Acta Botânica Brasílica (Sep 2011)
Frugivoria e potencial dispersão de sementes pelo marsupial Gracilinanus agilis (Didelphidae: Didelphimorphia) em áreas de Cerrado no Brasil central Frugivory and potential seed dispersal by the marsupial Gracilinanus agilis (Didelphidae: Didelphimorphia) in areas of Cerrado in central Brazil
Abstract
No presente estudo, investigamos o consumo de frutos e viabilidade de sementes consumidas pelo marsupial Gracilinanus agilis (Burmeister, 1854) em quatro áreas de cerradão do Brasil central. Análises fecais indicaram que este mamífero se alimenta de plantas pioneiras da família Melastomataceae (Miconia albicans (Sw.) Triana, M. cuspidata Naudin, M. ferruginata DC., M. pepericarpa DC., M. pohliana Cogn. e Ossaea congestiflora (Naudin) Cogn.), Solanaceae (uma espécie não identificada) e Viscaceae (Phoradendron perrottetii (DC.) Eichler, erva-de-passarinho). Detectamos o maior índice de consumo de frutos já registrado para o gênero Gracilinanus, com cerca de 45% das fezes contendo sementes e 86% contendo itens derivados de frutos (N=422). Com exceção de O. congestiflora, o restante das sementes das espécies testadas não sofreram efeitos negativos na germinabilidade ao passarem pelo trato digestório deste marsupial. A avaliação da variação intraspecífica no número de sementes encontradas nas fezes indicou que fêmeas de G. agilis defecam maior quantidade de sementes de Miconia (média±EP = 21,7±3,8) em comparação com os machos (14,4±3,0) (F=26,32; PIn the present study, we investigated patterns of fruit consumption and viability of seeds consumed by the marsupial Gracilinanus agilis (Burmeister, 1854) in four cerrado sites in central Brazil. Faecal analysis indicated that this mammal feeds on seeds of pioneer plant species of Melastomataceae (Miconia albicans (Sw.) Triana, M. cuspidata Naudin, M. ferruginata DC., M. pepericarpa DC., M. pohliana Cogn. and Ossaea congestiflora (Naudin) Cogn.), Solanaceae (one unidentified species), and Viscaceae (Phoradendron perrottetii (DC.) Eichler, mistletoe). We recorded the highest reported rate of fruit consumption for Gracilinanus, with about 45% of the scats containing seeds and 86% containing items derived from fruits (N = 422). With the exception of O. congestiflora, the remaining seed species tested did not suffer negative effects on germination rates after passing through the marsupial guts. The analysis of intraspecific variation in the total number of Miconia seeds found in scats indicated that females defecate a significantly greater number of seeds (mean±EP = 21.7±3.8) than males (14.4±3.0) (F = 26.32; P < 0.0001). The factor season was also significant (F=452.22; P<0.0001) as well as the interaction between sex and season (F=30.10; P < 0.0001). Both females and males increased their fruit consumption in the dry season, but in the rainy season females had more seeds than males in their faeces. Later during this season, we observed a higher number of Miconia seeds defecated by reproductive females (24.7±6.6) compared to non-reproductive females (12.9±2.8) (P = 0.031). Our results indicate that G. agilis feeds selectively on Melastomataceae, which suggests these plants play an important role in the diet of this marsupial in relation to energy and water demands, especially during the dry-cool season.
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