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, 4. Chromatin accessibility changes and gene expression differences due to the inversion, using ATAC-Seq and RNASeq data.