RT Journal Article SR Electronic T1 Genetic variants affecting plant size and chemical defenses jointly shape herbivory in Arabidopsis JF bioRxiv FD Cold Spring Harbor Laboratory SP 156299 DO 10.1101/156299 A1 AD Gloss A1 B Brachi A1 MJ Feldmann A1 SC Groen A1 C Bartoli A1 J Gouzy A1 ER LaPlante A1 CG Meyer A1 HS Pyon A1 SC Rogan A1 F Roux A1 J Bergelson A1 NK Whiteman YR 2017 UL http://biorxiv.org/content/early/2017/06/27/156299.abstract AB Herbivorous insects exhibit strong feeding preferences when choosing among plant genotypes, yet experiments to map loci mediating plant susceptibility to herbivory rarely incorporate host choice. To address this gap, we applied genome-wide association (GWA) mapping to uncover genetic polymorphisms mediating damage from foraging insects (two populations of Scaptomyza flava) across a mixture of Arabidopsis thaliana genotypes in experimental enclosures. The effect of chemical defenses (glucosinolates) on herbivory depended on herbivore genotype. Unlike many studies that minimize the effects of host choice behavior, we also found a large effect of plant size on herbivory—likely through its effect on plant apparency—that was independent of herbivore genotype. These herbivory-associated loci are polymorphic at fine spatial scales, and thus have potential to shape variation in herbivory within natural populations. We also show that the polymorphism with the largest effect on herbivory underlies adaptive latitudinal variation in Arabidopsis plant size across Europe. Overall, our results provide genetic support for ecological observations that variation in both chemical defenses and non-canonical defense traits (e.g., plant size and phenology) jointly shapes plant-herbivore interactions.