Pollinator-mediated floral divergence in a tropical plant species complex
Widespread species usually vary phenotypically across their range. This variation often but not always represents local adaptation, formation of ecotypes, and sometimes ecological speciation driven by divergent ecologically mediated natural selection. In animal-pollinated plants, the drivers of such divergent selection are often pollinators but may also include antagonist such as seed predators and herbivores, and recent work suggest that ancestral genetic constraints may also guide patterns of phenotypic divergence. To assess drivers of floral divergence in Dalechampia scandens, a species complex of euphorb vines, we have surveyed populations across much of the range, amassing data on pollination ecology and other biotic interactions. Here I use these data to explore pollinator-mediated floral divergence while considering the influence of other biotic interactors and of genetic constraints as quantified by multivariate genetic architecture of floral traits. Major emerging patterns include apparent adaptation to both local pollinator assemblages and pollination reliability, and that these patterns differ within and among member taxa of the D. scandens complex. I discuss these findings in light of processes driving local adaptation, formation of pollination ecotypes, and ecological speciation.
