title: Spatio-temporal genetic variation of the biting midge vector species Culicoides imicola (Ceratopogonidae) Kieffer in France.
abstract: BACKGROUND
  Introduction of vector species into new areas represents a main driver for the emergence and worldwide spread of vector-borne diseases. This poses a substantial threat to livestock economies and public health. Culicoides imicola Kieffer, a major vector species of economically important animal viruses, is described with an apparent range expansion in Europe where it has been recorded in south-eastern continental France, its known northern distribution edge. This questioned on further C. imicola population extension and establishment into new territories. Studying the spatio-temporal genetic variation of expanding populations can provide valuable information for the design of reliable models of future spread.
  
  
  METHODS
  Entomological surveys and population genetic approaches were used to assess the spatio-temporal population dynamics of C. imicola in France. Entomological surveys (2-3 consecutive years) were used to evaluate population abundances and local spread in continental France (28 sites in the Var department) and in Corsica (4 sites). We also genotyped at nine microsatellite loci insects from 3 locations in the Var department over 3 years (2008, 2010 and 2012) and from 6 locations in Corsica over 4 years (2002, 2008, 2010 and 2012).
  
  
  RESULTS
  Entomological surveys confirmed the establishment of C. imicola populations in Var department, but indicated low abundances and no apparent expansion there within the studied period. Higher population abundances were recorded in Corsica. Our genetic data suggested the absence of spatio-temporal genetic changes within each region but a significant increase of the genetic differentiation between Corsican and Var populations through time. The lack of intra-region population structure may result from strong gene flow among populations. We discussed the observed temporal variation between Corsica and Var as being the result of genetic drift following introduction, and/or the genetic characteristics of populations at their range edge.
  
  
  CONCLUSIONS
  Our results suggest that local range expansion of C. imicola in continental France may be slowed by the low population abundances and unsuitable climatic and environmental conditions.
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France. stephanie.jacquet@cirad.fr.|UMR 5290 Maladies Infectieuses & Vecteurs-Ecologie, Génétique, Ecologie, Contrôle (MIVEGEC), CNRS, Université de Montpellier, Montpellier, France. stephanie.jacquet@cirad.fr.|IRD, UR 224 MIVEGEC, Agropolis, BP 64501, 34 394, Montpellier cedex 5, France. stephanie.jacquet@cirad.fr.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Jacquet
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.|INRA, UMR1309 CMAEE, 34398, Montpellier, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Huber
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Guis
authors.affiliation: EID Méditérranée, 34184, Montpellier, France.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Setier-Rio
authors.affiliation: Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale', 64100, Teramo, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Goffredo
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Allène
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Ignace
authors.initials: I
authors.lastname: Rakotoarivony
authors.affiliation: UMR 5290 Maladies Infectieuses & Vecteurs-Ecologie, Génétique, Ecologie, Contrôle (MIVEGEC), CNRS, Université de Montpellier, Montpellier, France.|IRD, UR 224 MIVEGEC, Agropolis, BP 64501, 34 394, Montpellier cedex 5, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Chevillon
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Bouyer
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Baldet
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Balenghien
authors.affiliation: Cirad, UMR15 Contrôle des Maladies Animales Exotiques et Emergentes, Campus International de Baillarguet, TA-A15/G, 34398, Montpellier, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Garros
mesh_terms: D000818:Animals; D002519:Ceratopogonidae / Q000145:classification* / Q000235:genetics*; D004772:Entomology; D005602:France; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D060005:Genotyping Techniques; D018895:Microsatellite Repeats; D011157:Population Dynamics; D062211:Spatio-Temporal Analysis
keywords: Culicoides; Distribution range; Entomological survey; Mediterranean basin; Population genetics; Spatio-temporal