MITOCHONDRIAL-DNA SEQUENCE VARIATION AND PHYLOGEOGRAPHY OF PIMELIA DARKLING BEETLES ON THE ISLAND OF TENERIFE (CANARY-ISLANDS)

Four morphological taxa of the beetle genus Pimelia (Coleoptera, Teneb rionidae) are known to exist on the Atlantic island of Tenerife. We ha ve obtained DNA sequences for 61 individuals from these taxa across th e island for a 200 bp long fragment of the mitochondrial COI gene. In addition, a restriction site polymorphism in the nuclear rRNA ITS-1 se quence was identified and screened in a sample of these individuals us ing the enzyme Kpn2I. The results were analysed using approaches which allow inferences to be made about the population genetic structure an d the mitochondrial genealogy of these closely related beetles. The mt DNA haplotype distribution and the estimates of sequence divergence re vealed the presence of two ancient mtDNA lineages which coincide with the disjunct volcanic evolution of the island. The ITS-1 polymorphism was found to be diagnostic of these two lineages. However, the morphol ogical and mitochondrial phylogenies were found to be discordant. We a rgue that this is possibly the result of rapid morphological change, p roduced by selection in different habitats, which has been recently su perimposed on an older mitochondrial DNA divergence.