The karyotype of the threatened ant species Atta robusta is described so as to establish the evolutionary relationships of this taxon with other leafcutter ants. Standard Giemsa staining, C-banding, NOR banding, fluorochromes CMA3/DAPI, Hsc-FA technique and Fluorescence in situ Hybridization (FISH) using 18S rDNA probe were conducted on a population from Aracruz, state of Espírito Santo, Brazil, allowing for comparisons with data available on Atta and other fungus-growing ant species. The diploid chromosome number observed for A. robusta was 2n=22, and the karyotypic formula was 18m+2sm+2st. Heterochromatic blocks were observed in the centromeric region of most chromosomes, where one pair of metacentric chromosomes is characterized by a GC-rich heterochromatic band in the interstitial region of its long arm. The detection of 18S rDNA using FISH confirmed the presence of single NOR for A. robusta. This is the first report of rDNA 18S detection using FISH for leafcutter ants. The cytogenetic results of this study confirm the information available for Atta and allow us to confirm the conserved chromosome number, morphology and banding pattern within the genus for the taxa studied to date, which included species from three out of the four groups of Atta indicated by molecular data. The accumulation of cytogenetic data on fungus-growing ants enhances the understanding of the genomic evolutionary patterns of Atta, since it belongs to a group of recent origin between the most well studied ants. Cytogenetic data does not indicate restrictions in relocation or reintroduction in areas where populations were extinct due to the conserved karyotype. This study allows for cytogenetic comparison of A. robusta with other ants of Atta, emphasizing the importance of chromosomal information for species conservation.
The aim of the current study is to describe the genetic consequences of the reallocation process in order to preserve an entire Dinoponera lucida Emery, 1901 population. The sample collection and the mitochondrial data analysis were conducted before and after the reallocation of nests in two conservation unities in Espírito Santo State, Southeastern Brazil. The data analysis showed that the genetic variability inside the forest fragmentation has considerably increased above the natural levels. The importance of the present study relies on information and notifications about the herein studied populations, which will be provided to future studies.
Endemic species of Atlantic Forest Central Corridor may have evolved under adverse climate conditions, but their response to modern climate change is unclear. The aim of this study is to evaluate the response of the endemic and endangered ant species Dinoponera lucida to biotics and abiotics factors based on three scales: ecological factors inside forest fragment, physical attributes of landscape and climatic variables of the assessed region. Data collection took place in a representative selection of forest fragments in the region where the species is distributed in. Pitfalls were used to collect samples and to assure the presence and absence of the species in the site. We also checked the abundance of food resources and applied a hemispherical photography technique to measure shading inside the fragment, in loco. Landscape attributes data and climatic predictors were collected through geoprocessing techniques. All predictors were associated with binary “presence” and “absence” data based applied in logistic models. There was no significant response to environmental aspects within the fragment or to landscape, but there was strong and peculiar response to climatic variables such as temperature and rainfall. Accordingly, D. lucida presents a restricted realized niche, a feature shared among many endangered species that can disappear due to displacement and to habitat loss caused by climate and environmental changes. This species presents all the criteria necessary to be considered as rare, which is a controversial subject with political implications for Espírito Santo state, and makes D. lucida the ideal target for urgent conservation strategies.
Analisam-se as perspectivas teórico-metodológicas dos trabalhos apresentados nos Encontros de Pesquisa em Educação Ambiental (EPEA). Estas partem dos olhares e vivências dos coordenadores dos Grupos de Discussão em Pesquisa (GDP Metodologia) junto às discussões realizadas nesses grupos, cujos relatos encontram-se na forma de produções textuais, identificando-se os pontos limitantes e as potencialidades do campo metodológico da pesquisa em educação ambiental ao longo dos EPEAs. Em meio à multirreferencialidade de perspectivas presentes nesses trabalhos, problemas de natureza epistemológico-metodológica são identificados, principalmente em função de uma forte tendência em atrelar as escolhas metodológicas dos investigadores a uma pesquisa voltada para a transformação social e às perspectivas críticas e metodologias participativas como as abordagens metodológicas que melhor responderiam a essa tendência. Os dilemas envolvidos e as implicações disso para as discussões teórico-metodológicas no campo da pesquisa em EA são discutidos, trazendo avanços para as discussões no GDP Metodologia. Para além dessas questões, uma pesquisa subversiva, em consonância com uma EA subversiva, se avizinha no horizonte, trazendo novas discussões para esse cenário.
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