Aggressive interactions during reproductive cycle in Trachylepis atlântica (Squamata: Scincidae), endemic lizard of Fernando de Noronha, Archipelago

Introduction: Trachylepis atlantica are a small body-size, diurnal and onivorus lizard endemic to Fernando de Nronha Archipelago. Although T. atlantica is a relatively abundant in Fernando de Noronha, it is an endemic species and unic of the genus in Brazil. Habitat destruction, predation by rats, cats and Tupinambis merianae, species introduced to the island by humans, is leading to a sudden decline in the population of these lizards, threatening the species of extinction. Methods: The observations of the territory use, combats and copulations of T. atlantica were made in February of 2015 and 2016, during the dry season. Whe taken mesure of snout-vent length, , head and caudal length to testing sexual dimorphism. Results: During the reproductive season (dry season), we observed three combats and two mates. We observed with T. atlantica shows ritualized agonistic behavior that can be divided into three phases: the first consist visual display, the second fase consisting of encounter agonistic (agressive contact and fighting) the last: territory establishment, in which the winner male expelling the loser rival male from the territory. Frequently, adult males patrol their territory limits, cautiously watching for the entrance of individuals. When other males enter in territories are challenged to combat or immediately expelled, but females that eventually enter to territory are frequently courted. Males showed a larger body size, tail and head compared to females, which may be associated with combat behavior. Can concluded wich te sexual selection is a principal cause of dimorphism sexual.