A influência de impactos ambientais e do clima na ecologia de flebotomíneos (Diptera, Psychodidae) na Amazônia Maranhense

Abstract

Tegumentary leishmaniasis is endemic in the Brazilian Amazon, showing strong seasonal and environmental variation. The municipality of Buriticupu represents an important area of Amazonia of the State of Maranhão, with a high incidence of tegumentary leishmaniasis cases. The first epidemic outbreak of the disease documented in the 1970s was related to the forest areas that were beginning to be explored. New epidemiological profiles were reported in the 1980s, 1990s, and 1990s related to deforestation, while the diversity and seasonality of their biological vectors still need to be studied. In this sense, this work evaluated the community structure of phlebotominae in wild and anthropogenic environments in areas with different colonization times and degrees of deforestation in the municipality of Buriticupu-MA. Phlebotomines were captured in forest fragments and in peridomestic environments of rural settlements established at distinct times and categorized as "old" and "recent".The collections occurred during the years 1996/1997. The study resulted in the capture of 27.819 individuals from 43 species of phlebotomines, being 42 Lutzomyia and 1 Brumptomyia. The abundance was similar between the two areas, of recent occupation (13,931 individuals) and old occupation (13,888 individuals), but the richness was greater in the recent area (38 species) than in the old one (28 species). In the area of recent occupation the richness and abundance of the species were higher in the forest (35 species, 10,350 individuals) than in the peridomicile (18 species, 3,581individuals). In the area of old occupation was the opposite, the wealth and abundance were larger in the peridomestic (26 species and 13,190 individuals) than in the forest (18 species and 698 individuals). Regarding the seasonal occurrence, in the general computation, the abundance of the species was higher in the rainy season (51%) than in the dry season (49%), in the area of recent occupation; and the opposite occurred in the area of old occupation, abundance was higher in the dry season (52.5%) than in the rainy season (47,55). The type of environment (forests and peridomestic) changed the composition of the species in the sites sampled, being L. evandroi, L. whitmani, L. choti, L. serrana, L. triacantha, L. migonei, L. hirsuta, L. shannoni and L. brachyphalla the species that, together, contributed with more than 54% to the difference found between the sites. Only two species were indicative of forest environments - L. brachyphalla (Indval = 0.9565, p = 0.0277) and L. serrana (Indval = 0.9188, p = 0.0309); and one was indicative of peridomycin - L. evandroi (Indval = 0.9335, p = 0.0297). A composição, riqueza e abundância das espécies de flebotomíneos diferiram entre as áreas com diferentes períodos de ocupação humana e graus de mudança florestal. Nas áreas florestais mais conservadas (ocupação recentes), o número de espécies de flebotomíneos foi maior do que em fragmentos florestais alterados (ocupação antiga). The composition, richness and abundance of phlebotomine species differed between areas with different periods of human occupation and degrees of forest change. In the most conserved forest areas (recent occupation), the number of phlebotomine species was higher than in altered forest fragments (old occupation). However, several species absent in degraded forests have appeared in the shelters of domestic animals present in the adjacent rural settlements. Domestic animals and their shelters can be used as indicators to predict the occurrence of leishmaniasis vectors. There was a temporal variation in the community of phlebotomine, few species occur all year round; some appear in the dry season and others in the rainy season. The infestation of sandflies can be indicative of environmental problems in certain areas and used to predict future scenarios and guide preventive actions for leishmaniasis. Keywords: Amazon, phlebotomines, biodiversity, conservation, deforestation, biological vector.