title: Natural enemies drive geographic variation in plant defenses.
abstract: Plants defend themselves against attack by natural enemies, and these defenses vary widely across populations. However, whether communities of natural enemies are a sufficiently potent force to maintain polymorphisms in defensive traits is largely unknown. Here, we exploit the genetic resources of Arabidopsis thaliana, coupled with 39 years of field data on aphid abundance, to (i) demonstrate that geographic patterns in a polymorphic defense locus (GS-ELONG) are strongly correlated with changes in the relative abundance of two specialist aphids; and (ii) demonstrate differential selection by the two aphids on GS-ELONG, using a multigeneration selection experiment. We thereby show a causal link between variation in abundance of the two specialist aphids and the geographic pattern at GS-ELONG, which highlights the potency of natural enemies as selective forces.
authors.affiliation: Institute of Evolutionary Biology and Environmental Studies and Zürich-Basel Plant Science Center, University of Zürich, Zürich CH-8057, Switzerland. tobias.zuest@cornell.edu
authors.forename: Tobias
authors.initials: T
authors.lastname: Züst
authors.forename: Christian
authors.initials: C
authors.lastname: Heichinger
authors.forename: Ueli
authors.initials: U
authors.lastname: Grossniklaus
authors.forename: Richard
authors.initials: R
authors.lastname: Harrington
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kliebenstein
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Turnbull
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D000818:Animals; D001042:Aphids / Q000502:physiology*; D017360:Arabidopsis / Q000235:genetics*; D056426:Genetic Loci; D005843:Geography; D060434:Herbivory / Q000502:physiology*; D011110:Polymorphism, Genetic; D012641:Selection, Genetic; D013045:Species Specificity