Genomic evidence of genetic variation with pleiotropic effects on caterpillar fitness and plant traits in a model legume

Plant-insect interactions are ubiquitous, and have been studied intensely because of their relevance to damage and pollination in agricultural plants, and to the ecology and evolution of biodiversity. Variation within species can affect the outcome of these interactions. Specific genes and chemicals that mediate these interactions have been identified, but studies of genome- or metabolome-wide intraspecific variation might be necessary to better explain patterns of host-plant use and adaptation in the wild. Here, we present such a study. We assess the consequences of genome-wide genetic variation in the model plant Medicago truncatula for Lycaeides melissa caterpillar growth and survival (larval performance). Using a rearing experiment and a whole-genome SNP data set (>5 million SNPs), we find that polygenic variation in M. truncatula explains 9-41% of the observed variation in caterpillar growth and survival. Genetic correlations among caterpillar performance and other plant traits,...