MICROSTRUCTURE OF MOLLUSC SHELLS INFESTED WITH BORING POLYDORIDS (POLYCHAETA, SPIONIDAE) IN BARKLEY SOUND, VANCOUVER ISLAND, CANADA
Sato-Okoshi, W.
Laboratory of Aquatic Ecology, Division of Environmental Bioremediation, Graduate School of Agriculture, Sendai 981-8555, Japan
The microstructure of the shells of Hinnites giganteus, Ostrea lurida, Pododesmus cepic, Panopea generosa, Clinocardium nuttallii, Mytilus californianus, Haliotis kamtschatkana, Diodora aspera and Acmaea mitra that were infested with three polydorids, namely Polydora pygidialis, Dipolydora giardi and D. bidentata in Barkley Sound, Vancouver Island, Canada was studied. Scanning electron microscopy revealed many characteristic concentric-like holes on the surface of the self excavated burrows of all three species. These hols were distinctly observed especially in the foliated structure of Hinnites giganteus, Pododesmus cepio and Ostrea lurida and in the crossed-lamellar structure of Diodora aspera. These microstructural modifications were also observed previously in some other mollusc shells infested with some other polydorids in Japan, and they are discussed from the point of boring mechanism.