Date of Award

6-2014

Document Type

Open Access

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Leo Fleishman

Language

English

Keywords

lizard, species, cages, color, selection

Abstract

Lizards of the genus Anolis communicate through visual displays involving the opening and closing of an expandable flap of skin, called a dewlap, located on their throat. In some habitats up to ten species of Anolis are found in close proximity to one another. For a dewlap color to be effective an individual of the same species should be able to easily distinguish it from the dewlap color of other species located in the same habitat. We wanted to determine how different two colors must be in order to be reliably discriminated by an Anolis lizard. Lizards (Anolis sagrei) placed in small cages were presented with a flash of a small square of color, viewed against a background consisting of a gray scale checkerboard. We recorded whether or not lizards shifted their gaze toward the novel color as function of the distance in perceptual space between the stimulus color and the gray background. We found that lizard color discrimination increased as the distance in perceptual color space between the two stimuli increased. This suggests that selection pressures on dewlaps are in the direction of greater perceptual color difference between species.

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