ABSTRACT In order to reconstruct the vegetation history of the last 10.000 years, palynological analyses were carried out using 17 sedimentary samples of a core drilled in Parque Estadual do Rio Doce (PERD-MG). Twenty-one species of fern spores, 52 species of pollen grains and six species of fungi were identified. Phase 1 (10.375 - 9.350 cal. years BP) is characterized by a low concentration and diversity of pollen grains and is thus interpreted as a fluvial system with the presence of coarse-grained sediments. Phase 2 (9.062 - 8.195 cal. Years BP) is interpreted as a transition from a fluvial to lacustrine environment. Phase 3 (7.905 - 4.785 cal years BP) is characterized by increased trend of palynomorph concentration, highlighted by a high abundance and diversity of fern spores, which are indicative of a more a humid condition. The uppermost phase, Phase 4 (4.785 - 50 cal. Years AP), possessed a lower abundance of herbaceous flora, which is replaced by other vegetation groups (e.g. marsh, cerrado, Atlantic Forest). The uppermost sample represents the contemporary environment (~50 years), which is characterized as seasonally-flooded.

Despite the importance of the mosquito Aedes aegypti in the transmission of arboviruses, such as yellow fever, Chikungunya fever and dengue fever, some aspects of their behaviour remain unknown. In the present study, the oviposition behaviour of Ae. aegypti females that were exposed to different densities of breeding sites (2, 4, 8 and 16) was evaluated in laboratory and semi-field conditions. The number of breeding sites that were used was proportional to the number available, but tended towards stabilisation. Females used four-six breeding sites on average, with a maximum of 11. A high percentage of eggs was observed in the water, along with the presence of a breeding site termed “favourite”, which received at least 40% of the eggs. The results are discussed in ecological, evolutionary and epidemiological approaches.

Campos de altitude tropicais apresentam várias espécies com folhas micrófilas e altamente esclerófilas que co-ocorrem em manchas de solo específicas e, portanto, expostas a ambientes idênticos. Neste artigo, foi descrita a herbivoria entre espécies micrófilas co-ocorrendo em um ecossistema tropical de campos de altitude na Serra do Cipó, Minas Gerais, e testado o efeito de caracteres anatômicos variáveis no padrão de herbivoria foliar. Os caracteres anatômicos das folhas foram investigados em Baccharis imbricata Heering, Lavoisiera imbricata DC. e L. subulata Triana (espécies em foco). A herbivoria foi medida nos ramos e nas folhas de cada planta coletada e comparada entre as espécies estudadas em uma mancha multiespecífica e entre os indivíduos de L. subulata da mesma mancha e de uma mancha monoespecífica adjacente. Para todas as espécies e indivíduos foi estimada a proporção de folhas com diferentes níveis de área perdida. Para as espécies em foco, seis folhas foram sorteadas e submetidas a cortes histológicos com o objetivo de realizar medidas precisas das possíveis estruturas anatômicas de defesa. A média relativa de área foliar perdida diferiu significativamente entre as seis espécies encontradas na mancha multiespecífica. Indivíduos de L. subulata foram mais atacados na mancha multiespecífica que na mancha monoespecífica. Os caracteres anatômicos de proteção marginal tanto em B. imbricata quanto em L. imbricata apresentaram um efeito significativo contra a herbivoria. Os resultados sugerem o fato de alguns caracteres anatômicos terem efeito direto contra a herbivoria, mas seu efeito não é claramente perceptível entre os ramos de uma mesma planta ou entre plantas de uma mesma espécie.

Tropical high altitude grasslands present several species with both microphyllous and highly sclerophyllous leaves, and co-occur in specific soil patches, thus exposed to identical environments. In this article we describe herbivory among co-occurring microphyllous species in a tropical high altitude grassland ecosystem of Serra do Cipó, Minas Gerais state, and we tested the effect of variable anatomic traits on leaf herbivory patterns. Leaf anatomical traits were investigated for Baccharis imbricata Heering , Lavoisiera imbricata DC. and L. subulata Triana (focal species). Herbivory was measured from branches and leaves of individual plants and compared among co-occurring species within one multispecific shrub patch and among L. subulata individuals from this patch and an adjacent monospecific patch. For all present plant species and individuals we estimated the proportion of leaves with different levels of area lost. For the focal species, six leaves were sorted and taken for histological sectioning, in order to allow precise measures of defensive structures. Relative mean leaf area lost differed significantly among the six species found in the multispecific patch. Lavoisiera subulata individuals were more attacked in the multispecific than in the monospecific patch. Leaf margin protection traits in both B. imbricata and L. imbricata showed significant effect against herbivory. Data suggest that some anatomic traits have direct effect against herbivory but their effect are not clearly perceptible among branches within individual plants or among plants within the same species.

Duas populações de Mabea fistulifera (Euphorbiaceae) localizadas no Parque Estadual do Rio Doce (Minas Gerais, Brasil), mas em locais caracterizados como em diferentes estágios sucessionais, foram investigadas quanto a parâmetros genéticos e ecológicos. Em cada população, 20 indivíduos escolhidos de forma aleatória, foram avaliados quanto à presença de 43 marcadores RAPD, cinco características morfológicas e quanto à distribuição espacial. O índice de Shannon e a AMOVA revelaram que a maior parte da variação genética está localizada entre indivíduos dentro das populações, com apenas cerca de 9% da variação entre populações. As populações diferem geneticamente, mas possuem valores similares de diversidade genética. Os dados morfológicos revelaram marcantes diferenças entre as populações. Foram obtidas correlações significativas entre matrizes de distâncias genéticas, geográficas e morfológicas, considerando-se ambas as populações. Os dados revelaram ainda que dentro de uma mesma população, indivíduos espacialmente mais próximos tendem a ser mais semelhantes geneticamente. Os resultados são discutidos a respeito da biologia da espécie e das características das populações.

Two populations of Mabea fistulifera (Euphorbiaceae) located at Rio Doce State Park (Minas Gerais, Brazil) in places characterized as in different successional stages, were investigated through genetic and ecological traits. Twenty randomly chosen individuals from each population had its genetic data assessed by 43 RAPD markers and were also evaluated through five morphologic traits and its spatial distribution. Both Shannon's index and AMOVA reveled that most of the genetic variation was found between individuals within populations and about 9% of variation was located between populations. Moreover, populations differed genetically, but presented similar values of genetic diversity. Morphologic data showed differences between populations. Significant correlations among matrix of genetic, geographic and morphologic distances were obtained considering both populations, and spatially closer individuals were more similar genetically, characterizing genetic substructured populations.