Polymorphism in male genitalia of Aedes (Ochlerotatus) scapularis Rondani, 1848

Morphology of male genitalia of culicids is generally species-specific and often used as a taxonomic marker. However, some characters of the male genitalia vary intraspecifically and are not taxonomically diagnostic. This might be the case of Aedes scapularis, a Neotropical culicid with vector competence for arboviruses and filarial worms. Males of this species may or not present a retrorse process (RP) in the genitalic claspette filaments, which led authors to suspect that this variance might be indicative of population divergence or incipient speciation process. This suspicion has not been investigated hitherto and it is not known if there are variable patterns of RPs. We hypothesized that the presence of the RP varies intraspecifically in Ae. scapularis and then we statistically evaluated the variability of this character in a single population. To this study the genitalia of 73 males of Ae. scapularis were prepared, and their RPs were meristically quantified and categorized according to the phenotypes observed. We noted that the presence or RPs is a polymorphic character because it varied inter and intra-individually. The presence of a single RP on each claspette filament was the predominant pattern (77%), but absent or multiple RPs in each filament were also found either in bilateral symmetry or asymmetry. Thus, we conclude that the presence of RPs owing to its high variability is not indicative of populational divergence or diagnostic of species complex within Ae. scapularis.