Population genetic data (COI, ddRAD) of Sialis lutaria (Insecta, Megaloptera) from the Emscher catchment (Germany)

As no population genetic studies of <i>S.lutaria</i> have to our knowledge been published so far and genetic resources are generally scarce for this species, we generated and present here population genetic data for 70 <i>S.lutaria</i> specimens for the mitochondrial cytochrome c oxidase I (COI) gene and, more importantly, high resolution genomic single nucleotide polymorphism (SNP) data for 71 specimens, generated with double-digest restriction site-associated sequencing (ddRAD-seq). These data can be valuable for further studies, analysing the population genetic structure, dispersal pathways and potential gene flow barriers for <i>S.lutaria</i> on a larger geographic scale. Additional to presenting the data, we also give first insights in the population structure on a small geographic scale (area of approx. 15 km²). While the population differentiation was generally low, as expected on this small scale, we still found that gene flow was not equally strong between all populations, but that one population played a central role as a source and sink population, which cannot only be explained by the distance between populations.