Marco Antonio Alves Carneiro

Are gall midge species (Diptera, Cecidomyiidae) host-plant specialists?

Despite the speciose fauna of gall-inducing insects in the Neotropical region, little is known about their taxonomy. On the other hand, gall morphotypes associated with host species have been extensively used as a surrogate of the inducer species worldwide. This study reviewed the described gall midges and their galls to test the generalization on the use of gall morphotypes as surrogates of gall midge species in the Brazilian fauna. We compiled taxonomic and biological data for 196 gall midge species recorded on 128 host plant species. Ninety two percent of those species were monophagous, inducing galls on a single host plant species, whereas only 5.6% species were oligophagous, inducing galls on more than one congeneric host plant species. Only four species induced galls on more than one host plant genus. We conclude that gall morphotypes associated with information on the host plant species and attacked organs are reliable surrogates of the gall-inducing species.

Distribution of non-native invasive species and soil properties in proximity to paved roads and unpaved roads in a quartzitic mountainous grassland of southeastern Brazil (rupestrian fields)

One of the most important disturbances of roads is the facilitation of the increase of non-native invasive species into adjacent plant communities. The rupestrian fields of Serra do Cipó, a montane grassland ecosystem in southeastern Brazil, are recognized for their enormous richness of species and endemism rates. The presence of non-native invasive species in this ecosystem could threaten the existence of the native flora and its associated organisms. The aim of this study is to understand how non-native invasive species and native species are distributed along paved and unpaved roads, in a montaneous grassland ecosystem such as the Brazilian rupestrian fields. The two road surfaces provide differing gradients from their edges with respect to nutrients, soil chemical aspects and plant species diversity. High content of calcium at the roadside in the paved road resulted from the paving process, in which limestone gravel is used in one of the several paving phases. In these newly created habitats the toxicity of aluminum is drastically reduced and nutrient enriched, hence representing favorable sites from where non-native invasive species are capable to colonize and grow for undetermined period waiting the chance to invade the adjacent pristine habitats. Disturbances provoked by any natural or human-caused event can provide the opportunity for the non-native invasive species to colonize new plant communities.

Insetos indutores de galhas da porção sul da Cadeia do Espinhaço, Minas Gerais, Brasil

Galling species richness is higher at intermediate latitudes on warm habitats and sclerophyllous vegetation under water and nutrient stress. In the tropical region, galling species richness is higher in rupestrian fields. Here the gall-inducing insects and their host plants of the southern portion of the Espinhaco range, southeastern Brazil are described. 60 study sites from six distinct regions along the Espinhaco range, at Minas Gerais state were selected. In each study site 100 plants were sampled summing up to 6,000 plants censused along an altitudinal gradient ranging from 668m to 1860m a.s.l. A total of 241 distinct galls morphotypes were found on 142 host plant species belonging to 29 families from a total 384 species censused. The richest galling fauna was found in the Asteraceae (42%), mainly the genus Baccharis. The largest proportion of galls (85%) was induced by Cecidomyiidae followed by Lepidoptera (4%) and Homoptera (3%). Stems were the most frequently galled plant organ (72%) while the most common shapes were elliptical (37%) and globoid (36%). The host plant species presenting the highest number of gall morphotypes types was Baccharis pseudomyriocephala with 10 galls. This study supported the assertion that rupestrian fields present the highest galling species richness.

Relationship between invertebrate fauna and bromeliad size

Several bromeliads species store water and organic substrates, allowing the establishment of phytotelmata and associated fauna on their leaves. In this study, we sampled 70 individuals of Vriesea sp. (Carrière) (Bromeliaceae), in rupestrian fields in the Serra de Ouro Branco-MG, Brazil. The relationships between invertebrate species richness and abundance and size of bromeliads were tested using multiple regression. We found 19 species associated with bromeliads, mainly Diptera larvae. The abundance of the phytotelmate fauna increased principally in relation to the volume of water in the bromeliad reservoir. Phytotelmata richness was affected principally by diameter of the reservoir. There was a significant relationship between the abundance and richness of invertebrates associated with leaves with diameter and height of the plant. Invertebrate richness was better explained by abundance of individuals. These results suggest that the increase of richness was attended by higher numbers of microhabitats and more space for colonization of bigger bromeliads. Additionally, there was more chance of sampling different species in locales with greater abundance of individuals.

Efeitos do sexo, do vigor e do tamanho da planta hospedeira sobre a distribuição de insetos indutores de galhas em Baccharis pseudomyriocephala Teodoro (Asteraceae)

Several hypotheses have been proposed to explain the patterns of host plant utilization by herbivorous insects in natural communities. We tested four hypotheses aiming to understand the pattern of attack by gall-inducing insects on the dioecious shrub, Baccharis pseudomyriocephala (Asteraceae). The shrub occurs in the Parque Estadual do Itacolomi, Southeastern Brazil, and supports ten species of galling insects. The following hypotheses were tested: i) male plants are more attacked by galling insects than female plants; ii) larger plant modules are preferentially attacked by galling insects; iii) galling insects perform better on larger modules than on smaller modules; iv) galling insects increase in abundance with meristematic availability. To address these questions, 240 plants (120 of each sex) were sampled in both reproductive and vegetative periods. We recorded the growth rate (4 cm), inflorescence and fruit production, attack rates of the galling insects, and their survivorship and mortality per shoot (module). Modules were separated into size classes (cm) and analyzed by regressions and ANCOVAs. Module size and reproductive effort were positively correlated with host plant size. We did not observe any effect of host plant gender on either variables. In the same way, host plant sex did not show any influence on the abundance and richness of galling insects. Although the abundance of galling insects showed a positive correlation with shoot size, the trend disappeared when the analyses were performed taking into consideration the number of galls per unit of growth (number of galls/cm of shoot) or biomass (number of galls/dry weight). Larval survivorship was not influenced by shoot size. Also, we observed that the abundance of one species of hemipteran galling insect showed a positive relation with leaf biomass. Therefore, we conclude that gender and vigor of this plant species do not influence the community structure of its galling herbivores.

