The Opposite Effects of Atrazine and Warming on the Reproductive Processes in Female Lizards (<i>Eremias argus</i>): Potential Roles of Hypothalamic–Pituitary–Gonadal Axis Regulation and Energy Metabolism

Declines in reptile populations due to climate warming and environmental pollution have been documented. Although recent ecotoxicological studies of reptiles have increased, little is known about how these two stressors interact to affect reptile reproductive processes. This study investigated the single and combined effects of atrazine and warming on reproduction in female lizards (<i>Eremias argus</i>) following 10 weeks of exposure to environmentally relevant concentrations of atrazine (0-10 mg·kg^-1) at two temperature treatments (control or warming). Reproductive traits, clutch characteristics, and endpoints related to endocrine disruption (HPG axis gene expression) and energy metabolism (enzyme activity, hepatic metabolomics) were assessed. Atrazine inhibits female reproduction by disrupting HPG axis-related gene expression and energy metabolism, resulting in delayed spawning time and reduced fecundity. In contrast, warming promoted female reproduction and partly alleviated the inhibitory effects of atrazine, which is related to the upregulation of HPG axis-related gene expression and an additional energy metabolism compensatory response. Additionally, atrazine and/or warming altered the direction and intensity of the trade-off between egg number and size and affected maternal nutritional investment in eggs. These findings highlight the complex interplay of environmental stressors on lizard reproduction and add to a better understanding of reptile reproductive strategies and ecological consequences under environmental stress.