Studies on life cycle of a protogynous crustacean, Gnorimosphaeroma naktongense

原生甲壳动物 Naktongense Gnorimosphaeroma naktongense 生命周期的研究

• 批准号: 10640611
• 负责人: FUKUHARA Haruo
• 金额: $ 1.28万
• 依托单位: NIIGATA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640611/
• 关键词: Gnorimosphaeroma naktongense; Gnorimospaeroma chinense; sex chage; Protogynous hermaphroditism; Life cycle; Adaptation; Crustacea; Ecological distribution; 電気泳動; 比生性先熟性雌雄同体; イソコツブムシ類; 大卵小産; 汽水

The distribution and the life cycle of a protogynous hermaphroditic crustacean, Gnorimosphaeroma naktongense were investigated in two regions of fresh-water (L. Koikuchino-ike, Aomori Pref.) and brackish-water (Agano River, Niigata Pref.) bodies. This species was distributed in lakes along sea and rivers with brackish water, but they are entering in the part of pure fresh waters in the side of the Sea of Japan, for instance they live in a spring named as the Jimoto Spring, Niigata Prefecture. But in the side of the Pacific ocean, they were not found in the upper part of the river like as Kitakami River (Iwate Pref.). It was suggested that G. chinense which is dweller in brackish waters in the side of the Sea of Japan take a part of G. naktongense in the side of the Pacific ocean. G. nakotngense has two generations, summer generation starting from June and autumn starting from October, in brackish waters, though in fresh waters there is one clear generation starting from June. Detail analysis of sex-change pattern shows they are females in first reproductive season (about 1 year), and after they released their childrens, manca larvae, they change sex from females to males, and they have next reproductive season after about one year. They indicate clear sexual dimorphism, males are larger than female in body weight, and they have a inclination that larger males mate with larger females in many cases, or a size assorting mate system. Laboratory experiments indicated this phenomenon has been maintained in the cause that a larger male selects a larger female in precopula guarding, and a male changes his guarding female with a larger female, sometimes a sole larger male take out a female from a guarding couple. Populations inhabiting in fresh waters produced less clutch size than in brackish waters, but no change was observed in egg size between two populations. This suggests that populations inhabitiong freshwaters have not completely adapted in fresh water environments.

在淡水（青森县小口野池）和咸水（新泻县阿贺野河）两个地区对原生雌雄同体甲壳动物 Gnorimosphaeroma naktongense 的分布和生命周期进行了调查。该物种分布于沿海湖泊和微咸水的河流中，但现在正在进入日本海一侧的纯淡水部分，例如它们生活在新泻县名为本泉的泉水中。但在太平洋一侧，像北上川（岩手县）那样的河流上游并没有发现它们。有人提出，生活在日本海一侧的咸水水域的中国G.chinense 是太平洋一侧的G.naktongense 的一部分。 G. nakotngense 在咸水中有两代，夏季一代从 6 月开始，秋季从 10 月开始，但在淡水中，从 6 月开始有明显一代。对变性模式的详细分析表明，它们在第一个繁殖季节（约1年）为雌性，在释放其后代曼卡幼虫后，由雌性变为雄性，约1年后进入下一个繁殖季节。它们表现出明显的两性二态性，雄性体重大于雌性，并且在许多情况下倾向于较大的雄性与较大的雌性交配，或者是体型分类的交配系统。实验室实验表明，这种现象之所以得以维持，是因为在前系羽守卫中，体型较大的雄性会选择体型较大的雌性，而雄性则用体型较大的雌性替换其守卫的雌性，有时，体型较大的雄性会从守卫的一对雌性中夺走一只雌性。生活在淡水中的种群所产下的窝数小于咸水中的种群，但两个种群之间的蛋大小没有变化。这表明居住在淡水中的种群尚未完全适应淡水环境。

项目成果

福原晴夫: "宍道湖におけるコツブムシ科3種の分布"陸水学雑誌. 61(予定). (2000)

Haruo Fukuhara：“宍道湖三种精子科的分布”《湖沼学杂志》61（计划）（2000 年）。

Fukuhara, H., M. Abe and N. Kimura: "Distribution of three species of Sphaeromatidae in L. Shinji"Jpn. J. Limnology. 61 : (in print). (2000)

Fukuhara, H.、M. Abe 和 N. Kimura：“L. Shinji 中三种球菌科的分布”Jpn。

福原 晴夫: "甲殻類における性転換"海洋と生物. 121. 487-494 (1999)

Haruo Fukuhara：“甲壳类动物的性别变化”海洋和生物科学 121. 487-494 (1999)。

阿部 正敏: "阿賀野川下流域におけるイソコツブムシ属2種,Gnorimosphaeroma naktongenseとG.chinenseの分布"新潟県生物教育研究会誌. 34. 9-12 (1999)

阿部正敏：“阿贺野川下游的两种 Gnorimosphaeroma naktongense 和 G.chinense 物种的分布”新泻县生物教育研究会杂志 34. 9-12 (1999)。

Fukuhara, H.: "Sex change in Crustacea"Aquabiology. 21. 487-494 (1999)

Fukuhara, H.：“甲壳类动物的性别变化”水生生物学。