Preliminary observations on the timing and geometry of foraging activity in the intertidal pulmonate limpet Siphonaria pectinata

Abstract

Siphonaria pectinata (Mollusca: Gastropoda) at Gibraltar foraged when exposed continuously or intermittently to air, when the relative humidity at the rock surface exceeded 75%. The paths followed by individual limpets were either single or compound loops beginning and ending at a home scar. In the main, outward and inward tracks were independent and there was little evidence of trail following. Siphonaria pectinata exhibited a range of crawling speeds but spent much of the excursion stationary or moving very slowly. Both duration of excursion and maximum foraging distance were very variable. No correlation between the size of S. pectinata and the duration of the excursion was apparent. The timing of activity may reflect an adaptive response designed to provide enough time to forage while avoiding predation, desiccation and dislodgement by waves.