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Phenotypic divergence during the invasion of Phyla canescens in Australia and France: evidence for selection-driven evolution |
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| Authors: | Cheng-Yuan Xu Mic H Julien Mohammad Fatemi Christophe Girod Rieks D Van Klinken Caroline L Gross Stephen J Novak |
| Institution: | CSIRO Entomology, 120 Meiers Road, Indooroopilly, QLD 4068, Australia; CSIRO European Laboratory, Campus International de Baillarguet, Montferrier-sur-Lez 34980, France; Ecosystem Management, University of New England, Armidale NSW 2351, Australia; UMR7179 CNRS-MNHN, 91800 Brunoy, France; Department of Biological Sciences, Boise State University, Boise, ID 83725, USA |
| Abstract: | Rapid adaptive evolution has been advocated as a mechanism that promotes invasion. Demonstrating adaptive evolution in invasive species requires rigorous analysis of phenotypic shifts driven by selection. Here, we document selection-driven evolution of Phyla canescens , an Argentine weed, in two invaded regions (Australia and France). Invasive populations possessed similar or higher diversity than native populations, and displayed mixed lineages from different sources, suggesting that genetic bottlenecks in both countries might have been alleviated by multiple introductions. Compared to native populations, Australian populations displayed more investment in sexual reproduction, whereas French populations possessed enhanced vegetative reproduction and growth. We partitioned evolutionary forces (selection vs. stochastic events) using two independent methods. Results of both analyses suggest that the pattern of molecular and phenotypic variability among regions was consistent with selection-driven evolution, rather than stochastic events. Our findings indicate that selection has shaped the evolution of P . canescens in two different invaded regions. Ecology Letters (2010) 13: 32–44 |
| Keywords: | Biological invasions differentiation multiple introductions phenotypic evolution selection sexual reproduction stochastic events vegetative reproduction |