Term of Award
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (open access)
Department of Biology
Lance D. McBrayer
Committee Member 1
C. Ray Chandler
Committee Member 2
David C. Rostal
In territorial lizards, testosterone (T) has been suggested as a possible mediator of seasonal increases in endurance and bite force, which are important for maintaining territories and winning male-male competitions. Aspidoscelis sexlineata, a non-territorial lizard, has elevated bite force and endurance during the breeding season when T levels are elevated (Gowan 2008). Here, I investigated the effects of experimentally elevated T levels on bite force and endurance. Tonic-release implants elevated T levels for 2 weeks; however, they failed to increase performance during that time. Endurance decreased for all lizards in the lab study; suggesting that captivity negatively affects endurance. A second study was then conducted to examine the effects of training and T supplementation on locomotor performance in A. sexlineata. Training did not increase locomotor performance of male A. sexlineata; however, elevated T increased percent hematocrit. Ventral hue and testis volume decreased for all males in the second lab study, which may have been the result of chronic stress or the absence of environmental cues needed to induce or maintain breeding season condition. This study provides insight into the morphological and physiological traits under the influence of T in nonterritorial species.
O'Connor, Jennifer L., "Effects of Testosterone and Training on Performance in the Non-Territorial Lizard (Aspidoscelis Sexlineata)" (2009). Electronic Theses & Dissertations. 742.