Physiological Effects of Tail Regeneration following Autotomy in Italian Wall Lizards, Podarcis siculus

Abstract. Caudal autotomy (the voluntary loss of a tail) is an important antipredator defense in many lizard species. The subsequent regrowth of the tail, seen in most lizards with the ability to autotomize, may pose some physiological costs both during the regrowth process and during potential repeated autotomy. In this study, we examined the physiology and behavior of the lacertid lizard Podarcis siculus, as well as the physiology and activity of the detached tails, following autotomy. Evaporative water loss and respiratory exchange ratio increased after autotomy, showing both an increased loss and a redistribution of important resources inside the animal. The lizards exhibited no change in behavioral thermoregulation during regrowth, as thermal preference did not change. Males and females differed in tail energy content, suggesting differing energy storage needs between the sexes. The rate of regeneration and tail movement between the sexes were not different, but tail movement did vary between previously regenerated tails and original tails, indicating a possible detriment to future autotomy events. Overall, autotomy appears to influence more than just a lizard's ability to escape, as our study provides evidence of potential physiological tradeoffs associated with this antipredator behavior.