The life-cycle of Bucephalus haimeanus Lacaze-Duthiers, 1854 from Cardium edule L.

Abstract

Bucephalus haimeanus is shown to be an estuarine species. The cercaria from Cardium edule is briefly redescribed to include details of the nephridial system. The metacercaria is described for the first time, having been obtained experimentally in Pomatoschistus microps and Pleuronectes platessa. In Pomatoschistus microps it survives at least 10 months, development within this host being completed within 2 months. The main site of infection is the liver. Migration is completed within 1 h and in some instances within 10 min. During this period the metacercaria actively feeds on host tissue, the gut being greatly distended with food on encystment. A hyaline cyst wall is maintained throughout the remaining life of the metacercaria. ‘O’ group plaice are highly susceptible to invasion by B. haimeanus during early summer and 100% infections were recorded in catches from Ynys-las, Dovey Estuary, in June. Experiments showed that only 2% of the metacercariae survived more than two weeks and that ‘l’ group plaice were non-susceptible to infection. Plaice are therefore considered accidental hosts. The metacercaria was linked with the adult stage from Morone labrax on the basis of comparative morphology and the ecology of the hosts, the bass entering the estuarine habitat during the summer months. The adult is considered synonymous with Bucephalus minimus Stossich, 1887.