title: Insect herbivores drive real-time ecological and evolutionary change in plant populations.
abstract: Insect herbivores are hypothesized to be major factors affecting the ecology and evolution of plants. We tested this prediction by suppressing insects in replicated field populations of a native plant, Oenothera biennis, which reduced seed predation, altered interspecific competitive dynamics, and resulted in rapid evolutionary divergence. Comparative genotyping and phenotyping of nearly 12,000 O. biennis individuals revealed that in plots protected from insects, resistance to herbivores declined through time owing to changes in flowering time and lower defensive ellagitannins in fruits, whereas plant competitive ability increased. This independent real-time evolution of plant resistance and competitive ability in the field resulted from the relaxation of direct selective effects of insects on plant defense and through indirect effects due to reduced herbivory on plant competitors.
authors.affiliation: Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA. agrawal@cornell.edu
authors.forename: Anurag A
authors.initials: AA
authors.lastname: Agrawal
authors.forename: Amy P
authors.initials: AP
authors.lastname: Hastings
authors.forename: Marc T J
authors.initials: MT
authors.lastname: Johnson
authors.forename: John L
authors.initials: JL
authors.lastname: Maron
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Salminen
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004463:Ecology; D005638:Fruit / Q000235:genetics / Q000469:parasitology / Q000502:physiology; D060434:Herbivory / Q000502:physiology*; D009036:Moths / Q000502:physiology*; D031665:Oenothera biennis / Q000235:genetics / Q000469:parasitology / Q000502:physiology*; D011153:Population; D012639:Seeds / Q000235:genetics / Q000469:parasitology / Q000502:physiology; D012641:Selection, Genetic