953 resultados para Neotropical fauna
Resumo:
Studies of ant-plant relationships elucidate how top-down effects of the third trophic level can affect the biomass, richness, and/or species composition of plants. Although widespread in the neotropics, few studies have so far examined the direct effects of ants on plant fitness. Here, through experimental manipulation (ant-exclusion) under natural conditions, we examined the effect of ant visitation to extrafloral nectaries on leaf herbivory and fruit set in Chamaecrista debilis in the Brazilian savanna. As opposed to other Chamaecrista species, our results showed that visiting ants (15 species) significantly reduce herbivory and increase fruit set by more than 50% compared to plants from which ants were excluded. This mutualistic system is facultative in nature, and corroborates the potential beneficial role of exudate-feeding ants as anti-herbivore agents of tropical plants. (C) 2010 Elsevier GmbH. All rights reserved.
Resumo:
The advance of agricultural frontier may cause the Cerrado (Brazilian savanna) to disappear before 2030. This work focuses on measuring the impact of pasture implantation on a cerrado`s termite fauna. Termites were sampled in a cerrado sensu stricto and a pasture, originally cerrado. All species were classified as their feeder group, accumulation curves were made and Shannon-Wiener indexes and beta diversity were calculated for both areas. Cerrado was richer than pasture and species composition differed considerably, leading beta diversity to a high value. The humivorous was the most representative species, followed by grass/litter feeders, xylophagous and, less representative, the intermediates. There were more xylophagous and intermediates species on cerrado than in pasture; the grass/litter feeders were more abundant in pasture, but didn`t differed in number or species; and humivorous didn`t differed neither in richness nor in abundance. This work shows that the simplification of the habitat is indeed causing the extinction of populations that depend on some specifics resource.
Resumo:
Ficus arpazusa Casaretto is a fig tree native to the Atlantic Rain Forest sensu lato. High levels of genetic diversity and no inbreeding were observed in Ficus arpazusa. This genetic pattern is due to the action of its pollinator, Pegoscapus sp., which disperses pollen an estimated distance of 5.6 km, and of Ficus arpazusa`s mating system which, in the study area, is allogamous. This study highlights the importance of adding both ecological and genetic data into population studies, allowing a better understanding of evolutionary processes and in turn increasing the efficacy of forest management and revegetation projects, as well as species conservation.
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Gasteruptiinae is the largest Gasteruptiidae subfamily, with circa 400 species that have been grouped into the worldwide Gasteruption Latreille. Based on a cladistic analysis with 43 morphological characters, 40 ingroup taxa representing all biogeographic regions, and seven outgroups (four Hyptiogastrinae, two Aulacidae and one Evaniidae), I confirm the monophyly of Gasteruptiinae and Gasteruption and recognize three exclusively Neotropical small genera: Plutofoenus Kieffer (revalidated) (southern South America), Spinolafoenus Macedo n. gen. (Chile) and Trilobitofoenus Macedo n. gen. (Central and South America). Gasteruption, supported by four synapomorphies, remains the most speciose genus in the subfamily. The four Gasteruptiinae genera are keyed and described. Seven species are keyed and described or redescribed: Plutofoenus chaeturus (Schletterer) n. comb., P. edwardsi Turner, P. paraguayensis (Schrottky), Spinolafoenus ruficornis (Spinola) n. comb., Trilobitofoenus alvarengai Macedo n. sp., T. plaumanni Macedo n. sp. and T. sericeus (Cameron) n. comb. (lectotype designated).
Resumo:
Stibadocerina Alexander, a monotypic genus, includes the only known Neotropical species of the family Cylindrotomidae, S. chilensis Alexander, 1929, from South Central Chile (ca. 36 degrees 50`S-42 degrees 17`S). In this paper, Stibadocerina chilensis is redescribed and illustrated in detail. A study of wing-vein homology in the subfamily Stibadocerinae is provided, to identify the components of the reduced radial sector in Stibadocerina and related taxa. The proposed hypotheses of wing-vein homology are tested, and the systematic position of Stibadocerina is assessed through a cladistic analysis of 13 characters of the male imago, scored for exemplar species of the four genera included in the Stibadocerinae. A single most parsimonious tree supports the monophyly of the Stibadocerinae and the following relationships among its included genera: Stibadocerodes [Stibadocera (Stibadocerella + Stibadocerina)]. The subfamily includes one example of a vicariant distribution with a sister-group relationship between South Central Chilean and East Asian taxa, and supports a biogeographical interpretation of an ancestral trans-Pacific biota.
