Experimental admixture among geographically disjunct populations of an invasive plant yields a global mosaic of reproductive incompatibility and heterosis

• Autores: Irimia, Ramona E.; Hierro, Jose Luis; Branco, Soraia; Sotes, Gastón Javier; Cavieres, Lohengrin A.; Eren, Ozkan; Lortie, Christopher J.; French, Kristine; Callaway, Ragan M.; Montesinos, Daniel
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: ALLOPATRY; BIOLOGICAL INVASIONS; FECUNDITY; GENE FLOW; LOCAL ADAPTATION; REPRODUCTIVE ISOLATION; YELLOW STARTHISTLE
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Invasive species have the ability to rapidly adapt in the new regions where they are introduced. Classic evolutionary theory predicts that the accumulation of genetic differences over time in allopatric isolation may lead to reproductive incompatibilities resulting in decreases in reproductive success and, eventually, to speciation. However, experimental evidence for this theoretical prediction in the context of invasive species is lacking. We aimed to test for the potential of allopatry to determine reproductive success of invasive plants, by experimentally admixing genotypes from six different native and non-native regions of Centaurea solstitialis, an invasive forb for which preliminary studies have detected some degree of reproductive isolation between one native and non-native region. We grew plants under common garden conditions and outcrossed individuals originating from different source populations in the native and introduced range to evaluate reproductive success in terms of seed to ovule ratio produced. We also assessed geographical and genetic isolation among C. solstitialis regions as a potential driving factor of reproductive success. Experimental admixture generated mixed fitness effects, including significant increases, decreases and no differences in reproductive success as compared to crosses within population (control). Centaurea solstitialis invasive populations in the Americas generated preponderantly negative fitness interactions, regardless of the pollen source, suggesting selection against immigrants and reinforcement. Other non-native populations (Australia) as well as individuals from the native range of Spain demonstrated an increase in fitness for between-region crosses, indicating inbreeding. These differences show an asymmetrical response to inter-regional gene flow, but no evidence of isolation by distance. Synthesis. The speed of adaptation and the accumulation of reproductive incompatibilities among allopatric populations of invasive species might be more rapid than previously assumed. Our data show a global mosaic of reproductive outputs, showcasing an array of evolutionary processes unfolding during colonization at large biogeographical scales.
Fil: Irimia, Ramona E.. Eberhard Karls Universität Tübingen; Alemania. Universidad de Coimbra; Portugal
Fil: Hierro, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina
Fil: Branco, Soraia. Universidad de Coimbra; Portugal
Fil: Sotes, Gastón Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad de Chile; Chile
Fil: Cavieres, Lohengrin A.. Universidad de Chile; Chile. Universidad de Concepción; Chile
Fil: Eren, Ozkan. Adnan Menderes Universitesi; Turquía
Fil: Lortie, Christopher J.. University of York; Reino Unido
Fil: French, Kristine. No especifíca;
Fil: Callaway, Ragan M.. University of Montana; Estados Unidos
Fil: Montesinos, Daniel. Universidad de Coimbra; Portugal