Atmospheric change alters foliar quality of host trees and performance of two outbreak insect species

Abstract

This study examined the independent and interactive effects of elevated carbon dioxide (CO(2)) and ozone (O(3)) on the foliar quality of two deciduous trees species and the performance of two outbreak herbivore species. Trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) were grown at the Aspen FACE research site in northern Wisconsin, USA, under four combinations of ambient and elevated CO(2) and O(3). We measured the effects of elevated CO(2) and O(3) on aspen and birch phytochemistry and on gypsy moth (Lymantria dispar) and forest tent caterpillar (Malacosoma disstria) performance. Elevated CO(2) nominally affected foliar quality for both tree species. Elevated O(3) negatively affected aspen foliar quality, but only marginally influenced birch foliar quality. Elevated CO(2) slightly improved herbivore performance, while elevated O(3) decreased herbivore performance, and both responses were stronger on aspen than birch. Interestingly, elevated CO(2) largely offset decreased herbivore performance under elevated O(3). Nitrogen, lignin, and C:N were identified as having strong influences on herbivore performance when larvae were fed aspen, but no significant relationships were observed for insects fed birch. Our results support the notion that herbivore performance can be affected by atmospheric change through altered foliar quality, but how herbivores will respond will depend on interactions among CO(2), O(3), and tree species. An emergent finding from this study is that tree age and longevity of exposure to pollutants may influence the effects of elevated CO(2) and O(3) on plant-herbivore interactions, highlighting the need to continue long-term atmospheric change research.

Climate Influences the Content and Chemical Composition of Foliar Tannins in Green and Senesced Tissues of Quercus rubra

“…Furthermore, by influencing the chemical composition of senesced litter that fuels the metabolism of soil heterotrophs, the climate-induced physiological alterations in plants could also influence soil nutrient cycling and ecosystem productivity. For example, climate-induced changes in the composition of senescing leaves (Top and Filley, 2014; Suseela et al, 2015) could affect the subsequent detritivory (Currano et al, 2008; Couture et al, 2012) that regulates the cycling of soil carbon and mineral nutrients (Aerts, 1997; Liu et al, 2009; Suseela et al, 2013), which in turn could influence ecosystem productivity. These protracted influences of environmental stress on ecosystem performance could be mediated in part by climatic regulation of defense compounds that retain their biological-inhibitory properties even after tissue senescence.…”

Atmospheric change alters performance of an invasive forest insect

“…single instar) performance of gypsy moths (Couture et al, 2012); in this study we examined effects of these gases on the long-term performance (survivorship, development time, pupal weight, and fecundity). Recent findings from this site have shown that aspen and birch exposed to elevated CO 2 and O 3 alter the short-term (i.e.…”

Fecal-FT-NIRS as a Noninvasive Tool for Assessing Diet Quality of Mediterranean Deer

“…This is positively correlated with the digestibility of the diet as well (Irwin et al 1993). Increased C:N ratio due to reductions in the concentrations of N and increases in structural carbohydrates lead to foliar quality decrease (Couture et al 2012).…”