M. Coelho

Gall inducing arthropods from a seasonally dry tropical forest in Serra do Cipó, Brazil

Highly diverse forms of galling arthropods can be identified in much of southeastern Brazils vegetation. Three fragments of a Seasonally Dry Tropical Forest (SDTF) located in the southern range of the Espinhaco Mountains were selected for study in the first survey of galling organisms in such tropical vegetation. Investigators found 92 distinct gall morphotypes on several organs of 51 host plant species of 19 families. Cecidomyiidae (Diptera) was the most prolific gall-inducing species, responsible for the largest proportion of galls (77%) observed. Leaves were the most frequently galled plant organ (63%), while the most common gall morphotype was of a spherical shape (30%). The two plant species, Baccharis dracunculifolia (Asteraceae) and Celtis brasiliensis (Cannabaceae), presented the highest number of gall morphtypes, displaying an average of 5 gall morphotypes each. This is the first study of gall-inducing arthropods and their host plant species ever undertaken in a Brazilian SDTF ecosystem. Given the intense human pressure on SDTFs, the high richness of galling arthropods, and implied floral host diversity found in this study indicates the need for an increased effort to catalogue the corresponding flora and fauna, observe their intricate associations and further understand the implications of such rich diversity in these stressed and vulnerable ecosystems.

Gall-inducing insects from Serra do Cabral, Minas Gerais, Brazil

Our goal was describe the gall richness through the characterization of their external shapes and occurrence patterns in their host plants from Parque Estadual da Serra do Cabral. In a universe of 34 families, 64 genera and 89 plant species, 47 gall-inducing insects in 21 families, 32 genera and 39 host plant species were recorded. The families, which hosted higher gall richness, were those with highest abundance. Asteraceae represented 33% of the species collected followed by Malpighiaceae 8% and Fabaceae 8%, each one concentrating 25%, 19% and 8% of gall-inducing insects, respectively. The organ most attacked was the leaf (51%), followed by the stem (42%) and the terminal branch (4%). Ninety-six percent (96%) of galls were glabrous. Only 25.5% of the galls described in our study have been already recorded in previous studies, reinforcing the need to increase the sampling effort toward a better understanding of the richness, distribution, and natural history of gall-inducing insects from Brazil.

Gall-inducing insects from Campos de Altitude, Brazil

Gall-inducing insects are very specious in vegetations of southeastern Brazil. Our goal was describe the gall richness by characterizing their external forms and their patterns of occurrence on host plants. Samples were collected from Campos de Altitude at four regions of the Mantiqueira Range: 1) Parque Estadual da Serra do Brigadeiro, 2) Parque Nacional do Caparao, 3) Parque Estadual do Ibitipoca, 4) Parque Nacional do Itatiaia. We found 93 gall species within 13 families, 30 genera and 50 host plant species. We recorded 38 gall species in Parque Estadual da Serra do Brigadeiro, 21 in Parque Nacional do Caparao, 23 in Parque Estadual do Ibitipoca and 20 in Parque Nacional do Itatiaia. Asteraceae represented 33% of the species collected, followed by Melastomataceae at 17%; with each one concentrating 56% and 18% of the galling insects, respectively. 98% of galls were Cecydomiidae (Diptera). The most attacked organ was the stem (56%), followed by the leaf (23%). Only 12% of the galls described in our study had been already recorded in previous studies, thus reinforcing the need to increase the sampling effort toward a better understanding of the richness and the natural history of gall-inducing insects from Brazil.

