Renner's research interests focus on the
phylogenetics, mating system evolution, and
biogeography of flowering plants, in both temperate and tropical regions. Renner's early research was on the phylogeny and reproductive biology of plants. She has also worked on
dioecy and
sex chromosomes in plants. The use of genetic tools enables Renner to track the movement of plants across ocean basins, define the separation of land masses following the breakup of
Pangaea 153 million years ago, and define the origin of agricultural crops including cucumbers and melons and gourds. Renner's work on watermelons revealed that they originate from the northeast Africa in the
Kordofan area and not South Africa as previously indicated. She has tracked the relationship between
Philidris nagasau ants and
Squamellaria plants over the past 3 million years, an interaction that is a type of farming because the ants place seeds into tree bark and then return later to eat the resulting growth. Her research followed the co-evolution between
sword-billed hummingbirds and
passion flowers, an interaction that has been gained and lost multiple times over the past 11 million years. In urban areas, her research on bees, how they collect pollen, and the role of flower strips in attracting bees is relevant given the impact of climate change on interactions between plants and insects. == Selected publications ==