The effects of parasitism by the daughter sporocyst of Cercaria bucephalopsis haimaena Lacaze-Duthiers, 1854, on the digestive tubules of the cockle, Cardium edule L.

Abstract

The effects of parasitism by the daughter sporocyst of Cercaria bucephalopsis haimaena Lacaze-Duthiers, 1854, on the digestive cells of Cardium edule L. was investigated by comparing histochemically stained cells in healthy and parasitized animals. Two effects were apparent: (a) the branches of the daughter sporocysts compress the walls of the digestive gland ducts and tubules, and cut off the more distal tubule cells from their food supply, inducing starvation autolysis, (b) in digestive tubule cells not so cut off, glucose, glycogen, glycoproteins, phospholipid and proteolipid food storage globules and acid mucopolysaccharide are reduced. Neutral lipids, fatty acids, alkaline phosphatase, acid phosphatase and non-specific esterase are increased and there is also a compensatory increase in the number of food vacuoles. In the visceral haemocoel, in the neighbourhood of the parasite, glucose, fatty acids, neutral lipids and acid mucopolysaccharide are increased and glycogen reduced.We are grateful to Professor E. W. Knight-Jones, for helpful comments and good working facilities, and to the Science Research Council, for the grant of a research studentships to one of us (E.A.B.).