Vieira Emerson M, de Camargo Nícholas F, Colas Paul F, Ribeiro Juliana F, Cruz-Neto Ariovaldo P
Laboratório de Ecologia de Vertebrados, Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, Brazil.
Departamento de Zoologia, Instituto de Biociências de Rio Claro, Universidade Estadual Paulista (UNESP), Rio Claro, São Paulo, SP, Brazil.
PLoS One. 2017 Jan 4;12(1):e0168495. doi: 10.1371/journal.pone.0168495. eCollection 2017.
The temporal activity of animals is an outcome of both biotic and abiotic factors, which may vary along the geographic range of the species. Therefore, studies conducted with a species in different localities with distinct features could elucidate how animals deal with such factors. In this study, we used live traps equipped with timing devices to investigate the temporal activity patterns of the didelphid Gracilinanus agilis in two dry-woodland areas of the Brazilian savanna (Cerrado). These areas were located about 660 km apart, one in Central Brazil and the other in Southeastern Brazil. We compared such patterns considering both reproductive and non-reproductive periods, and how it varies as a function of temperature on a seasonal basis. In Central Brazil, we found a constant, and temperature-independent activity during the night in both reproductive and non-reproductive periods. On the other hand, in Southeastern Brazil, we detected a constant activity during the reproductive period, but in the non-reproductive period G. agilis presented a peak of activity between two and four hours after sunset. Moreover, in this latter we found a relation between temporal activity and temperature during the autumn and spring. These differences in temporal activity between areas, observed during the non-reproductive period, might be associated with the higher seasonal variability in temperature, and lower mean temperatures in the Southeastern site in comparison to the Central one. In Southeastern Brazil, the decrease in temperature during the non-reproductive season possibly forced G. agilis to be active only at certain hours of the night. However, likely due to the reproductive activities (intensive foraging and searching for mates) this marsupial showed constant, temperature-independent activity during the night in the reproductive period at both sites.
动物的时间活动是生物和非生物因素共同作用的结果，这些因素可能会因物种的地理分布范围而有所不同。因此，在具有不同特征的不同地点对同一物种进行研究，可以阐明动物如何应对这些因素。在本研究中，我们使用配备定时装置的活套来调查巴西热带稀树草原（塞拉多）两个干燥林地地区的灵长目动物敏捷 Gracilinanus 夜间活动模式。这两个地区相距约660公里，一个位于巴西中部，另一个位于巴西东南部。我们比较了繁殖期和非繁殖期的这种模式，以及它如何随季节温度变化而变化。在巴西中部，我们发现在繁殖期和非繁殖期，夜间活动持续且与温度无关。另一方面，在巴西东南部，我们在繁殖期检测到持续的活动，但在非繁殖期，敏捷 Gracilinanus 在日落后两到四个小时出现活动高峰。此外，在后者中，我们发现秋季和春季的时间活动与温度之间存在关系。在非繁殖期观察到的不同地区之间时间活动的这些差异，可能与温度的季节性变化较大以及东南部地区与中部地区相比平均温度较低有关。在巴西东南部，非繁殖季节温度的下降可能迫使敏捷 Gracilinanus 只在夜间的特定时间活动。然而，可能由于繁殖活动（密集觅食和寻找配偶），这种有袋动物在两个地点的繁殖期夜间都表现出持续的、与温度无关的活动。
