Community genetics aims to understand the effects of intraspecific genetic variation on community composition and diversity, thereby connecting community ecology with evolutionary biology. Research has shown that plant genetics shape the community of insects that can colonize the plant. Yet until recently, this research has been focused at the genotypic level, thus the plant genes and gene networks that influence insect community composition remain poorly understood. WisAsp, a genetic mapping garden of aspen (Populus tremuloides), addresses that void. We have surveyed multiple ecologically-important tree traits and insect communities over several years at WisAsp.
Here, we describe the results for one trait, leaf phenology, and how it shapes communities of leaf-modifying insects. Date of bud break varied by 27 and 34 days among the aspen genotypes at WisAsp in 2014 and 2015, respectively. Bud break date was correlated with insect community nonmetric multidimensional scaling (NMDS) coordinates (P < 0.001), indicating that insect communities differed between genotypes with early and late leaf phenologies. Early bud breaking genotypes had more oblique-banded leaf-roller caterpillars (Choristoneura rosaceana), while late bud breaking genotypes had more serpentine leaf-miners (Phyllocynistis populiella; species indicator analysis, P < 0.001). Next, we will use genome-wide association (GWA) to identify the genes in aspen that likely underlie variation in both aspen leaf phenology and insect community composition. Our findings will provide insights into the genetic bases of plant-insect interactions in a natural, community context and shed light on potential mechanisms of trophic interactions and community evolution.