Comparando a estrutura de redes planta-herbívoro de diferentes guildas de insetos

Abstract

1. Studies about interspecific interactions are historically important in ecology and have been gaining prominence in recent times with the studies focused on ecological networks. In this context, interactions involving herbivorous insects and their host plants, which besides the high diversity of species, also present different life-forms and trophic guilds. In this work, we tested the hypothesis that the structure of plant herbivore networks differs between guilds of galling, sucking and chewing insects. 2. Six areas of cerrado sensu stricto were studied in two localities of the North of Minas Gerais, Brazil. Five plots of 10x10m were established in each area, where all woody plants were selected for the collect of the exophagous insects with the use of the rag and the galling insects through active search by the selected plants. In each area the interactions between plant and insect species were used to build networks for the different guilds (gallers, suckers and chewers). 3. In total, we built 18 plant-herbivore networks composed of 313 insect species, 50 plant species and 489 distinct interactions. The networks were characterized using the following network structure measures: network size, connectance, modularity and specialization (H2). 4. Our results showed that did not were difference in the network size and connectance, but there was a difference in the network modularity, because galling networks were less modular than the exophagous networks. On the other hand, we observe a greater specialization for the networks of galling insects in comparison to the exophagous networks. 5. The networks of exophagous insects presented a great structural variation with some networks little connected and very modular, presenting differences with the networks of gallers. Being different than expected, exophagous networks were the most modular. In addition, the specialization of galling networks was always very high due to the great specificity of the insects in relation to their plants, to contrary of exophagous networks. The present study stands out as being the first to systematically compare the network structure of different herbivore guilds in Neotropical savannas.