GLOCHIDIAL HOSTS AND OTHER ASPECTS OF THE LIFE HISTORY OF THE CUMBERLAND PIGTOE (PLEUROBEMA GIBBERUM)

Abstract

Abstract The endangered Cumberland pigtoe is a small mussel endemic to the upper Caney Fork River drainage in middle Tennessee, USA. Gravid individuals were collected from late June through August. Conglutinates obtained from these individuals contained few glochidia and were composed primarily of unfertilized eggs. In the laboratory, 18 species of fish were exposed to glochidia, and metamorphosis occurred on telescope shiners and striped shiners 8 to 10 days later. Although conglutinates contained few (< 50) glochidia, ≥ 30% of the telescope shiners collected from the Collins River were infested with glochidia, and juvenile Cumberland pigtoes excysted from naturally-infested telescope shiners returned alive to the laboratory. The consistent predominance of unfertilized eggs in conglutinates of the Cumberland pigtoe and the high incidence of glochidia encysted on telescope shiners collected from the Collins River support the hypothesis that a high proportion of unfertilized eggs in conglutinates may be ad...