Feeding in some monogenean skin parasites: Entobdella soleae on solea solea and Acanthocotyle Sp. on Raia clavata

Abstract

Entobdella soleae, a monogenean skin parasite of the common sole was induced to feed on its host. The feeding organ (,pharynx-) is protruded during feeding and encloses a circular area of host skin. The gland cells in the feeding organ produce a proteolytic secretion which digests the epidermis of the fish. The liquid food is then pumped by the feeding organ into the intestinal diverticula, where it is absorbed.Acanthocotyle sp. from the skin of an elasmobranch fish, Raia clavata, feeds on epidermis in the same way as Entobdella soleae. Observations on other skin and gill-parasitic monopisthocotylineans indicate that the majority of them are epidermis feeders, although there is evidence that some gill parasites, for example Amphibdella torpedinis, may feed on blood.The evolution of parasitism in the Monogenea is tentatively attributed to the outstanding qualities offish epidermis as a food for a potential ectoparasite and in particular to its rapid rate of regeneration.