Caracterização de trato gastrointestinal e dieta de pequenos mamíferos (rodentia, didelphimorphia) em áreas da caatinga de Alagoas e Sergipe

Abstract

The Caatinga is the only biome exclusively Brazilian. It is a rich environment in biodiversity and endemism, still poorly studied in terms of its biodiversity, but already has about 180 species of mammals recorded. Non-volant small mammals (Orders Rodentia and Didelphimorphia) are known to have a great adaptive capacity in their diet; however, knowledge about the diet and morphology of the gastrointestinal tract (GIT) of these Caatinga animals is still scarce. Considering the absence of such analyses for the state of Alagoas, this study aimed to analyze the morphology of the gastrointestinal tract and the diet of marsupials and rodents from four municipalities located in the Caatinga biome in the states of Alagoas and Sergipe. A total of 44 specimens of seven species (Didelphis albiventris [1], Gracilinanus agilis [9], Monodelphis domestica [6], Oligoryzomys stramineus [9], Wiedomys cerradensis [2], Wiedomys pyrrhorhinus [5], Thrichomys laurentius [12]) were analyzed. Comparing the measurements of the GIT (stomach, small intestine, large intestine, and cecum), it was found that in all measurements, D. albiventris had the longest lengths among marsupials, followed by M. domestica and G. agilis. For rodents, T. laurentius had the largest measurements, followed by W. cerradensis, O. stramineus, and W. pyrrhorhinus. When examining the composition of food items in the stomachs of specimens, items of animal origin (Class Insecta, Phylum Arthropoda, Orders Blattodea, Coleoptera, Diptera, Lepidoptera, Hemiptera, Hymenoptera, Orthoptera) and plant material (seeds and unidentified plant matter) were found, present in 100% of the samples. Marsupials consumed seven Orders of invertebrates, with a higher proportion of Coleoptera (53.84%), while rodents consumed five Orders, with a higher consumption of Hymenoptera (46.42%). However, no significant difference was found in the composition of diets among the species analyzed, and no relationship was found between stomach morphology and diet. It was possible to conclude that the morphology of the gastrointestinal tract is not influenced by the diet for the studied animals, that rodents in the Caatinga showed a high consumption of arthropods, and that in general, both rodents and marsupials in the Caatinga have opportunistic feeding habits. This study was pioneering in the examination of stomach morphology of the sampled species in the Caatinga biome and fills gaps in the knowledge about the feeding habits of marsupials and rodents in the Caatinga. Here, the second record of Blattodea predation by G. agilis was also obtained.