Individual organisms face trade-offs when dealing with predation—more time spent avoiding predators often results in less time allocated to energy acquisition and reproductive-related activities. Individuals that optimize this trade-off and respond appropriately to current risk levels in their environment should be at an advantage. What is less clear is whether this tradeoff changes when individuals are repeatedly exposed to a predation threat. There may be advantages to responding consistently to every signal of threat, but it might also be advantageous to modulate individual behavior. Moreover, it is unclear how evolutionary history of a population might affect such individual responses. Our study was designed to address two questions: (1) how do B. rhabdophora respond to repeated exposures of a predation cue; and (2) do repeated responses differ based on evolutionary history? To answer these questions, we used a predation cue stimulus to repeatedly expose B. rhabdophora individuals from both high- and low-predation populations. We measured the change in total distance traveled in a 15-minute trial before and after each cue exposure, and then compared the proportional change in response to the first cue to that of each successive cue (repeated four times) to see if a decrease in response occurred. We found that fish responded consistently to each cue exposure. Both populations showed similar decreases in activity in response to each exposure and did not return to normal baseline activity until the cue was removed from the test tank. That both high- and low-predation populations respond consistently to repeated cues of predation with no reinforcement prompts questions as to the potential importance of the relative length of risk and safe periods in affecting response variation. It also provides a starting point in understanding how recent risk exposure and the evolutionary history of risk in a population both interact to influence individual response to threats over time.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-11193 |
| Date | 12 December 2022 |
| Creators | Nate, Madeleine S. |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | https://lib.byu.edu/about/copyright/ |
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