Observations on the development of Bunodera luciopercae (Müller, 1776) (Trematoda: Allocreadiidae) under field and laboratory conditions

Abstract

Abstract. The intramolluscan development of Bunodera luciopercae was studied in laboratory infected pisidia maintained at three thermal regimes and compared with the seasonal development within a population of naturally infected first intermediate hosts at Llyn Tegid, Wales. At 4–8°C B. luciopercae did not develop beyond the sporocyst stage, although the development at 16–21°C We s similar to that reported by previous workers. The early stages of the intramolluscan development of B. luciopercae at Llyn Tegid were similar to the observed development at 16–21°C. However, the results suggest that falling autumn‐winter temperatures may initiate the production of immature cercariae within first generation rediae. Cercariae matured and were shed at Llyn Tegid during a short period between March and May. Live, juvenile B. luciopercae were artificially transferred from recently killed perch Perca fluviatilis, gill netted from Llyn Tegid, into live uninfected, laboratory maintained perch. The effect of temperature on the development of B. luciopercae in its definitive host was investigated at four thermal regimes. At 16–20°C development did not proceed normally and the infection had disappeared after 130 days. At 4–8°C and at natural environmental temperatures, gravid flukes were produced after 158–168 days. An increase in temperature on infected fish maintained at 4–8°C for 43 days did not stimulate parasite maturation. It is suggested that B. luciopercae may require an extended period of vernalization to elicit maturation in its definitive host and that temperature has a major influence on the life history of this parasite.