Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones.

In this study we recorded the occurrence of insect galls, inductors and parasitoids in plants of several physiognomies of Brazilian Cerrado in the Serra dos Pireneus, Goiás State, Brazil. We found 62 morphotypes of gall on 28 botanical families, comprising 44 genera and 51 species. The plant families that showed the greatest richness of galls were Fabaceae, with eight morphotypes, and Styracaceae with six. Styrax pohlii (Styracaceae) was the host plant species with the greatest gall richness, featuring five morphotypes. Most of galls occurred on the leaves (82.6%), 45.1% in vegetation of typical savanna and 35.4% in rocky savanna. Dipteran, Hemipteran and Lepidopteran galls were found, being 50.9% of them induced by Cecidomyiidae (Diptera). Several parasitoids were obtained, Eulophidae (Hymenoptera: Chalcidoidea) was the most representative group (occurring in approximately 40% of the galls). Nine species of plants were recorded for the first time in the Neotropical as host of gallers.

In this study we perform an inventory of the insect leaf galls of the Parque Nacional das Emas, Goiás State, Brazil. We found 97 gall morphotypes, distributed on 24 botanical families comprising 37 genera and 55 species. The plant taxa that showed the greatest richness of galls were the families Myrtaceae, with 17 morphotypes and Fabaceae with 14, and the genera Myrcia (Myrtaceae) and Qualea (Vochysiaceae) with 10 and eight morphotypes, respectively. The plant species Andira cujabensis Benth. (Fabaceae) and Myrcia guianensis (Aubl.) DC., with four morphotypes each, were the most diverse. We found galling insects belonging to Diptera, Hemiptera and Lepidoptera. The galling insects of family Cecidomyiidae (Diptera) were the most common inducing 38.1% of the gall morphotypes. All recorded gall morphotypes are first records to Parque Nacional das Emas. Among the 55 host plant species listed in the survey, 16 species (20%) have the first report of hosting galls.