Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus (0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats.

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Dengue epidemics in Brazil have become more frequent and more severe and involving larger populations in the last years. In Brazil Aedes aegypti is the only known vector. During the 2007-2008 period, Rio de Janeiro state experienced the most severe dengue epidemics ever reported in terms of morbidity and mortality. During this period, 322,371 cases and 240 deaths were registered, with 100 deaths due to dengue haemorragic fever/ dengue shock syndrome and 140 due to other dengue-related complications. Dengue transmission is influenced by closely related factors, many of which directly associated to the environment. Every city has its own specificities that are mainly given by its landscape and human populations. Rio de Janeiro is a city of 6 million individuals who share a heterogeneous space of ~1,200km 2 . Human population density ranges from 5,000 inhabitants/km 2 average mainly in the lowlands, with slums (or favelas) mainly in the slopes, where densities reach ~40,000 inhabitants/km 2 . These 6 million individuals live in highly urbanized, medium-urbanized and peri-urban transition zones with pockets of rural and semi-rural areas surrounded by the expanding city, mostly in the lowlands interspersed by three mountain complexes. To analyze the heterogeneous space of the city of Rio de Janeiro in relation to dengue, neighborhoods land cover maps where juxtaposed to dengue georeferenced cases, during the epidemic period 2007-2008. This analysis resulted in the observation of spatial clusters of high incidence dengue cases (hotspots) in 7 areas, namely, Jacarepaguá, Downtown, Island, Guaratiba, Northern, Western and Pedra. The most important cluster was constituted by the Jacarepaguá lowland urban ecosystem. Do the different urban ecosystems differ epidemiologically in terms of when and how dengue is transmitted? In Rio de Janeiro, is there a dengue of highly urbanized areas, a dengue of medium urbanized areas and a dengue of medium-high vegetated areas? Or in all those different urban ecosystems there is a shared characteristic that favor dengue transmission? Even though further studies should be conducted taking other aspects into account, the present study indicates that the different urban ecosystems observed might influence dengue transmission in Rio de Janeiro. Keywords: Dengue; Rio de Janeiro; urban ecosystem. RESUMODENGUE E A HETEROGENEIDADE DA COBERTURA DA TERRA NO RIO DE JANEIRO. As epidemias de dengue no Brasil têm sido cada vez mais frequentes, de maior incidência e gravidade. No

-This is the fi rst record of immature stages of species belonging to the subgenus Nyssorhynchus (Blanchard) in eutrophized breeding habitats. Larvae of Anopheles (Nys.) evansae (Brethes), Anopheles (Nyssorhynchus) rangeli (Gabaldon et al), Culex nigripalpus (Theobald) and Culex quinquefasciatus (Say) (Diptera: Culicidae) were collected in a rural eutrophized dam in Rio de Janeiro State, in Southeastern Brazil. Eutrophication was substantiated by the low diversity of mosquitoes, the high incidence of Cx. quinquefasciatus (42%) and of Daphinia sp. and, the high levels of both organic nitrogen (0.28 mg/l) and total phosphorus (0.02 mg/l).