Fight strategies differ with size and allometric growth of claws in crayfish, Orconectes rusticus

This study examines differences in fighting strategies between small and large male crayfish, Orconectes rusticus. Due to allometric growth of claws, fighting weapons are of disproportionate size in large crayfish compared to those in smaller individuals. Presumably, such differences in the prominence of claws are reflected in differences in the likelihood of injuries, and we thus explored fighting in size-matched pairs of small or large crayfish and assessed associated strategies in situations of conflict. Although fighting reached the highest intensities in a similar proportion of instances in small and large pairs, differences in fighting strategies were evident. Small crayfish escalated more rapidly, fights were settled more quickly, and were resolved overall at lower intensities. This may be explained by lower risks of injury compared to encounters among larger males due to proportionally smaller claws. Larger males thus appear to spend considerably more time in assessing their opponent's fighting ability before each escalation event.