Dominance order and resting site fidelity in the intertidal pulmonate limpet Siphonaria sirius (Pilsbry)

Abstract

AbstractConsequences of ‘pushing contests’ between pairs of the intertidal pulmonate limpet Siphonaria sirius were analyzed, focusing on the relationship between dominance order and resting site fidelity. The pushing contests occurred near patches of Enteromorpha sp., their favorite algal food resource. Three or four dominance ranks were determined from the consequences of the contests in different seasons. Individuals in lower dominance ranks tended to shift their resting sites significantly more than those in higher ranks. The dominance order of limpets is considered to play an important role in migration by its effect on resting site fidelity. Density dependent dispersal, from the lower to the upper part of limpets' habitats, was observed in late summer to winter when desiccation was not a problem and food resources became abundant in less populated areas. In late spring to summer, however, migration was directed downwards, from less to more populated areas, where desiccation pressure was relatively weaker. This migration is considered to have a survival advantage, and the behavior of the limpets may have masked density‐dependent dispersal during the two seasons. Distribution of home site was also considered affected by aggressive social behavior during the two periods.