Archipelago of Montane Forests Surrounded by Rupestrian Grasslands: New Insights and Perspectives

In this chapter, we describe, for the first time, the natural islands of Atlantic rainforests, regionally known as capoes (heretofore called Atlantic forest islands, or simply forest islands), associated to the Espinhaco Range under the perspective of the landscape context in which they are immersed. The structure, composition and reproductive aspects of the vegetation are analyzed, as are their soil properties. Forest islands of the Espinhaco Range have a similar floristic composition to the semi-deciduous forests of southeastern Brazil, that are associated to the Atlantic rainforest domain, despite having been classified in its climate regime as ombrophilous vegetation. The forest islands of the Espinhaco Range are classified as disjunctions of broadleaved, evergreen, cloud, montane tropical forest located on mountain ridges, rocky slopes or swamps. Forest islands are always associated to mountains, which have concentrated rainfall and cloudiness. The forest islands are located in an ecological transition zone and are strongly influenced by elements of the Atlantic rainforest biome, despite the elements of the Cerrado biome (in the present case, in a matrix of rupestrian grasslands), which are present in minor proportions. The influence of the rupestrian grassland ecosystem increases according to the levels of disturbance suffered by the vegetation. The forest islands are an edaphoclimatic formation, hence dependent on specific climate and soil properties for their development. Soil physical properties, such as drainage, are more relevant than their chemical properties, like nutrient input, to the establishment and development of the forest islands. Among the several threats, fire stands out, causing large decreases in the dimensions of the forest and changes in the successional dynamics of the vegetation. These natural islands, which are mostly immersed in matrices of rupestrian grasslands, have a high biogeographical importance, especially as a refuge for the seasonal surrounding environment. However, they may be under a fast-paced threat due to recurrent anthropogenic fires and the potential effects of climate and land use changes.

Galling Insects of the Brazilian Páramos: Species Richness and Composition Along High-Altitude Grasslands

Abstract In this work, we investigated the factors that determine the distribution of galling insects in high-altitude grasslands, locally called ‘campos de altitude’ of Mantiqueira Range and tested whether 1) richness of galling insects decreases with altitude, 2) galling insect richness increases with plant richness, 3) variation in galling insect diversity is predominantly a consequence of its β component, and 4) turnover is the main mechanism driving the beta diversity of both galling insects and plants. Galling insect richness did not exhibit a negative relationship with altitude, but it did increase with plant richness. The additive partition of regional richness (γ) into its local and beta components showed that local diversity (α) of galling insects and plants was relatively low in relation to regional diversity; the β component incorporated most of the regional diversity. This pattern was also found in the multiscale analysis of the additive partition for galling insects and plants. The beta diversity of galling insects and plants was driven predominantly by the process of turnover and minimally by nesting. The results reported here point out that the spatial distribution of galling insects is best explained by historical factors, such as the distribution of genera and species of key host plants, as well as their relation to habitat, than ecological effects such as hygrothermal stress – here represented by altitude.

Neotropical Insect Galls: Status of Knowledge and Perspectives

This book seeks to expose the reader to those studies which have made the greatest contribution to the body of knowledge surrounding the insect galls in the Neotropical region. There seems to be countless groups of researchers working both in Brazil and in other tropical regions of the Americas. The chapters presented here report the diversity of studies conducted to date as well as indicate the quality of the studies in progress.

Species turnover drives β-diversity patterns across multiple spatial scales of plant-galling interactions in mountaintop grasslands

This study describes differences in species richness and composition of the assemblages of galling insects and their host plants at different spatial scales. Sampling was conducted along altitudinal gradients composed of campos rupestres and campos de altitude of two mountain complexes in southeastern Brazil: Espinhaço Range and Mantiqueira Range. The following hypotheses were tested: i) local and regional richness of host plants and galling insects are positively correlated; ii) beta diversity is the most important component of regional diversity of host plants and galling insects; and iii) Turnover is the main mechanism driving beta diversity of both host plants and galling insects. Local richness of galling insects and host plants increased with increasing regional richness of species, suggesting a pattern of unsaturated communities. The additive partition of regional richness (γ) into local and beta components shows that local richnesses (α) of species of galling insects and host plants are low relative to regional richness; the beta (β) component incorporates most of the regional richness. The multi-scale analysis of additive partitioning showed similar patterns for galling insects and host plants with the local component (α) incorporated a small part of regional richness. Beta diversity of galling insects and host plants were mainly the result of turnover, with little contribution from nesting. Although the species composition of galling insects and host plant species varied among sample sites, mountains and even mountain ranges, local richness remained relatively low. In this way, the addition of local habitats with different landscapes substantially affects regional richness. Each mountain contributes fundamentally to the composition of regional diversity of galling insects and host plants, and so the design of future conservation strategies should incorporate multiple scales.

