title: Ongoing ecological speciation in Cotesia sesamiae, a biological control agent of cereal stem borers.
abstract: To develop efficient and safe biological control, we need to reliably identify natural enemy species, determine their host range, and understand the mechanisms that drive host range evolution. We investigated these points in Cotesia sesamiae, an African parasitic wasp of cereal stem borers. Phylogenetic analyses of 74 individual wasps, based on six mitochondrial and nuclear genes, revealed three lineages. We then investigated the ecological status (host plant and host insect ranges in the field, and host insect suitability tests) and the biological status (cross-mating tests) of the three lineages. We found that one highly supported lineage showed all the hallmarks of a cryptic species. It is associated with one host insect, Sesamia nonagrioides, and is reproductively isolated from the other two lineages by pre- and postmating barriers. The other two lineages had a more variable phylogenetic support, depending on the set of genes; they exhibited an overlapping and diversified range of host species and are not reproductively isolated from one another. We discuss the ecological conditions and mechanisms that likely generated this ongoing speciation and the relevance of this new specialist taxon in the genus Cotesia for biological control.
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France ; INRA, UMR 1392, Institut d'Ecologie et des Sciences de l'Environnement de Paris Paris, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Kaiser
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France ; icipe: African Insect Science for Food and Health Nairobi, Kenya.
authors.forename: Bruno Pierre
authors.initials: BP
authors.lastname: Le Ru
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France.
authors.forename: Ferial
authors.initials: F
authors.lastname: Kaoula
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais, UFR Sciences et Techniques Tours, France.
authors.forename: Corentin
authors.initials: C
authors.lastname: Paillusson
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Capdevielle-Dulac
authors.affiliation: icipe: African Insect Science for Food and Health Nairobi, Kenya.
authors.forename: Julius Ochieng
authors.initials: JO
authors.lastname: Obonyo
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais, UFR Sciences et Techniques Tours, France.
authors.forename: Elisabeth A
authors.initials: EA
authors.lastname: Herniou
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais, UFR Sciences et Techniques Tours, France.
authors.forename: Severine
authors.initials: S
authors.lastname: Jancek
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France ; Ecologie, Systématique et Evolution, UMR - 8079 UPS-CNRS-AgroParisTech, Univ. Paris-Sud Orsay Cedex, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Branca
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France ; icipe: African Insect Science for Food and Health Nairobi, Kenya.
authors.forename: Paul-André
authors.initials: PA
authors.lastname: Calatayud
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Silvain
authors.affiliation: Laboratoire Evolution, Génomes, Comportement et Ecologie, UMR CNRS-Univ. Paris-Sud-IRD, Univ. Paris-Saclay Gif-sur-Yvette Cedex, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Dupas
keywords: Africa; Hymenoptera; adaptation; cryptic species; ecological niche; evolution; geographic distribution; host range; parasitic wasp; phylogeny; reproductive isolation; virulence