Ecology of Haemagogus sp. and Sabethes sp. (Diptera: Culicidae) in relation to the microclimates of the Caxiuanã National Forest, Pará, Brazil

This study was conducted in a meteorological tower located in the Caxiuanã Forest (municipality of Melgaço, Pará, Brazil) with the aim of assessing the vertical stratification of species of Haemagogus and Sabethes, potential vectors of the yellow fever virus. To investigate the role of microclimates in mosquito stratification, bimonthly collections were conducted at ground level (0 m), 8 m, 16 m and 30 m (canopy level), with the aid of entomological nets and suction tubes, from July 2005-April 2006. A total of 25,498 mosquitoes were collected; specimens of Sabethes sp. and Haemagogus janthinomyswere found mostly at heights of 16 m and 30 m while Hg. leucocelaenus was most frequently observed at ground level. The largest number of vector species was collected during the rainiest months, but this difference between seasons was not statistically significant. However, the number of Hg. janthinomys was positively correlated with variations in temperature and relative humidity.

Assessing the vulnerability of women to sexually transmitted diseases STDS/ HIV: construction and validation of markers

Objective To construct and validate markers of vulnerability of women to STDs/HIV, taking into consideration the importance of STDs/HIV. Method Methodological study carried out in three stages: 1) systematic review and identification of elements of vulnerability in the scientific production; 2) selection of elements of vulnerability, and development of markers; 3) establishment of the expert group and validation of the markers (content validity). Results Five markers were validated: no openness in the relationship to discuss aspects related to prevention of STDs/HIV; no perception of vulnerability to STDs/HIV; disregard of vulnerability to STDs/ HIV; not recognizing herself as the subject of sexual and reproductive rights; actions of health professionals that limit women’s access to prevention of STDs/HIV. Each marker contains three to eleven components. Conclusion The construction of such markers constituted an instrument, presented in another publication, which can contribute to support the identification of vulnerabilities of women in relation to STDs/HIV in the context of primary health care services. The markers constitute an important tool for the operationalization of the concept of vulnerability in primary health care and to promote inter/multidisciplinary and inter/multi-sectoral work processes.


Artrópodos associados à copa de Attalea phalerata Mart. (Arecaceae), na região do Pantanal de Poconé, Mato Grosso, Brasil

Six individuals of the palm A. phalerata, in Poconé floodplains of Mato Grosso, were sprayed with a synthetic pyrethroid (0.25% concentration) in order to study the biomass, diversity, and richness of the canopy arthropods. A total of 17,188 (238.7±80.6 ind./m²) arthropods belonging to 22 Orders, was collected in a 72 m² funnel area. Two hours after spraying, 58.9% of the total number fell into the funnels, 37.6% was obtained by shaking the trees, and finally, 3.5% after cutting and washing all the palm leaves. The Coleoptera (27.4%), Hymenoptera-Formicidae (19.0%), Collembola (13.6%), Psocoptera (10.7%), Diptera (9.0%) and Araneae (6.4%) were the predominant. The total biomass was 15.1 g dry weight (0.4mg/m²; 0.13+0.04/tree). A total of 4,715 beetles representing 48 families and 326 morphospecies were obtained. Tenebrionidae (22.9%), Curculionidae (22.0%), Carabidae (10.9%) and Staphylinidae (7.9%) were the most abundant, while Curculionidae (44 spp.), Staphylinidae (40 spp.) and Chrysomelidae (34 spp.) presented the largest number of morphospecies. Herbivores (37.5%) were the dominant in the trophic guilds of adult Coleoptera, followed by predators (35.4%), fungivores (14.6%), and saprophages (12.5%). Although most arthropod Orders were represented in all the palms sampled, analysis of variance showed no significant differences in their composition, however there was a significant difference in their frequency of occurrence.

Aspectos ecológicos da comunidade de Araneae (Arthropoda, Arachnida) em copas da palmeira Attalea phalerata Mart. (Arecaceae) no Pantanal de Poconé, Mato Grosso, Brasil

Seis palmeiras de Attalea phalerata foram amostradas durante a fase aquática (cheia) no Pantanal de Mato Grosso (fevereiro/2001), utilizando-se a metodologia de nebulização de copas "canopy fogging". Este estudo objetivou avaliar a composição, distribuição espacial, guildas comportamentais, biomassa e sazonalidade da comunidade de Araneae em copas dessa palmeira que forma adensamentos monodominantes, típicos nessa região. Um total de 1326 aranhas foram coletadas em 99 m² de área amostral (13,4 + 8,2 indivíduos/m²), representando 20 famílias, sendo Salticidae e Araneidae as mais abundantes. A biomassa total de 704 aranhas em três palmeiras correspondeu a 0.6172 mg de peso seco (0,0123+ 0,04 mg/m²). Dez guildas comportamentais demonstraram a coexistência de diferentes espécies em um mesmo habitat. Representantes de Salticidae, Oonopidae e Ctenidae dominaram entre as caçadoras, e Araneidae e Dictynidae, dentre as tecelãs. A análise de distribuição espacial demonstrou que a maior abundância de aranhas ocorreu na região central da copa, provavelmente devido à quantidade de recursos disponíveis nesse local. A comparação desses resultados com aqueles obtidos durante o período de seca, demonstra diferenças sazonais influenciadas pelo pulso de inundação, principalmente com relação à composição das famílias amostradas entre os períodos de seca e cheia.

Composição da comunidade de Formicidae (Insecta, Hymenoptera) em copas de Attalea phalerata Mart. (Arecaceae), no Pantanal de Poconé, Mato Grosso, Brasil

Três indivíduos da palmeira Attalea phalerata Mart (Arecaceae) foram amostrados durante a fase aquática (cheia) no Pantanal de Mato Grosso (fevereiro/2001) utilizando-se a metodologia de nebulização de copas "canopy fogging". Este estudo objetivou avaliar a diversidade, hábitos alimentares e a distribuição espacial da comunidade de Formicidae em copas dessa palmeira que forma adensamentos monodominantes, típicos nessa região. Cada palmeira foi nebulizada uma única vez e realizadas três coletas subseqüentes. Um total de 966 formigas, pertencentes a 6 subfamílias, 13 tribos e 29 espécies foram amostradas em 49 m² de área amostral (19,7±52,7 indivíduos/m²) representando 3,9% do total de artrópodes obtidos. Myrmicinae foi a subfamília mais representativa, com 6 tribos e 14 espécies, destacando-se Solenopsidini com 5 espécies. Formicinae foi a segunda subfamília mais abundante com 3 tribos e 8 espécies. Pheidole sp. 2 foi dominante na amostragem geral (284 indivíduos; 29,4% da captura total) seguida por Camponotus (Myrmobrachys) crassus (182 individuos; 18,8%) e Crematogaster (Orthocrema) sp. 1 pr. quadriformis (119 individuos; 12,3%). Os índices de diversidade foram consideráveis (H'=2,185; D= 0,835) apesar de demonstrarem baixos valores de equitabilidade (0,649 e 0,248, respectivamente). Este resultado demonstra a heterogeneidade da comunidade de Formicidae associada à copa dessa palmeira. A análise da distribuição espacial desmonstrou que a maior abundância e riqueza de Formicidae ocorrem na região central da copa, próximo ao caule.

Terrestrial arthropods from tree canopies in the Pantanal of Mato Grosso, Brazil

Terrestrial arthropods from tree canopies in the Pantanal of Mato Grosso, Brazil. This study represents a contribution to the knowledge of the diversity of arthropods associated to the canopy of Vochysia divergens Pohl (Vochysiaceae). Three trees individuals were sampled during two seasonal periods in this region: a) by spraying one tree canopy during high water (February); b) by fogging two tree canopies during low water (September/October). The 15,744 arthropods (183.2±38.9 individuals/m²) obtained from all three trees (86 m²) represented 20 taxonomic orders, 87.1% were Insecta, and 12.9% Arachnida. The dominant groups were Hymenoptera (48.5%; 88.9 individuals/m²), mostly Formicidae (44.5%; 81.4 individuals/m²), followed by Coleoptera (14.0%; 25.5 individuals/m²) and Araneae (10.2%; 19.5 individuals/m²), together representing 62.5% of the total catch. Fourteen (70%) of all orders occurred on three trees. Dermaptera, Isoptera, Neuroptera, Odonata, Plecoptera and Trichoptera were collected from only one tree. Of the total, 2,197 adult Coleoptera collected (25.5±11.3 individuals/m²), 99% were assigned to 32 families and 256 morphospecies. Nitidulidae (17.9% of the total catch; 4.6 individuals/m²), Anobiidae (16.7%; 4.3 individuals/m²), Curculionidae (13.2%; 3.4 individuals/m²) and Meloidae (11.4%; 2.9 individuals/m²) dominated. The communitiy of adult Coleoptera on V. divergens indicated a dominance of herbivores (37.8% of the total catch, 127 spp.) and predators (35.2%, 82 spp.), followed by saprophages (16.2%, 32 spp.) and fungivores (10.8%, 15 spp.). The influence of the flood pulse on the community of arboreal arthropods in V. divergens is indicated by the seasonal variation in evaluated groups, causing changes in their structure and composition.

