The emergence of cercariae of Trichobilharzia ocellata and its relationship to the activity of its snail host Lymnaea stagnalis

Publisher Website
Google Scholar
Abstract
The emergence pattern of cercariae of T. ocellata from L. stagnalis was examined at 2 h intervals from infected snails acclimatized to 12 h light-12 h dark periods. A marked diel pattern of emergence was found during the periods of illumination; this was reversed when the light-dark regime was reversed. A method for the continuous recording of the locomotory activity of L. stagnalis is described. Snails acclimatized to either normal or reversed dark-light regimes showed a consistent diel pattern of activity during illumination. Peak activity occurred in the first few hours of illumination. The diel activity pattern probably results from an internal rhythm in which the snail becomes entrained to the lighting regime. The close association between the diel activity pattern of the snail and the emergence of T. ocellata indicates that host movement stimulates cercarial emergence. Light may influence the cercariae directly and indirectly through the snail.

This publication has 7 references indexed in Scilit: