CONICET | Buscador de Institutos y Recursos Humanos

The information about ecological topics of mosquitoes at the southernmost tip of South America is fragmentary and scarce. In the present study were evaluated the lentic freshwater habitat located surrounding of main roads (about 1000 km) as potential larval habitat for culicids, and was analyzed the relationship between the presence of immature stages and environmental variables, in Grand Island of Tierra del Fuego. Mosquito inmatures were collected with nets, and at each freshwater habitat were recorded environmental variables (water turbidity, presence of gramineans, macrophytes, crustaceous cyanobacteria and filamentous chlorophyceans). Adult mosquitoes presence was assed using human bait catches. The collections were made in 47 lentic freshwater habitat: Roadside pools, Floodplain pools, Large ponds, Beaver ponds, Peatland ponds, Flooded quarries. The preimaginal stages were found in the 17.02% (8/47) of freshwater habitat, and 4 of the 49 (8.1%) human bite were positive for mosquitoes. Ochlerotatus albifasciatus was the only species of culicid reported. All specimens were found in roadside pools in the southern woodland zone of the island. Correspondence Analysis carried out study the relationship between the presence of immature stages of Oc. albifasciatus and environmental variables showed a positive relationship between presence of this species and presence of gramineans, and crustaceous cyanobacteria. The grass and algae may provide shelter from predation, may indirectly improve food supply or may act as an oviposition attractant. This analysis also showed a negative relationship with presence of macrophytes and deeper than 1 m. The macrophytes presence could represent habitat of more permanency of water. This is in agreement with the reproductive strategy of the genus Ochlerotatus, whose females lay eggs on the wet soil of habitats subject to cycles of drought and flood.