Altitudinal distribution and species richness of herbaceous plants in campos rupestres of the Southern Espinhaço Range, Minas Gerais, Brazil

Abstract The variation in the species richness of herbaceous plants along an altitudinal gradient was analyzed in the Serra do Ouro Branco and Serra do Ribeiro, in the townships of Ouro Branco and Ouro Preto, respectively. Plant similarity between both serras was also assessed. Twenty spots were sampled along a 440 m (1105 m to 1545 m) altitudinal range; at each site, herbs were collected within ten 1 m2 plots, totaling 200 m². We found 101 species distributed in 59 genera and 25 families. The richest plant families in Serra do Ouro Branco were Poaceae (22 spp.), Asteraceae (14 spp.) and Cyperaceae (10 spp.), while in Serra do Ribeiro, they were Poaceae (17 spp.), Cyperaceae (12 spp.) and Asteraceae (8 spp.). Variation between the number of species and altitude was not significant. The higher number of species in Serra do Ouro Branco may be due to different local environmental factors and to the occurrence of grazing and fires. The serras presented a high similarity value (J = 0.44), but cluster and ordination analysis indicated the formation of two distinct groups, reflecting the importance of local factors to determine the floristic composition of neighboring areas of campos rupestres. Resumo A variacao da riqueza de plantas herbaceas ao longo do gradiente altitudinal foi estudada em campos rupestres das Serras do Ouro Branco e do Ribeiro, localizadas respectivamente nos municipios de Ouro Branco e Ouro Preto. A similaridade entre a flora das serras tambem foi verificada. Foram amostrados 20 pontos num gradiente altitudinal de 440 m (1.105 m a 1.545 m); em cada ponto, as ervas foram coletadas em parcelas de 1 m2, totalizando 200 m². Foram encontradas 101 especies em 59 generos e 25 familias. Na Serra do Ouro Branco, as familias com maior numero de especies foram Poaceae (22 spp.), Asteraceae (14 spp.) e Cyperaceae (10 spp.), enquanto na Serra do Ribeiro foram Poaceae (17 spp.), Cyperaceae (12 spp.) e Asteraceae (8 spp.). Nao houve variacao significativa da riqueza de especies com a altitude e a Serra do Ouro Branco apresentou um maior numero de especies. As serras apresentaram elevada similaridade entre si (J = 0,44), porem houve a formacao de dois grupos distintos nas analises de agrupamento e ordenacao, indicando que a riqueza de especies em areas relativamente proximas de campo rupestre podem estar sob influencia de fatores locais predominantes.

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.

Cerrado to Rupestrian Grasslands: Patterns of Species Distribution and the Forces Shaping Them Along an Altitudinal Gradient

Due to clear variations in a relatively small area, mountains represent natural laboratories for evolutionary and ecological studies. In a large degree, these variations are driven by changes in climate and soil that occur along altitudinal gradients and influence the ecology, evolution and geography of species. In spite of being old and eroded, the southern Brazilian mountains provide enough variation and heterogeneity to influence species distribution and diversity. The best-known Brazilian mountain range is the Espinhaco (the Backbone mountains). The Espinhaco is a large natural watershed divider of major ecological importance in eastern Brazil. The altitudinal gradient in the Espinhaco Mountains is low when compared to other tall mountains in the world as it only varies from ca. 650 to 2.072 m a.s.l. at the Sun Peak (Pico do Sol). This chapter synthesizes the results of 10 studies that have collectively examined the soil, climate to better understand patterns and processes associated with biodiversity of key groups of organism, including of plants, termites, dung beetles, ants, butterflies, arbuscular mycorrhizal fungi, insect herbivores and birds in an altitudinal gradient (from 800 to 1400 m a.s.l.) at Espinhaco mountain range. In this mountain range, the soils are primarily poor and the vegetation is dominated by rupestrian grasslands, and both are known to vary along the altitudinal gradient hence providing opportunities for variation in the associated organisms.

Senescent stem-galls in trees of Eremanthus erythropappus as a resource for arboreal ants

Senescent stem-galls in trees of Eremanthus erythropappus as a resource for arboreal ants. Members of the dipteran families Tephritidae and Cecidomyiidae are inducers of stem-galls in Eremanthus erythropappus (DC.) MacLeish (Asteraceae), a tree common in the state of Minas Gerais, Brazil. When senescent, these galls become available to other organisms, such as ants. The present study describes a community of ants having benefitted from this process of ecosystem-engineering. The colonies in question inhabit the senescent stem-galls of trees of E. erythropappus and were examined in view of answering the following questions: i) whether the presence of stem-galls had any bearing on the richness, composition, or size of the ant colonies therein; and ii) whether the ants displayed any preferences regarding the shape and/or size of the galls. The study was conducted in populations of E. erythropappus trees near the city of Ouro Preto, MG. A total of 227 galls were collected, 14% of which were occupied by ants, belonging to eight different species. Half of the species occupied galls of both morphotypes (fusiform and globular), although we observed a marked preference for larger, globular shapes. Overall, our results showed the galls to be an effective and abundant resource, helping to maintain the diversity of the ants in the canopy. We also observed the occurrence of outstations and polydomic nests, although an in-depth examination of the influence of galls on this type of structuring has not been investigated.