Call for talks and posters for ESEB symposium "Evolution of Biotic Interactions across Scales" (Symposium #S18) at ESEB 2025, in Barcelona Spain. The ESEB 2025 Congress will be held at the International Convention Centre of Barcelona (CCIB) in Barcelona, Spain, from August 17 to 22,2025. We consider this symposium to be the home of all things biotic interactions, e.g. from host-parasite co-evolution to predator-prey interactions, from genomic conflicts to mutualisms. Specifically, we encourage contributions that study the evolutionary ecology of biotic interactions, as described below. Biotic interactions are a core component of evolutionary ecology. Understanding their evolution is key to predicting how global change will impact on ecosystems. Their nature is mediated by the costs and benefits experienced by the interacting partners. Increasingly, it is becoming clear that biotic interactions do not fall into fixed categories, but rather form a continuum from antagonism to mutualism. Moreover, the nature of any given interaction can depend on the ecological conditions currently experienced, with otherwise virulent pathogens potentially conveying stress resistance, or former mutualists starting to cheat. While the concept of a dynamic mutualism-antagonism continuum has been embraced in some fields, in others these categories remain rigid. This hinders our understanding of the evolution and the potential for plasticity of biotic interactions in rapidly changing ecosystems. Here, we want to bring together researchers across different fields and scales, i.e. from host-pathogen interactions to classical mutualisms, and from sub-cellular interactions such as transposable elements to the interactions of multi-cellular organisms such as plants and pollinators. The ultimate aim of the symposium is to work towards a common theoretical and experimental framework for studying the dynamic evolutionary ecology of biotic interactions under conditions of rapid global change. Invited speakers: Prof. Stineke van Houte, University of Exeter, UK Prof. Jordi Bascompte, University of Zurich, Switzerland Organizers: Prof. Lena Wilfert, University of Ulm - lena.wilfert@uni-ulm.de Dr. Peter Czuppon, University of Münster Prof. Dr. Lena Wilfert University of Ulm Institute of Evolutionary Ecology and Conservation Genomics Albert-Einstein Allee 11 D-89069 Ulm Germany Tel.: 0049-731-5030615 Fax: 0049-731-5022683 email: lena.wilfert@uni-ulm.de Website: https://www.uni-ulm.de/nawi/evolutionary-ecology-and-conservation-genomics/prof-dr-lena-wilfert Lena Wilfert Ulm (to subscribe/unsubscribe the EvolDir send mail to golding@mcmaster.ca)