[Immature mosquitoes (Diptera: Culicidae) in a public city park].

OBJECTIVE To identify and compare the immature Culicidae population and their predators in different breeding places in a public city park. METHODS The study was carried out in an ecological park situated in the outskirts of the city of São Paulo, Brazil. Four Culicidae breeding places were selected: one semi-permanent, two permanent and one polluted brook. Throughout a year, at monthly intervals, systematic and standardized collections of Culicidae and their predators were undertaken to assess mosquito frequency, and estimate the index of abundance and predatory potential of the associated fauna. RESULTS A total of 9,065 Culicidae were collected at the four breeding places studied. Twenty-two species or groups were obtained, generally at low frequencies, except for Culex quinquefasciatus, the only species at the polluted breeding place seen highly frequent. This was the most abundant species in this study, followed by others of the Culex genus. CONCLUSIONS It was found an imbalance in the polluted breeding place as a result of a high concentration of pollutants and absence of predators, which leads to an intense proliferation of only one species. At the other breeding places, there is evidence that the associated fauna promotes a natural biological balance.