Período de atividade e padrões de uso do espaço do rato-de-espinho Clyomys laticeps (Thomas, 1909) (Rodentia: Echimyidae)

Abstract

Each species present a specific multidimentional ecological niche which dimensions correspond to their environmental conditions and resources. Individuals’ activity and space use patterns reveal the behavior in the time and space niche dimensions, respectively. The subterranean rodents have the habit to dig and live underground galleries, and those that get their food basically from the above-ground (named as semi- fossorial), are directly influenced by the environmental factors when in activity aboveground. In this way, both environmental influence and intrinsic factors (e.g. social interactions, body size, diet, morphology) have influence on the daily activity period choice to perform survival and reproduction. Besides the distribution in time, the individuals’ space use patterns reflect the ecological and physiological activities, as well as, indicate about the species’ social and reproductive behavior. We evaluated the aboveground daily activity choice by the semi-fossorial spiny rat Clyomys laticeps along one year through camera traps use. Furthermore, along ten months we evaluated, with spool- and-line technique, the space use patterns in response to the intrinsic factors (sex and body mass) and extrinsic (food availability) through the Minimum Convex Polygon method (95%). Our study revealed that temperature had influence on the activity period selected by C. laticeps. It presented preference for lower daily temperatures (10-25°C), presenting so, a predominant nocturnal activity, independently from the activity period overlap with their potential predators. This result indicates us that the activity period choice is restricted by the occurrence of high temperatures during the day, as occur in the Cerrado biome, so that the advantages of this choice seems to exceed the costs associated to predation. In relation to space use pattern, the spiny rat’s daily home range varied between sexes. Males had larger daily home range than females, as probably response to their greater energy demands to maintain their bigger body mass and to their reproductive behavior. Adult females presented larger intensity habitat use, exploring more the galleries’ surroundings, as well as fidelity behavior during the study period. This space use pattern seems to be related to the maternal care, once this species seems to present a non-seasonal reproduction in our study. In relation to food availability, the palm Allagoptera campestris ’ fruit availability variation didn’t prove to be a good predictor of the individuals’ daily home range size, even the palm being very abundant in the study area. The absence of food’s availability effect on the Clyomys laticeps’ daily home range size can be explained through individuals’ year round reproductive activity, as well as by other food items inclusion in their diet when Allagoptera campestris ’ fruits is reduced in the area.