Palynological overview of annual honey and pollen reserves of the stingless bees Tetragonisca angustula fiebrigi and Plebeia droryana in well preserved forests of Misiones, Argentina

Information on floral resource use by stingless bees in the Paranaense forest remains scarce, particularly for Plebeia species. Annual composite honey and pollen reserves of Tetragonisca angustula fiebrigi and Plebeia droryana from two sites within the Yabotí Biosphere Reserve, Misiones, Argentina, were compared using melissopalynology and complementary ecological analyses. A total of 79 pollen types belonging to 35 plant families were recorded. Tetragonisca angustula fiebrigi showed a broader and more even use of floral resources, whereas P. droryana was characterized by a strong association with Syagrus romanzoffiana, particularly in pollen reserves. Despite these differences, both species shared most floral resources, showing extensive niche overlap, especially in honey samples. Variation between the two bee species and reserve types was mainly associated with differences in the relative abundance of shared resources, rather than with the use of distinctive pollen types. These results provide new insights into trophic resource use by stingless bees in one of the best-preserved sectors of the Paranaense forest.