Date of Award:

5-2026

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Committee Chair(s)

Susannah S. French (Committee Chair), John B. Iverson (Committee Co-Chair)

Committee

Susannah S. French

Committee

John B. Iverson

Committee

Karen M. Kapheim

Committee

Kezia Manlove

Committee

Charles R. Knapp

Abstract

The lifespan and reproduction of an animal depends on maintaining a healthy physiology. The proportion of individuals that survive to an age at which procreation can occur is important to long-term stability of populations and contributes to species survival. Health in an animal is measured in a variety of ways, including through monitoring of the body’s physiological systems, as well as its ability to respond to invading pathogens, and through the different types of bacteria present in the gut. Relationships among those different health metrics have been discovered in recent years and have been found to play important roles in maintaining a healthy physiology. The body’s systems can by impacted in a variety of ways, including drastic changes in diet. Dietary changes can happen naturally but can also be “forced” by things like habitat destruction, over-hunting, or direct feeding by humans. Such challenges can impact population dynamics. In an island chain in the Bahamas, tourists have been feeding populations of endangered iguanas food that is not a part of their normal diet. These iguanas typically consume fruits and leaves found on the islands. In the past few decades, tourists visits to these islands has increased and the tourists have been feeding the iguanas a variety of foods including bread, lettuce, grapes, and all kinds of “leftovers” from meals. To understand how these changes in diet are impacting the health of these iguana populations, we monitored their physiology, gut microbiome and immune response over several years. We were able to compare these health metrics across populations that were fed and those that have not been fed by tourists. It was clear from our study that these populations differed in their physiology and gut microbiome, and some physiology measures differed from year to year. We also uncovered differences between males and females, and between reproductive females and non-reproductive females. Finally, we were able to compare health across different ages, and discovered differences in hormone levels and the gut microbiome associated with growth and development in the earlier years of life. Overall, we were able to elucidate complexities of animal health and a continuing need to monitor populations to inform ongoing species conservation efforts.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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