Dinâmica temporal da estrutura de comunidades de Drosophilidae (Insecta, Diptera) em frutos do cerrado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The communities may experience great changes in time and space. Seasonal variations are common in most ecosystems and can affect the conditions of micro-habitat, resource availability and even the relationships between organisms. In this study, divided into two parts, we investigated the influence of temporal variation in the resource usage and in the patterns of aggregation and stability of species coexistence using the same resource. For this, we used species of the family Drosophilidae which breed in fruits of Mauritia flexuosa and Solanum lycocarpum as models. In the first study, the species density in the dry season was lower than in the wet season, suggesting that the former can act as selective pressure, with few species being collected. We found that when populations were small (dry season), a minor proportion of the fruits was used, and the mean density of individuals in fruits was lower. Thus, fruits do not appear to regulate the populations of drosophilid in the stressful season. Moreover, six new species were recorded in the Cerrado biome. In the second study, we found that populations were aggregated in patches of resource (individual fruits) and, despite the heterospecific associations had been higher than expected, the coexistence of species was ensured. The aggregation levels were lower in the dry season, as well as the stability of coexistence, suggesting that stressful seasons can weaken the stability of the community, causing the exclusion of some species. However, these species can use other resources, and so they can prevent their local extinction.

ASSUNTO(S)

coexistence agregação variação temporal temporal variation uso de recursos resource using coexistência ecologia aggregation

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