ADAMS, J.A.*; MOORE, P.A.: The effect of molt status on fight dynamics in the crayfish, Orconectes rusticus

Many animals participate in agonistic interactions to acquire shelter or gain access to food or mates. Success in these interactions is highly dependent upon physical features such as body and weapon size. For crustaceans, individuals must undergo molting to increase in size and to possibly gain an advantage in future combats. During the molting process, the succession of events in an agonistic interaction may change due to physical or chemical changes in the animal, including the shedding of the hard exoskeleton and alterations in physiology. We hypothesized that this stereotyped succession of events would be altered in crayfish (Orconectes rusticus) when one of the individuals has recently undergone ecdysis. Size-matched males were forced to interact for 15 minutes in a fight chamber while videotaped from above. Pair-wise interactions were arranged between recently molted (M) and intermolt (I) crayfish for a total of three treatments (M-M, M-I, I-I) with 10 replicates per treatment. Parameters measured were duration of fight, time to specific intensities, and number of encounters in the first five minutes. These parameters were analyzed using a MANOVA. There were no significant differences between any treatments for any of the parameters. Therefore, at this stage of the molt cycle (stage A), the process of molting has no affect on the fight dynamics of crayfish when they are forced to interact. Immediately following ecdysis, crayfish may spend more time hiding and avoiding conflicts. However, when molted individuals are forced to participate, the fights still follow the same stereotypical pattern seen in intermolt contests.