Resumo:
Streams located in areas of sugarcane cultivation receive high concentrations of metal ions from soils of the adjacent areas causing accumulation of metals in the aquatic sediment. This impact results in environmental problems and leads to bioaccumulation of metal ions in aquatic organisms. In the present study, metal concentrations in different predatory insects were studied in streams near sugarcane cultivation and compared to reference sites. Possible utilisation of predatory insects as bioindicators of metal contamination due to sugarcane cultivation from 13 neotropical streams was evaluated. Ion concentrations of Al, Cd, Cr, Cu, Zn, Fe, and Mn in adult Belostomatidae (Hemiptera) and in larvae of Libellulidae (Odonata) were analysed. Nine streams are located in areas with sugarcane cultivation, without riparian vegetation (classified as impacted area) and four streams were located in forested areas (reference sites). Metal concentrations in insects were higher near sugarcane cultivations than in control sites. Cluster analysis, complemented by an ANOSIM test, clearly showed that these insect groups are good potential bioindicators of metal contamination in streams located in areas with sugarcane cultivation and can be used in monitoring programmes. We also conclude that Libellulidae appeared to accumulate higher concentrations of metals than Belostomatidae.
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The endemic Neotropical long-horned caddisfly subgenus Notalina (Neonotalina) Holzenthal contains nine described species, but its immature stages are unknown. In this paper the larvae and pupae of Notalina morsei Holzenthal 1986 from southeastern Brazil are described and illustrated. Larvae of the subgenus are easily recognized from other Neotropical leptocerids by the following characters: ventral apotome which is broad anteriorly and narrow posteriorly; the metanotum with three sclerites; the metasternum bearing 10-12 setae; the gill arrangement, usually including ventral and dorsal filaments from abdominal segments II to VI; and abdominal tergite IX with 6 long and 4 short setae. An updated key to known larvae of Neotropical Leptoceridae genera is provided.
Resumo:
We investigated two of the most studied relationships in the macroecological research program (species richness vs. body size and abundance vs. body size) of a local chironomid assemblage from southeastern Brazil. Although numerous Studies have examined these relationships, few have investigated how they vary at different temporal scales. We used data from a forested stream to document and examine these patterns at monthly intervals. Both the species body size distribution and the abundance-body size relationship varied temporally. In some months the body size distribution was skewed to the right. whereas in others it approached normality. We Found both linear relationships (with different values of slopes). and a polygonal pattern in the abundance-body size relationship. This temporal variation was not related to environmental variables. Our results suggest that body size relationships are temporally instable properties of this chironomid assemblage. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.
Resumo:
The current Brazilian Ixodes fauna is composed of the following eight species: I. amarali Fonseca, 1935; I. aragaoi Fonseca, 1935; I. auritulus Neumann, 1904; I. fuscipes Koch, 1844; I. loricatus Neumann, 1899; I. luciae S,nevet, 1940; I. paranaensis Barros-Battesti, Arzua, Pichorim & Keirans, 2003; and I. schulzei AragA o pound & Fonseca, 1951. Further studies are needed to establish the taxonomic status of I. serrafreirei Amorim, Gazeta, Bossi & Linhares, 2003, a recently proposed species based solely on the nymphal stage. We present an up-to-date key to adults of the currently valid Brazilian species of Ixodes based on scanning electron microscopy. The relationships between Brazilian and other Neotropical Ixodes are also discussed.
