Although many ecological and evolutionary studies focus on single species or two-species interactions, there is a growing recognition that the factors determining the distribution and abundance of species, and the evolution of phenotypic traits, can only be understood in the context of multiple interactions. For example, interactions with antagonists and mutualists have historically been studied independently, although plants are often under simultaneous and potentially conflicting selective pressures exerted by both groups. My research integrates plant-animal interactions across mutualisms and antagonisms, including floral, foliar, and belowground tissues, to arrive at a more complete understanding of how multiple species select on resistance and attractive traits. My approach has combined novel techniques and experimental manipulations in the field with greenhouse and laboratory experiments to dissect aspects of this complex empirical question, and involves studies in both basic and applied systems.