An Assessment of Song Admixture as an Indicator of Hybridization in Black-capped Chickadees (Poecile atricapillus) and Carolina Chickadees (Poecile carolinensis)

Vocal admixture often occurs where differentiated populations or species of birds meet. This may entail song sympatry, bilingually singing birds, and songs with intermediate or atypical characteristics. Different levels of vocal admixture at the range interface between Black-capped Chickadees (Poecile atricapillus) and Carolina Chickadees (P. carolinensis) have been interpreted as indicating that hybridization is frequent at some locations but not others. However, song ontogeny in these birds has a strong nongenetic component, so that inferences regarding hybridization based on vocal admixture require confirmation. We used diagnostic genetic markers and quantitative analyses of song to characterize population samples along two transects of the chickadee contact zone in the Appalachian Mountains. More than 50% of individuals at the range interface were of hybrid ancestry, yet only 20% were observed to be bilingual or to sing atypical songs. Principal component analysis revealed minimal song intermediacy. This result contrasts with an earlier analysis of the hybrid zone in Missouri that found considerable song intermediacy. Re-analysis of the Missouri data confirmed this difference. Correlation between an individual\u27s genetic composition and its song type was weak in Appalachian hybrid populations, and genetic introgression in both forms extended far beyond the limits of vocal admixture. Therefore, song is not a reliable indicator of levels of hybridization or genetic introgression at this contact zone. Varying ecological factors may play a role in producing variable levels of song admixture in different regions of the range interface

Estimating total body fat using a skinfold prediction equation in Brazilian children

Background: The double burden of obesity and underweight is increasing in developing countries and simple methods for the assessment of fat mass in children are needed. Aim: To develop and validate a new anthropometric predication equation for assessment of fat mass in children. Subjects and methods: Body composition was assessed in 145 children aged 9.8 +/- 1.3 (SD) years from Sao Paulo, Brazil using dual energy X-ray absorptiometry (DEXA) and skinfold measurements. The study sample was divided into development and validation sub-sets to develop a new prediction equation for FM (PE). Results: Using multiple linear regression analyses, the best equation for predicting FM (R-2 - 0.77) included body weight, triceps skinfold, height, gender and age as independent variables. When cross-validated, the new PE was valid in this sample (R-2 = 0.80), while previously published equations were not. Conclusion: The PE was more valid for Brazilian children that existing equations, but further studies are needed to assess the validity of this PE in other populations

Soil types select for plants with matching nutrient-acquisition and -use traits in hyperdiverse and severely nutrient-impoverished campos rupestres and cerrado in central Brazil

Understanding the mechanisms that underlie the generation of beta-diversity remains a challenge in ecology. Underground plant adaptations to environmental gradients have received relatively little attention. We studied plant nutrient-acquisition strategies and nutrient-use efficiency at three stages of pedogenesis in infertile soils from campos rupestres and on less infertile soil from cerrado sensu stricto in Brazil. All soils support very high plant diversity with high species turnover between soil types at small spatial scales (metres). We expected that differences in nutrient-acquisition and -use strategies would be associated with this high species turnover. With severely decreasing phosphorus (P) availability, we expected the effectiveness of arbuscular mycorrhizal (AM) symbioses for plant P acquisition to decrease, and reliance on nonmycorrhizal strategies (NM) to increase, while maintaining efficient nutrient use. Concentrations of total soil P and nitrogen (N) were greater in soils in cerrado than in those from campos rupestres, and the more weathered soils from campos rupestres were severely P and N impoverished. The proportion of the root length colonized by AM fungi was 71% in the soils from the cerrado and campos rupestres. Conversely, the proportion of species with nonmycorrhizal P-acquisition strategies such as rhizosheaths was greater in the most P-impoverished soils. Leaf [P] and [N] were very low and decreased with decreasing soil [P] and [N]. Leaf N:P ratios suggest P limitation of plant productivity in the campos rupestres but N-P colimitation in the cerrado. Photosynthetic rates decreased with increasing P impoverishment, but photosynthetic P-use efficiency was very high and photosynthetic N-use efficiency moderately high on all soils. Most species had very high P-remobilization efficiency during leaf senescence (>70%), but only moderate N-remobilization efficiency (similar to 50%). Synthesis. We observed very high P-use efficiency and moderately high N-use efficiency in campos rupestres and cerrado species, consistent with plant productivity being more strongly limited by P than by N. Our findings demonstrate that different soil characteristics (nutrient availability and soil texture) select for species differing in nutrient-acquisition and -use strategies (especially below-ground traits) which is likely key for the very high species turnover at a very small scale between soil types (i.e., beta-diversity) in campos rupestres and cerrado107313021316CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo88881.068071/20142010/17204-0; 2011-52072-

Factors that influence the yield and composition of Brazilian propolis extracts

During the extraction of propolis several factors were varied in order to determine how they affected the yield and phenolic composition of the obtained extracts. Six samples of green propolis from the Southeastern region of Brazil were tested. The results indicate that the highest yield of propolis extracts obtained by maceration, which also had the greatest number of components, were those using 70% (v/v) ethanol or more as a solvent. The Soxhlet extraction procedure resulted in even higher yields. No differences were observed between extracts macerated in the presence or absence of light. An increase in yield was observed between extracts macerated for 10 and 30 days although the phenolic content did not vary significantly. The total phenolic content of all extracts varied from 6.41 to 15.24 % but no direct correlation could be found between any of the factors tested