Document: RIC-3-43-8

Consequences of enriched CO₂ and O₃ for forest insects.

LINDROTH, R.L.*, B.J.KOPPER and C.S.AWMACK

University of Wisconsin, Madison, WI 53706 USA ¹

Abstract:
Elevated levels of atmospheric CO₂, both alone and in combination with other pollutants such as O₃, have been shown to alter interactions between trees and tree-feeding insects. Previous studies indicated that chewing insects may be adversely affected by changes in plant quality, whereas sap-feeding insects may benefit. Most of these studies, however, have been conducted in controlled environments. We investigated the effects of enriched CO₂ and O₃ on performance of aspen blotch leafminers (Phyllonorycter tremuloidiella) and aphids (Chaitophorus stevensis) at a Free-Air CO₂ Enrichment (FACE) site in northern Wisconsin, U.S.A. Rates of leaf colonization by leafminers declined in all elevated CO₂ or O₃ treatments. The pollutants had relatively small effects on leafminer performance (development, pupal weight), however, with the largest impacts deriving from combined CO₂ and O₃. With respect to aphids, pollutant treatment had no discernible effects on development time, fecundity, or intrinsic rate of increase, but did influence adult weight (highest at elevated CO₂) and embryo number (highest at ambient CO₂). Variation in aphid population densities among treatments appeared to be related to differential impact of the pollutants on natural enemy complexes.

Keywords: carbon dioxide, ozone, FACE, plant-insect interactions

This abstract is being presented at: 9:30 AM in session:
Oral Session #4: Herbivore Responses to Plants.