Characterization of Malpighiaceae flower-visitor interactions in a Brazilian savannah: How do floral resources and visitor abundance change over time

Abstract

The plants of Malpighiaceae are diverse and produce specific floral resources that provide a parameter of habitat quality for oil-collecting bees. We studied three species of Malpighiaceae from the Brazilian savannah, Banisteriopsis campestris, B. malifolia and Peixotoa tomentosa, and investigated (I) the quantitative and qualitative composition of floral resources and (II) the temporal distribution of floral visitors according to plant phenology. We used gas chromatography and mass spectrometry to determine the chemical composition of floral oil. We also quantified pollen weight and oil volume, and registered floral visitors and plant phenology. The floral resources varied quantitatively and qualitatively among plant species. The 31 observed bee species showed different preferences for the plant species, which also were related to reproductive periods and floral resources of the plants. According to sequential flowering of co-occurring species of Malpighiaceae, we argue that the qualitative and quantitative similarity of floral resources (oil and pollen) and their availability for bees throughout the year, benefits these interactions between plants and bees.