Scolytidae (Coleoptera) degradadores de essências de mangue no Município do Rio de Janeiro

Abstract

Studies to observe insects of the family Scolytidae (Coleoptera) in mangrove essences were carried in the city of Rio de Janeiro, Barra da Tijuca, Parque da Gleba "E" (Area 1) and Barra de Guaratiba (Area 2) during 25 months from August 1999 to August 2001, based on weekly observations of stems of three essences occurring in these areas: Rhysophora mangle L. (Rhysophoraceae), Avicennia schaueriana STAPFT & LEECHM (Acanthaceae) and Hibiscus pernambucensis L. (Malvaceae). It was utilized 120 stems of each essence in each area. After the observation of occurrence of Scolytidae attack in essences samples of 10cm of each stem were take biweekly for laboratory observation. The numbers of perforations, the number of insects captured, number of galleries and larvae were analyzed statistically and graphically compared to weather data collected from the Estação Meteorológica do Aeroporto de Jacarepaguá (área 1) and the Estação Experimental do Instituto Nacional de Meteorologia, INMET, RJ, located in Barra de Guaratiba (area 2). Were captured nine species of Scolytidae, distributed in six genera: Xileborus, Hypotenemus, Premnobius, Ambrosiodmus, Cryptocaremus and Cnesinus. The most significant species in the two areas were Xileborus affinis (29.70%), Hypothenemus eruditos (23.17%) and Ambrosiodmus haguedorni (20.78%). There was significant correlation between population density and climatic variations for the three species of Scolytidae with the highest percentage of occurrence. The peak of occurrence was observed in January and February and decreased in June, July and August. There was significant variation in the incidence of beetles preference regarding botanical essences, Rhysophora mangle being the most attacked and Hibiscus pernambucensis unless attacked. Were also used traps baited with alcohol Modelo Carvalho - 47, to catch the Scolytidae. The observations and collections of insects were held weekly. The data underwent the same statistical methods. The results obtained with the traps did not differ from those obtained with the use of stem. It was verified that the area with the highest incidence of insects was the area 2, which presents more degraded vegetation at the expense of area 1 which presents a more preserved mangrove.