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On the feeding and comparative biology of iron in coelenterate-associated gammaridean Amphipoda (Crustacea) from N. Norway

1994; Elsevier BV; Volume: 178; Issue: 2 Linguagem: Inglês

10.1016/0022-0981(94)90037-x

1879-1697

P. G. Moore, Philip S. Rainbow, Wim Vader,

Ichthyology and Marine Biology

Data are presented on the morphology of the mandible, morphometry of the stomach, composition of stomach contents, fine structure of the ventral caeca, and concentration of trace metals (Fe, Cu, Zn, Cd, Mn) in three species of coelenterophagous amphipod: Andaniexis sp. L (Stegocephalidae), Stenothoe brevicornis G.O. Sars (Stenothoidae) and Onisimus normani G.O. Sars (Lysianassidae) collected from sites off Tromsø, N. Norway. Andaniexis sp.L. has a blade-like incisor and highly distensible stomach compatible with functioning ecologically as a gluttonous batch processor of soft food. Stomachs in animals of this species from one site contained nematocyst-bearing soft tissue of coelenterate origin (identity not established) and sand grains, together with occasional polychaete remains. Andaniexis sp. L. from two sites differed in terms of their gut fullness and contribution of coelenterate material to the diet. Octahedral crystals of ferritin were variably present in cells of the ventral caeca; these crystals being a typical feature of the Fe detoxification system of stegocephalid amphipods. The Fe, Cu and Zn concentrations of Andaniexis sp. L., however, did not differ between sites. Stenothoe brevicomis also has a well developed, cutting incisor. This species, though, has a small stomach, compatible with its continuous association with its host sea anemone [Actinostola callosa (Verrill)]. Analysis of stomach contents showed that it can consume the tentacular tissue of Actinostola callosa. Onisimus normani, also has a blade-like incisor. It lives within the enteron of sea anemones (Actinostola callosa, Bolocera tuediae) and consumes mesenterial tissue. Although both Stenothoe brevicomis and Onisimus normani proved to have Fe concentrations which were no different from those in Andaniexis sp. L., only the last-mentioned species exhibited ferritin crystals. The reason for this difference in Fe handling strategy is presently unclear and may require knowledge of the Fe challenge posed by the unknown food organism of Andaniexis sp. L. in explanation. This stegocephalid genus is proving to be a less specific feeder on coelenterates than related genera which have been the subject of previous investigations. Calcium phosphate granules detoxify a range of potentially toxic trace metals including Fe in Andaniexis sp. L., Stenothoe brevicornis and Onisimus normani.