Relations between Eudendrium glomeratum (Cnidaria, Hydromedusae) and its associated vagile fauna
G. Bavestrello, C. Cerrano, R. Cattaneo-Vietti and M. Sarà
The vagile fauna associated with Eudendrium glomeratum Picard, 1958 (Cnidaria: Hydromedusae) has been studied on colonies growing from the beginning of the autumn to the end of the spring along the vertical cliff of the Portofino Promontory (Ligurian Sea). The mucus secretion of this species sticks sediment rich in organic matter extracted from the water column, and supports a large detritus-feeding assemblage. A relation between the amount of sediment collected by the E. glomeratum and the number of harpacticoid copepods living on it has been found. Interactions between the copepods and the hydroid are discussed. The presence of larva1 pycnogonids (protonymphon stages) in the hydranths, the commensalism of caprellids and the importance of the involvement of nudibranchs in the population dynamics of Eudendrium glomeratum are also considered.