title: Morphological changes in the spiracles of Anopheles gambiae s.l (Diptera) as a response to the dry season conditions in Burkina Faso (West Africa).
abstract: BACKGROUND
  Survival to dry season conditions of sub-Saharan savannahs is a major challenge for insects inhabiting such environments, especially regarding the desiccation threat they are exposed to. While extensive literature about insect seasonality has revealed morphologic, metabolic and physiological changes in many species, only a few studies have explored the responses following exposure to the stressful dry season conditions in major malaria vectors. Here, we explored morphological changes triggered by exposure to dry season conditions in An. gambiae s.l. mosquitoes by comparing females reared in climatic chambers reflecting environmental conditions found in mosquito habitats during the rainy and dry seasons in a savannah area of Burkina Faso (West Africa).
  
  
  RESULTS
  Using scanning electron microscopy (SEM) and confocal imaging, we revealed significant changes in morphological features of the spiracles in females An. gambiae s.l. exposed to contrasted environmental conditions. Hence, the hairs surrounding the spiracles were thicker in the three species when raised under dry season environmental conditions. The thicker hairs were in some cases totally obstructing spiracular openings. Specific staining provided evidence against contamination by external microorganisms such as bacteria and fungi. However, only further analysis would unequivocally rule out the hypothesis of experimental artifact.
  
  
  CONCLUSIONS
  Morphological changes in spiracular features probably help to limit body water loss during desiccating conditions, therefore contributing to insect survival. Differences between species within the An. gambiae complex might therefore reflect different survival strategies used by these species to overcome the detrimental dry season conditions in the wild.
authors.affiliation: Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545, Bobo-Dioulasso, Burkina Faso. mwjosephfr@yahoo.fr.|MIVEGEC, UMR IRD 224-CNRS 5290-Université de Montpellier, Institut de Recherche pour le Développement, 911 Avenue Agropolis, BP 64501, 34394, Montpellier, cedex 5, France. mwjosephfr@yahoo.fr.|Université Polytechnique de Bobo-Dioulasso (UPB), Bobo-Dioulasso, Burkina Faso. mwjosephfr@yahoo.fr.|Institut de Recherche pour le Développement, Antenne de Bobo Dioulasso, BP 171, Bobo Dioulasso 01, Burkina Faso. mwjosephfr@yahoo.fr.
authors.forename: Wadaka
authors.initials: W
authors.lastname: Mamai
authors.affiliation: Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545, Bobo-Dioulasso, Burkina Faso. karine.mouline@ird.fr.|MIVEGEC, UMR IRD 224-CNRS 5290-Université de Montpellier, Institut de Recherche pour le Développement, 911 Avenue Agropolis, BP 64501, 34394, Montpellier, cedex 5, France. karine.mouline@ird.fr.
authors.forename: Karine
authors.initials: K
authors.lastname: Mouline
authors.affiliation: Université Pierre et Marie Curie, 75005, Paris, France. jparvy@snv.jussieu.fr.|CGM, UPR 3404, CNRS, 91190, Gif-sur-Yvette, France. jparvy@snv.jussieu.fr.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Parvy
authors.affiliation: Université de Rennes 1, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 263 Avenue du Gal Leclerc, CS 74205 35042, Rennes, Cedex, France. jo.lelannic@univ-rennes1.fr.
authors.forename: Jo
authors.initials: J
authors.lastname: Le Lannic
authors.affiliation: Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545, Bobo-Dioulasso, Burkina Faso. dabire_roch@hotmail.com.
authors.forename: Kounbobr Roch
authors.initials: KR
authors.lastname: Dabiré
authors.affiliation: Université Polytechnique de Bobo-Dioulasso (UPB), Bobo-Dioulasso, Burkina Faso. oga@fasonet.bf.
authors.forename: Georges Anicet
authors.initials: GA
authors.lastname: Ouédraogo
authors.affiliation: Université de Rennes 1, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 263 Avenue du Gal Leclerc, CS 74205 35042, Rennes, Cedex, France. david.renault@univ-rennes1.fr.
authors.forename: David
authors.initials: D
authors.lastname: Renault
authors.affiliation: MIVEGEC, UMR IRD 224-CNRS 5290-Université de Montpellier, Institut de Recherche pour le Développement, 911 Avenue Agropolis, BP 64501, 34394, Montpellier, cedex 5, France. frederic.simard@ird.fr.
authors.forename: Frederic
authors.initials: F
authors.lastname: Simard
mesh_terms: D000818:Animals; D000852:Anopheles / Q000502:physiology / Q000648:ultrastructure*; D002050:Burkina Faso / Q000453:epidemiology; D003681:Dehydration; D017753:Ecosystem; D004777:Environment; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000502:physiology / Q000648:ultrastructure*; D008288:Malaria / Q000635:transmission*; D008297:Male; D010641:Phenotype; D012621:Seasons