This study evaluates the importance of native bromeliads growing on rocky outcrops interspersed with urbanized areas as breeding sites for the Aedes aegypti (L.) in Vitória, state of Espírito Santo, Brazil. Oviposition traps were installed in backyards of houses in two separate zones. In the irst zone houses were up to 50 m away from the rocky outcrops, while in the second zone they were at least at 200 m from the rocky outcrops. Aedes aegypti was signi icantly more abundant in the latter zone. The inding was that rocky outcrops with native bromeliads, even with the greater availability of potential breeding sites, do not play an important role as breeding sites for A. aegypti. This conclusion supports the hypothesis that the macrobiota of native bromeliads plays an important role in the natural control of A. aegypti. Besides, the interspeci ic competition between species of mosquitoes and the attractiveness of bromeliads could also be important factors.
Introducti onThe African mosquito Aedes aegypti (L.) became adapted to arti icial breeding habitats, accompanying human migrations throughout the tropics and subtropics (Barrett & Higgs 2007). Its preferred breeding sites include arti icial containers that allow rainwater to accumulate, particularly in areas of high human population density (Mazine et al 1996). In Brazil, A. aegypti acted as the vector of urban yellow fever in recent decades, and has also been responsible for dengue fever epidemics (Vasconcelos 2002, Braga 2007. Various researchers have reported inding immatures of this species in bromeliads used for urban ornamentation, leading public health authorities to discourage maintenance of these plants in residential areas (e.g. Forattini & Marques 2000, Cunha et al 2002. Aedes aegypti were also reported in native bromeliads growing on rocky outcrops interspersed with urbanized areas in Vitória, state of Espírito Santo, Brazil (Varejão et al 2005). Therefore, the objective of the present study was to evaluate whether native bromeliads in their natural habitat represent important breeding sites for A. aegypti. Bromeliads and the human-produced breeding sites in residences close to rocky outcrops would be readily available and more exposed to infestation by A. aegypti than those situated at greater distances from these rocky outcrops, if bromeliads prove to be playing an important role as breeding sites for this species.
Material and MethodsThe study was carried out in the Vitória neighborhoods of Santa Lúcia and Bela Vista (Fig 1), where A. aegypti had already been reported breeding in native bromeliads Billbergia amoena, Billbergia tweedieana, and Vriesea extensa (Varejão et al 2005). The climate of the region is de ined by the Köppen-Geiger classi ication as tropical monsoon (Peel et al 2007), with a mean annual temperature of 25ºC and an annual precipitation of 1100 . Five surveys were conducted between 2007 and 2008, when ovitraps were simultaneously installed in the selected houses every three months. These traps remained exposed for ive da...