Semen Evaluation from Dominant Males of the Viviparous Mexican Lizard Sceloporus torquatus, Wiegmann, 1828 (Sauria: Phrynosomatidae)

While most lizard species are polygamous, dominant males typically have greater access to females and copulate more frequently than submissive ones. Several studies suggest that applying assisted reproduction techniques to this taxon could be an effective tool to enhance conservation programs. Therefore, the proper selection of males for assisted breeding programs is crucial for their overall success. In this study, we report for the first time data on semen and sperm quality from dominant males of the Mexican lizard <i>Sceloporus torquatus</i> using techniques commonly employed in assessing mammalian fertility. The semen and sperm characteristics were as follows: volume, 14.0 µL; sperm concentration, 125.7 × 10⁶ cells/mL; wave motion, 2.7; total motility, 87.8%; sperm viability, 89.0%; normal morphology, 88.8%; plasma membrane integrity, 87.7%; low plasma membrane fluidity, 94.9%; capacitation status: uncapacitated (F), 90.5%; capacitated (B), 7.2%; sperm with acrosome reaction (AR), 2.3%; and, acrosome integrity, 88.8%. These results suggest that, according to mammalian fertility parameters, dominant males of <i>S. torquatus</i> are fertile. This series of tests provides a valuable tool for conducting a comprehensive analysis of the functional changes that may occur in sperm handling during assisted processes, and that may contribute-along with the proper selection of individuals-to reproductive success.