Ecology of the Leptoconchus spp. (Gastropoda, Coralliophilidae) infesting Fungiidae (Anthozoa, Madreporaria)

Papua New Guinea (Laing Island, Madang and Motupore), Singapore, the Maldives (Ari Atoll and South Male Atoll), the Red Sea (Hurghada), Indonesia (Makassar, Sulawesi) and examination of I ,000 fungi ids from museum collections (mainly, National Museum of Natural History, Leiden) have shown that 36 coral species were infested by several species of Coralliophilidae belonging to the genus Leptoconchus. The rate of infestation of the mushroom coral assemblage varied from 0 to 7%. The two most infested Fungiidae were Fungia ( Fungia) fimgites and F. (Verril/ofimgia) repanda. At the east side of-Laing Island, F. (F.) fimgites reached an infestation rate of 19%, the highest value ever recorded. The rate of infestation was positively correlated with hydrodynamics and negatively with turbidity. It was, however, not correlated with the density of the fungiid assemblage. Infestation was maximum in shallow water (1 -5 m); nearly no Leptoconchus spp. were found deeper than 20 m. Place of settlement of the mollusc (coral centre or edge), opening of the burrow (oral/aboral side of the coral) and deformation of coral skeleton varied according to the coral species infested. These variations seemed specifically related to the different Leptoconclws species rather than the infested host species.