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,
Plantago asiatica. We investigated effects of the genotype
of neighbour sibling or
non-sibling P. asiatica plants on competition with Trifolium repens plants when Plantago plants were separated above or below
ground from T. repens, separated
below ground from each other or not separated. Seed production of P. asiatica individuals was negatively
correlated with biomass of Trifolium
repens. Sibling but not non-sibling pairs of P. asiatica plants increased leaf placement in the direction of T. repens plants, which was negatively
correlated with biomass of T. repens and
positively correlated with seed production of P. asiatica. Seed production of P. asiatica plants competing with T. repens 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.