title: Host tracking or cryptic adaptation? Phylogeography of Pediobius saulius (Hymenoptera, Eulophidae), a parasitoid of the highly invasive horse-chestnut leafminer.
abstract: Classical biological control is often advocated as a tool for managing invasive species. However, accurate evaluations of parasitoid species complexes and assessment of host specificity are impeded by the lack of morphological variation. Here, we study the possibility of host races/species within the eulophid wasp Pediobius saulius, a pupal generalist parasitoid that parasitize the highly invasive horse-chestnut leaf-mining moth Cameraria ohridella. We analysed the population genetic structure, host associations and phylogeographic patterns of P. saulius in Europe using the COI mitochondrial gene. This marker strongly supports a division into at least five highly differentiated parasitoid complexes, within two of which clades with differing degrees of host specialization were found: a Balkan clade that mainly (but not only) attacks C. ohridella and a more generalist European group that attacks many hosts, including C. ohridella. The divergence in COI (up to 7.6%) suggests the existence of cryptic species, although this is neither confirmed by nuclear divergence nor morphology. We do not find evidence of host tracking. The higher parasitism rates observed in the Balkans and the scarcity of the Balkan-Cameraria haplotypes out of the Balkans open the possibility of using these Balkan haplotypes as biological control agents of C. ohridella elsewhere in Europe.
authors.affiliation: INRA, UR0633 Zoologie Forestière Orléans, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Hernández-López
authors.affiliation: ECODIV, EA1293, University of Rouen Mont-Saint-Aignan, France.
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Rougerie
authors.affiliation: INRA, UR0633 Zoologie Forestière Orléans, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Augustin
authors.affiliation: INRA, UR0633 Zoologie Forestière Orléans, France ; Department of Entomology Natural History Museum, London, UK.
authors.forename: David C
authors.initials: DC
authors.lastname: Lees
authors.affiliation: University of Forestry Sofia, Bulgaria.
authors.forename: Rumen
authors.initials: R
authors.lastname: Tomov
authors.affiliation: CABI Europe-Switzerland Delémont, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Kenis
authors.affiliation: Plant Protection Department, Faculty of Agriculture and Environment, Agricultural University of Tirana Tirana, Albania.
authors.forename: Ejup
authors.initials: E
authors.lastname: Çota
authors.affiliation: Department of Horticulture, Faculty of Agriculture and Food, Agricultural University of Tirana Tirana, Albania.
authors.forename: Endrit
authors.initials: E
authors.lastname: Kullaj
authors.affiliation: Department of Entomology Natural History Museum, London, UK.
authors.forename: Christer
authors.initials: C
authors.lastname: Hansson
authors.affiliation: Institute of Plant Health, Austrian Agency for Health and Food Safety Vienna, Austria.
authors.forename: Giselher
authors.initials: G
authors.lastname: Grabenweger
authors.affiliation: INRA, UR0633 Zoologie Forestière Orléans, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Roques
authors.affiliation: INRA, UR0633 Zoologie Forestière Orléans, France.
authors.forename: Carlos
authors.initials: C
authors.lastname: López-Vaamonde
keywords: Cameraria ohridella; cryptic species; invasion; phylogeography; polyphagy