title: Can parasites halt the invader? Mermithid nematodes parasitizing the yellow-legged Asian hornet in France.
abstract: Since its introduction in France 10 years ago, the yellow-legged Asian bee-hawking hornet Vespa velutina has rapidly spread to neighboring countries (Spain, Portugal, Belgium, Italy, and Germany), becoming a new threat to beekeeping activities. While introduced species often leave behind natural enemies from their original home, which benefits them in their new environment, they can also suffer local recruitment of natural enemies. Three mermithid parasitic subadults were obtained from V. velutina adults in 2012, from two French localities. However, these were the only parasitic nematodes reported up to now in Europe, in spite of the huge numbers of nests destroyed each year and the recent examination of 33,000 adult hornets. This suggests that the infection of V. velutina by these nematodes is exceptional. Morphological criteria assigned the specimens to the genus Pheromermis and molecular data (18S sequences) to the Mermithidae, due to the lack of Pheromermis spp. sequences in GenBank. The species is probably Pheromermis vesparum, a parasite of social wasps in Europe. This nematode is the second native enemy of Vespa velutina recorded in France, after a conopid fly whose larvae develop as internal parasitoids of adult wasps and bumblebees. In this paper, we provide arguments for the local origin of the nematode parasite and its limited impact on hornet colony survival. We also clarify why these parasites (mermithids and conopids) most likely could not hamper the hornet invasion nor be used in biological control programs against this invasive species.
authors.affiliation: Institut de Systématique, Évolution, Biodiversité, ISYEB, UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum National d'Histoire Naturelle, Sorbonne Universités , Paris , France.
authors.forename: Claire
authors.initials: C
authors.lastname: Villemant
authors.affiliation: Service de Systématique moléculaire, UMS 2700 CNRS, Muséum National d'Histoire Naturelle , Paris , France.
authors.forename: Dario
authors.initials: D
authors.lastname: Zuccon
authors.affiliation: Institut de Systématique, Évolution, Biodiversité, ISYEB, UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum National d'Histoire Naturelle, Sorbonne Universités , Paris , France.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Rome
authors.affiliation: Institut de Systématique, Évolution, Biodiversité, ISYEB, UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum National d'Histoire Naturelle, Sorbonne Universités , Paris , France.
authors.forename: Franck
authors.initials: F
authors.lastname: Muller
authors.affiliation: Department of Integrative Biology, Oregon State University , Corvallis, OR , USA.
authors.forename: George O
authors.initials: GO
authors.lastname: Poinar
authors.affiliation: Institut de Systématique, Évolution, Biodiversité, ISYEB, UMR 7205 - CNRS, MNHN, UPMC, EPHE, Muséum National d'Histoire Naturelle, Sorbonne Universités , Paris , France.
authors.forename: Jean-Lou
authors.initials: JL
authors.lastname: Justine
keywords: Asian hornet; Biological control; France; Hymenoptera; Invasive species; Nematodes