Characterization of shelters and use of vertical space by Marmosa demerarae and Marmosa murina (Didelphimorphia: Mammalia) using artificial nests in an Atlantic Forest fragment

Abstract Artificial nests allow us to analyze the use of space by animals without influencing their behavior. We characterized the shelters built by marsupials and the plant resources used for their construction. We also evaluated the use of vertical space through artificial nests arranged at 1.5 m and 3 m height in an area of Atlantic Forest in Sergipe, Brazil, between April 2022 and May 2023. A total of 124 shelters with preferably dry leaves were recorded. Only 18.4% of artificial nests were occupied, one of them with two sub-adult individuals of Marmosa murina . The animals used leaves from the Rubiaceae (all shelters), Melastomataceae, Phyllanthaceae and Erythroxylaceae families. There was no difference between the types of shelters built by the species. There was no relationship between the body size of the animal and the built-up area of the shelter. Marmosa demerarae was more frequent at 3.0 m while M. murina did not differ in the use of strata. The frequency of records between the strata differed between these species, despite the high overlap observed. Both species used artificial nests in both strata of vegetation and built their shelters with the leaves available on the ground. The regular availability of this resource has made it possible to occupy the artificial nests regardless of seasonality. The shelter is built gradually, resulting in different configurations. However, the scarcity of information on the architecture and composition of the shelters built by marsupials makes it difficult to understand the factors that influence the use of these sites by the species.