Luttbeg, BernardAguiar, Olivia K.2024-10-182024-10-182024-07https://hdl.handle.net/20.500.14446/345057Animals are exposed to different types of stressors throughout their lives. Stressors can range from temperature, competition, and predation risk. These stressors can occur with varying frequency and an individual may be exposed to multiple types of stress at the same time. This thesis endeavored to investigate how risk responses change with experience and if there is any relationship between different types of risk responses. In Chapter 1 I investigated how Physa acuta predation risk responses change with age and number of previous exposures. I studied risk responses through behavior by measuring time to exit water after being exposed to predator cue. I found that previous experience did not impact predation risk responses, but age did. Predation risk responses grew stronger as individuals became older, becoming strongest just before onset of reproduction. This result provides support for the asset protection principle. I also found that there were consistent individual differences in how individuals responded to predation risk, suggesting that individual identity is an important component of predation risk responses. Because of these results, I suggest that future investigations of predation risk responses control for age and consider individual identity. In Chapter 2 I compared the previous trends of predation risk responses to a toxicant risk response to determine if fear generalization was present, and investigated if exposure to multiple stressors at once affected risk responses. I found that P. acuta responded in similar ways to predation risk and atrazine risk. Responses to both types of risk became stronger as individuals became older and consistent individual differences were present. Individuals exposed to both types of risk during the experiment had a weaker negative relationship between age and time to exit water. However, responses to predation risk and atrazine risk were not correlated within individuals, suggesting that fear generalization was not present. I suggest that future investigations of fear generalization include multiple measures of behavior and consider weaker concentrations of atrazine than those used in this thesis. Overall, this thesis provided evidence that the asset protection principle may be driving risk responses, and although fear generalization was not supported it did demonstrate that there are similarities in trends between different types of risk responses.application/pdfCopyright is held by the author who has granted the Oklahoma State University Library the non-exclusive right to share this material in its institutional repository. Contact Digital Library Services at lib-dls@okstate.edu or 405-744-9161 for the permission policy on the use, reproduction or distribution of this material.Thesis