The Behavior of Gammarus sp. When Exposed to Predation Cues

• Main Authors: Ellis, Will A, Chapman, Trevor, Bidwell, Joseph
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2017
• Subjects: amphipod; gammarus; kairomone; alarm; cue; predatory; Life Sciences
• Online Access: https://dc.etsu.edu/honors/377; https://dc.etsu.edu/cgi/viewcontent.cgi?article=1431&context=honors

Predator avoidance behaviors are a critical defense mechanism that can increase the chances of survival for potential prey species. We tested the avoidance behavior of the freshwater amphipod, Gammerus sp., under two different chemical predation cues. The first was the presence of kairomone, which was derived from a species of fish, Gambusia affinis, that was fed a diet exclusively of amphipods. The second predation cue was potential alarm cue derived from macerated conspecific amphipods from the same population as the test species. Response variables included time spent moving after the introduction to the signal as well as the time spent in refuge. Movement of amphipods significantly decreased and time spent in refuge significantly increased when amphipods were exposed to alarm cue as compared to control organisms that received no exposure to predation cues. Exposure to the fish kairomone treatments significantly increased time spent in the refuge but did not significantly influence time spent moving during the trials. These results suggest that amphipods exhibit predator avoidance behavior primarily when there is evidence that an attack has occurred (evidenced by the death of conspecifics within the population), but will also demonstrate avoidance behaviors to a lesser degree when a predator is detected.