Phylogeographic pattern of the plane leaf miner, Phyllonorycter platani (STAUDINGER, 1870) (Lepidoptera: Gracillariidae) in Europe.

Background: The plane leaf miner, Phyllonorycter platani is a widely distributed insect species on plane trees and has a well-documented colonisation history in Europe over the last century. However, phylogeographic data of the species are lacking.

Results: We analysed 284 individuals from 38 populations across Europe, Asia, and North America. A 1242 bp fragment of the mitochondrial COI gene and an 893 bp fragment of the 28S rDNA has been Sanger sequenced. Twenty-four haplotypes were detected on the COI gene, and two alleles were identified on the 28S rDNA. We revealed two distinct clades for both markers reflecting the geographic origins, Asia and Europe. The genetic distance between the two main clades is 2.08% on the COI gene and 0.10% on the nuclear DNA. An overlapping zone of the two clades was found across Eastern Europe and the Anatolian Peninsula. We detected heterozygote individuals of the 28S rDNA gene in Moldavia, Ukraine and in the southern part of Turkey. These suggest that the two clades can hybridise. Furthermore, the presence of European type homozygote individuals has been confirmed in the southern part of Turkey as well.

Conclusions: We have shown that both post-glacial recolonization and recent expansion events influenced the present genetic structure of P. platani. The genetic patterns revealed at least two refugia during the last ice age: one in the Balkan Peninsula and the other in the Caucasus region. Recent expansion was detected in some European and Central Asian populations. The two main clades (Europe/Asia) show definite genetic differences; however, several hybrid individuals were found in the overlapping zone as well (stretching over Eastern Europe and the Anatolian Peninsula). Discrepancies in mitochondrial and nuclear data indicate introgressions in the southern part of the Anatolian Peninsula.