Oocyte and embryonic development, size at sexual maturity, and spawning season of Charybdis bimaculata
Oocyte and embryonic development, size at sexual maturity, and spawning season of Charybdis bimaculata
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双斑轮虫的卵母细胞和胚胎发育、性成熟时的大小和产卵季节
DOI：
10.1007/s12562-022-01601-5
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发表时间：
2022
影响因子：
1.9
通讯作者：
Ohtomi Jun
中科院分区：
文献类型：
--
作者：
Nawer Fairuz;Doi Wataru;Ohtomi Jun
本研究首次对双斑？雌虫的卵母细胞和胚胎发育以及性成熟时的大小进行了全面的研究。2018年10月至2020年1月，在日本南部鹿儿岛湾中部地区共采集了1211只雌性。组织学检查证实卵母细胞有6个连续的发育阶段，双斑库蚊的卵巢发育为异步型。因此，从卵巢中发现的最晚期卵母细胞确定卵巢成熟状态（未成熟、成熟和成熟）。具有证明生殖囊泡破裂或迁移核的卵母细胞的雌性被定义为成熟的。成熟的女性从19.0至30.6毫米的甲壳宽度。性成熟时的大小估计为21.8毫米的甲壳宽度的基础上的50%的成熟大小。产卵季节确定为5~11月，成熟雌鱼出现。显微镜观察证实了四个连续的胚胎发育阶段。大多数具有最后阶段胚胎的雌性具有成熟的卵巢，这意味着生殖的连续性。不同步型卵巢，连续繁殖，连续育雏表明在一个产卵季节多次产卵。双斑隐翅虫的潜伏期在1个月以内。
This study describes the first thorough investigation of oocyte and embryonic development as well as histologically confirmed size at sexual maturity of femaleCharybdis bimaculata. A total of 1211 females were collected from the central part of Kagoshima Bay, southern Japan, from October 2018 to January 2020. Six sequential oocyte developmental stages were confirmed by histological examination.C. bimaculataexhibited asynchronous-type ovarian development. Therefore, ovarian maturity status (immature, maturing, and mature) was determined from the most advanced oocyte found in the ovary. Females having oocytes evidencing either germinal vesicle breakdown or migratory nucleus were defined as mature. Mature females ranged from 19.0 to 30.6 mm in carapace width. The size at sexual maturity was estimated to be 21.8 mm in carapace width based on the 50% maturity size. The spawning season was determined from May to November when mature females occurred. Microscopic observation confirmed four sequential embryonic developmental stages. The majority of females with final-stage embryos had mature ovaries signifying continuity of reproduction. Asynchronous-type ovary, continuous reproduction, and consecutive broods suggest multiple spawning in a single spawning season. The incubation period was estimated to be under 1 month forC. bimaculata.