Crayfish establish dominance through aggressive encounters and display dominance and submissiveness through posturing. The neural circuitry involved in posturing utilizes the neurotransmitters seratonin and octopamine (Livingstone et. al 1980, Kravitz 1988, Huber et. Al. 1997). The neurophysiological effect of these neurotransmitters can be either excitatory or inhibitory depending on the social status of the individual (Yen et. al. 1996, 1997). In this series of experiments, students design behavioral scenarios to test their predictions using variables such as size, sex, resident/intruder status, and prior social experience. Using knowledge of neurotransmitter actions in the tail-flip escape response, students generate hypotheses concerning neurotransmitter levels and behavioral manifestations in dominant and subordinate crayfish. Previously, (Conley, 1999; SFN abs#104.24), students investigating the effects of elevated octopamine on dominant and submissive behaviors find that octopamine injection causes ...