LONGITUDINAL-STUDY ON ANOPHELES-GAMBIAE S1 BREEDING SITES IN A DISTRICT OF ANTANANARIVO PROVINCE (MADAGASCAR HIGHLANDS)

This field study was designed to measure the Anopheles productivity of different larval breeding sites, in Alasora district, Madagascar Highlands. The study covered a period of one year. The highest A. gambiae s. l. larval densities were recorded in temporary breeding sites like small rainy water pools. Although ricelands have lower larval densities, represent the most important breeding sites because of the extensive area that cover 2/3 of the district. The asynchronous two planting cicles (<< varyaloha >> and << vakiambiaty >>) in the ricefields ensure a continual production of A. gambiae larval stages during all the year. The different stages of rice plants growth may influence the presence and the density of larval population in the fields. Fields with rice in the early stages of growth, with young short plants, represent the most productive breeding sites. On the contrary field in full growth with dense and long plants do not allow the development of A. gambiae larvae.