Variação genetica e morfologica em populações de Zaprionus indianus (Diptera: Drosophilidae) / Genetic and morphological variation in populations of Zaprionus indianus (Diptera: Drosophilidae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The species Zaprionus indianus has recently expanded its geographical distribution with the invasion of the South American continent. The first record dates of only six years, and the origin is probably the South Africa. Nowadays, individuals of this species can be found in a latitudinal range of 35o, from Uruguai to Belém (Brazil). The arrival of Z. indianus in Brazil presents a rare opportunity of studying an event of invasion from its beginning. The study of physiological, morphological and genetic traits in Brazilian populations may contribute to generate hypothesis for the success of Z. indianus in the stages of invasion. Also, it may indicate the potential for evolution and phenotypic differentiation. One physiological trait studied in the current thesis was the relationship of fertility and the temperature of development. Extreme temperatures cause sterility in males and the study of the limits (upper and lower) of the fertility curve complements the data on viability for the characterization of the potential of cosmopolitan species to occupy new areas. One morphological character studied was the sexual dimorphism for the number of abdominal bristles in one African population. A significant sexual dimorphism for this trait was observed in several species in previous studies, though different patterns have been found. In the current work the pattern observed in Z. indianus was compared to the pattern for another cosmopolitan species, Drosophila melanogaster. The third approach of this thesis was the study of the phenotypic variation (size and shape of the wing) present in 10 Brazilian populations. Besides the differences among populations, an interesting approach is the amount of variation present within each population. Also, it is important to know the proportion of this variation that is heritable, which allows an estimate of the evolutionary potential of the population. This study revealed the occurrence of high phenotypic variability within and between populations. In addition, enough additive genetic variation exists to promote the evolution of traits related to the shape of the wing

ASSUNTO(S)

drosofila variação morfologica thermal stresses morphological variation estresses termicos drosophila invasões biologicas biological invasions dimorfismo sexual sexual dimorphism

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