Linking insect herbivory with plant traits: Phylogenetically structured trait syndromes matter

Abstract

AbstractQuestionsHerbivory is a fundamental ecological interaction underlying energy and mass flow between primary producers and consumers. Ecological theory describes plant biomass quality in terms of food for herbivores as a functional effect trait. We asked how leaf functional traits affect insect herbivory in a species‐rich meadow community.LocationČertoryje National Nature Reserve, Bílé Karpaty (White Carpathians) Protected Landscape Area, Czech Republic.MethodsWe assessed herbivory of 24 plant species co‐occurring in a species‐rich semi‐natural grassland by measuring herbivore damage caused by leaf‐chewing insects. Identification of trait–herbivory links was conducted by a comparative analysis based on a phylogenetically informed regression.ResultsPlant species strongly differed in leaf‐chewer herbivory. Interspecific differences in herbivory and most traits displayed a strong phylogenetic signal associated with the deep evolutionary split between monocot graminoids and dicot forbs. There were also pronounced correlations among individual traits. Herbivory was tightly related to an intercorrelated trait set describing fibre composition and Ca content. There was also a less pronounced negative effect of leaf biomass C:N ratio on herbivory. However, the observed association between traits and herbivory was phylogenetically structured in agreement with the univariate tests of phylogenetic signal.ConclusionHerbivory was associated with a whole syndrome of intercorrelated traits, among which it is not possible to choose a single best trait predictor. Moreover, the principal pattern in this trait syndrome was related to a macro‐evolutionary singularity. Such linkage among an ecosystem process, traits, and phylogeny complicates linking ecosystem processes with particular functional traits and may also occur elsewhere in natural ecosystems.