Frugivoria e potencial dispersão de sementes pelo marsupial Gracilinanus agilis (Didelphidae: Didelphimorphia) em áreas de Cerrado no Brasil central

Abstract

(Frugivory and potential seed dispersal by the marsupial Gracilinanus agilis (Didelphidae: Didelphimorphia) in areas of Cerrado in central Brazil). In 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 congestifl ora (Naudin) Cogn.), Solanaceae (one unidentifi ed 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. congestifl ora, the remaining seed species tested did not suff er negative eff ects on germination rates aft er passing through the marsupial guts. Th e analysis of intraspecifi c variation in the total number of Miconia seeds found in scats indicated that females defecate a signifi cantly greater number of seeds (mean±EP = 21.7±3.8) than males (14.4±3.0) (F = 26.32; P < 0.0001). Th e factor season was also signifi cant (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.

Effects of gut passage on the germination of seeds ingested by didelphid marsupials in a neotropical savanna

“…Fruit consumption and seed dispersal by neotropical didelphid marsupials have previously been observed in areas of the Atlantic Forest (Cáceres & MonteiroFilho 2000;Cáceres 2002;Cáceres & Monteiro-Filho 2007;Pinheiro et al 2002) and in different vegetation types of the cerrado (Lessa & Costa 2010;Camargo et al 2011). With regards to fruit consumption, Melastomataceae fruits, mainly those belonging to the genera Clidemia and Miconia, stand out as an important food resource in cerrado areas (Lessa & Costa 2010;Camargo et al 2011), being present in the diet of all seven studied didelphids.…”

“…In the neotropics, the role of didelphids as potential seed dispersers is usually related to the consumption of a wide variety of fruits and the presence of intact seeds in their feces with generally increased germinability (Cáceres & Monteiro-Filho 2007;Raíces & Bergallo 2008;Lessa & Costa 2010;Cáceres & Lessa 2012). However, the process of gut scarification of the seed coat by passage through the digestive tract of didelphid dispersers does not always have positive effects on the germinability and germination time of the ingested seeds (see Cantor et al 2010;Camargo et al 2011;Cáceres & Lessa 2012).…”

Intra- and inter-individual variation show distinct trends as drivers of seasonal changes in the resource use of a neotropical marsupial

“…Additionally, there was an increase in the consumption of both termites and bugs in the cool–dry season, whereas, in the warm–wet season, G. agilis increased the consumption of ants. These diet changes are not only a result of the availability of fruits (Batalha & Martins, ) and arthropods (Pinheiro et al ., ), but probably also a result of hydric (Camargo et al ., ) and energetic‐nutritional requirements (Camargo et al ., ) related to the reproductive condition of the animals (Fisher et al ., ).…”

“…Preliminary analysis did not indicate significant differences in resource availability among grids for fruits (permutational analysis of variance with 10 000 iteractions: F 2,138 = 0.418; P = 0.67) or for the most consumed arthropod orders (permutational multivariate analysis of variance with 10 000 iteractions: F 2,51 = 0.895; P = 0.51), either (see Supporting information, http://onlinelibrary.wiley.com/doi/10.1111/bij.12258/suppinfo). More detailed methods on resource availability are provided elsewhere (Camargo et al ., , ). Moreover, we tested for possible differences among the three sites in dietary preferences of G .…”

“…However, we consider this is not a limitation because we evaluated resource availabilities in each sampled site (i.e. arthropod biomass and fruit abundance) and found no differences among them (Camargo et al ., , ). Thus, we were able to determine whether patterns regarding seasonal changes in G. agilis trophic niche would hold for distinct sites sampled independently.…”