Population and feeding ecology of Gracilinanus microtarsus (Marsupialia: Didelphidae)

Author(s)

Eduardo Guimarães Martins

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2007-08-15

Examining board members

Sérgio Furtado dos Reis; Arício Xavier Linhares; Wesley Augusto Conde; Sonia Aparecida Talamoni; Renata Pardini

• Advisor: Sérgio Furtado dos Reis

Abstract

The gracile mouse opossum Gracilinanus microtarsus (Marsupialia: Didelphidae) is a small marsupial with nocturnal and arboreal habits that lives in the Atlantic Rainforest and forested areas of the Cerrado in Brazil. The objectives of this study were to determine the placement of G. microtarsus along two ecological scales, namely, reproductive strategy and diet, as well as to define levels of aggregation relevant to the dynamics of this species. This study was conducted from August 2000 to February 2003 in an area of cerradão located in Américo Brasiliense, São Paulo. Data were collected from individuals captured in a 3,600 m2 trapping grid. A total of 91 individual G. microtarsus was captured. The results showed that males have high mortality rates after the beginning of the mating period, which suggests that G. microtarsus is best described as partially semelparous. Using survival estimates and additional data on the biology of G. microtarsus, it was constructed a stochastic population dynamic model. The results of the simulations showed that quasi-extinction and extinction probabilities of G. microtarsus are sensitive to the number of individuals that survive fires in the cerradão. As for the diet, the results showed that G. microtarsus is primarily insectivorous and that its diet is significantly affected by sex, season, and food resource. Furthermore, diet varies among individuals and the variation also is affected by sex and season (AU)