Honors Program


Document Type


Date of this Version



Hill, M. M. 2024. Analyzing Phototaxis and Related Visual Behaviors Among Diverse Species of Drosophila. Undergraduate Honors Thesis. University of Nebraska-Lincoln.


Copyright Madeline M Hill 2024


Phototaxis and related visual behaviors can vary between species, and thus members of the genus Drosophila make an excellent study system to examine the evolution of vision. While some existing research points to these phototactic behaviors arising due to mating requirements or due to their species-specific ecology or environmental factors, there exists a lack of understanding as to why striking behavioral differences can exist between closely related species, or between members belonging to the same genus. The present research seeks to uncover the specifics regarding these discrepancies in visual evolution and aims to provide a foundation of knowledge about visual behaviors for these flies. Here, 14 species of Drosophila were exposed to a Y-tube behavioral choice assay, with each terminal end providing a distinct difference in light or darkness, allowing the fly to make a phototactic choice. It was found that there was variability in the choice itself as well as the time to make a choice, including across species within both the melanogaster and the obscura groups. While most melanogaster group species were found to prefer light, there was still variability to the degree to which light was preferred, along with how long each species took to choose between light and dark. The obscura group was more variable in their preferences between light and dark but took less time on average to choose when compared to the melanogaster group. Reasons for these differences can potentially be explained by a variety of factors, including ecology, courtship, and neurobiology – which are discussed in this thesis.