title: Parallel evolution in an invasive plant: effect of herbivores on competitive ability and regrowth of Jacobaea vulgaris.
abstract: A shift in the composition of the herbivore guild in the invasive range is expected to select for plants with a higher competitive ability, a lower regrowth capacity and a lower investment in defence. We show here that parallel evolution took place in three geographically distinct invasive regions that differed significantly in climatic conditions. This makes it most likely that indeed the shifts in herbivore guilds were causal to the evolutionary changes. We studied competitive ability and regrowth of invasive and native Jacobaea vulgaris using an intraspecific competition set-up with and without herbivory. Without herbivores invasive genotypes have a higher competitive ability than native genotypes. The invasive genotypes were less preferred by the generalist Mamestra brassicae but more preferred by the specialist Tyria jacobaeae, consequently their competitive ability was significantly increased by the first and reduced by the latter. Invasive genotypes showed a lower regrowth ability in both herbivore treatments.
authors.affiliation: Institute of Biology, Section Plant Ecology and Phytochemistry, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Lin
authors.affiliation: Institute of Biology, Section Plant Ecology and Phytochemistry, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands.
authors.forename: Peter G L
authors.initials: PG
authors.lastname: Klinkhamer
authors.affiliation: Institute of Biology, Section Plant Ecology and Phytochemistry, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands.
authors.forename: Klaas
authors.initials: K
authors.lastname: Vrieling
mesh_terms: D000818:Animals; D019659:Asteraceae / Q000235:genetics* / Q000254:growth & development*; D005075:Biological Evolution; D001517:Coleoptera; D005838:Genotype; D060434:Herbivory; D058865:Introduced Species; D007814:Larva; D009036:Moths
keywords: Biological invasions; Mamestra brassicae; Tyria jacobaeae; evolution of increased competitive ability hypothesis; herbivore preference; herbivory; plant-insect interactions; ragwort; shift defence hypothesis