The clover-rhizobium and bee-virus systems are linked through plant traits that have important implications for bee biology. Furthermore, the clover-rhizobium system is also important to multiple insect herbivores which depend on the nutrient-rich tissue of legume plants. Therefore, we hypothesize that the evolution of less cooperative rhizobia in response to long-term nitrogen (N)-addition will affect interactions with pollinators and herbivores because of changes in floral and other plant traits. Adam Dolezal, Jen Lau, Alex Harmon-Threatt, and others will test these hypotheses by quantifying the effects of both N and rhizobium evolution on plant traits and investigating how these traits affect bee visitation, behavior, and physiology, as well as herbivore survival and development. This starting point will facilitate future work that aims to identify how observed changes in plant traits affect bee immunity and health, as well as how rhizobium evolutionary effects on bee visitation feeds back to affect plant demography and might contribute to observed legume declines in high N environments in the field.