HOMING PATTERN, ACTIVITY AREA AND TRAIL FOLLOWING OF THE HIGH SHORE MEDITERRANEAN LIMPET PATELLA-RUSTICA L (MOLLUSCA GASTROPODA)

Motographic recordings using time-lapse photography have been carried out on the intertidal limpet Patella rustica on the boulders of a brea kwater in central Italy. The reconstruction and analysis of the indivi dual paths allowed a detailed description of the geometry of foraging excursions of this algal grazer. P. rustica at Cala Galera showed a co nsistent homing pattern and reuse of the same home scar over long peri ods. Foraging excursions were scattered around the scar, but longest e xcursions were upwardly polarized, minimizing the overlap of grazing a rea with respect to other species (P. caerulea and P. aspera) coexisti ng on the same shore. The segmental analysis of the foraging routes po inted out a typical tri-phasic pattern of activity: relatively fast ou tward trip, slow and randomly oriented grazing in the central part of the path, and fast locomotor activity during the homeward lag. Limpets showed an extensive use of intra-individual trail following during th e return phase of each excursion, while very low overlap appeared betw een successive excursions of the same individual. On the other hand, t he long term monitoring of spatial activity showed a persistent fideli ty to the home scar and relative constancy of the individual feeding a rea.