ABSTRACT
Monthly oviposition activity and the seasonal density pattern of Aedes aegypti were studied using larvitraps and ovitraps during a research carried out by the Public Health Ministry of Salta Province, in Tartagal, Aguaray and Salvador Mazza cities, in subtropical Argentina. The A. aegypti population was active in both dry and wet seasons with a peak in March, accordant with the heaviest rainfall. From May to November, the immature population level remained low, but increased in December. Ae. aegypti oviposition activity increased during the fall and summer, when the relative humidity was 60 percent or higher. Eggs were found in large numbers of ovitraps during all seasons but few eggs were observed in each one during winter. The occurrence and the number of eggs laid were variable when both seasons and cities were compared. The reduction of the population during the winter months was related to the low in the relative humidity of the atmosphere. Significant differences were detected between oviposition occurrences in Tartagal and Aguaray and Salvador Mazza cities, but no differences in the number of eggs were observed. Two factors characterize the seasonal distribution pattern of Ae. aegypti in subtropical Argentina, the absence of a break during winter and an oviposition activity concomitant of the high relative humidity of the atmosphere
Subject(s)
Animals , Male , Female , Aedes , Behavior, Animal , Oviposition , Seasons , Aedes , ArgentinaABSTRACT
Aedes albifasciatus, a floodwater mosquito, is widely distributed in freshwater habitats in Argentina. At high population densities it is an important pest in urban areas. A two year study was conducted in a natural population of A. albifasciatus around La Plata area, Buenos Aires province, Argentina. The breeding site was weekly sampled from May, 1996 to April, 1998. Immature stages of A. albifasciatus were collected with a standard 300 ml dipper. Each sample unit consisted of 100 dipper. Highest densities of mosquito larvae occurred when the breeding site was flooded among 90 and 100 porcent of its capacity after remaining dry for severa days or weeks. The larvae required between six and eight days to become adult in summer (temperature mean 24.6§C in January and 21.3§C in Febrary). In autumn-winter, 43 days (temperature mean 10.6§C) and in spring 22 days (temperature mean 15.5§C). Key words: Neotropical Culicidae, Aedes albifasciatus, mosquito larvae, Argentina