title: Larval competition between An. coluzzii and An. gambiae in insectary and semi-field conditions in Burkina Faso.
abstract: Competition in mosquito larvae is common and different ecological context could change competitive advantage between species. Here, larval competition between the widely sympatric African malaria mosquitoes, Anopheles coluzzii and Anopheles gambiae were investigated in controlled insectary conditions using individuals from laboratory colonies and under ambient conditions using wild mosquitoes in a semi-field enclosure in western Burkina Faso. Larvae of both species were reared in trays at the same larval density and under the same feeding regimen in either single-species or mixed-species populations at varying species ratios reflecting 0%, 25%, 50% and 75% of competitor species. In the insectaries, where environmental variations are controlled, larvae of the An. coluzzii colony developed faster and with lower mortality than larvae of the An. gambiae colony (8.8±0.1 days and 21±3% mortality vs. 9.5±0.1 days and 32±3% mortality, respectively). Although there was no significant effect of competition on these phenotypic traits in any species, there was a significant trend for higher fitness of the An. coluzzii colony when competing with An. gambiae under laboratory conditions (i.e. lower development time and increased wing length at emergence, Cuzik's tests, P<0.05). In semi-field experiments, competition affected the life history traits of both species in a different way. Larvae of An. gambiae tended to reduce development time when in competition with An. coluzzii (Cuzick's test, P=0.002) with no impact either on mortality or size at emergence. On the other hand, An. coluzzii showed a significant trend for reduced larval mortality with increasing competition pressure (Cuzick's test, P=0.037) and production of smaller females when grown together with An. gambiae (Cuzick's test, P=0.002). Our results hence revealed that competitive interactions between larvae of the two species are context dependent. They further call for caution when exploring ecological processes using inbred laboratory colonies in this system of utmost medical importance.
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France; 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. Electronic address: geoffrey.gimonneau@gmail.com.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Gimonneau
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France. Electronic address: lou.brossette@live.fr.
authors.forename: Lou
authors.initials: L
authors.lastname: Brossette
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France; 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. Electronic address: mwjosephfr@yahoo.fr.
authors.forename: Wadaka
authors.initials: W
authors.lastname: Mamaï
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. Electronic address: dabire_roch@hotmail.com.
authors.forename: Roch K
authors.initials: RK
authors.lastname: Dabiré
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France; 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. Electronic address: frederic.simard@ird.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Simard
mesh_terms: D000818:Animals; D000852:Anopheles / Q000254:growth & development*; D002050:Burkina Faso; D004463:Ecology; D004777:Environment; D005260:Female; D006801:Humans; D007814:Larva / Q000254:growth & development*; D008018:Life Cycle Stages; D008288:Malaria / Q000635:transmission; D010641:Phenotype; D061350:Sympatry
keywords: An. coluzzii; An. gambiae; Asymmetrical competition; Insectary; Larvae; Semi-field