Análise da Ocorrência de Seis Grupos de Coleoptera em Dois Ecossistemas Perturbados Ecologicamente

Abstract

Embora os insetos sejam considerados relevantes nos processos ecológicos, esses organismos constituem um dos grupos menos registrados entre os animais levantados na fauna brasileira. Também são entendidas como insuficientes às pesquisas que investigam sua ocorrência em ambientes com características ecológicas distintas. Nesse contexto, o objetivo deste trabalho é analisar a ocorrência de seis táxons de insetos (Scolytinae, Platypodinae, Bostrichidae, Cerambycidae, Curculionidae e Nitidulidae) em duas áreas com características ecológicas distintas, pastagem e fragmento florestal. Objetiva-se também proporcionar uma discussão que fomente o entendimento da ocorrência destes insetos em relação às características do ambiente, gerando dados que sinalizem a possibilidade de bioindicação em trabalhos futuros com estes organismos. As coletas foram realizadas semanalmente em Ipiabas, distrito de Barra do Piraí, RJ, através da instalação de oito armadilhas de impacto, modelo semifunil, sendo quatro armadilhas em cada ecossistema, distantes 50 metros uma da outra. As amostras foram obtidas no período de maio de 2012 a maio de 2013. Coletou-se 4.796 coleópteros, sendo que 3.275 (67,9%) indivíduos foram capturados no fragmento florestal e 1.521 (32,03%) em área de pastagem. A subfamília Scolytinae foi mais freqüente no pasto durante o período seco, enquanto a família Nitidulidae apresentou maior freqüência no fragmento florestal e no período chuvoso. Dentre os grupos avaliados, os nitidulídeos demonstraram ocorrer distintamente entre os ambientes, indicando que esta família responde de forma mais evidente às mudanças ambientais entre os ecossistemas avaliados, em relação aos outros grupos taxonômicos identificados neste levantamento.Analysis of the Occurrence of Six Groups of Coleoptera in Two Ecologically Disturbed EcosystemsAbstract. The aim of this study was to analyze the occurrence of six groups of insects (Scolytinae, Platypodinae, Bostrichidae, Cerambycidae, Curculionidae and Nitidulidae) in a pasture area and forest fragment, in order to provide a discussion that fosters the understanding of the occurrence of these insects in function of the assessed ecosystem, generating data that signal the possibility of bioindication in future work with these organisms. The samples were obtained weekly in Ipiabas, a district of Barra do Pirai, RJ, by the installation of eight impact traps, semifunil model, in the study areas, being four traps in the pasture´s area and four in the forest fragment, respecting the distance of 50 meters between them. Samples were collected from May 2012 to May 2013. A total of 4,796 beetles were collected, of which 3,275 (67.9 %) individuals were captured in the forest fragment and 1,521 (32.03%) in the pasture. The subfamily Scolytinae was more frequent in the pasture and during the dry season, while the Nitidulidae family showed higher frequency in the forest fragment and in the rainy season. Among the studied groups, the nitidulídeos had greater variation in occurrence’s patterns, indicating that this family has the potential to be used as an indicator of environmental quality.

Population Fluctuation of Coleobrocas (Coleoptera) in Six Forest Fragments in Atlantic Forest

“…For other wood borer beetles, we can see a higher population density for Bostrichidae and Scolytinae, as it can be seen in (Galdino-da-Silva et al, 2016). In the sampling area of the river Guapiaçu and in neighboring municipalities, the forest restoration has focusedon the fauna, especially on bird fauna and bat fauna.…”

“…Coleopters can be used as bioindicators of environmental quality in fragments and reforestation, once in environments where disclimax, i.e., who have suffered changes like deforestation or fire, for example, tend to have a higher density of wood-eating insects (Bradley & Tueller, 2001;Galdino-da-Silva et al, 2016). The analysis of their populations' growth, fluctuations, size, and environmental factors is fundamental in the study of pestilent insects.…”

“…Wood-eating beetles may suffer action of biotic factors such as competition, predation and the availability of food, as well as of abiotic factors, such as temperature, precipitation and relative humidity (Galdino-da-Silva et al, 2016). According to Carvalho & Trevisan (2015), the number of dead trees by wood-eating beetles action, especially in the sub-family Scolytinae, has increased significantly in recent years in all regions, mainly in forests damaged by storms, fires and poor conditions of management.…”

“…As a result of deforestation or excessive exploitation of the forest, the Atlantic Forest biome has its areas presenting different successional stages of regeneration or recovery (Cortines & Valcarcel, 2009). There are many attacks of restoration in this biome, however the monitoring of forest restoration, merely restricted to the phytosociological monitoring of restored areas, often ignores the relationship of fauna and flora, especially the relationship between insect-plant (Galdino-da-Silva et al, 2016).…”