Effects of Stressors on the Development and Resilience of Adult Fish Behavior
Open Access
- Author:
- Miller, Sharmaine Larue
- Graduate Program:
- Biology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- March 15, 2019
- Committee Members:
- Victoria Anne Braithwaite-Read, Dissertation Advisor/Co-Advisor
James Harold Marden, Committee Chair/Co-Chair
Tracy Langkilde, Committee Member
Sonia Angele Cavigelli, Committee Member
Sonia Angele Cavigelli, Outside Member - Keywords:
- fish behavior
temperament
stress
environmental context
predictability
facial recognition - Abstract:
- Stressful experiences, whether encountered at certain stages of development or throughout life, can have a profound impact on an animal’s future behavior. How these stressors affect the animal can be influenced by the future environments an animal finds itself in. If an animal experiences an environment that matches its stressful rearing environment, the animal may have an advantage because it is already physiologically and behaviorally adapted to these conditions. On the other hand, a mismatched environment (one without stressors) may put a developmentally stressed individual at a disadvantage. This concept, known as the match/mismatch hypothesis, has recently been investigated in mammals, but little is known about these kinds of processes in fish. With their relatively simpler nervous system, and the ability to study populations in the field and in captivity, fish could be an interesting taxonomic group in which to investigate the effects of the match/mismatch phenomenon. My dissertation investigates how a fish's developmental and evolutionary ecology affect its future temperament and coping style in different environmental contexts. First, I investigated the effect of a brief exposure to stress in early-life on future, adult exploration behavior in guppies (Poecilia reticulata). I found that fish descended from a wild-caught Trinidad population behaved differently to fish bred from a domesticated population. Exposing guppies to stressors during development changed how the fish explored a novel environment as adults, and their behaviors varied depending on whether they were tested in a threatening, or a non-threatening context. Together, these results demonstrate that adult behavior can be influenced both by an animal’s background (descended from a wild or a domesticated strain) as well as its early life experience. Following on from this, I conducted a field project with wild Panamanian bishop fish (Brachyrhaphis episcopi) to examine context-dependent stress-related behavioral responses. Using populations that varied in how much experience they had with predation throughout life, I investigated anxiety-related behaviors in bishop fish from high and low predation sites. The fish were tested in a novel tank diving test before or after exposure to an acute confinement stressor. I found that low predation fish behaved more anxiously compared to high predation fish and that this was consistent after exposure to the acute stressor. In a second study, I examined how varying levels of predation exposure affected exploration behavior in terms of how bishop fish responded towards two different kinds of object. Depending on stream origin, populations were found to differ in how they explored a novel arena and objects within it. Together, these results highlight how local ecology and contrasting experiences of predation threat promote different levels of anxiety, and they also affect how the fish respond to novelty. In a final study, I investigated how the appraisal of specific stimuli influences zebrafish (Danio reio) behavior. Here, I tested whether the fish could learn to discriminate between two humans and associate them with either a positive or a negative experience. I found that zebrafish not only distinguished between two different people, but they were also able to correctly assign a particular role to each person. These results suggest that giving human caretakers specific roles in fish research laboratories could help the fish prepare for different kinds of experience, e.g. feeding versus handling. My dissertation illustrates how factors, such as evolutionary background and stress exposure affect future adult behavior and stress-coping responses. Moreover, the context in which a fish finds itself; i.e., safe or threatening, rewarding or aversive, can alter how it responds based on its previous experience. My results also have implications for the welfare of captive populations, and indicate that the captive environment can be made more predictable by giving individual caretakers specific husbandry roles.