The effect of temperature on the longevity of Trichobilharzia ocellata cercariae in laboratory conditions.

Abstract

Our experiment investigated the effect of temperature on the longevity of Trichobilharzia ocellata cercariae. Since cercariae emerge from their intermediate snail host in search of their definitive avian hosts, cercarial longevity affects trematode transmission success, which in turn influences abundance and distribution of host populations. Recently emerged cercariae were placed in three temperature intervals, 18.5°C, 23.5°C, and 28.5°C, representing low, intermediate, and high temperatures of Douglas Lake, Michigan; cercariae were counted in time intervals until death. Cercariae in high temperatures experienced significantly lower survivorship than low and intermediate temperatures. Cercariae in the 28.5°C temperature setting lived to a maximum of approximately 45 hours post-emergence, while cercariae in the 23.5°C and 18.5°C temperature settings lived approximately 70 hours post-emergence (at maximum). Observed trends were consistent with results from pervious studies.