Research in the area of community genetics has been generating substantial evidence from many different plant-based systems to show that within-species plant genetic variation can have strong and wide-ranging effects on associated communities living on or in the plant, such as herbivores, parasites or mutualists. The majority of community genetics research has been conducted on trees and arthropods, particularly on foundation tree species, i.e., trees that play a pivotal role in defi ning the structure of the community (Whitham et al. 2012), and through this create locally stable conditions for other species by modulating and stabilizing fundamental ecosystem processes (Ellison et al. 2005). However, there is building evidence that within-species plant variation is also important in non-foundation species, such as short-lived or annual plants, that can infl uence population dynamics at small-scales and over a single season.