Resumo:
Although antibodies to Bartonella henselae have been described in all neotropical felid species, DNA has been detected in only one species, Leopard us wiedii. The aim of this study was to determine whether DNA of Bartonella spp. could be detected in blood of other captive neotropical felids and evaluate risk factors and hematological findings associated with infection. Blood samples were collected from 57 small felids, including 1 Leopard us geoffroyi, 17 L wiedii, 22 Leopardus tigrinus, 14 Leopardus pardalis, and 3 Puma yagouaroundi; 10 blood samples from Panthera onca were retrieved from blood banks. Complete blood counts were performed on blood samples from small felids, while all samples were evaluated by PCR. DNA extraction was confirmed by amplification of the cat GAPDH gene. Bartonella spp. were assessed by amplifying a fragment of their 16S-23S rRNA intergenic spacer region; PCR products were purified and sequenced. For the small neotropical felids, risk factors [origin (wild-caught or zoo-born), gender, felid species, and flea exposure) were evaluated using exact multiple logistic regression. Hematological findings (anemia, polycythemia/hyperproteinemia, leukocytosis and leukopenia) were tested for association with infection using Fisher`s exact test. The 635 bp product amplified from 10 samples (10/67 = 14.92%) was identified as B. henselae by sequencing. Small neotropical felid males were more likely to be positive than females (95% CI = 0.00-0.451, p = 0.0028), however other analyzed variables were not considered risk factors (p > 0.05). Hematological abnormalities were not associated with infection (p > 0.05). This is the first report documenting B. henselae detection by PCR in several species of neotropical felids. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
A total of 57 captive neotropical felids (one Leopardus geoffroyi, 14 Leopardus pardalis, 17 Leopardus wiedii, 22 Leopardus tigrinus, and three Puma yagouaroundi) from the Itaipu Binacional Wildlife Research Center (Refugio Bela Vista, Southern Brazil) were anesthetized for blood collection. Feces samples were available for 44 animals, including one L. geoffroyi, eight L. pardalis, 14 L. wiedii, 20 L. tigrinus, and one P. yagouaroundi. Total DNA and RNA were extracted from blood and feces, respectively, using commercial kits. Blood DNA samples were evaluated by polymerase chain reaction (PCR) for feline leukemia virus (FeLV) proviral DNA, whereas reverse transcriptase-PCR was run on fecal samples for detection of coronavirus RNA. None of the samples were positive for coronaviruses. A male L. pardalis and a female L. tigrinus were positive for FeLV proviral DNA, and identities of PCR products were confirmed by sequencing. This is the first evidence of FeLV proviral DNA in these species in Southern Brazil.
Resumo:
Toxoplasma gondu is the causative intracellular protozoan of toxoplasmosis inhuman being and animals Members of the Felidae family are considered the single definitive host for the infection both wild and domestic cats are able to excrete oocysts in the environment Wild cats maintained in captivity may serve as source of infection for other clinically susceptible animals in the same environment The aim of this study was to determine the frequency of T gondu IgG antibodies in 57 neotropical felids (1 Leopardus geoffroyi 3 Puma yagouaroundi 17 Leopard us wiedu 22 Leopardus tigrinus and 14 Leopard us pardalis) kept at the Bela Vista Biological Sanctuary Itaipu Binacional Southern Brazil by the modified agglutination test (MAT) using titer 16 as cut-off point Seropositivity was observed in 38/57 (66 67% 95% CI 53 66-77 51%) samples with higher frequency in ocelots (71 43%) Wild-caught felids were three times more likely to be infected when compared to zoo-born animals (P <= 0 05) and age of wild-caught animals (P= 0 6892 95% CI = 0 7528-166) was not significant as a risk factor for the infection the same occurring with zoo-born animals (P=0 05 95% CI = 06267-24052) These results suggest that despite efforts to control T gondu infection in zoo facilities such as individual pens hygiene monitoring veterinary care and pre-frozen meat offered as food non-domestic feuds kept in captivity particularly the wild-caught specimens may be invariably exposed to infection due to other environmental sources (C) 2010 Elsevier B V All rights reserved
Resumo:
We tested the hypothesis that tree species in a subtropical rain forest in south-east Queensland are ecologically equivalent and therefore have identical environmental requirements for their regeneration. We assessed the evidence that juveniles of species differed in their distributions in treefall gap microsites and along gradients of light availability, soil pH, soil PO4-P availability and soil NO3-N availability. Pairwise comparisons were made on a subset of the common species selected on the basis that they showed a relatively high level of positive association, and would therefore, a priori, be expected to have similar regeneration requirements. Detailed comparisons between the species failed to demonstrate evidence for species differentiation with respect to their tolerance of the disturbance associated with gap microsites or to the gradient of NO3-N availability. However, species differed markedly in their distributions along the soil pH gradient and along the gradients of light availability and soil PO4-P availability. The overall level of ecological differentiation between the species is high: seven out of the 10 possible species pairings showed evidence for ecological differentiation. Such niche differentiation amongst the juveniles of tree species may play an important role in maintaining the species richness of rain-forest communities.