Behaviour 2019
Individual rank and group-level social dominance pattern dynamics in monk parakeets: a perturbation experiment
Annemarie van der Marel, Elizabeth A Hobson. University of Cincinnati, Cincinnati, OH, United States

In species with dominance hierarchies, better-informed individuals could avoid fights they are unlikely to win. Species can use simpler (recognizing individual attributes) to more information-rich (emergent rank information) rules to infer rank. From agonistic interactions, 3 group-level social dominance patterns can emerge that differ in the level of social information: individuals randomly aggress toward others below self (downward heuristic), individuals preferentially aggress toward others much lower in rank (bullying) or nearby in rank (close competitors). We used experimental perturbations in monk parakeets (removal and reintroduction of individuals) to determine how individual ranks and group-level dominance patterns were affected and to test whether the social system was resilient or robust by these changes. The system would be resilient if individual ranks changed but dominance patterns remained the same, but robust if both rank and patterns remained stable. Using this experimental approach, we can determine how social upheaval might alter the information in groups and drive species to use simpler or more complex rules.