A FIELD TECHNIQUE FOR RECORDING THE ACTIVITY OF LIMPETS

A field technique for recording both temporal and spatial parametersof activity in limpets was tested on a Tyrrhenian populationof Patella rustica Linnaeus which shows definite homing behaviour.Timing of foraging excursions was recorded using reed switchesactivated by a magnet glued to the shell apex. The ‘lsquo;athome-away’ status of each animal was continuously screenedthroughout one month by interfacing the sensors with a computer.Moreover, individual excursions were minutely reconstructedby using a moto-graphic technique which combined LED-tracking(nocturnal activity) and instantaneous photography (daytimemovements). An original wave-meter was designed to monitor thesea-status during the study period. The quality of the temporaland spatial data obtained with this technique is evaluated,and further improvements of the technique are discussed. (Received 24 October 1989; accepted 25 January 1990)