Gametogenesis in the Imposex-affected Oyster Drills, Thais Clavigera and Thais rufotincta

雌性雄化之蚵岩螺及紅棕岩螺的生殖腺發育變異

鄭青怡(Ching-Yi Cheng) ； 劉莉蓮(Li-Lian Liu)

《臺灣水產學會刊》 31卷1期 (2004/03) Pp. 55-65

https://doi.org/10.29822/JFST.200403.0005

摘要

本實驗研究蚵岩螺(Thais clavigera)及紅棕岩螺(T. rufotincta)生殖腺發育是否受雌性雄化影響而有變異存在。樣本採集於台灣西海岸－香山、台西、布袋、七股和東港；研究發現所有蚵岩螺族群均有雌性雄化現象，所謂雌性雄化(imposex)，是指在雌雄異體的腹足類雌螺身上發現長有雄性的生殖構造。雌性雄化的程度以相對陰莖指數(RPS-Relative Penis Size)來看，蚵岩螺的雌性雄化程度較紅棕岩螺高，分別是9-28%與0-1%。在蚵岩螺和紅棕岩螺的生殖腺組織發現，雄螺精巢組織內曲細精管裡有各發育階段的精細胞，雌螺卵巢也充滿了成熟的卵細胞，但香山和布袋蚵岩螺的卵巢內發現有血細胞，而雌性雄化之紅棕岩螺的生殖形態未發現異常現象。過去研究發現嚴重雌性雄化會導致蚵岩螺生殖開口阻塞，造成雌螺無法產下卵鞘；研究則顯示雄化雌螺不具卵精巢組織及由雌轉雄的性轉變現象。

關鍵字

雌性雄化 ； 蚵岩螺 ； 紅棕岩螺 ； 生殖腺發育

並列摘要

Histological examination on gonads of Thais clavigera and T. rufotincta was conducted to evaluate the possible reproductive abnormality caused by imposex. Snails were collected from the west coast of Taiwan, including Shunsun, Taishi, Budai, Chiku and Tungkang. For T. clavigera, females from all of the surveyed populations have shown 'imposex' which refers to the development of additional male sex organs in females. The relative penis sizes (RPS values) of T. clavigera were greater than T. rufotincta, i.e. 9-28% vs. 0-1%, indicating a high degree of imposex in T. clavigera. Histological studies in T. clavigera and T. rufotincta showed that male testis tissues from all sampling sites contained sperm cells in various developing stages. In the ovary, there was no obvious abnormality in the imposex-affected T. rufotincta. However, some haemocytes were found in the ovary tissues of T. clavigera from Shunsun and Budai. Although the development of imposex and sterilization causing by the blockage of female opening are reported, the phenomena of ov o-testis and sex change do not occur in the species of Thais.

並列關鍵字

Imposex ； Thais clavigera ； Thais rufotincta ； Gametogenesis