Larval competition between An. coluzzii and An. gambiae in insectary and semi-field conditions in Burkina Faso

Gimonneau Geoffrey, Brossette Lou, Mamaï Wadaka, Dabiré Roch Kounbobr, Simard Frédéric. 2014. Larval competition between An. coluzzii and An. gambiae in insectary and semi-field conditions in Burkina Faso. Acta Tropica, 130 : 155-161.

https://doi.org/10.1016/j.actatropica.2013.11.007

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Quartile : Q2, Sujet : TROPICAL MEDICINE / Quartile : Q2, Sujet : PARASITOLOGY

Résumé : 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.

Mots-clés Agrovoc : Anopheles, Anopheles gambiae, larve, compétition biologique, expérimentation, interactions biologiques, facteur du milieu

Mots-clés géographiques Agrovoc : Burkina Faso

Mots-clés complémentaires : Anopheles coluzzii

Mots-clés libres : Anopheles coluzzii, Anopheles gambiae, Larvae, Insectary, Semi-field, Asymmetrical competition

Classification Agris : L72 - Organismes nuisibles des animaux

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

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