Mark Robert Sandfoss Natalie Claunch Andrea F. Currylow Ian A. Bartoszek Ian Easterling Amy A. Yackel Adams Christina Romagosa Gabriela Logo 2026 <p><span>South Florida's subtropical climate has facilitated the establishment of numerous invasive species, including the Burmese python (</span><i>Python bivittatus</i><span>). Despite decades of efforts to manage the invasive python population across South Florida, we lack a comprehensive understanding of their reproductive physiology, limiting the development of targeted control strategies. Here, we characterized seasonal patterns of testosterone (T) and corticosterone (CORT) in free-ranging adult male pythons and evaluated environmental correlates of hormone variation. Results indicate that T peaks before the onset of the breeding season and declines through the season to baseline levels in the non-breeding season. CORT did not show a clear seasonal trend but showed greater variability during the breeding season. These findings reveal that photoperiod and ambient temperature are key environmental correlates of male hormone cycles, contributing to our understanding of the endocrine phenology of a tropical ectotherm in a novel environment.</span></p> application/pdf 10.1016/j.ygcen.2026.114959 en Elsevier Characterizing the annual cycle of steroid hormones in males from an invasive vertebrate (Python bivittatus) of management concern article