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University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

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Sensory mechanisms used by Rusty crayfish to determine between predator and prey.

Project Abstract: 
The purpose of this study is to understand how crayfish determine when another organism is their prey and when this other organism is their predator. Crayfish and crayfish share this relationship. When the catfish are small compared to the crayfish, crayfish will prey upon the catfish. When catfish are larger, crayfish are preyed upon by the catfish. At some point during the growth of both organism, the prey-predator relationship changes. We are investigating which senses are involved in the recognition of this change in relationship. We will do so by reversibly lesioning different senses in the crayfish and pairing those impaired crayfish with catfish of different sizes and observing the behavior of the crayfish toward the catfish. This study will provide insight on the decision making processes and sensory mechanisms that organisms use to determine whether another organism is prey or a predator.
Investigator(s): 
Ana M Jurcak
Paul Moore
Years Active: 
2012
Methods: 
There will be four different treatments in this study: Control, chemical lesion, visual lesion, and mechanical lesion. Within each treatment there will be three different sizes of catfish that crayfish will encounter: smaller than the crayfish, same size as the crayfish and larger than the crayfish. Each treatment will have 30 trials, 10 trials for each size of catfish. The total number of trials for this study will be 120. A naïve crayfish will be used for each trial to prevent any learning by the crayfish. The trials will last for 15 minutes each in an experimental arena which will be an open flow system. The behavior of the crayfish will be compared to a behavioral ethogram which will give each behavior a numerical value. The numerical values will be used in statistical analysis to compare between the treatments of lesions and size differences in catfish.