Activity Patterns in Siphonaria Populations

Résumé du livre

Directional choice and the effects of size and grazing frequency on activity were studied in the pulmonate limpets Siphonaria normalis Gould at Enewetak Atoll and S. alternata (Say) in Bermuda. Whenever individual limpets made a second grazing trip on the same tide, they avoided moving in the direction taken on the first trip. When a longer time interval separated two trips, heading choice on the second excursion was random. Headings within groups of siphonariid limpets active on the same tide were also randomly distributed. Infrequent grazers moved further per trip than their less sedentary neighbors at both sites in Bermuda; larger animals moved further than smaller ones at one of these sites. At Enewetak, there were no significant associations between distance and size or grazing interval. Frequency of movement and median time spent off scars remained unaffected by size at all sites, and there was no evidence that grazing frequency affected the length of time that limpets spent off scars.