Plant-herbivore-parasitoid interactions in an elevated CO2 environmentCO2 effects on tree phytochemistry and on the performance of Lymantria dispar and its natural enemy Glyptapanteles liparidis
Abstract
Predicted increases in atmospheric CO2 levels may alter important plant-insect-parasitoid associations due to the indirect effects of CO2 enrichment on phytochemicals important for herbivore and parasitoid nutrition. We will follow CO2-induced changes in leaf chemistry of three hardwood tree species, consequent effects on a leaf feeding lepidopteran generalist, and the direct and indirect host-mediated impacts on the third trophic level, an endoparasitoid of the herbivore larvae. The outcomes of the project will enhance our predictability of how the forecast atmospheric CO2 enrichment may increase the risks of gypsy moth outbreaks due to altered host tree-insect-parasitoid interactions. The proposed study will be conducted within the Swiss Canopy Crane Project in a full-size natural mixed-species forest at the web-FACE study site near Basel, Switzerland. We will investigate the effects of CO2 on the interaction between gypsy moth (Lymantria dispar L.) larvae and mature oak (Quercus petraea), beech (Fagus sylvatica) and hornbeam (Carpinus betulus) trees by bagging larvae from second instar within the canopy at (1) ambient CO2 and (2) elevated CO2 (520 µl l-1 CO2). Larvae will be reared to pupation in the tree canopy and leaf samples will be taken biweekly to determine levels of total nitrogen, carbon, water, fiber, non-structural carbohydrates, fatty acids and an estimate of phenolic defensive compounds (condensed and hydrolyzable tannins, protein precipitating ability) in the tree foliage. Effects of elevated CO2 on the third trophic level will be studied by keeping bagged gypsy moth larvae previously parasitized by the braconid wasp Glyptapanteles liparidis Bouché in the tree canopy until the parasitoids emerge from their host. Gypsy moth and parasitoid growth and development parameters will be recorded. A second set of experiments will be done under laboratory conditions: both unparasitized and parasitized gypsy moth larvae will be fed with leaf powder diet made from lyophilized foliage of either oak, beech or hornbeam grown under ambient and elevated CO2 levels, respectively. Growth, consumption, and utilization patterns of the larvae on the different diets will be recorded. In the parasitization experiment, we will follow parasitoid development success, wasp sex ratio, weight, and longevity. In a parasitization choice experiment with preconditioned larvae feeding leaf powder diets from either ambient or elevated CO2 foliage, we will demonstrate if female wasps are able to develop oviposition strategies for low-quality and high-quality hosts.
elevated CO2 Plant-Insect Interaction Parasitization Phytochemistry
Publikationen
Insect pests in an elevated CO2 atmosphere: a multiyear study with gypsy moth, Lymantria dispar and its natural enemy Glyptapanteles liparidis.
Autoren: Schafellner, C; Schopf, A Jahr: 2010
Conference & Workshop proceedings, paper, abstract
Living in a greenhouse: insect responses to atmospheric CO2 enrichment
Autoren: Schafellner, C; Schopf, A Jahr: 2008
Conference & Workshop proceedings, paper, abstract
The greenhouse effect: Host-parasitoid responses to atmospheric CO2 enrichment
Autoren: Schafellner, C Jahr: 2007
Conference & Workshop proceedings, paper, abstract
Altered performance of forest pests under elevated atmospheric CO2: a case study with gypsy moth
Autoren: Schafellner, C Jahr: 2006
Conference & Workshop proceedings, paper, abstract
Multitrophic species interaction in a CO2 enriched world: A case study with gypsy moth
Autoren: Schafellner, C Jahr: 2006
Conference & Workshop proceedings, paper, abstract
Project staff
Christa Schafellner
Priv.-Doz. Dr.phil. Christa Schafellner
christa.schafellner@boku.ac.at
Tel: +43 1 47654-91619
Project Leader
16.12.2004 - 15.12.2007
BOKU partners
External partners
University of Basel, Insitute of Botany
Prof. Christian Körner
partner
University of Vienna, Insitute of Ecology and Conservation Biology
Prof. Dr. Marianne Popp
partner