Distribution of Culex (Microculex) (Diptera: Culicidae) in forest cover gradients

Microculex is a subgenus of wild mosquitoes belonging to genus Culex, closely related to preserved environments. Its immature forms are generally associated with natural breeding sites, especially bromeliads. Recent years have witnessed the presence of some Microculex species in anthropic environments, including immature forms in artificial breeding sites, which may represent an adaptive tendency. This study aimed to investigate the variation in the abundance and dispersal of Microculex species in environments with different forest cover proportions. Three sites with different proportions of plant cover (60%, 70%, and 90%) were selected in an environmental protection area in the city of São Paulo, with varying degrees of modification and human presence. Collection was performed from March 2015 to April 2017, targeting bromeliads and artificial containers. Variations in the species' richness, composition, and abundance in different environments were analyzed. Variations in mean abundance and larval density between the different forest cover gradients were analyzed with generalized linear mixed-effects models. A total of 1,028 specimens belonging to 14 species were collected. Richness and composition were similar across the environments. Culex (Mcx.) imitator and Cx. (Mcx.) pleuristriatus were the most abundant species. The results showed a relationship between forest cover reduction and an increase in larval abundance and density for Cx. (Mcx.) pleuristriatus. Cx. (Mcx.) imitator showed a decrease in larval abundance related to a reduction in forest cover. Species from Pleuristriatus Series were found both in bromeliads and in artificial breeding sites. The findings emphasize that the Microculex Group of mosquitoes is not limited to preserved environments, but that some species such as Cx. (Mcx.) pleuristriatus appear to be well-adapted to areas impacted by human activity, colonizing artificial breeding sites, which may suggest a possible domiciliation process.