Distinct physiological, biochemical and morphometric adjustments in the malaria vectors Anopheles gambiae and A. coluzzii as means to survive dry season conditions in Burkina Faso

Kévin Hidalgo (1, 2, 3) , C Montazeau (4) , D Siaussat (5) , V Braman (5) , Marie Trabalon (6) , F Simard (7) , D Renault (1) , R K Dabiré (8) , K Mouline (8, 4)

1 ECOBIO - Ecosystèmes, biodiversité, évolution [Rennes]
2 INRA - Institut National de la Recherche Agronomique
3 QuaPA - Qualité des Produits Animaux
4 MIVEGEC - Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle
5 iEES Paris - Institut d'écologie et des sciences de l'environnement de Paris
6 EthoS - Ethologie animale et humaine
7 MIVEGEC-DEEVA - Diversity, ecology, evolution & Adaptation of arthropod vectors
8 Institut de Recherche en Sciences de la Santé (IRSS) / Centre Muraz

Aestivation and dispersive migration are the two strategies evoked in the literature to explain the way in which malaria vectorsandsurvive the harsh climatic conditions of the dry season in sub-Saharan Africa. However, the physiological mechanisms regulating these two strategies are unknown. In the present study, mosquito species were exposed to controlled environmental conditions mimicking the rainy and dry seasons of south western Burkina Faso. Survival strategies were studied through morphometric (wing length), ecophysiological (respiratory gas exchanges), biochemical (cuticular hydrocarbons composition) and molecular (AKH mRNA expression levels) parameters, variations of which are usually considered to be hallmarks of aestivation and dispersion mechanisms in various insects. Our results showed that ecophysiological and morphometric adjustments are made in both species to prevent water losses during the dry season. However, the usual metabolic rate modifications expected as signatures of aestivation and migration were not observed, highlighting specific and original physiological mechanisms sustaining survival in malaria mosquitoes during the dry season. Differences in epicuticular hydrocarbon composition and AKH levels of expression were found between the permanent and temporarypopulations, illustrating the great phenotypic plasticity of this mosquito species. Altogether, our work underlines the diverse and complex pattern of changes occurring in the two mosquito species and at the population level to cope with the dry season and highlights potential targets of future control tools.

Keywords: Aestivation; Adipokinetic hormone (AKH); Migration; Cuticular hydrocarbons; Metabolic rate

Domains: Life Sciences [q-bio]; Animal biology; Invertebrate Zoology

Kévin Hidalgo, C Montazeau, D Siaussat, V Braman, Marie Trabalon, et al.. Distinct physiological, biochemical and morphometric adjustments in the malaria vectors Anopheles gambiae and A. coluzzii as means to survive dry season conditions in Burkina Faso. Journal of Experimental Biology, 2018, 221 (6), pp.jeb174433. ⟨10.1242/jeb.174433⟩. ⟨hal-01744160⟩