Espécies de borrachudos (Diptera, simuliidade) na mesorregião do noroeste Rio-Grandense: dados bionômicos e chaves para sua identificação

Abstract

Basic studies in the zoology area as the survey of the black flies diversity in the hydro graphic basin are essential to the application to a regional level of the way control and management of the species with sanitary importance. In these context, the paper had as a main goal gather information regarding to taxonomy, local diversity and bio ecology of the species of black flies (Diptera Simuliidae) of the northwest of the Rio Grande do Sul state (RS), trough the bibliographic studies and fauna survey in different micro basin, searching for new registers of black flies especially to the sub basin of the Ijuí river. It was developed a bibliographic study near the Simuliidae species valid in the actual scientific scenery as the nomenclature, as well a review in the species occurrence to the interest regions to these study, verifying the cities with register of the black flies. In additional, it was developed a field study, with direction reach to arroyos of different cities of the northwest region, observing the micro basin distribution inside the sub hydro graphic region of Ijuí river. The regional survey was developed from August to October 2015, including 13 cities, localized in the main regions (high, medium and low) of the Ijuí river basin, contemplating 27 points of sampling. The collection of the biological material in these water courses was directed in the black flies underdeveloped form, constituted by larva and pupa, which are developed in aquatic places. The search was performed in two main substrates: vegetation and swindle, observing a sampling time of thirty minutes, on average, to each point of sampling. The activities in laboratory consisted initially in sorting, to then proceed to the identification and counting of the individuals. Trough this sampling effort it was gotten a total of 47.551 underdeveloped individuals: these 9.038 specimen (last stage larva and pupa) were examined to identification effect, ignoring than, the initial stages of larva, which had appeared in a great pattern, more exactly 38.513 larva. The black flies diversity found in Ijuí river basin, were of 10 species of Simulium, as follow: Simulium (Psaroniocompsa) incrustatum, Simulium (Psaroniocompsa) jujuyense, Simulium (Psaroniocompsa) inaequale, Simulium (Psaroniocompsa) travassosi, Simulium (Chirostilbia) pertinax, Simulium (Chirostilbia) subpallidum, Simulium (Psilopelmia) perflavum, Simulium (Psilopelmia) lutzianum, Simulium (Trichodagmia) orbitale e Simulium (Trichodagmia) rubrithorax. Simulium pertinax was the larger and it corresponds to the main responsible specie to the grievance caused by black flies in the south of Brazil. With respect to the occurrence registers of Simuliidae in the Northwest masoregion of Rio Grande do Sul, it was checked the existence of 23 species. The number of the cities with occurrence registres had advances, as well that new micro basins still disadvantaged of information were investigated. In this way, the obtained results high improve the knowledge al about the Simuliidae Family in the Rio Grande do Sul state, especially about the Northwest region, which has 23 species of the 31 registered in the state.