Tau-Fluvalinate Inhibits the Molting Process of Lizards ( Eremias argus ) by Disrupting Thyroid Hormone Signaling

Molting is a critical physiological process essential for lizard growth and survival, primarily regulated by the thyroid system. The potential risks of pyrethroids, as known thyroid disruptors, on ecdysis in lizards remain poorly understood. This study examined the impact of Tau-fluvalinate (FA) on the molting process of lizard (Eremias argus) at 1, 5, and 50 mg/kg soil doses. High-dose FA exposure reduced the incidence of skin shedding and prolonged the ecdysis duration in lizards. Histopathological analysis revealed a significant dose-dependent reduction in the thickness of live strata in lizard skin, along with significant alterations in the key ecdysone-regulated genes in the FA-exposed groups. Mechanistically, FA inhibits molting dynamics and skin cell proliferation as a potential thyroid receptor antagonist by disrupting thyroid hormone signaling. Given the importance of molting for lizard survival, these findings highlight the need to reevaluate the ecological risks of thyroid-disrupting pesticides on lizards.