Do outbreaks affect genetic population structure ? A worldwide survey in #Locusta migratoria$, a pest plagued by microsatellite null alleles Chapuis M.P. auteur aut IRD Lecoq M. auteur aut IRD Michalakis Yannis auteur aut IRD Loiseau A. auteur aut IRD Sword G.A. auteur aut IRD Piry S. auteur aut IRD Estoup A. auteur aut IRD text journalArticle eng text/pdf born digital access An understanding of the role of factors intrinsic to a species' life history in structuring contemporary genetic variation is a fundamental, but understudied, aspect of evolutionary biology. Here, we assessed the influence of the propensity to outbreak in shaping worldwide genetic variation in Locusta migratoria, a cosmopolitan pest well known for its expression of density-dependent phase polyphenism. We scored 14 microsatellites in nine subspecies from 25 populations distributed over most of the species' range in regions that vary in the historical frequency and extent of their outbreaks. We rejected the hypothesis that L. migratoria consists of two genetically distinct clusters adapted to habitats either rarely (nonoutbreaking) or cyclically (outbreaking) favourable to increases in population density. We also invalidated the current subspecific taxonomic classification based on morphometrics. Bayesian inferences indicated evidence of a homogenizing effect of outbreaks on L. migratoria population structure. Geographical and ecological barriers to gene flow in conjunction with historical events can also explain the observed patterns. By systematically assessing the effects of null alleles using computer simulations, we also provide a template for the analysis of microsatellite data sets characterized by a high prevalence of null alleles. specialized Computer simulation Life-history evolution Locust Phase polyphenism Spatial dynamics Subspecies 076 080 020 Molecular Ecology 17 16 3640-3653 2008 0962-1083 https://www.documentation.ird.fr/hor/fdi:010042721 10.1111/j.1365-294X.2008.03869.x 0962-1083 [F B010042721] https://www.documentation.ird.fr/hor/fdi:010042721 https://www.documentation.ird.fr/intranet/publi/2008/08/010042721.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2008-09-19 2017-08-23 fdi:010042721 fre