Biogeography of the yeasts of ephemeral flowers and their insects.

We studied specific yeast communities vectored by beetles, drosophilids, and bees that visit ephemeral flowers, mostly in the genus Hibiscus and in the families Convolvulaceae and Cactaceae, in the Neotropical, Nearctic, and Australian biogeographic regions. The communities consist mostly of yeasts in four clades centered around the genera Metschnikowia, Kodamaea, Wickerhamiella, and Starmerella. The largest geographic discontinuity occurs as a function of the nitidulid beetle species that dominate the non-pollinator insect visitors of the flowers. This partitions the New World, where the dominant beetle is in the genus Conotelus, from the Australian biogeographic region, dominated by species of Aethina. Distinct but sympatric insects may also carry radically different yeast communities.