Demographic processes shaping genetic variation of the solitarious phase of the desert locust

Between plagues, the solitarious desert locust (Schistocerca gregaria) is generally thought to exist as small populations, which are particularly prone to extinction events in arid regions of Africa and Asia. Given the high genetic structuring observed in one geographical area (the Eritrean coast) b...

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Published in	Molecular ecology Vol. 23; no. 7; pp. 1749 - 1763
Main Authors	Chapuis, Marie‐Pierre, Plantamp, Christophe, Blondin, Laurence, Pagès, Christine, Vassal, Jean‐Michel, Lecoq, Michel
Format	Journal Article
Language	English
Published	England Blackwell Publishing Ltd 01.04.2014 Wiley
Subjects	Africa Animal behavior Animal populations Animals Arid zones Asia Bayes Theorem Bayesian inference bottleneck Cluster Analysis Evolution extinction Genetic diversity Genetic Variation genetics Genetics, Population Grasshoppers Grasshoppers - genetics Insects Life Sciences Linkage Disequilibrium Mass extinctions Metapopulations microsatellite Microsatellite Repeats Models, Biological Orthoptera pest plague Population Density Population Dynamics Population genetics Population number population size remission Schistocerca gregaria Species extinction Asia Africa microsatellite pest Bayesian inference Orthoptera population dynamics bottleneck
Online Access	Get full text
ISSN	0962-1083 1365-294X 1365-294X
DOI	10.1111/mec.12687

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Summary:	Between plagues, the solitarious desert locust (Schistocerca gregaria) is generally thought to exist as small populations, which are particularly prone to extinction events in arid regions of Africa and Asia. Given the high genetic structuring observed in one geographical area (the Eritrean coast) by former authors, a metapopulation dynamics model involving repeated extinction and colonization events was favoured. In this study, we assessed the validity of a demographic scenario involving temporary populations of the solitarious phase of the desert locust by analysing large‐scale population genetic data. We scored 24 microsatellites in 23 solitarious population samples collected over most of the species range during remission. We found very little genetic structuring and little evidence of declining genetic diversity. A Bayesian clustering method distinguished four genetically differentiated units. Three groups were largely consistent with three population samples which had undergone recent bottleneck events. Nevertheless, the last genetically homogeneous unit included all individuals from the remaining 18 population samples and did not show evidence of demographic disequilibrium. An approximate Bayesian computation treatment indicated a large population size for this main genetic group, moderately reduced between plague and remission but still containing tens of thousands of individuals. Our results diverge from the hypothesis of a classical metapopulation dynamics model. They instead support the scenario in which large populations persist in the solitarious phase of the desert locust.
Bibliography:	http://dx.doi.org/10.1111/mec.12687 istex:FEF5E1956F0D422BECE7931E7F9D049644520563 ArticleID:MEC12687 CIRAD ark:/67375/WNG-HFC2MQDX-M Fig. S1 Posterior probability densities for the mutation-scaled effective population sizes during plague (A, B) and remission (C, D) periods, when considering log-uniform distributions of the effective population size priors. Fig. S2 Allele frequency distributions for the 24 microsatellites. Fig. S3 Inbreeding coefficient distributions. Fig. S4 Hierarchical Structure clustering analyses based on the Coulon et al.'s () approach.Table S1 Prior distributions for diyabc demographic and mutational parameters. Table S2 Bias and precision of effective population size estimation using diyabc. Table S3 Mean, median and 2.5 and 97.5% quantile estimates from diyabc posterior distribution samples of demographic parameters, when considering log-uniform distributions of the effective population size priors. Table S4 Genetic diversity for 23 S. gregaria population samples at all 24 microsatellite markers. Table S5 Pairwise FST values (Weir ) for 23 S. gregaria population samples (above the diagonal) and confidence intervals based on 2000 bootstrap samples (below diagonal) for all 24 microsatellite markers. Table S6 Pairwise FST values (Weir ) 23 S. gregaria population samples for the 21 microsatellite markers at selective neutrality (above the diagonal) and confidence intervals based on 2000 bootstrap samples (below diagonal). Table S7 Robustness of diyabc inferences on the intensity of the population size decline associated with the end of plagues (α) to rejection and estimation procedures. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 content type line 23
ISSN:	0962-1083 1365-294X 1365-294X
DOI:	10.1111/mec.12687