マツカサガイのグロキディウム幼生の寄生生態

抄録

Availability of host fish for glochidia of the freshwater unionid mussel Pronodulariajapanensis was examined for the following eleven species of fish: Zacco temminckii, Phoxinus longowskii steindachneri, Gnathopogon elongatus elongatus, Pseudorasbora parva, Cyprinus carpio, Tanakia lanceolata, Acheilognathus tabira subsp. R, Misgurnus anguillicaudatus, Pseudobagrus tokiensis, Rhinogobius sp. OR and Gymnogobius urotaenia. The hosts to which the glochidia were attached in a paddy field ditch were cultured in tanks for seventeen days. Glochidia and juveniles which became detached from the hosts were counted daily. Juveniles appeared about nine days after glochidia attachment. Rhinogobius sp. OR, G. urotaenia, Z. temminckii and C. carpio were the most suitable hosts on which over 69% of attached glochidia metamorphosed to juveniles. Three hosts, G. e. elongatus, M. anguillicaudatus and Rhinogobius sp. OR, were investigated as to the position and number of attached glochidia. Most glochidia were attached to fish fins and gills. More glochidia were attached to Rhinogobius sp. OR than to the other species. However in the study ditch, M. anguillicaudatus was most numerous and therefore the major host species.