Outbreaks, gene flow and effective population size in the migratory locust, Locusta migratoria: a regional-scale comparative survey

Authors

  • MARIE-PIERRE CHAPUIS,

    1. Unité Mixte de Recherche Centre de Biologie et Gestion des Populations (INRA/IRD/Cirad/Montpellier SupAgro), Institut National de la Recherche Agronomique, Campus international de Baillarguet, CS 30016, F-34988 Montferrier-sur-Lez cedex, France
    2. Génétique et Evolution des Maladies Infectieuses Unité Mixte de Recherche 2724 CNRS-IRD, Institut de la Recherche et du Développement, 911 avenue Agropolis, 34394 Montpellier Cedex 5, France
    3. Centre de coopération internationale en recherche agronomique pour le développement Acridologie, TA A-50/D, F-34398, Montpellier, France
    4. School of Biological Sciences, University of Sydney, The Macleay Building A12, Sydney, NSW 2006, Australia
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  • ANNE LOISEAU,

    1. Unité Mixte de Recherche Centre de Biologie et Gestion des Populations (INRA/IRD/Cirad/Montpellier SupAgro), Institut National de la Recherche Agronomique, Campus international de Baillarguet, CS 30016, F-34988 Montferrier-sur-Lez cedex, France
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  • YANNIS MICHALAKIS,

    1. Génétique et Evolution des Maladies Infectieuses Unité Mixte de Recherche 2724 CNRS-IRD, Institut de la Recherche et du Développement, 911 avenue Agropolis, 34394 Montpellier Cedex 5, France
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  • MICHEL LECOQ,

    1. Centre de coopération internationale en recherche agronomique pour le développement Acridologie, TA A-50/D, F-34398, Montpellier, France
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  • ALEX FRANC,

    1. Centre de coopération internationale en recherche agronomique pour le développement Acridologie, TA A-50/D, F-34398, Montpellier, France
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  • ARNAUD ESTOUP

    1. Unité Mixte de Recherche Centre de Biologie et Gestion des Populations (INRA/IRD/Cirad/Montpellier SupAgro), Institut National de la Recherche Agronomique, Campus international de Baillarguet, CS 30016, F-34988 Montferrier-sur-Lez cedex, France
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Marie-Pierre Chapuis, Fax: +61 (02) 9351 4119; E-mail: chapuimp@supagro.inra.fr

Abstract

The potential effect of population outbreaks on within and between genetic variation of populations in pest species has rarely been assessed. In this study, we compare patterns of genetic variation in different sets of historically frequently outbreaking and rarely outbreaking populations of an agricultural pest of major importance, the migratory locust, Locusta migratoria. We analyse genetic variation within and between 24 populations at 14 microsatellites in Western Europe, where only ancient and low-intensity outbreaks have been reported (non-outbreaking populations), and in Madagascar and Northern China, where frequent and intense outbreak events have been recorded over the last century (outbreaking populations). Our comparative survey shows that (i) the long-term effective population size is similar in outbreaking and non-outbreaking populations, as evidenced by similar estimates of genetic diversity, and (ii) gene flow is substantially larger among outbreaking populations than among non-outbreaking populations, as evidenced by a fourfold to 30-fold difference in FST values. We discuss the implications for population dynamics and the consequences for management strategies of the observed patterns of genetic variation in L. migratoria populations with contrasting historical outbreak frequency and extent.

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