Meeting Abstract
Individual recognition is important for maintaining stable social hierarchies and minimizing aggression intensity. While status recognition facilitates discrimination based on individual behavior that resulted from prior winning or losing experience, it does not assume individual discrimination. In crustaceans, evidence for individual recognition is scarce. The goal of our study was to assess whether crayfish Orconectes obscurus can recognize individuals based on previous experience with the individual, and not social status. We examined the ability of O. obscurus to distinguish between previously known opponents and unknown opponents of the same status. After a one week isolation period, two individuals were placed in a tank and allowed to establish dominance in a familiarization trial. Once dominance was established, the opponents were isolated for another week. At the end of this isolation period each individual was paired with 3 opponents; 1) known opponent from the familiarization trial, 2) an unknown opponent of the same status as known opponent, and 3) naïve individual. Order of opponent presentation was randomized. We compared average fight durations and aggression levels in familiarization trials to subsequent fights. While fight duration between known and unknown opponents did not differ significantly, aggression intensity reflected extent of previous experience with opponents. Dominants exhibited less aggression towards known subordinates than towards unknown subordinates or naïve individuals. Subordinate individuals exhibited least aggression towards known dominants, while aggression towards unknown opponents varied. Our preliminary data suggest that O. obscurus can distinguish between individuals of different status, but can also distinguish between individuals based on previous social experience.
