A importância da floração seqüencial de Malpighiaceae para a manutenção da diversidade de tripes (Thysasanoptera) no cerrado

Abstract

To understand the role of each plant species in the ecology of thrips, two principal criteria need to be quantified: the regularity with which individuals are found on a plant species over time, and their abundance on that particular plant species relative to other ones. The choice of representative plants may supply subsidies to define temporary patterns and to evaluate the importance of environmental factors on the community of these insects. In this context sequential flowering plants can provide insightful information about the importance of each host in supporting thrips populations along the year. This study aimed to test the hypothesis that Malpighiaceae sequential flowering is responsible for the maintenance of thrips throughout the year, assuming the premise that thrips migrate from different plants according to the flowering phenology. Fieldwork was carried out from March 2007 to February 2009 at a strictu sensu Cerrado area in Uberlândia, Minas Gerais State, Brazil. The plants studied comprised Banisteriopsis malifolia, B. campestris, B. laevifolia, Byrsonima intermedia, and Peixotoa tomentosa. We found a total of 19 species of thrips in eight genera distributed in the three families Phlaeothripidae, Thripidae and Heterothripidae. Phenological analysis showed that the five Malpighiaceae species studied presented sequential flowering, enabling thrips to migrate from plants and to find food and shelter along the year. The plant which presented more thrips was P. tomentosa, followed by B. laevifolia whereas the diversity was higher in B. malifolia. The only thrips species present in all plants and likely to migrate from hosts according flowering phenology were Frankliniella condei, Scutothrips nudus, Frankliniella sp. 1 and Heterothrips peixotoa. The richness and diversity recorded are the highest ever sampled for thrips occurrence in a group of related taxonomic plants, because the conservative aspect of Malpighiaceae flowers provide food resources and protection against predators. This study showed that sequential flowering Malpighiaceae plays an important role in the maintenance of thrips diversity, being an important natural resource to help in the survivorship and diversification of these insects in Brazilian Savanna.