Diversity of Pentatomoidea (Hemiptera) in riparian forests of southern Brazil: taller forests, more bugs

Riparian forests are important features of any ecosystem, especially on grassland and savannah vegetation types. However, riparian forests in southernmost Brazil have received much less attention than elsewhere. This is the first quantitative study of pentatomoid (Hemiptera) diversity in the Pampa biome, surveying riparian forests of brooks and rivers in the environs of the municipality of Bagé, Rio Grande do Sul state, southern Brazil. The aim was two-fold: taxonomic characterization of the fauna and a primary ecological study of bug diversity. Sweeping net and beating tray were used to sample trees and shrubs on the border of sampling sites; sampling was carried out during three consecutive days, from March 28th to 30th 2006. Overall 154 individuals of 32 species of Pentatomoidea were captured, almost all species are new records for the local fauna. Taller forest canopy sites had higher abundance overall and higher species richness than shorter forest canopy sites. Of the 32 species, 11 were singletons and four were doubletons. There were no differences for pentatomoid species composition between the two environments differing in vegetation structure. Association to the Pampa biome of the most abundant species found are discussed. Although based on a rapid assessment protocol of faunal inventories, our results add important bioecological information to the pentatomoid fauna of the Pampa biome, especially associated to riparian forests.

Local-scale spatial variation in diversity of social wasps in an Amazonian rain forest in Caxiuanã, Pará, Brazil (Hymenoptera, Vespidae, Polistinae)

Polistine wasps are important in Neotropical ecosystems due to their ubiquity and diversity. Inventories have not adequately considered spatial attributes of collected specimens. Spatial data on biodiversity are important for study and mitigation of anthropogenic impacts over natural ecosystems and for protecting species. We described and analyzed local-scale spatial patterns of collecting records of wasp species, as well as spatial variation of diversity descriptors in a 2500-hectare area of an Amazon forest in Brazil. Rare species comprised the largest fraction of the fauna. Close range spatial effects were detected for most of the more common species, with clustering of presence-data at short distances. Larger spatial lag effects could also be identified in some species, constituting probably cases of exogenous autocorrelation and candidates for explanations based on environmental factors. In a few cases, significant or near significant correlations were found between five species (of Agelaia, Angiopolybia, and Mischocyttarus) and three studied environmental variables: distance to nearest stream, terrain altitude, and the type of forest canopy. However, association between these factors and biodiversity variables were generally low. When used as predictors of polistine richness in a linear multiple regression, only the coefficient for the forest canopy variable resulted significant. Some level of prediction of wasp diversity variables can be attained based on environmental variables, especially vegetation structure. Large-scale landscape and regional studies should be scheduled to address this issue.

Temporal variation in the composition of ant assemblages (Hymenoptera, Formicidae) on trees in the Pantanal floodplain, Mato Grosso do Sul, Brazil

Temporal variation in the composition of ant assemblages (Hymenoptera, Formicidae) on trees in the Pantanal floodplain, Mato Grosso do Sul, Brazil. In this paper we investigate how seasonal flooding influences the composition of assemblages of ants foraging on trees in the Pantanal of Mato Grosso do Sul. During the flood in the Pantanal, a large area is covered by floods that are the main forces that regulate the pattern of diversity in these areas. However, the effects of such natural disturbances in the ant communities are poorly known. In this sense, the objective of this study was to evaluate the effect of temporal variation in assemblages of ants foraging on trees in the Pantanal of Miranda. Samples were collected during a year in two adjacent areas, one who suffered flooding during the wet period and another that did not suffer flooding throughout the year. In 10 sites for each evaluated habitat, five pitfall traps were installed at random in trees 25 m apart from each other. In the habitat with flooding, the highest richness was observed during the flooding period, while there was no significant change in richness in the area that does not suffer flooding. The diversity of species between the two evaluated habitats varied significantly during the two seasons. Most ants sampled belong to species that forage and nest in soil. This suggests that during the flood in flooded habitats, ants that did not migrate to higher areas without flooding adopt the strategy to search for resources in the tree canopy.

Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil

Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil. Pierce's disease of grapevines, caused by Xylella fastidiosa, is a serious problem in some regions of North America, not yet reported in Brazil. In this study, a survey of potential sharpshooter (Hemiptera, Cicadellidae, Cicadellinae) and spittlebug (Hemiptera, Cercopidae) vectors of X. fastidiosa was conducted in vineyards at the São Francisco River Valley, a major grape growing region in Brazil. Four vineyards of Vitis vinifera L. were sampled fortnightly from June/2005 to June/2007, using yellow sticky cards, each placed at two different heights (45 cm aboveground and 45 cm above the crop canopy) in 10 sampling localities. A total of 4,095 specimens of sharpshooters were collected, nearly all from 3 Proconiini species, Homalodisca spottii Takiya, Cavichioli & McKamey, 2006 (96.8% of the specimens), Tapajosa fulvopunctata (Signoret, 1854) (3.1%), and Tretogonia cribrata Melichar, 1926 (1 specimen). Hortensia similis (Walker, 1851) (2 specimens) was the only Cicadellini species. Only 1 cercopid specimen, belonging to Aeneolamia colon (Germar, 1821), was trapped. Even though they are not considered potential Xylella vectors, 2 Gyponini leafhoppers were collected: Curtara samera DeLong & Freytag, 1972 (11 specimens) and Curtara inflata DeLong & Freytag, 1976 (1 specimen). Homalodisca spottii was observed feeding and mating on green branches of grapevines, in addition to egg masses. Because of its prevalence on the crop canopy, occurrence throughout the year (with peaks from February to August), and ability to colonize grapevines, H. spottii could be an important vector if a X. fastidiosa strain pathogenic to grapevines becomes introduced at the São Francisco River Valley.

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.

Influence of tree species on the herbaceous understory and soil chemical characteristics in a silvopastoral system in semi-arid northeastern Brazil

Studies from some semi-arid regions of the world have shown the beneficial effect of trees in silvopastoral systems, by promoting the formation of resource islands and increasing the sustainability of the system. No data are available in this respect for tree species of common occurrence in semi-arid Northeastern Brazil. In the present study, conducted in the summer of 1996, three tree species (Zyziphus joazeiro, Spondias tuberosa and Prosopis juliflora: ) found within Cenchrus ciliaris pastures were selected to evaluate differences on herbaceous understory and soil chemical characteristics between samples taken under the tree canopy and in open grass areas. Transects extending from the tree trunk to open grass areas were established, and soil (0-15 cm) and herbaceous understory (standing live biomass in 1 m² plots) samples were taken at 0, 25, 50, 100, 150 and 200% of the average canopy radius (average radius was 6.6 ± 0.5, 4.5 ± 0.5, and 5.3 ± 0.8 m for Z. joazeiro, P. juliflora, and S. tuberosa , respectively). Higher levels of soil C, N, P, Ca, Mg, K, and Na were found under the canopies of Z. joazeiro and P. juliflora: trees, as compared to open grass areas. Only soil Mg organic P were higher under the canopies of S. tuberosa trees, as compared to open grass areas. Herbaceous understory biomass was significantly lower under the canopy of S. tuberosa and P. juliflora trees (107 and 96 g m-2, respectively) relatively to open grass areas (145 and 194 g m-2). No herbaceous biomass differences were found between Z. joazeiro canopies and open grass areas (107 and 87 g m-2, respectively). Among the three tree species studied, Z. joazeiro was the one that presented the greatest potential for use in a silvopastoral system at the study site, since it had a larger nutrient stock in the soil without negatively affecting herbaceous understory biomass, relatively to open grass areas.

