title: Detection of genetically isolated entities within the Mediterranean species of Bemisia tabaci: new insights into the systematics of this worldwide pest.
abstract: BACKGROUND
  The taxonomy of the species complex Bemisia tabaci, a serious agricultural pest worldwide, is not well resolved yet, even though species delimitation is critical for designing effective control strategies. Based on a threshold of 3.5% mitochondrial (mtCOI) sequence divergence, recent studies have identified 28 putative species. Among them, mitochondrial variability associated with particular symbiotic compositions (=cytotypes) can be observed, as in MED, which raises the question of whether it is a single or a complex of biological species.
  
  
  RESULTS
  Using microsatellites, an investigation was made of the genetic relatedness of Q1 and ASL cytotypes that belong to MED. Samples of the two cytotypes were collected in West Africa where they live in sympatry on the same hosts. Genotyping revealed a high level of differentiation, without evidence of gene flow. Moreover, they differed highly in frequencies of resistance alleles to insecticides, which were much higher in Q1 than in ASL.
  
  
  CONCLUSIONS
  Q1 and ASL are sufficiently reproductively isolated for the introgression of neutral alleles to be prevented, suggesting that they are actually different species. This indicates that nuclear genetic differentiation must be investigated within groups with less than 3.5% mtCOI divergence in order to elucidate the taxonomy of B. tabaci at a finer level. Overall, these data provide important information for pest management.
authors.affiliation: Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Villeurbanne, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Mouton
authors.forename: Olivier
authors.initials: O
authors.lastname: Gnankiné
authors.forename: Hélène
authors.initials: H
authors.lastname: Henri
authors.forename: Gabriel
authors.initials: G
authors.lastname: Terraz
authors.forename: Guillaume
authors.initials: G
authors.lastname: Ketoh
authors.forename: Thibaud
authors.initials: T
authors.lastname: Martin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Fleury
authors.forename: Fabrice
authors.initials: F
authors.lastname: Vavre
mesh_terms: D000354:Africa, Western; D000818:Animals; D005260:Female; D051456:Gene Flow; D005838:Genotype; D006430:Hemiptera / Q000145:classification* / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008928:Mitochondria / Q000235:genetics*
keywords: B. tabaci complex species; MED species; bacterial symbionts; insecticide resistance; microsatellites