14560151
负责人：
OHTSUKA Susumu
金额：
$ 2.3万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The host-specificity, ultra-structure and life-cycle of the apostome ciliate Vampyrophyra pelagica parasitic on pelagic copepods were studied in the Seto Inland Sea. Completion of its life cycle usually needs feeding by invertebrate predators such as chaetognaths on copepods with phoronts of the ciliates. In contrast predation by fish larvae was not involved in it. Cilia of the ciliates are formed within the phoront, which guarantees quick excystation. Numerous thick membranes detected in the cytoplasm are considered to be precursors of food vacuole membranes of the trophont, and totally disappeared in the fully-grown cell. The morphology of the cytostome was newly revealed with SEM and TEM. Relationships between water temperature and duration of each stage of the ciliate were investigated in the laboratory. The maximum time from phoront hatching to tomite appearance at the lowest temperature (10℃) was nearly 20 times as long as the minimum time at the highest temperature (25℃), which seems to be caused by prolongation of the tomont. Apostome phoronts were broadly found from copepods collected from oceanic islands, deep-sea hyperbenthic layers, and brackish waters. This strongly suggests their paramount importance in marine food webs.A nicothoid copepod and an epicaridean isopod were newly described from the marsupium of the mysid Siriella okadai in the Seto Inland Sea. The maximum incidences of these parasites were up to 11 and 19 %, respectively. These parasites may compete severely with the same habitat and food.Intersex individuals of the shrimp Acetes sibogae and the mysid Siriella japonica izuensis were discovered, in the latter of which it seems to have been caused by infection of ellobiopsids. The occurrence of the dinoflagellate Oodinium inlandicum on pelagic chaetognaths in Korean and of the ellobiopsid Thalassomyces marsupii on the amphipod Scina vosseleri were also reported for the first time.

研究了泽东内海寄生于中上层桡足类上的纤毛虫Vampyroporra pelagica的寄主专一性、超微结构和生活史。其生命周期的完成通常需要无脊椎动物捕食者的摄食，例如具有纤毛虫附着体的桡足类上的毛喉虫。相比之下，鱼类幼体的捕食没有参与其中。纤毛虫的纤毛在纤毛体内形成，这保证了快速的激发作用。在细胞质中检测到的大量厚膜被认为是营养体的食物液泡膜的前体，并在完全生长的细胞中完全消失。用扫描电子显微镜和透射电子显微镜观察了细胞气孔的新形态。在实验室内研究了水温与纤毛虫各阶段历时的关系。在最低温度(10℃)下，白云母从孵化到出现绒毛的最长时间是在最高温度(25℃)下最短时间的近20倍，这可能是由于白云母的延长所致。使徒型藻类广泛存在于从海洋岛屿、深海超底栖动物和微咸水中采集的桡足类动物中。这有力地表明了它们在海洋食物链中的至高无上的重要性。在内海的Mysid Siriella okadai的有袋类中新描述了一种尼古丁类桡足类动物和一种表观等足类动物。这些寄生虫的最高发病率分别高达11%和19%。这些寄生虫可能会在相同的栖息地和食物上激烈竞争。发现了西伯利亚对虾和日本小天牛的两性个体，后者似乎是由伊氏杆菌感染引起的。还首次报道了在韩国远洋毛鞘上发现的南方甲藻Ooddium inlandicum和在端足类Scina vosseleri上发现的弹状生物--海链霉菌Marsupii。