Coelopa frigida is an important coastal invertebrate along the Scandinavian coastline that inhabits “wrackbeds” (accumulations of decomposing seaweed) and has an inversion polymorphism on chromosome I (spanning 10% of the genome and containing at least 100 genes) that consists of an α and β version. This project encompasses several sub-projects with the overall goal of understanding how the inversion has evolved and contributed to adaptation. There are several ongoing projects that are using this space: 1. Analysis of whole genome re-sequencing data from 6 populations across Sweden and Norway, 2. Analysis of whole genome sequencing data from a number of closely related species of seaweed flies, 3. Simulation study testing changes in allelic content of inversions over long time scales.