Estudo ecológico de Vochysia divergens Pohl. (Vochysiaceae) : concentração de fenóis totais e sua relação com a comunidade de Heteroptera e Coleoptera em suas copas, no Pantanal de Mato Grosso

Abstract

The Pantanal of Mato Grosso is characterized for vegetable mosaics like monodominants forests sites as “cambarazais” with predominance of Vochysia divergens Pohl. (Vochysiaceae) and, strongly, by the seasonality. This research aimed to evaluate the concentration of phenolic compounds from Vochysia divergens Pohl. (Vochysiaceae) leaves in the different seasons in the north region of the Pantanal of Mato Grosso and its relationship with the Heteroptera (Hemiptera) and Coleoptera (Curculionidae and Chrysomelidae) community. Were selected samples from 15 trees from September 2012 to June 2013. After screening, the leaves were dried, crushed and then macerated aiming to achieve the ethanoic extract. For the quantification of the phenols compounds, we have made use of the molecular spectrometry in the region of the visible by the Folin-Ciocalteau method. The insects were sampled in 2004 using the canopy fogging method in 12 canopies of V. divergens, during the high water, low water, dry season and flood period. The concentration of total phenols obtained showed a gradual increase over the seasonal periods. Low water period showed higher concentration. A total of 7.116 adults insects were collected, and Hemiptera (3.902 ind.) was the most representative taxon followed by Coleoptera (3.214 ind.). Auchenorrhyncha (3.122 ind.) was predominant among the Hemiptera, followed by Sternorrhyncha (539 ind.) and Heteroptera (241 ind.). In the Coleoptera comunnity the highest abundance was observed to Curculionidae (2.168 ind.) accompanied by Chrysomelidae (1.046 ind.). The species richness along seasonal periods was higher, Heteroptera were represented by 54 species and Coleoptera by 174 (Curculionidae by 97 and Chrysomelidae by 77). The community composition in the taxa studied differed significantly during the Pantanal seasons in Coleoptera, but not in Heteroptera. These results might indicate some relationships between the seasonal phenol concentrations of V. divergens and the presence of Heteroptera. Since Curculionidae and Chrysomelidae are distributed almost equally at all Pantanal seasons at V. divergens, phenol concentration differences might not have an impact on their community structure. Thus, one can infer that V. divergens houses high species richness in their hearts, playing an important role within the wetland ecosystem. In addition, there is necessary to expand the studies of the insect-plant interactions in floodplain environments in order to contribute to the knowledge of regional biodiversity and the functioning of these ecosystems studies, as well as to subsidize the development and implementation of projects conservation of wetland ecosystems.