Ecologia alimentar e estratégias de germinação de sementes consumidas por marsupiais (Didelphimorphia: Didelphidae) em uma área de Cerrado no sudeste do Brasil

Abstract

In Brazil, the family Didelphidae comprises 54 species widely distributed in different habitats and a dietary pattern that can vary from species more frugivorous to the most insectivorous/carnivorous. The main objective of this study was to evaluate the relationship between the diet of seven species of didelphids (Caluromys philander, Didelphis albiventris, Gracilinanus agilis, G. microtarsus, Marmosa (Micoureus) paraguayana, Marmosops incanus e Metachirus nudicaudatus) and the selection of the available food resources (arthropods and fruits). The study was conducted between November 2009 and October 2011 in a riparian area of Cerrado in the Parque Estadual do Rio Preto, Minas Gerais, Brazil. Arthropods, fruits, flowers and vertebrates were consumed in different proportions by the studied species. Flowers and vertebrates were consumed mainly in the dry season and the diversity of the diet of all species was higher during the rainy season. Not all resources (arthropods and fruits) were consumed according to their availability in the study site. Although abundant, Hymenoptera (Formicidade) was rejected by all species being consumed below their local availability. The didelphids selected fruits of Melastomataceae (Miconia and Clidemia urceolata spp.) and rejected fruits of Rubiaceae, a feature highly abundant in the study site. The results suggest that the frequent use of a food item may be associated both with the preference (selection) of the consumers, as well as the local availability of the resource. Most seeds that remained intact after passage through the digestive tract of animals, do not show significant differences in their rates of germination compared with seeds from the control group and the average time of dormancy consumed by marsupials ranged from 30 (Cipocereus minensis) and 175 days (Cordiera sessilis). Gracilinanus agilis and G. microtarsus, which occur sympatrically in the study site, although having a high niche overlap showed differences in habitat use and dietary diversity.