Publication Date

2010-05-12

Availability

Open access

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Biology (Arts and Sciences)

Date of Defense

April 2010

First Committee Member

Richard Tokarz - Committee Chair

Second Committee Member

Keith Waddington - Committee Member

Third Committee Member

William Searcy - Committee Member

Fourth Committee Member

Manuel Leal - Outside Committee Member

Abstract

Males of the Mexican lizard Sceloporus minor (Phrynosomatidae) exhibit striking variation in dorsal coloration, both within and among populations, which may have arisen by sexual selection. The possible significance of this trait was investigated through a combination of observational and experimental approaches. This research revealed that males in one population (La Manzana) in NW Hidalgo exhibit three discrete color morphs (blue, yellow, red) each characterized by morphological, physiological and behavioral differences. Furthermore, these morphs can be identified by an objective approach to color assessment (spectroradiometry). In addition, males in a second population (Escalerillas) from SE San Luis Potosí were also found to occur in at least two color morphs (yellow and red), suggesting that color polymorphism may be general in this species. The hypothesis of sensory exploitation by male contest competition was tested for S. minor from Escalerillas; however, no support for this hypothesis was found. Overall, results from this study are consistent with the hypothesis of alternative reproductive tactics in S. minor.

Keywords

Sceloporus Minor; Color Polymorphism; Sexual Selection; Alternative Reproductive Tactics

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