Intraspecific Variation In Plant Economic Traits Predicts Trembling Aspen Resistance To A Generalist Insect Herbivore

Abstract

Patterns of trait expression within some plant species have recently been shown to follow patterns described by the leaf economics spectrum paradigm. Resistance to herbivores is also expected to covary with leaf economics traits. We selected multiple mature Populus tremuloides genotypes from a common garden to assess whether aspen leaf economics patterns follow those observed among species globally. We also evaluated leaf economics strategies in the context of insect resistance by conducting bioassays to determine the effects of plant traits on preference and performance of Lymantria dispar. We found that: 1) intraspecific trait patterns of P. tremuloides parallel those exhibited by the interspecific leaf economics spectrum, 2) herbivores preferred leaves from genotypes with resource-acquisitive strategies, and 3) herbivores also performed best on genotypes with resource-acquisitive strategies. We conclude that a leaf economics spectrum that incorporates defense traits is a useful tool for explaining intraspecific patterns of variation in plant strategies, including resistance to herbivores.

Genomic and transcriptomic analyses reveal polygenic architecture for ecologically important traits in aspen (Populus tremuloides Michx.)

“…This may also be true for extended phenotypes, such as associated insect communities. In work concurrent with that reported here, Morrow (2022) found that several community metrics for herbivorous insects at the WisAsp common garden likely have undetected genetic associations-indicating that extended phenotypes themselves may exhibit polygenic architectures.…”

“…Genotype‐mediated growth‐defense trade‐offs are well established in aspen (Cole et al, 2021; Cope et al, 2019; Osier & Lindroth, 2006) and have been shown to differentially affect population genetic composition in contrasting environments (Cope et al, 2021). Moreover, divergent growth and defense phenotypes in aspen influence the community metrics of associated insect assemblages (Barker et al, 2019; Morrow, 2022). For example, a gibberellin 3‐beta‐dioxygenase gene (Potra003968g23830) associated with salicinoid phenolic glycosides in our GWA analyses has also been linked to the regulation of growth and defense responses in Solanum and Nicotiana spp.…”

Vertical stratification of leaf physical traits exerts bottom-up pressures on insect herbivory in a sugar maple temperate forest

“…However, much of the variation in plant leaf traits occurs in response to light intensity in line with the leaf economic spectrum (Messier et al 2017), in order to maximize photosynthesis under different conditions. These functional traits can also influence leaf resistance to herbivores and can therefore spatially structure bottom-up pressures on herbivores along sunlight gradients (Reich 2014;Messier et al 2017;Morrow et al 2022). This study investigates the importance of leaf traits heterogeneity across a vertical gradient in a temperate forest in structuring a pattern of insect herbivore damage.…”