HABITAT SELECTION BY 2 MEDITERRANEAN SPECIES OF APLYSIA - APLYSIA-FASCIATA POIRET AND APLYSIA-DEPILANS GMELIN (MOLLUSCA, OPISTHOBRANCHIA)

Factors influencing habitat selection were examined in 2 spp. of Mediterranean Aplysia. Animals and egg masses were found in 4 types of habitats that varied in degree of exposure to wave action. Both species were frequently found in groups. Neither species was common in areas cut off from the surge of the sea. No difference in food preference was observed. A. depilans-Gmelin were primarily found in areas subject to greater wave action, while A. fasciata Poiret dominated the calmer habitats. Both species were common in intermediate environments. In late summer, when A. depilans are absent, A. fasciata penetrated some environments previously dominated by the former. Morphological and behavioral features of A. depilans and A. fasciata are consistent with adaptation to rough and calm habitats, respectively.