No limiar da auto-mutilação: fatores ecológicos e morfológicos envolvidos na autotomia caudal em Tropidurus itambere (Rodrigues, 1987) (Sauria:Tropiduridae)

Abstract

Autotomy is an anti-predator behavior widely employed by lizards. The energetic consequences of this process are vastly describe in literature, yet the details involved in it’s occurrence lack thoroughness. This study intent to evaluate if there are differences related to body weight in propensity to realize autotomy, in body and caudal growth, both during the hot/wet season (tropical summer) and the cold/dry season (tropical winter). To accomplish that three groups of lizards (n = 19) with different body mass (P1, P2 and P3) were kept in out-doors cages during cold (July to September 2012) and hot seasons (November 2012 to January 2013). Autotomy was induced by constriction of the tail, while measuring the pression applie to it’s surface as well as the time until it’s release. Morphometric data was assessed weekly and processed using two-tailed t-test for unpaired samples, comparing variables according to body weight. The released portion of the tail was preserved in alcohol and dissected, as were the four lizards that happened to die during the experimental process. Caudal anatomy was analyzed and compare with preexisting descriptions. A three-dimensional model with didactic and analytic potential was elaborated. We found an average of 32 caudal vertebraes in T. itambere. Most of the analyzed parameters did not present statistical significance, due to the small sample size. However we present and discuss every tendency and possibility in face of the current literature. We did found a significant inverse relation between cloacal temperature and the time subjects took to undergo autotomy.