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In this study, we investigated the color-changing capabilities of Trinidadian killifish, Anablepsoides hartii, through exposure to varied color conditions over defined periods of time. Our experiment aims to understand adaptive responses when killifish are subjected to different color backgrounds, exploring their mechanisms to change color. By subjecting the species to different environmental color variations, we sought to discern color change patterns, which could indicate adaptive responses related to camouflage, stress, behavior clues, and physiological adjustments. Carefully controlling environmental factors, we monitored and documented the fishes’ color changes, aiming to provide insights into the interplay between fish’s developmental plasticity and its ability to respond to diverse environmental stimuli. This research contributes to our understanding of complex interactions between environmental factors and the phenotypic expression of Trinidadian Killifish, thus shedding light on their potential to exhibit crypsis in nature. In this study, 62 first generation lab reared Trinidadian killifish from the Arima River were housed in tanks with either white or black background color. Fish were immobilized for photography, and landmarks were placed for shape and color calibration. Image processing techniques were used to analyze color profiles, and data analysis involved Principal Component Analysis (PCA), two-sample t-tests, and linear modeling to assess the impact of background color and sex on color variation. Another short-term experiment was conducted on killifish to test whether A. hartii could rapidly respond to changes in substrate color. Results identified principal components 1-2 as pivotal in primary patterns of color variation among the killifish population. There were distinct differences in body coloration between the killifish reared on light versus dark backgrounds with no overlap, supporting that they are undergoing plasticity to match the color of their background. Sex was found to play a small role in color change, while weak evidence was found for the role of familial groups in phenotypic plasticity, background color emerges as a predominant factor influencing color variance in shaping PC1. Results showed that fish placed in black backgrounds significantly changed color, while fish in white and orange backgrounds did not. These results provide empirical support that plasticity plays a role in killifish populations to match their respective background color. Having made the first scientific documentation of Trinidadian killifish undergoing color change, our findings suggest the v need for further research to explore how phenotypic plasticity influences their evolution in the presence of predators


Animal Experimentation and Research | Aquaculture and Fisheries | Integrative Biology | Laboratory and Basic Science Research | Marine Biology | Zoology

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Faculty Mentor of Honors Project



I am deeply grateful to Dr. Matthew Walsh for extending to me the opportunity to work in his lab at The University of Texas at Arlington and for his invaluable mentorship throughout my research. Dr. Walsh's support and guidance have been instrumental, and I will always appreciate the excellent opportunity he provided me. I also wish to express my heartfelt gratitude to Mr. Marcus Lee, my Ph.D. mentor, for his unwavering assistance and guidance throughout the research process. Mr. Lee's training in laboratory techniques and his mentorship have been crucial to the success of this experiment. I am immensely thankful for his patience and dedication in imparting essential knowledge to me, as well as for the thorough preparation he provided my last semester, which equipped me to navigate the complexities of our projects in the laboratory. Furthermore, I extend my sincere appreciation to the Department of Biology for providing me with a conducive working environment. Lastly, I am deeply indebted to my parents, friends, and peers for their unwavering moral support throughout my time in the lab. Their encouragement has been invaluable on this journey.


Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.



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