ИСТИНА

Polychaetes are abundant and often leading members of benthic communities known for habitat structuring. Many of the polychaetes build tubes or burrows secreting whole tubes or adhesives used for ground particles gluing. Protective buildings of investigated polychaetes vary greatly in morphological features and structure. Agglutinated tubes are built of tine ground particles such as sand, shell pieces, or silt, fastened together with matrix - organic cement. In the current study we investigated fine tube structure of 5 families members: Maldanidae, Pectinariidae, Oweniidae, Terebellidae, and Spionidae. We obtained SEM of the tubes and managed to classify tube structure types based on morphology diversity. Here we give data for 14 polychaete species. All the investigated tubes have the same organization plan. Inner surface of the tube is made of hardened organic pavement, secreted by the worm. On the outer side of the pavement, some filaments come off and blend into matrix fastening ground particles. Despite single organization plan, a few structure types were revealed. First type is characteristic to inner membrane (fine pavement easily separated from matrix) and outer tube part made of particles with matrix. This type was found in Maldanidae and Pectinariidae. Second type is shown for Oweniidae and Terebellidae polychaetes. Here matrix makes envelopes for each sand particle, and the inner membrane is also present. Members of Spionidae family build another type of tubes, with no membrane, substituted by thickened inner matrix layer. Fine particles in the outer layer are mixed with matrix, and larger particles are easily detached from the tube. We did not observe any correlation between type of tube and chaetal types. Probably, the tube structure correlates with the mode of its construction and arrangement of mucous glands over the worm’s body.