Data.xls

The outcome of interspecific competition is affected by numerous abiotic and biotic factors. Here we demonstrate an aspect of interspecific competition: the genotype of a conspecific neighbour determines the outcome of interspecific competition through phenotypic plasticity in a perennial plant,<i> Plantago asiatica</i>. We investigated effects of the genotype of neighbour sibling or non-sibling <i>P. asiatica </i>plants on competition with <i>Trifolium repens</i> plants when <i>Plantago</i> plants were separated above or below ground from <i>T. repens</i>, separated below ground from each other or not separated. Seed production of <i>P. asiatica</i> individuals was negatively correlated with biomass of <i>Trifolium repens</i>. Sibling but not non-sibling pairs of <i>P. asiatica </i>plants increased leaf placement in the direction of <i>T. repens</i> plants, which was negatively correlated with biomass of <i>T. repens </i>and positively correlated with seed production of<i> P. asiatica</i>. Seed production of <i>P. asiatica</i> plants competing with <i>T. repens</i> was greater in individuals paired with siblings than in those paired with non-. siblings These results support the hypothesis that the genetic spatial structure within a species influences outcomes of interspecific competition through genetic-structure-dependent plasticity.<b></b>