Effects of habitat complexity, dominance and personality on habitat selection: Ideal despotic cichlids

Habitat structure can impede visibility and movement, resulting in lower resource monopolization and aggression. Consequently, dominant individuals may prefer open habitats to maximize resource gain, or complex habitats to minimize predation risk. We explored the role of dominance on foraging, aggression and habitat choice using convict cichlids (Amatitlania nigrofasciata) in a two-patch ideal free distribution experiment. Groups of six fish of four distinct sizes first competed for shrimp in one-patch trials in both an open and complex habitat; half the groups experienced each habitat type first. Following these one-patch trials, each group then chose between habitat types in a two-patch trial while competing for food. Finally, each fish underwent an individual behavioural assessment using a battery of "personality" tests to determine if behaviour when alone accurately reflected behaviour within a social context. In the one-patch trials, dominant fish showed similar food consumption between habitats, but chased more in the complex habitat. In the two-patch choice trials, dominants preferred and defended the complex habitat, forming an ideal despotic distribution with more than half the fish and competitive weight in the open habitat. Within the groups, individual fish differed in foraging and chasing, with repeatabilities of 0.45 and 0.23 across all treatments. Although a higher foraging rate during the individual assessment predicted foraging rate and use of the complex habitat during the group trials, aggression and boldness tests were not reflective of group behaviour. Across groups, heavier dominants and those with higher foraging rate in the open habitat used the open habitat more, suggesting that both risk and energetic state affect habitat preference in dominant convict cichlids.