To maximize reproductive output, plants need to deal with antagonists such as herbivores, while engaging in interactions with mutualists such as pollinators. Most plants respond to attack by herbivores with phenotypic changes to repel or kill the attackers, and these responses are often herbivore-specific. When plants are flowering, herbivore-induced plant responses can result in changes in flower traits, with consequences for the visitation by flower visitors. The aim of this thesis project was to address specificity of herbivore-induced changes in flower traits, and consequences for plant interactions with antagonistic and mutualistic flower visitors, and plant reproduction. This thesis makes an important contribution to our understanding of how species traits can influence ecological network structure. The demonstrated importance of trait variation in plant-mediated (indirect) herbivore – flower-visitor interactions for flower-visitor community dynamics and associated plant fitness consequences will stimulate further research on ecological and evolutionary dynamics in multispecies communities with antagonists and mutualists.