Studying the evolutionary history of trait divergence, in particular those related to dispersal capacity, is of major interest for the process of local adaptation and metapopulation dynamics. Here, we reconstruct the evolution of different alleles at the nuclear encoded mitochondrial NADP+-dependent isocitrate dehydrogenase (mtIdh) locus of the ground beetle Pogonus chalceus that are differentially and repeatedly selected in short- and long-winged populations in response to different hydrological regimes at both allopatric and sympatric scales along the Atlantic European coasts. We sequenced 2,788 bp of the mtIdh locus spanning a ~7 kb genome region and compared its variation with that of two supposedly neutral genes. mtIdh sequences show (i) monophyletic clustering of the short-winged associated mtIDH-DE haplotypes within the long-winged associated mtIDH-AB haplotypes, (ii) a more than tenfold lower haplotype diversity associated with the mtIDH-DE alleles compared to the mtIDH-AB alleles, and (iii) a high number of fixed nucleotide differences between both mtIDH haplotype clusters. Coalescent simulations suggest that this observed sequence variation in the mtIdh locus is most consistent with a singular origin in a partially isolated subpopulation, followed by a relatively recent spread of the mtIDH-DE allele in short-winged populations along the Atlantic coast. These results demonstrate that even traits associated with decreased dispersal capacity can rapidly spread and that reuse of adaptive alleles plays an important role in the adaptive potential within this sympatric mosaic of P. chalceus populations.,Location and codesTable containing code, locations, species names and GenBank accession numbersSequence_alignmentsSequence alignments of Pogonus chalcesu mitochondrial NADP+-dependent isocitrate dehydrogenase (mtIdh), cytoplasmic NADP+-dependent isocitrate dehydrogenase (cytIdh), enolase, cytochrome oxidase subunit one (cox1), a mitochondrial region spanning the NADH subunit I (180 bp), the tRNA-Leu gene (64 bp) and the 16S rRNA gene (111 bp) and cytochrome b (cob; 468 bp)Tree_filesNexus files containing Bayasian Interference trees of mitochondrial NADP+-dependent isocitrate dehydrogenase, ctoplasmic NADP+-dependent Isocitrate dehydrogenase, enolase and concatenated alignement of cox1, nad1, cob. Used for phylogentic reconstruction and divergence time estimates.Scripts coalescent simulationsPython script used for performing coalescent simulations, including bash script fro cluster submission and instructions to adjust dendropy module.Scripts_coalescent_simulations.rar,