Does tail autotomy affect thermoregulation in an accurately thermoregulating lizard? Lessons from a 2200‐m elevational gradient

Abstract

AbstractTail autotomy is an antipredatory defense that allows lizards to escape predator attacks by shedding their tails. While the benefits of preserving life are indisputable, tail loss implies a number of physiological, social, reproductive and even metabolic costs derived from tail regeneration and reduced motility. In addition, predation risk is increased in lizards with autotomized tails. Metabolic rates increase with body temperature, which in ectotherms depends on external heat sources. Ectotherm thermoregulation is costly in terms of time consumption and exposure to predators, this cost depending on habitat thermal quality. In this work, we seek to disentangle the effects of tail autotomy on field and selected body temperature of an accurately thermoregulating lizard Psammodromus algirus in different thermal environments along a 2200‐m elevational gradient. We test two non‐mutually exclusive hypotheses. According to a physiological hypothesis, we expect lizards with autotomized tails to show higher body temperatures that allow them to regenerate lost tissues faster, at least when the thermal environment is not limiting (at mid and low elevations). By contrast, according to an ethological hypothesis, we expect lizards with autotomized tails to avoid exposure to predators by reducing thermoregulation time, thus showing lower temperatures than lizards with non‐autotomized tails. However, we found that the tail state did not significantly affect lizard field or selected body temperatures. On the one hand, a warmer thermal optimum could imply greater exposure to predators during basking, making motility‐impaired lizards with autotomized tails more vulnerable, which could explain why the physiological hypothesis of autotomy thermal effect does not apply. On the other hand, lower body temperatures could be physiologically costly for lizards, which, together with the other costs resulting from tail autotomy, could jeopardize lizard fitness. Therefore, both hypotheses were not supported.