Padrão de atividade em Clyomys laticeps (Thomas, 1909)

Abstract

Animals schedule their activity in order to maximize the chances of finding food and mates and reduce predation risks. The resulting activity patterns reflect species temporal niche, which are affected by interactions, such as predation and competition, and abiotic factors, such as temperature and light. Among small mammals, ambient temperature is one of the the main factors influencing the temporal niche, due to the energetic cost of maintaining homeostasis. Moreover, seasonal changes in climatic conditions and physiological differences associated with sex and age can also lead to differences in activity patterns within populations. In order to verify the activity pattern of the semi-fossorial rodent Clyomys laticeps, we tested the role of sex, season, temperature and lunar phase on their daily activity patterns. The study was carried out in the Serra de Caldas Novas State Park (GO, Brazil) in a Cerrado area using the telemetry method. The 20 tracked individuals performed their activities at night and avoided warmer periods of the day, as a probable response to thermal stress. There was a difference in the above-ground activity patterns between the sexes, with males showing a uniform and constant activity throughout the daily cycle while females restricted their activities to periods with milder temperatures. This difference appears to be a result of the reproductive behavior of males and physiological and behavioral characteristics of females. In a polygynandrous system, as in C. laticeps, males invest more time searching for reproductive partners. On the other hand, apparently females minimize their activity as a stratety to cope with the combined costs of thermoregulation and continuous, non-seasonal reproduction, which is energetically costly and limits female movement due to parental care. Both sexes had activities limited by temperature, which was the main factor shaping the activity pattern of the population studied. Finally, C. laticeps individuals were more active in full moon nights, refuting the hypothesis of lunar phobia in this species.