ABSTRACT. Ecological parameters such as trophic niche overlap and niche breadth were computed from the frequency of all drosophilid species collected in 2001 and 2002, in the urban area of Porto Alegre city, Brazil. Independently of place, drosophilids community composition and components breeding or feeding sites, the highest frequencies of Zaprionus indianus (Gupta, 1970) were obtained during seasons with higher average temperatures, especially during summer. From a total of the 19,146 individuals of Z. indianus sampled, 80% were found in this season. The data of trophic niche breadth suggest a higher opportunism of adult flies in feeding substrate use, but the females are still selective in oviposition substrate choice. For the values of niche overlap, only for some species, did we find any correlation between these and species richness and/or number of resources, and the most of the correlation values considering breeding and feeding sites were positive. The colonization of Z. indianus in Porto Alegre could be leading to adjustments in the survival strategies of the resident species, but it is possible that many species have conditions for coexisting with the invader.

Comparative genomics in Drosophila began in 1940, when Muller stated that the ancestral haploid karyotype of this genus is constituted by five acrocentric chromosomes and one dot chromosome, named A to F elements. In some species of the willistoni group such as Drosophila willistoni and D. insularis, the F element, instead of a dot chromosome, has been incorporated into the E element, forming chromosome III (E + F fusion). The aim of this study was to investigate the scope of the E + F fusion in the willistoni group, evaluating six other species. Fluorescent in situ hybridization was used to locate two genes of the F element previously studied-cubitus interruptus (ci) and eyeless (ey)-in species of the willistoni and bocainensis subgroups. Moreover, polytene chromosome photomaps corresponding to the F element (basal portion of chromosome III) were constructed for each species studied. In D. willistoni, D. paulistorum and D. equinoxialis, the ci gene was located in subSectction 78B and the ey gene in 78C. In D. tropicalis, ci was located in subSection 76B and ey in 76C. In species of the bocainensis subgroup, ci and ey were localized, respectively, at subsections 76B and 76C in D. nebulosa and D. capricorni, and 76A and 76C in D. fumipennis. Despite the differences in the subsection numbers, all species showed the same position for ci and ey. The results confirm the synteny of E + F fusion in willistoni and bocainensis subgroups, and allow estimating the occurrence of this event at 15 Mya, at least.

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Body color polymorphism of urban populations of cosmopolite fly Drosophila kikkawai Burla, 1954 was investigated in relation to its possible association with environmental temperature. Samples of D. kikkawai were collected in spring, summer, autumn and winter between 1987 to 1988, in zones with different levels of urbanization in the southern Brazilian city of Porto Alegre, Rio Grande do Sul. A clear association was observed between darker flies and both seasons with low temperatures and areas of low urbanization (where temperature is generally lower than in urbanized areas). Results of preliminary laboratory experiments involving six generations of flies grown in chambers at temperatures of 17 o and 25 o C confirmed this tendency to a relationship between body color and temperature, with allele frequency of the main gene involved in body pigmentation changing over time.

Doge, J.S., Gottschalk, M.S., Bizzo, L.E.M., Oliveira, S.C.F., Schmitz, H.J., Valente, V.L.S. & Hofmann, P.R.P. 1925 and Z. vittimaculosa Burla 1956. Except for Z. bilineata and Z. hypandriata, these are the new southernmost records for the geographical distribution of these species. All the collected species were represented by few individuals, probably as a consequence of the collection method, and most of them was captured in winters and springs. Five species were restricted to the more preserved studied site, and most individuals were collected in forest sites. Nevertheless, four species were also captured in urban or xeric environments, indicating a higher tolerance and a wider ecological versatility in this genus as compared to what was previously thought, at least for some species. O presente estudo reúne dados de pesquisa de nove locais de coleta no estado de Santa Catarina, sul do Brasil. Foram obtidas amostras durante aproximadamente quatro anos em áreas florestais, litorâneas e urbanas. As moscas foram atraídas através de isca de banana fermentada e capturadas em armadilhas. Dentre as espécies do gênero Zygothrica