Queue selection and switching by false clown anemonefish, Amphiprion ocellaris

Abstract

Social groups of false clown anemonefish have been described as queues because, following settlement, fish acquire social rank passively by outliving more dominant groupmates. Within each queue, reproduction is restricted to the dominant pair. Therefore, individuals should adopt tactics that maximize their likelihood of attaining social dominance. Field observations indicated that, independent of an anemone's size, postlarval false clowns are more likely to settle to an anemone if the resident group is smaller, suggesting that settlers prefer shorter queues. Some individuals (switchers) moved postsettlement. There was no indication that false clowns use switching as a tactic to enhance rank: characteristics of switching and nonswitching false clowns did not differ, and switching rarely resulted in improved social rank within the new group. Some high-ranked switchers acquired larger partners. Thus, while settlement preferences increased the likelihood of acquiring social dominance, switching may function, in part, to increase the benefit associated with social dominance once it has been acquired.