Over the past decade it has become clear that variation between individuals of the same species (called intraspecific variation) can have profound effects on ecological communities. Variation between genotypes of the same species in key functional traits, like plant phenology or predator feeding morphology, can cascade to alter community structure and ecosystem functions. For this study we used a factorial experiment to assess how variation in two species within the same ecosystem, a primary producer and top predator, interact to shape the ecological community and ecosystem functions. We uncovered interactive effects, whereby the combinations of genotypes from these two species had notable effects on the the ecological community. The results from this paper highlight that the true importance of intraspecific variation in ecology may be underappreciated, as few studies have assessed the effects of this variation in multiple co-occurring species.