title: Differential adaptation drives ecological speciation in campions (Silene): evidence from a multi-site transplant experiment.
abstract: In order to investigate the role of differential adaptation for the evolution of reproductive barriers, we conducted a multi-site transplant experiment with the dioecious sister species Silene dioica and S. latifolia and their hybrids. Crosses within species as well as reciprocal first-generation (F1) and second-generation (F2) interspecific hybrids were transplanted into six sites, three within each species' habitat. Survival and flowering were recorded over 4 yr. At all transplant sites, the local species outperformed the foreign species, reciprocal F1hybrids performed intermediately and F2hybrids underperformed in comparison to F1hybrids (hybrid breakdown). Females generally had slightly higher cumulative fitness than males in both within- and between-species crosses and we thus found little evidence for Haldane's rule acting on field performance. The strength of selection against F1and F2hybrids as well as hybrid breakdown increased with increasing strength of habitat adaptation (i.e. the relative fitness difference between the local and the foreign species) across sites. Our results suggest that differential habitat adaptation led to ecologically dependent post-zygotic reproductive barriers and drives divergence and speciation in this Silene system.
authors: Plant Ecological Genetics, ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092, Zurich, Switzerland.|Department of Molecular Evolution and Plant Systematics & Herbarium (LZ), Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103, Leipzig, Germany.
authors: Adrien
authors: A
authors: Favre
authors: Plant Ecological Genetics, ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092, Zurich, Switzerland.
authors: Alex
authors: A
authors: Widmer
authors: Plant Ecological Genetics, ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092, Zurich, Switzerland.|Department of Ecology and Genetics, Plant Ecology and Evolution, Uppsala University, Norbyvägen 18 D, 752 36, Uppsala, Sweden.
authors: Sophie
authors: S
authors: Karrenberg
mesh_terms: D000222:Adaptation, Physiological; D003433:Crosses, Genetic; D017753:Ecosystem; D035264:Flowers / Q000502:physiology; D056084:Genetic Fitness; D049810:Genetic Speciation; D006824:Hybridization, Genetic; D008954:Models, Biological; D012744:Sex Ratio; D029751:Silene / Q000235:genetics* / Q000502:physiology*
keywords: 
  Silene dioica
  ; 
  Silene latifolia
  ; Haldane's rule; dioecy; habitat adaptation; hybrid breakdown; reproductive isolation; sex ratio