title: Plant acclimation to elevated CO₂ affects important plant functional traits, and concomitantly reduces plant colonization rates by an herbivorous insect.
abstract: Plants growing under elevated CO₂ concentration may acclimatize to this environmental change by modification of chemical, physiological, and/or morphological traits. As a consequence, not only plant functioning but also plant-insect interactions might be altered, with important consequences particularly for agricultural systems. Whereas most studies have focused on the plant acclimation effects of elevated CO₂ with regard to crop growth and productivity, acclimation effects on the behavioral response of insects associated with these plants have been largely neglected. In this study, we used a model system comprised of Brussels sprout Brassica oleraceae var. gemmifera and a specialized herbivorous insect, the cabbage aphid Brevicoryne brassicae, to test for the effects of various periods of exposure to an elevated (2× ambient) CO₂ concentration on key plant functional traits and on host plant location behavior by the insect, assessed as plant colonization rates. Elevated CO₂ had no measurable effect on colonization rates or total plant volatile emissions after a 2-week exposure, but it led to 15 and 26 % reductions in plant colonization rates after 6- and 10-week exposures, respectively. This reduction in plant colonization was associated with significant decreases in leaf stomatal conductance and plant volatile emission. Terpene emission, in particular, exhibited a great reduction after the 10-week exposure to elevated CO₂. Our results provide empirical evidence that plants might acclimatize to a future increase in CO₂, and that these acclimation responses might affect host plant choice and colonization behavior by herbivorous insects, which might be advantageous from the plant's perspective.
authors.affiliation: ETH Zurich, Institute of Agricultural Sciences/Applied Entomology, Schmelzbergstrasse 9/LFO, 8092, Zurich, Switzerland.
authors.forename: Jeannine
authors.initials: J
authors.lastname: Klaiber
authors.forename: Adriana J
authors.initials: AJ
authors.lastname: Najar-Rodriguez
authors.forename: Rafal
authors.initials: R
authors.lastname: Piskorski
authors.forename: Silvia
authors.initials: S
authors.lastname: Dorn
mesh_terms: D000064:Acclimatization / Q000187:drug effects*; D000818:Animals; D001042:Aphids / Q000502:physiology*; D001937:Brassica / Q000378:metabolism / Q000469:parasitology*; D002245:Carbon Dioxide / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects; D008401:Gas Chromatography-Mass Spectrometry; D060434:Herbivory / Q000187:drug effects; D006790:Host-Parasite Interactions / Q000187:drug effects; D054046:Plant Stomata / Q000187:drug effects / Q000378:metabolism; D013729:Terpenes / Q000032:analysis / Q000378:metabolism; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism
chemical_list: D013729:Terpenes; D055549:Volatile Organic Compounds; D002245:Carbon Dioxide