台灣匙指蝦類體表兩種外共生蛭蚓目及切頭類之共棲

Cohabitation of Ectosymbiotic Branchiobdellida (Annelida, Clitellata) and Scutarielloidae (Platyhelminthes, Rhabditophora, Temnocephalida) on Atyid Shrimps in Taiwan

在台灣5個樣站，共採集458隻匙指蝦類個體，其中，3個樣站發現兩種生態上相似但通常具地理區隔的蛭蚓目branchiobdellidans（Annelida），Holtodrilus truncatus及切頭類temnocephalidans（Platyhelminthes），Scutariella japonica於匙指蝦體表上共生。這3個樣站中的2個樣站，其匙指蝦類同一檢體上共棲著該2種體表寄生的物種。觀察這2種體表寄生的物種彼此並無相互影響的現象。H. truncatus之數量與宿主蝦體大小有統計上顯著正相關；但S. japonica則否。

Occurrences of two ecologically similar but normally geographically separated ectosymbionts, branchiobdellidans (Annelida) and temnocephalidans (Platyhelminthes), were studied on 458 atyid shrimps collected from five localities in Taiwan. The shrimps, Neocaridina spp. and Caridina pseudodenticulata, carried a scutariellid temnocephalidan, Scutariella japonica, at three localities, while a branchiobdellidan, Holtodrilus truncatus, was found at two of the three localities where it co-inhabited with S. japonica. No negative or positive interactions toward each other were observed. Statistically significant larger numbers of branchiobdellidans were found on larger shrimps, while such a tendency was not detected in S. japonica.