Spineless and overlooked: Metabarcoding fills knowledge gaps of population genetic structure in Mediterranean invertebrates

Anna Thomasdotter

Population connectivity is a fundamental aspect of ecology and has effects on resilience, adaptation ability, and evolutionary potential. In the marine environment, benthic invertebrates frequently have limited dispersal and thus comparatively low connectivity between populations. This increases their vulnerability to environmental shifts. In the present study, I use metabarcoding to investigate intraspecific genetic patterns in benthic invertebrates and fill knowledge gaps in this group of organisms. I present diversity estimates and haplotype networks for 145 species from three regions in the Mediterranean Sea, of which many are studied at population level for the first time. Several species exhibit genetic patterns that indicate population structure or the presence of cryptic lineages. For species that have previously been studied in the Mediterranean, this study provides information for additional regions and presents new haplotypes. I conclude that these methods provide added value to population-level studies in the appropriate context but are currently limited by poor database coverage for a significant number of invertebrate species.