Intraspecific variability in the parasitoid wasp Trichogramma chilonis: can we predict the outcome of hybridization?

Authors

  • Chiara Benvenuto,

    1. Biology of Introduced Populations, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
    Current affiliation:
    1. UCD School of Biology & Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
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  • Elisabeth Tabone,

    1. Research and Development in Biological Control, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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  • Elodie Vercken,

    1. Biology of Introduced Populations, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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  • Nathalie Sorbier,

    1. Research and Development in Biological Control, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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  • Etty Colombel,

    1. Research and Development in Biological Control, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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  • Sylvie Warot,

    1. Research and Development in Biological Control, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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  • Xavier Fauvergue,

    1. Biology of Introduced Populations, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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  • Nicolas Ris

    Corresponding author
    1. Research and Development in Biological Control, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
    • Biology of Introduced Populations, Institute Sophia-Agrobiotech, INRA–CNRS–UNS, Sophia-Antipolis, France
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Correspondence

Nicolas Ris, Research and Development in Biological Control, Institute Sophia-Agrobiotech, (INRA–CNRS–UNS), Sophia-Antipolis, France.

Tel.: +33 4 923 86501;

fax: +33 4 923 86401;

e-mail: nicolas.ris@sophia.inra.fr

Abstract

In the framework of biological control, the selection of effective natural enemies determines the final pest control. Thus, the genetic improvement of biocontrol agents could enhance the efficiency of biocontrol programs. Although promising, this approach has rarely been applied in this field. At the intraspecific level, hybridization between divergent populations of biocontrol agents is expected to promote hybrid vigor (heterosis), but it is not clear to what extent. An even more difficult task is the ability to predict the fitness of hybrids from the biological characteristics of their parents. We investigated these general questions by crossing seven populations of the parasitoid wasp Trichogramma chilonis (Hymenoptera: Trichogrammatidae). Our results show different levels of mating compatibilities among populations, including asymmetric or almost complete reproductive isolation. Hybrids' performance (fitness of the F 1 generation) ranges from inbreeding depression to heterosis. It was possible, to some extent, to predict hybrid fitness from pairwise genetic and phenotypic distances among parents, in accordance with the ‘dominance’ hypothesis. This may provide general guidelines for the genetic improvement of biological control agents.

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