Intraspecific phytochemical variation shapes community and population structure for specialist caterpillars

Abstract

Summary Chemically mediated plant–herbivore interactions contribute to the diversity of terrestrial communities and the diversification of plants and insects. While our understanding of the processes affecting community structure and evolutionary diversification has grown, few studies have investigated how trait variation shapes genetic and species diversity simultaneously in a tropical ecosystem.We investigated secondary metabolite variation among subpopulations of a single plant species, Piper kelleyi (Piperaceae), using high‐performance liquid chromatography (HPLC), to understand associations between plant phytochemistry and host‐specialized caterpillars in the genus Eois (Geometridae: Larentiinae) and associated parasitoid wasps and flies. In addition, we used a genotyping‐by‐sequencing approach to examine the genetic structure of one abundant caterpillar species, Eois encina, in relation to host phytochemical variation.We found substantive concentration differences among three major secondary metabolites, and these differences in chemistry predicted caterpillar and parasitoid community structure among host plant populations. Furthermore, E. encina populations located at high elevations were genetically different from other populations. They fed on plants containing high concentrations of prenylated benzoic acid.Thus, phytochemistry potentially shapes caterpillar and wasp community composition and geographic variation in species interactions, both of which can contribute to diversification of plants and insects.

Discovering variation of secondary metabolite diversity and its relationship with disease resistance inCornus floridaL.

“…It has been demonstrated that even small differences in genetic diversity (such as single amino acid substitutions) can yield large differences in chemical profiles (Kampranis et al., 2007), and several studies have found that higher intraspecific genetic diversity reduces herbivory and disease in plant populations (Hughes, Inouye, Johnson, Underwood, & Vellend, 2008). Moreover, emerging evidence has demonstrated how variation in intraspecific chemodiversity influences community diversity among different trophic interactions (Glassmire et al., 2016; Richards et al., 2015). In the context of this study, it is important to note the similarity between clustering patterns derived from genetic and metabolite data in addition to noting evidence that some diseased mountain subpopulations (Figure 1) have lower genetic and chemical diversity.…”

Host conservatism, geography, and elevation in the evolution of a Neotropical moth radiation

“…Thus, Eois could have diversified along phytochemical niche axes that were not quantified (Glassmire et al. ), which would also support the perspective that diversification in this group is driven by ecological opportunity associated with synergistic effects among multiple adaptive zones (Wilson et al. ).…”

“…) and even within a single species (Glassmire et al. ). Thus, Eois could have diversified along phytochemical niche axes that were not quantified (Glassmire et al.…”

“…Elevational differences, especially associated with the Andes Mountains, are also thought to promote Eois diversification (Strutzenberger and Fiedler ; Glassmire et al. ), resulting in elevationally stratified Eois communities (Rodríguez‐Castañeda et al. ).…”

Plant Antiherbivore Defense in Diverse Environments

“…In Piper, prenylated benzonic acid, chromene, and dimeric chromane at concentrations higher than 10% of dry weight of leaf material that compounds have synergistic or additive effect against herbivore attack also have been reported. In addition, concentration of these metabolites is correlated with increasing elevation in relation with UV exposure and photoactive properties, and more toxic plants support a lower diversity of specialist herbivores [81].…”