STUDIES ON MOSQUITOS (DIPTERA, CULICIDAE) AND ANTHROPIC ENVIRONMENT -3-SURVEY OF ADULT STAGES AT THE RICE IRRIGATION SYSTEM AND THE EMERGENCE OF ANOPHELES-ALBITARSIS IN SOUTH-EASTERN, BRAZIL

A study of adult Culicidae ecology was carried out from January 1992 t hrough January 1993 at the rice irrigation system of the Ribeira Valle y Experimental Station. The adaptation of Anopheles albitarsis to the anthropic environment became evident through the adult collections mad e at its various habitats represented by the irrigation system and the edge of the residual pond, as well as at those made within the local patchy residual woods. Other potential disease vectors were prevalent in the irrigated system too. There were Aedes scapularis, Culex nigrip alpus and Cx. ribeirensis that were collected at various habitats. Rem arkable differences among their prevalences were obtained such as betw een the natural forest and anthropic environments. In the former An. a lbitarsis was practically non-existent, thus suggesting that it might be considered as eusynathropic. As the populations of other species se emed to increase in the anthropic environment, they may be regarded as hemisynanthropes. Observations suggest die hypothesis that the develo pment of irrigated land may be a factor in the emergence of An. albita rsis, and some other species, as well as the possibility of an increas e in the transmission of mosquito-borne diseases such as malaria.