Aspectos comportamentais de Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae: Phlebotominae) na área urbana de Campo Grande, Mato Grosso do Sul

Abstract

Some aspects concerning the behavior of insect vectors, such as population dispersion, are needed to determine the spread of vector diseases. However, such studies which assess the ability of shifting sand flies in tropical forests are scarce in Brazilian urban areas. Due to its wide geographical distribution, with increasing number of notifications, the visceral leishmaniasis became endemic in Campo Grande, Mato Grosso do Sul, Brazil. This study aimed to analyze the spatial distribution of Lutzomyia longipalpis in the urban environment. Six phases of capture, mark and release were performed, with attempts to recapture the insects weekly for four weeks in the same release site and in 13 points distant 50, 100 and 200 meters. Through the manipulation of satellite images (IKONOS-2), on March 2006 it was obtained from the normalized difference vegetation index (NDVI) and from a spherical densiometer the rates of vegetation cover. These data were correlated with information obtained in the experiments of dispersion. The results showed maximum displacement of 241 meters and 92,45% of insects were recaptured in the same release site. Simple linear analysis of variance showed evident predominance of males recaptured. Correlation analysis revealed low levels of intensity between the canopy and all the males scored, unmarked males, marked females and unmarked females. The NDVI correlations were positive for marked males, for unmarked males; for unmarked females. Except for the marked females there were no correlated. In relation to climatic variables, only wind speed had a negative difference statistically significant. The greater population peaks were observed in the wet season. The distribution of canine LV cases during the research concentrated near areas with medium and high densities of this vector and regions with considerable amounts of vegetal covering. It is suggested that the insect movement in an urban area presents a focal pattern with major effect of vegetation cover, the NDVI and wind speed.