Date of Award
Bachelor of Science
lizard, behavior, color, pattern, speciation
Anolis is a genus of fairly common lizards; over 300 species of Anolis inhabit areas close to the equator. One of their most unique features is the dewlap, a colorful throat fan that the lizards can extend and contract to denote certain behaviors. Dewlap color and pattern varies between species, and therefore aids in species identification. For this reason, color vision and color discrimination is especially important in Anolis lizards. Over a 10-week period a series of training experiments using color markers were done with four lizards of the Anolis sagrei species. The lizards were trained to move a color marker of a trained color and uncover a worm (2 were trained to orange, 2 to blue). In the second set of experiments, a second color marker was introduced which was a series of 4 color markers in a color span ranging from a similar color to the trained marker to a very different color. It was predicted that the lizards would make more errors when the two markers were close in color, and fewer errors when the color marker was more different. Two potential patterns were predicted: as the colors got more different the number of errors made would gradually decrease, or, once the color markers could be discriminated the number of errors would significantly decrease and that value would stay constant as the two colors became increasingly different. The findings of this experiment give physical results to support or contradict predictions made by anoline eye computer models, and contribute to a deeper understanding of the driving force of dewlap color evolution. Future experiments can be done with a larger sample size, and with color markers that eliminate brightness as a factor.
Singleton, Rachael A., "Color Vision and Color Discrimination in Anolis sagrei" (2011). Honors Theses. 1064.