Preface to the Proceedings of the 18th International Symposium on Insect–Plant Relationships

Abstract The 18th Symposium on Insect‐Plant Relationships (SIP‐18) took place in Bielefeld, Germany, in August 2024. Since the previous meeting (SIP‐17) could be executed only online because of the pandemic, we enjoyed meeting in person even more. The conference has resulted in five exciting contributions to the journal Entomologia Experimentalis et Applicata . Two of these are reviews, one presenting an overview of the arthropod fauna associated with the plant genus Annona and the other providing an ecological and evolutionary perspective on pharmacophagy—that is, the attraction of insects to plant specialized metabolites and their use for purposes other than nutrition in insects. Three research articles show original work on differential gene expression in larvae sequestering plant metabolites, resistance to thrips in several Chrysanthemum accessions, and the role of light intensity in physical defense against native and invasive caterpillar species in trees, respectively. These articles are presented in this themed issue as the proceedings of SIP‐18, in addition to nine other articles relevant to the research field of insect–plant relationships.