The influence of dominance on shelter preference and eviction rates in the crayfish, Orconectes rusticus

The establishment and reinforcement of dominance status is thought to provide an individual with increased access to preferred resources, such as food, mates, and shelter. Resources within an environment vary based on their availability, abundance, and specific characteristics of the resource. Animals can exhibit preferences for resources by increasing the intensity of competition for access to the resource. We investigated the role that dominance has in acquiring and controlling resources within crayfish populations. Populations of 5 size-matched crayfish were allowed to establish a social hierarchy in the presence of shelters of differing structure in 10 different trials. Crayfish agonistic interactions and the use and control of shelters were quantified from 96 h continuous video recordings. Shelter preference was defined by crayfish use of specific shelter types that were occupied for longer durations. Analysis of the social hierarchy demonstrated that crayfish have a linearity hierarchy in this context. In addition, it is clear that dominance rank had a significant impact on shelter use, shelter acquisition, and shelter eviction. Crayfish with lower average dominance ranks selected specific shelter types (smaller and fewer openings). Dominant crayfish used big shelters and were less likely to be evicted from shelters. These results demonstrate that dominance in crayfish serves a role in the acquisition of resources and is also important for the control of those resources.