Mitochondrial and microsatellite DNA markers reveal a Balkan origin for the highly invasive horse-chestnut leaf miner Cameraria ohridella (Lepidoptera, Gracillariidae)

Authors


  • Romain Valade did his MSc project on invasion genetics of C. ohridella anad is currently doing a PhD at INRA Grignon. Marc Kenis, Sylvie Augustin, Ferenc Lakatos and Alain Roques are forest entomologists and invasion ecologists. Antonio Hernandez is a post-doctoral researcher at INRA Orleans. Neus Mari developed microsatellites for C. ohridella during her MSc thesis. Rodolphe Rougerie is a systematist working on DNA barcoding of Lepidoptera. Emmanuelle Magnoux is research assistant in the molecular lab at INRA Orleans. Carlos Lopez, along with Sylvie Augustin, supervised Roman and Neus' MSc thesis. Carlos works on evolutionary ecology and molecular systematics of insects.

C. Lopez-Vaamonde, Fax: +33 (0) 2 38 41 78 79; E-mail: carlos.lopez-vaamonde@orleans.inra.fr

Abstract

Biological invasions usually start with a small number of founder individuals. These founders are likely to represent a small fraction of the total genetic diversity found in the source population. Our study set out to trace genetically the geographical origin of the horse-chestnut leafminer, Cameraria ohridella, an invasive microlepidopteran whose area of origin is still unkown. Since its discovery in Macedonia 25 years ago, this insect has experienced an explosive westward range expansion, progressively colonizing all of Central and Western Europe. We used cytochrome oxidase I sequences (DNA barcode fragment) and a set of six polymorphic microsatellites to assess the genetic variability of C. ohridella populations, and to test the hypothesis that C. ohridella derives from the southern Balkans (Albania, Macedonia and Greece). Analysis of mtDNA of 486 individuals from 88 localities allowed us to identify 25 geographically structured haplotypes. In addition, 480 individuals from 16 populations from Europe and the southern Balkans were genotyped for 6 polymorphic microsatellite loci. High haplotype diversity and low measures of nucleotide diversities including a significantly negative Tajima’s D indicate that C. ohridella has experienced rapid population expansion during its dispersal across Europe. Both mtDNA and microsatellites show a reduction in genetic diversity of C. ohridella populations sampled from artificial habitats (e.g. planted trees in public parks, gardens, along roads in urban or sub-urban areas) across Europe compared with C. ohridella sampled in natural stands of horse-chestnuts in the southern Balkans. These findings suggest that European populations of C. ohridella may indeed derive from the southern Balkans.

Ancillary