Quelques aspects des mécanismes nutritionnels chez l’isopode cymothoidae : Ceratothoa oestroides (Risso, 1826)

Abstract

Some nutritional mechanisms of the isopod Cymothoidae Ceratothoa oestroides, haematophagic parasite of the teleostean sparid fish Boops boops have been studied in female sexual phase individuals. The study of qualitative (hepatopancreas repletion, different colouration) and quantitative variations (weight variations-) of digestive tract and its appendages has permitted to observe that blood absorption is close related to sexual developmental stages and intermolt cycle. The general pattern seems as follows: food intake is made prior or just before vitellogenesis and after releasing of "pulli". The use of ingested nutriments and reserves allow vitellogenesis and intramarsupium larval development. We have also tried to investigate if it does exist a mechanism starting blood absorption and attempted to elucidate its nature. A such mechanism seems indeed to exist, it might have been partially dependent upon a stimulus such as osmotic pressure or ionic composition of host blood. Moreover, chemoreceptors activity is envisaged those could likely occur as bucal appendages, bucal cavity or even the oesophagian region of parasites.