Sexual and Asexual Reproduction of the Tropical Corallimorpharian Rhodactis (=Discosoma) indosinensis (Cnidaria: Corallimorpharia) in Taiwan

臺灣產印支圓盤擬珊瑚海葵之有性及無性生殖

陳昭倫(A. Chao-Lun Chen) ； 陳章波(Chang-Po Chen) ； 陳一鳴(I-Ming Chen)

《Zoological Studies》 34卷1期 (1995/01) Pp. 29-40

摘要

從1988年到1990年在台灣南部萬里桐低潮線附近淺水域研究印支圓盤擬珊瑚海葵生殖學。印支圓盤擬珊瑚海葵為群集性生物，在研究地點形成3個大群集。在有性生殖方面：印支圓盤擬珊瑚海葵為雌雄異體，卵發育需要9個月，精子發育需要3個月。成熟卵直徑為850微米。卵與精子皆在5月成熟，而在5～6月間釋放配子。本研究記錄印支圓盤擬珊瑚海葵三種無性生殖方式：縱分裂、反口出芽及雙口裂。其中後兩種無性生殖方式未曾在花蟲綱報導過。縱分裂為印支圓盤擬珊瑚海葵主要的無性生殖方式，發生在口盤直徑大於50毫米的個體，生殖高峰在夏季。反口出芽為次要的無性生殖方式，發生在口盤直徑大於30毫米的個體，生殖高峰在冬、春之際。雙口裂只偶然發生。無性生殖起始於高潮位的群集及無性生殖頻度高峰出現在水溫回昇時，是以推測環境因子中水溫可能影響無性生殖的發生。

關鍵字

生殖周期 ； 配子發生

並列摘要

Reproduction of the tropical corallimorpharian Rhodactis ( =Oiscosoma) indosinensis Carlgren 1943, was studied for two years (1988-1990) in shallow waters off Wanglitung, southern Taiwan. Rhodactis indosinensis occurred gregariously, and formed three large aggregations in the study site. R. indosinensis is gonochoristic. Oogenesis takes about nine months, while spermatogenesis three months. Mature eggs are large (maximum diameter 850 I'm). Both sperm and eggs matured in May and spawning occurred between May and June. Three modes of asexual reproduction, i.e., longitudinal fission, inverse budding, and two-mouth fission, were recorded; the latter two have not been reported previously for anthozoans. Longitudinal fission is the dominant mode and occurs with high frequency during summer in polyps greater than 50 mm in oral disc diameter. Inverse budding is the second most common mode, occuring in the period between winter and spring in polyps from 30 to 60 mm in oral disc diameter. Two-mouth fission occurs only occasionally. Asexual reproduction occurred earlier in the aggregation located near the shore, and the frequency of asexual reproduction was higher when water temperature increased, suggesting that environmental factors (e.g., temperature) affect the onset of asexual reproduction in R. indosinensis.

並列關鍵字

Reproductive periodicity ； Gametogenesis