Aboveground activity, reproduction, body temperature and weight of armadillos (Xenarthra, Chlamyphoridae) according to atmospheric conditions in the central Monte (Argentina)

Abstract

Hairy armadillos are generalist species widely distributed in South America. Three of these species, Chaetophractus vellerosus, C. villosus and Zaedyus pichiy, are sympatric in the arid central Monte. The objective of this study is to make a contribution to current knowledge about these species, the ecological interactions among them and their responses to arid environments. Aboveground activity, rectal temperature, body weight and reproductive status were measured in wild populations. The influence of seasonal and daily atmospheric conditions were estimated through generalized linear models. Seasonality affected the Z. pichiy reproduction cycle, body weight and aboveground frequency of occurrence. There was a higher frequency of animals with low body weight in late winter and spring, mostly breeding animals. Armadillos regained body weight in autumn, but their aboveground frequency decreased. Females showed higher weight variability than males in autumn. Daily atmospheric temperature proved to be the most relevant weather condition for Z. pichiy, with a positive influence on aboveground activities and body temperature. This species had the broadest range of body temperature, without relation to body weight. Typical dry and clear days of the central Monte were favorable conditions for Z. pichiy activity. Its diurnal activity had a higher probability of occurrence at twilight, and nocturnal activity occurred during summer. Presence of C. vellerosus was positively influenced by atmospheric temperature, whereas presence of C. villosus was not influenced by any weather condition. Differences in the use of solar radiation could represent a partial temporal segregation, promoting the coexistence of these sympatric species.