The effects of defeat on future aggressive interactions in the crayfish, Orconectes propinquus.

Abstract

Crayfish which have been defeated in an aggressive interaction have been observed to be more likely to lose in following interactions. This study attempted to verify and describe these trends of losing after a defeat. I tested the percentage of fights lost 10 minutes, 1 hour, and 24 hours after losing a fight. The null hypothesis was that time elapsed after a fight would have no effect on the probability of a crayfish losing future fights. The data did not show significant differences between the percentage of wins and losses after the three time intervals, but there was a trend for the percentage of losses to decrease as time after the losing interaction increased. This effect, while not statistically significant, does corroborate with previous observations of crayfish aggressive behavior. It may be one of the ways in which territorial boundaries and dominance hierarchies are maintained in the crayfish population.