Genomic distinctness despite shared color patterns among threatened populations of a tiger beetle

Conservation biologists have long debated the value of subspecies, which are morphologically and geographically identifiable but not necessarily evolutionarily distinctive. One example of a controversial subspecies is Cicindela formosa gibsoni, a tiger beetle that is nationally listed as threatened in Canada and whose taxonomic status is based primarily on its unique elytral (forewing) color pattern. To determine whether C. f. gibsoni represents one or more genetically distinctive units, we sampled 14 populations within or near this subspecies’ disjunct North American range and assessed their genetic differentiation from neighboring and phenotypically distinctive populations of C. f. formosa and C. f. fletcheri. Instead of clustering by color pattern, analyses of mitochondrial and nuclear markers recovered three geographically structured genetic groupings: a northern cluster from Canada, a southwestern cluster from northwestern Colorado, and a southeastern cluster of US populations east...