Dewlap Color Variation and Male Visual Grasp Response Across Populations in a Neotropical Lizard

Authors: Janelle Talavera, Lindsey Swierk, Thomas Powell

Field of Study: Science, Technology, Engineering, and/or Math

Program Affiliation: NSF GRFP Swierk Lab and Powell Lab

Faculty Mentors: Lindsey Swierk, Thomas Powell

Easel: 81

Timeslot: Midday

Abstract: The sensory drive hypothesis proposes that signals evolve to be most effective in their respective environment, and that the receiver’s sensory systems in that environment should evolve to match those signals. Differences in sexual signals and sensory systems in adjacent habitats may operate as isolating mechanisms. Male Anolis lizards have brightly colored dewlaps that they use for communication. Anolis aquaticus, a Costa Rican species that exhibits intraspecific variation, was studied as populations’ dewlaps vary in redness or yellowness. It is hypothesized that this variation is shaped by sensory drive and facilitates species isolation in A. aquaticus. Visual modeling was used to simulate anole vision, model dewlap conspicuousness to A. aquaticus, conduct visual grasp response (VGR) trials, and employ ddRADSeq genotyping. It was found that “yellow-ness” of a dewlap varies among populations and larger males respond to yellow stimuli more than smaller males. However, preliminary VGR results currently do not support the sensory drive facilitating isolation hypothesis.