Samples of corbicular and stored pollen gathered by Tetragonisca angustula (Latreille, 1811) in an Amazon-Chiquitano transitional forest during the dry season were analyzed. The pollen spectrum was established as well as the dynamics of the relationship between the stingless bee and the surrounding flora. Pollen samples obtained from three rational hives were subjected to acetolysis and 55 pollen types were identified, the most frequent being from Anadenanthera (Fabaceae), Chenopodiaceae, and Dydimopanax (Araliaceae). Significant differences in pollen families used between hives along the months of collection were found in stored pollen and non-significant differences in corbicular pollen. Mean values of alpha diversity (H') showed T. angustula as a generalist while beta diversity qualitatively showed that pollen composition was similar between two hives both of which differed from the third hive. Pollen types in corbicular and stored pollen were in general related with richness of flowering plants in the foraging area; the pollen offer was less diverse than the pollen collected, and a trend to prefer the collection of pollen from the most abundant flowering species could be discerned. T. angustula showed polylectic feeding habits and a capacity to adapt to food availability.
Keywords: Pollen spectrum, stingless bees, stored and corbicular pollen, floral resources, reference pollen collection.