ABSTRACT
The study of organisms and their resources is critical to further understanding population dynamics in space and time. Although drosophilids have been widely used as biological models, their relationship with breeding and feeding sites has received little attention. Here, we investigate drosophilids breeding in fruits in the Brazilian Savanna, in two contrasting vegetation types, throughout 16 months. Specifically, larval assemblages were compared between savannas and forests, as well as between rainy and dry seasons. The relationships between resource availability and drosophilid abundance and richness were also tested. The community (4,022 drosophilids of 23 species and 2,496 fruits of 57 plant taxa) varied widely in space and time. Drosophilid assemblages experienced a strong bottleneck during the dry season, decreasing to only 0.5% of the abundance of the rainy season. Additionally, savannas displayed lower richness and higher abundance than the forests, and were dominated by exotic species. Both differences in larval assemblages throughout the year and between savannas and gallery forests are consistent with those previously seen in adults. Although the causes of this dynamic are clearly multifactorial, resource availability (richness and abundance of rotten fruits) was a good predictor of the fly assemblage structure.
ABSTRACT
The Paranã Valley, located in the Central Brazil Plateau, within the domain of the Cerrado biome, is frequently cited as a center of endemism and diversity. Nonetheless, this region is poorly known, mainly considering its invertebrate fauna. Here, drosophilid flies were used as biological tools to contribute to a broader inventory, whose goals were mapping the Cerrado biodiversity and identifying areas to be conserved. Three previously unsampled areas in the Paranã Valley were sampled. Amongst the 12,297 specimens collected 45 species were identified, which represents 50 percent of the drosophilid species previously recorded in the Cerrado. Moreover, this sampling presented eight new occurrences for the biome (Drosophila annulosa, D. calloptera, D. papei, D. neomorpha, D. roehrae, Gitona bivisualis, Rhinoleucophenga lopesi, and the genus Diathoneura) and three species that had only one record for the biome, or that were recorded only in a specific area. Therefore, this study confirms the importance of the Paranã Valley as a center of biodiversity in the Cerrado biome, and recommends the establishment of conservation units in this region.
O Vale do Paranã localiza-se no Brasil Central, no domínio do bioma Cerrado, e é freqüentemente citado como um centro de diversidade e endemismo. Entretanto, essa região ainda é pouco conhecida, principalmente no que se refere à fauna de invertebrados. Este estudo apresenta a fauna de drosofilídeos de três áreas nunca avaliadas anteriormente no Vale do Paranã, visando contribuir para um inventário mais amplo, cujos objetivos foram mapear a biodiversidade da região e identificar áreas para serem preservadas. Dentre os 12.297 espécimes coletados foram identificadas 45 espécies, correspondendo a 50 por cento dos drosofilídeos previamente registrados no Cerrado. Além disso, este trabalho acrescentou oito novas ocorrências para o Cerrado (Drosophila annulosa, D. calloptera, D. papei, D. neomorpha, D. roehrae, Gitona bivisualis, Rhinoleucophenga lopesi e o gênero Diathoneura) e três outras espécies com apenas uma única ocorrência para o Cerrado, ou registradas em apenas uma área específica do bioma. Nesse contexto, este estudo confirma a importância do Vale do Paranã como um centro de biodiversidade do Cerrado, e recomenda o estabelecimento de unidades de conservação nessa região.