Consequences of social dominance on crayfish resource use

Our study examined the effect of dominance on feeding, mating behaviour, and shelter use in the crayfish, Orconectes rusticus. In three different experiments, dominance and resource use were recorded in male populations, mixed-sex populations, and when crayfish were alone. Crayfish established dominance status in populations or through status conditioning and had access to variable resources (food, mates, and/or shelters) in each experiment. Subsequent resource use was quantified and compared to dominance rank. Our results did not match conventional predictions that dominance would confer increased access to resources. Top ranked dominant crayfish occupied shelter significantly less than lower ranks. This differential shelter use may be due to dominant motivation to reinforce status, as dominants also participated in the most agonistic interactions. When dominant crayfish had access to resources in the absence of conspecifics, dominant crayfish occupied shelter significantly more than subordinate and naive crayfish. This result illustrates that present social context has a significant impact on behavioural decisions in crayfish. Social history and social context interact to determine shelter occupancy in this case. Feeding and mating was unaffected by social status in our populations. This is a surprising result given current views on the role of dominance and aggression in many animal systems. The consequences of dominance for resource use in crayfish do not follow our current understanding of resource holding potential. We hypothesize that these consequences vary due to changing behavioural motivations in different social contexts. Future studies should examine under which conditions dominance may impact feeding and mating and whether differential resource use results in differential reproductive success.