Format: ORAL

Simone Cappellari-Rabeling1,4, Rosana Tidon2, John L. Neff3 and Beryl B. Simpson4

1. Department of Plant Evolutionary Biology, Institute of Biology, University of Hohenheim, Stuttgart, Germany 2. Department of Genetics and Morphology, University of Brasilia, Brazil. 3. Central Texas Mellitological Institute, Austin, TX, USA. 4. Department of Integrative Biology, The University of Texas at Austin, USA.

Neotropical habitats harbor over 40% of the worlds angiosperm diversity including several plant families with specialized pollination systems such as the Orchidaceae, Malpighiaceae, and the Plantaginaceae. The Malpighiaceae is considered one of the most common elements of the Neotropical Flora and is known for its specialized pollination system involving the production of floral oils (i.e., lipids) which are harvested by solitary, oil-collecting bees and used for larval provisioning or nest construction. Comprising 1,300 species, the Malpighiaceae has its center of diversity in South America, where the family is thought to have originated 65 Mya. Among South American biomes, the Brazilian Cerrado, a seasonally dry savannah-like vegetation considered one of the Worlds Biodiversity Hotspots for angiosperms, is especially rich in Malpighiaceae species. But how do these specialists coexist and persist successfully in sympatry if competition for pollination services and risk for hybridization (i.e., via interspecific pollen transfer) among close relatives is expected to be high? Here, we explore the niche ecology of 33 sympatric Malpighiaceae species, focusing on potential temporal, spatial, behavioral, and morphological partitioning mechanisms. Among other factors, we show the importance of temporal niche partitioning in phenology promoting the Malpighiaceae species richness that characterizes the Cerrado vegetation throughout its geographic range. We discuss the relevance of the emergent patterns observed in this system to improve our understanding of niche and community ecology in other Neotropical plant communities where specialized pollination is also widespread.