Diversity of fruit-feeding butterflies in a mountaintop archipelago of rainforest

We provide the first description of the effects of local vegetation and landscape structure on the fruit-feeding butterfly community of a natural archipelago of montane rainforest islands in the Serra do Espinhaço, southeastern Brazil. Butterflies were collected with bait traps in eleven forest islands through both dry and rainy seasons for two consecutive years. The influence of local and landscape parameters and seasonality on butterfly species richness, abundance and composition were analyzed. We also examined the partitioning and decomposition of temporal and spatial beta diversity. Five hundred and twelve fruit-feeding butterflies belonging to thirty-four species were recorded. Butterfly species richness and abundance were higher on islands with greater canopy openness in the dry season. On the other hand, islands with greater understory coverage hosted higher species richness in the rainy season. Instead, the butterfly species richness was higher with lower understory coverage in the dry season. Butterfly abundance was not influenced by understory cover. The landscape metrics of area and isolation had no effect on species richness and abundance. The composition of butterfly communities in the forest islands was not randomly structured. The butterfly communities were dependent on local and landscape effects, and the mechanism of turnover was the main source of variation in β diversity. The preservation of this mountain rainforest island complex is vital for the maintenance of fruit-feeding butterfly community; one island does not reflect the diversity found in the whole archipelago.

Galls in Brazilian Mountains: New Reports and Perspectives

In the last decade, a significant project was undertaken with the objective of studying the patterns of distribution of gall-forming insects across different individual mountains in the Espinhaco mountain range and Serra da Mantiqueira. Three hypotheses were tested that seek to describe the patterns of gall-inducing insects in order to test their “generality”. (1) hypothesis of altitudinal gradient, which predicts that the richness of gall-forming insects diminishes with altitude, (2) hypothesis of plant richness, which predicts that richness of gall-forming insects increases with plant richness, and (3) hypothesis of plant density, which predicts that the richness of gall-forming insects increases with plant density. We have found that the richness of gall-forming insects does not vary linearly with altitude. Gall-inducing insects respond significantly to the number and composition of host plants. The majority of regional richness of gall-forming insects is explained by their beta richness component, suggesting that the composition of the community of gall-forming insects reflects the patterns of distribution of their host plants in the tropics.

Antagonistic Interactions in the Rupestrian Grasslands: New Insights and Perspectives

Antagonistic interactions are main ecological forces in terrestrial communities and include several examples involving plants and animals. The studies performed in the rupestrian grasslands have mostly focused on patterns of herbivory and on the effects of plant quality and natural enemies on insect herbivore abundance and distribution. Herbivory rates recorded for plants in this ecosystem are within the range proposed for open areas (ca. 15 %), although a wider range of studies are still needed. Galling insect richness is highly variable amongst sites (between 18 and 241 species) and are mostly rich and abundant in xeric habitats compared to mesic habitats, corroborating the hypothesis of environmental harshness. Several new galling insect species have been discovered in this very diverse landscape, indicating its importance for insect radiation and evolution. Galling insect communities associated to host plants are influenced by host plant sex. Male plants generally host higher insect richness and herbivory levels than female plants. Gall insect richness sampled on 138 host plants in several rupestrian grassland sites indicates that larger plant families also host higher number of galling insects than smaller plant families or genera. Amongst the factors that influence host plant selection by herbivores in rupestrian grasslands aspects of plant quality such as leaf asymmetry, leaf sclerophylly and ant-interactions have been evaluated. However, mixed results for the effects of plant quality on insect abundance and performance have been found depending upon the insect-host system evaluated. Another antagonist interaction evaluated involves parasitism by two common species of mistletoes and results have shown that parasitism represents another important source of stress for host plants in the rupestrian grasslands. Finally, in this chapter we summarize several antagonistic, multitrophic and indirect interactions using plants in the genus Baccharis as a model, aiming to provide information and guidance for future studies.