瘤蜷（Tarebia granifera Lamarck, 1822）原產於東南亞，是一種以孤雌生殖（parthenogenetic）及卵胎生（ovoviviparous）方式產生子代的淡水螺。瘤蜷經由人為的傳播，已經快速擴散到世界各地，並威脅當地原生種的生存。瘤蜷是多種複殖性吸蟲（digenetic trematodes）的第一中間宿主。自2003年4月至2004年1月間，我們以台東縣金崙溪的瘤蜷為材料，進行季節性的採樣，解剖其育幼囊，計算各期胚胎的數量。並且在夏季及冬季進行母螺排放子螺的實驗，以及育螺在育幼囊外存活的狀況。另一方面，調查金崙溪瘤蜷寄生蟲的感染率，並探討寄生蟲對於瘤蜷生殖方面造成的影響。
在四個不同季節中採樣解剖的結果，發現採樣區之瘤蜷一年四季皆處於生殖狀態，四季中的胚胎組成相似，但以秋季的孕育量最大，春天最少。相對於冬天而言，夏季排出的子螺數量較多但體型較小，並且低溫會抑制排子螺的行為。從育幼囊取出的育螺除殼高0.25∼0.5mm這組的存活率偏低外，其他較大的育螺在母體外存活率均接近100％。檢查247隻金崙溪的瘤蜷，37隻感染寄生蟲，感染率為15％。大的個體（殼高大於20mm）感染率顯著大於小的個體。感染寄生蟲的瘤蜷懷孕的機率以及懷孕量顯著小於未感染的個體。
歸納以上結果可得知：季節的變化和寄生蟲感染與否會對野外的瘤蜷的生殖力造成影響。溫度會改變母螺的生殖行為。母螺與育幼囊內較大的育螺間除了有親代對子代持續的照顧（extended parental care）外，亦存在著利益衝突（parent-offspring fitness conflict）的關係。

Tarebia granifera is an ovoviviparous and parthenogenetic freshwater snail indigenous to South East Asia. T. granifera was introduced into many areas of the world as a result of human activity and caused detrimental effects on native freshwater snails. T. granifera also served as the first intermediate hosts of many digenetic trematodes.
Specimens of T. granifera were collected seasonally in Jinlun River, S.E. Taiwan, from April, 2003 to January, 2004. The embryo composition in the brood pouches was compared among seasons. We found the species was fertile and the embryo composition was similar throughout the year. The maximum embryo number occurred in October, 2003, and the minimum occurred in January, 2004. T. granifera was reared to compare juvenile releasing rates in summer and winter. More juveniles were released per mother-snail in summer than in winter. And low water temperature seemed to inhibit juvenile release in cold days. The survival rates of brooded juveniles outside brood pouches were tested. Except the smallest size group (shell height=0.25~0.50mm), all others (0.5~1.25mm) had high survival rates approaching 100%. About 15% of the snails were infested by unidentified xiphidiocercariae. Larger snails were more likely to be infected and the infected snails were less likely to be fertile than uninfected ones.

目次 頁碼
壹、前言--------------------------------------------------1
貳、材料與方法--------------------------------------------5
實驗一：不同季節，母螺的育螺狀況----------------------5
實驗二：季節對產螺數量、大小的關係--------------------6
實驗三：育螺在母體外的存活率與成長率------------------6
實驗四：寄生蟲對瘤蜷生殖的影響------------------------7
實驗五：金崙溪瘤蜷受寄生蟲感染的狀況------------------7
參、實驗結果----------------------------------------------8
實驗一：不同季節，母螺的育螺狀況----------------------8
實驗二：季節對產螺數量、大小的關係--------------------9
實驗三：育螺在母體外的存活率與成長率------------------9
實驗四：寄生蟲對瘤蜷生殖的影響-----------------------10
實驗五：金崙溪瘤蜷受寄生蟲感染的狀況-----------------11
肆、討論與結論-------------------------------------------12
伍、參考文獻---------------------------------------------19
圖-------------------------------------------------------26
表-------------------------------------------------------43
附錄1、母螺的殼高與殼寬關係圖----------------------------48
附錄2-1、四個季節，個體E/T期胚胎數量散佈圖---------------49
附錄2-2、四個季節，個體E/T期平均胚胎量比較圖-------------50
附錄2-3、四個季節，個體V期胚胎數量散佈圖-----------------51
附錄2-4、四個季節，個體V期平均胚胎量比較圖---------------52
附錄2-5、四個季節，個體S期胚胎數量散佈圖-----------------53
附錄2-6、四個季節，個體S期平均胚胎量比較圖---------------54
附錄2-7、四個季節，個體J期胚胎數量散佈圖-----------------55
附錄2-8、四個季節，個體J期平均胚胎量比較圖---------------56

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