L'accroissement des résistances aux insecticides chez les anophèles vecteurs de Plasmodium sont mises en cause dans la baisse d'efficacité des principales stratégies de lutte antivectorielle (LAV) en Afrique. Des techniques de combinaisons d'insecticides, évaluées au Bénin, n'ont pas été plus efficaces pour réduire la morbidité palustre et limiter l'extension des résistances que la stratégie préconisée par le Programme National de Lutte contre le Paludisme (moustiquaires imprégnée seules). Dans cette thèse, nous avons cherché à identifier les facteurs opérationnels, biologiques et environnementaux pouvant expliquer cet échec. Nous avons modélisé le risque d'exposition de l'homme aux piqûres de vecteurs en fonction de variables environnementales afin (i) d'identifier les déterminants de la présence et de la densité des vecteurs et (ii) d'analyser l'impact des méthodes de LAV. Nos résultats ont montré à l'échelle des villages une forte hétérogénéité spatio-temporelle de la population vectorielle, caractérisée par des niches écologiques et comportementales différentes qui a ont pu moduler l'efficacité de la LAV. Nous avons mis en évidence le rôle vectoriel majeur de An. funestus qui assurait la transmission en saison sèche tandis que le taux d'utilisation des moustiquaires diminuait en raison des fortes températures et de la baisse de nuisance culicidenne. Nous avons observé des modifications comportementales chez les vecteurs suite à la mise en place de méthodes de LAV. Nous faisons des propositions pour l'amélioration des méthodes actuelles de LAV, pour définir les caractéristiques des futures méthodes et pour mieux choisir les méthodes à implémenter en fonction du faciès entomologique. / Insecticide resistance in malaria vector has increased in Africa. Implications for the effectiveness of the most widely implemented vector control (VC) techniques are questioned. To manage resistance, two VC strategies combining two different insecticides were evaluated during a randomised controlled trial in Benin. These strategies did not show a better efficacy than the baseline intervention recommended by the National Malaria Control Program (insecticidal nets alone). The aim of this thesis was to identify operational, biological and environmental factors that could explain this failure. We modelled the risk of exposure to malaria vectors according to environmental factors to (i) identify the determinants of the vectors' presence and density and to (ii) analyse the impact of VC strategies. Our results showed high spatial-temporal heterogeneities of vector populations at the village scale. The vector populations were characterized by different ecological and behavioural niches which could have impacted the effectiveness of VC. We highlighted the importance of An. funestus in malaria transmission during the dry season when people are less likely to use nets because of hot temperatures and low mosquito biting nuisances. We also observed changes in vectors biting behaviour following the implementation of VC. We therefore provide suggestions to improve actual VC tools, to define characteristics of new tools and to better select tools to implement in the field according to the entomological facies.

Neomegalotomus parvus (Westwood, 1842) (Hemiptera: Alydidae) is distributed in the neotropical region from Mexico to northern Argentina and Caribbean. In Brazil it has been reported in soybean and bean in the Cerrado biome. This species is known as " broad-headed bugs" because the nymphs mimic ants. the attack of this bug can transmit the fungus Nematospora coryles Peglion, which causes the "blight-yeast" disease which reduces the quality and crop yield. Macroptilium atropurpureum Urb (Leguminosae: Papilionoideae) is a leguminous plant, herbaceous and climbing, popularly known as siratro. Originally from Mexico, it was introduced in Brazil to be cultivated in association with grasses. However, due to the lack of control, it has become an invasive plant. In the field, the bugs were collected in M. atropurpureum in a vacant lot in the city of Maceió, Alagoas State (9°40'11.7"/S and 35°44'38.8"/W). We obtained 32 eggs and, after hatching, nimphs were isolated in containers made with 2 L PET bottles with 300mL final volume. And food (branches with green pods), wich was changed every three days. The N. parvus stadiums length in days, were [mean ± standard error, total amplitude (min-max), coefficient of variation (CV)]: embryonic period= 8.9 ± 0.2, 3(7-10) days, CV=11.4%; N1= 2.5 ± 0.1, 1(2-3) days, CV=20.4%; N2=5.2 ± 0.4, 8(4-12) days, CV= 35.0%; N3=3.9 ± 0.2, 3(3-6) days, CV=21.3%; N4= 4.6 ± 0.2, 3(4-7) days, CV= 19.4%; N5=9.7 ± 0.6, 9(5-14) days, CV=31.3%. The total development was 34.9 ± 0.8, 12 (28-40) days, CV=11.0%. The sex ratio was 0.5 indicating a balance between sexes. The viability of eggs was 100% and mortality during development was 31.2%. This performance with obtaining viable adults indicates that M. atropurpureum can be considered as an alternative plant-food. / Fundação de Amparo a Pesquisa do Estado de Alagoas / Neomegalotomus parvus (Westwood, 1842) (Hemiptera: Alydidae) se distribui na região neotropical desde o México até o norte da Argentina e Caribe. No Brasil, tem sido relatado em soja e feijão nas regiões de cerrados. Esta espécie é conhecida popularmente como formigão , pois as ninfas mimetizam formigas. O ataque deste percevejo pode transmitir o fungo Nematospora coryli Peglion, que causa a doença mancha-de-levedura , a qual reduz a qualidade e o rendimento da cultura. Macroptilium atropurpureum Urb. (Leguminosae: Papilionoideae) é uma leguminosa herbácea e trepadeira, conhecida popularmente como siratro. Originária do México foi introduzida no Brasil para ser usada em cultivo associado com gramíneas forrageiras. No entanto, pela falta de controle, tornou-se uma planta-invasora. Em campo, os percevejos foram coletados em M. atropurpureum em terreno baldio no município de Maceió, Estado de Alagoas (9°40 11.7 S e 35º44 38.8 W). Foram obtidos 32 ovos, as ninfas eclodidas foram individualizadas em recipientes feitos com garrafas PET 2 L, sendo o volume final de 300mL. O alimento (ramos com vagens verdes) era trocado a cada três dias. Os estádios, em dias de N. parvus, foram [média±erro-padrão, amplitude total (mínmáx) e coeficiente de variação (CV)]: Período embrionário= 8,9±0,2, 3(7-10) dias, CV=11,4%; N1= 2,5±0,1, 1(2-3) dias, CV=20,4%; N2=5,2±0,4, 8(4-12) dias, CV=35,0%; N3=3,9±0,2, 3(3-6) dias, CV=21,3%; N4=4,6±0,2, 3(4-7) dias, CV=19,4%; N5=9,7±0,6, 9(5- 14) dias, CV=31,3%. O Desenvolvimento total foi 34,9±0,8, 12(28-40) dias, CV=11,0%. A razão sexual foi de 0,5 indicando equilíbrio entre os sexos. A viabilidade dos ovos foi de 100% e a mortalidade ao longo do desenvolvimento foi de 31,2%. Esse desempenho com obtenção de adultos viáveis, indica que M. atropurpureum pode ser considerada como plantaalimentícia alternativa.