Graduation Semester and Year
Spring 2026
Language
English
Document Type
Thesis
Degree Name
Master of Science in Biology
Department
Biology
First Advisor
Matthew Walsh
Second Advisor
Marcus Lee
Third Advisor
Walter Schargel
Abstract
The ability to camouflage is a widespread trait in both vertebrates and invertebrates that enhances survival in risky environments. The ability of organisms to respond to shifts in environmental conditions and change color is a conspicuous example of camouflage. Such coloration plasticity can occur rapidly (seconds to minutes) versus longer periods of time (days to months). There are numerous examples of physiological coloration plasticity (short-term) and morphological coloration plasticity (long-term). Yet, there are few tests of the conditions that drive the evolution of physiological vs. morphological coloration plasticity. In this study we use Trinidadian killifish (Anablepsoides hartii) as a model to study the long-term coloration plasticity among populations from sites that differ in predation intensity. We recently found that killifish from sites with predators are darker in coloration compared to fish from sites that lack predators. In this study, we exposed killifish from sites with and without predators to light and dark backgrounds for several months. If there is a significant component of morphological plasticity to the expression of color, then we hypothesized the differences in coloration will increase over time. Our findings show that an accumulation of changes in color occur in killifish that are exposed to different backgrounds over a long time period. Such results illustrate a morphological component of coloration plasticity. However, our results did reveal consistent differences in coloration between the contrasting predation regimes. The differences in coloration between the sites with and without predators varied between the color backgrounds and replicate streams. Thus, increased predation is not associated with consistent shifts in morphological coloration and the morphological coloration plasticity is maintained in the complete absence of predators. This study also gives insight into the various factors that influence color plasticity, suggesting that complex interactions exist to drive these adaptations.
Keywords
color, predator-prey interactions, plasticity, morphological plasticity, evolved traits
Disciplines
Ecology and Evolutionary Biology
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Laux, Alyssa M., "TESTING THE INFLUENCE OF INCREASED PREDATION ON THE EVOLUTION OF MORPHOLOGICAL COLORATION PLASTICITY IN TRINIDADIAN KILLIFISH (ANABLEPSOIDES HARTII)" (2026). Biology Theses. 2.
https://mavmatrix.uta.edu/biology_theses2/2