An abundance of empirical studies have shown that plant species diversity and genotypic diversity have important effects on interactions between plants and higher trophic levels. While these studies greatly improved our understanding of the potential consequences of plant diversity, they left unresolved the trait-mediated mechanisms by which plant diversity influences plant-animal interactions. This organized oral session highlights and synthesizes recent work that is moving beyond the traditional focus on species and genotypic diversity to examine how plant-animal interactions depend on diversity and variability in plant traits. Speakers in the session will discuss plant trait diversity and variability across a range of spatial and temporal scales. At fine scales, plant traits, including key defenses, vary temporally within individual plants through ontogeny. At intermediate scales, neighboring plants often differ in phytochemistry in important ways. At large scales, plant traits vary dramatically across entire landscapes, and different landscapes can have different levels of trait variability. This session, by examining differences and similarities across scales of plant trait diversity, aims to develop a holistic and mechanistic understanding of the consequences of plant trait diversity and variability for higher trophic levels.