Structure and Function of the Peritrophic Membranes of Copepods

Abstract

Peritrophic membranes are formed in all the 25 species examined. The peritrophic membranes of free-living and commensal notodelphyoid copepods are formed in the whole region of the mid-gut, whereas they are formed in the posterior region of the mid-gut in some cyclopoid associates of marine bivalves and parasitic copepods. The peritrophic membranes of free-living copepods are generally thicker than those of parasitic copepods. A chitosan test and histochemical and ultrastructural examinations revealed that the peritrophic membranes of free-living Tigriopus and parasitic Panaietis consist of chitinous microfibrils arranged in a disperse texture and a ground substance containing acid mucopolysaccharides and proteins, and chitinous microfibrils of Tigri-opus are much thicker than those of Panaietis. In Lernaea, faecal pellets are produced at considerably regular intervals. On the basis of these findings some possible roles of the peritrophic membranes of copepods are discussed. © 1988, The Japanese Society of Fisheries Science. All rights reserved.