Divergent floral evolution driven by pollinators and herbivores

Florian Schiestl

Interacting organisms drive plant evolution in various ways, however, we know little about the speed of this process and how interaction can drive speciation in plants. In my group, in the past years, we have used field work with orchids pollinated on a highly specific basis. In these studies, we have documented that few floral volatiles mediate specific pollinator attraction, floral isolation is strong, and pollination success decreases with population density, a prerequisite for disruptive selection. In a system with fast cycling Brassica rapa plants, we have used experimental evolution to investigate the effects of different specific pollinators and combinations of pollinators and herbivores on plant trait and mating system evolution. These data show that selection mediated by different pollinators drives rapid divergent trait evolution, and switches in mating systems. Herbivores impact floral evolution mostly through indirect effects on pollinator behavior and lead to rapid increase of selfing. In summary, my data show that biotic interactions drive rapid floral evolution, which can lead to speciation when pollination is specific.

University of Zurich, Switzerland

florian.schiestl@systbot.uzh.ch

Recent publications:

¹ Gervasi, D.D. and Schiestl, F.P. (2017) Real-time divergent evolution in plants driven by pollinators. Nature Communications, 14, 14691.

² Gervasi, D.D. Selosse, M-A. Sauve, M. Francke, W. Vereecken, N.J. Cozzolino, S. Schiestl, F.P. (2017) Floral scent and species divergence in a pair of sexually deceptive orchids.                   Ecology and Evolution, 00, 1-12.

³ Ramos, S.E. and Schiestl, F.P. (2019) Rapid plant evolution driven by the interaction of pollination and herbivory. Science, 364, 193-196.