Larval habitat of Ochlerotatus albifasciatus (Diptera: Culicidae) in the southern edge of the Americas, Tierra del Fuego Island

Abstract

The information about ecological topics of mosquitoes at the southernmost tip of South America is fragmentary and scarce. The present study evaluates lentic freshwater habitat located in the surroundings of main roads of the Argentine sector of Tierra del Fuego as larval habitat of Ochlerotatus albifasciatus, also analyzes the relationships between their presence and several environmental variables: water turbidity, percentage of gramineans, percentage of macrophytes, presence of crustaceous cyanobacteria, and filamentous chlorophyceans. Mosquito inmatures were collected with dip nets. A generalized linear model (GLM) with negative binomial error distribution was used to determine the effects of different variables of the water bodies on abundance of Oc. albifasciatus in the larval habitats. Collections were made in 45 lentic freshwater bodies. Preimaginal stages were found in 17.70% of the studied habitats. Oc. albifasciatus was the only culicid registered. The GLM explained 93.17% of the variability, and showed a negative relationship between the abundances of Oc. albifasciatus and water turbidity, and a positive relationship with percentage of gramineans. The gramineans would improve food supply, because the plants are providing suitable substrate for different types of microbiota, a layer of leaves would protect eggs from extreme temperatures, and could help the larvae to hide from potential predators. The negative association between abundance of this species with water turbidity could be related to the presence of vegetation that favors retaining the substrate, reducing water turbidity.