Fertilizer 15N balance in a coffee cropping system: a case study in Brazil

Knowledge about the fate of fertilizer nitrogen in agricultural systems is essential for the improvement of management practices in order to maximize nitrogen (N) recovery by the crop and reduce N losses from the system to a minimum. This study involves fertilizer management practices using the 15N isotope label applied in a single rate to determine the fertilizer-N balance in a particular soil-coffee-atmosphere system and to deepen the understanding of N plant dynamics. Five replicates consisting of plots of about 120 plants each were randomly defined within a 0.2 ha coffee plantation planted in 2001, in Piracicaba, SP, Brazil. Nine plants of each plot were separated in sub-plots for the 15N balance studies and treated with N rates of 280 and 350 kg ha-1 during 2003/2004 and 2004/2005, respectively, both of them as ammonium sulfate enriched to a 15N abundance of 2.072 atom %. Plant shoots were considered as separate parts: the orthotropic central branch, productive branches, leaves of productive branches, vegetative branches, leaves of vegetative branches and fruit. Litter, consisting of dead leaves accumulated below the plant canopy, was measured by the difference between leaves at harvest and at the beginning of the following flowering. Roots and soil were sampled down to a depth of 1.0 at intervals of 0.2 m. Samples from the isotopic sub-plots were used to evaluate total N and 15N, and plants outside sub-plots were used to evaluate dry matter. Volatilization losses of NH3 were estimated using special collectors. Leaching of fertilizer-N was estimated from deep drainage water fluxes and 15N concentrations of the soil solution at 1 m soil depth. At the end of the 2-year evaluation, the recovery of 15N applied as ammonium sulfate was 19.1 % in aerial plant parts, 9.4 % in the roots, 23.8 % in the litter, 26.3 % in the fruit and 12.6 % remaining in the 0_1.0 m soil profile. Annual leaching and volatilization losses were very small (2.0 % and 0.9 %, respectively). After two years, only 6.2 % N were missing in the balance (100 %) which can be attributed to other non-estimated compartments and experimental errors. Results show that an enrichment of only 2 % atom 15N allows the study of the partition of fertilizer-N in a perennial crop such as coffee during a period of two years.

Enzymatic activity and mineralization of carbon and nitrogen in soil cultivated with coffee and green manures

There are great concerns about degradation of agricultural soils. It has been suggested that cultivating different plant species intercropped with coffee plants can increase microbial diversity and enhance soil sustainability. The objective of this study was to evaluate enzyme activity (urease, arylsulfatase and phosphatase) and alterations in C and N mineralization rates as related to different legume cover crops planted between rows of coffee plants. Soil samples were collected in a field experiment conducted for 10 years in a sandy soil in the North of Paraná State, Brazil. Samples were collected from the 0-10 cm layer, both from under the tree canopy and in-between rows in the following treatments: control, Leucaena leucocephala, Crotalaria spectabilis, Crotalaria breviflora, Mucuna pruriens, Mucuna deeringiana, Arachis hypogaea and Vigna unguiculata. The soil was sampled in four stages of legume cover crops: pre-planting (September), after planting (November), flowering stage (February) and after plant residue incorporation (April), from 1997 to 1999. The green manure species influenced soil enzyme activity (urease, arylsulfatase and phosphatase) and C and N mineralization rates, both under the tree canopy and in-between rows. Cultivation of Leucaena leucocephala increased acid phosphatase and arilsulfatase activity and C and N mineralization both under the tree canopy and in-between rows. Intercropped L. leucocephala increased urease activity under the tree canopy while C. breviflora increased urease activity in-between rows.

Emission of nitrous oxide and carbon dioxide from semi-arid tropical soils in Chiapas México

The semi-arid region of Chiapas is dominated by N2 -fixing shrubs, e.g., Acacia angustissima. Urea-fertilized soil samples under maize were collected from areas covered and uncovered by A. angustissima in different seasons and N2O and CO2 emissions were monitored. The objective of this study was to determine the effects of urea and of the rainy and dry season on gas emissions from semi-arid soil under laboratory conditions. Urea and soil use had no effect on CO2 production. Nitrons oxide emission from soil was three times higher in the dry than in the rainy season, while urea fertilization doubled emissions. Emissions were twice as high from soil sampled under A. angustissima canopy than from arable land, but 1.2 lower than from soil sampled outside the canopy, and five times higher from soil incubated at 40 % of the water-holding capacity (WHC) than at soil moisture content, but 15 times lower than from soil incubated at 100 WHC. It was found that the soil sampling time and water content had a significant effect on N2O emissions, while N fertilizer and sampling location were less influent.