Ohio Wesleyan University 1 article published in JoVE Neuroscience Assays to Detect UV-reflecting Structures and Determine their Importance in Mate Preference using the Sailfin Molly Poecilia latipinna Shala J. Hankison1, Meredith S. Palmer2 1Department of Zoology, Ohio Wesleyan University, 2Department of Ecology, Evolution, & Behavior, University of Minnesota This protocol outlines the use of spectrophotometry to detect ultraviolet-reflecting structures on organisms (in this example, the sailfin molly Poecilia latipinna) and describes dichotomous choice tests for fish that allow inferences to be made on the role of ultraviolet cues during mate selection.