Hybridization as a path to success? Adaptive hybridization in willows in face of biotic and abiotic pressures
Hybridization is widespread among angiosperms. It leads to introgression and new combinations of functional traits, such as defensive chemistry. In this collaborative project, we use Salix as a diverse and dominant key-stone plant genus to explore if the hybridization in plants is fuelled by the adaptive value of hybrids in face of biotic and abiotic selection pressures. Together with the team of Nicole M. van Dam, we explore if hybrids extend the ecological niches and functional diversity in their parental species. Specifically, we test how chemical α- and β-diversity in hybrid chemistry help them to cope with biotic and abiotic stress along elevational gradients. By using an integrative approach including effects of various types of stress, we hope to draw generalizations on plant hybridization and roles of chemical diversity in plants.
Figure 1. Willow (Salix) hybrids and parental species can be seemingly morphologically similar (A) but can show distinct chemical profiles. Here the species- and hybrid-specific metabolites are shown as coloured dots and joined into networks based on their mass spectra (B). Unique metabolites produced by hybrids can be structurally related to those of their parents (C; in black circles). However, they can be also structurally distinct and form clusters separated from the metabolites found in either parent (C; in a red circle). The chemical composition affects interaction networks between hybrids and their parents (D). Their chemistry can alter the susceptibility of hybrids to insects. Here the width of columns in lower row reflects the abundance of herbivores on parental species and their hybrids. Herbivores (top row) uniquely found on parental species or hybrids are coloured. Based on Volf et al., unpublished data.