Host tracking or cryptic adaptation? Phylogeography of Pediobius saulius (Hymenoptera, Eulophidae), a parasitoid of the highly invasive horse-chestnut leafminer

Antonio Hernandez Lopez (1) , Rodolphe Rougerie (2) , Sylvie Augustin (1) , David Lees (1, 3) , Rumen Tomov (4) , Marc Kenis (5) , Ejup Cota (6) , Endrit Kullaj (7) , Christer Hansson (3) , Giselher Grabenweger (8) , Alain Roques (1) , Carlos Lopez-Vaamonde (1)

1 URZF - Unité de recherche Zoologie Forestière
2 ECODIV - Étude et compréhension de la biodiversité
3 Department of Entomology
4 UF - University of Forestry
5 CABI Europe - Switzerland - Centre for Agricultural and Biosciences International Europe - Switzerland
6 Plant Protection Department, Faculty of Agriculture and Environment
7 Department of Horticulture, Faculty of Agriculture and Food
8 Institute of Plant Health

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.

Mots clés: invasive alien species; horse chestnut leafminer; parasitoid; phylogenetic tree; cryptic species; host-parasitoid interaction; DNA sequencing; phylogeography; taxonomy; morphological variation; polyphagy

Domaines: Sciences du Vivant [q-bio]

Antonio Hernandez Lopez, Rodolphe Rougerie, Sylvie Augustin, David Lees, Rumen Tomov, et al.. Host tracking or cryptic adaptation? Phylogeography of Pediobius saulius (Hymenoptera, Eulophidae), a parasitoid of the highly invasive horse-chestnut leafminer. Evolutionary Applications, 2012, 5 (3), pp.256-269. ⟨10.1111/j.1752-4571.2011.00220.x⟩. ⟨hal-01190259⟩