Wing sexual dimorphism in Aedes scapularis (Diptera: Culicidae)

The sex in mosquitoes (Culicidae) is relevant for faunistic and epidemiological surveys because only females are competent to transmit pathogens. Sexual dimorphism comprising genitalia and cephalic appendages is ordinarily visible in culicids. Wings may be also dimorphic and thus be complementary to traditional sexing methods. Nevertheless, such dimorphism is not easily noticeable to direct observation. Aiming to formally describe the sexual dimorphism in Aedes scapularis, a mosquito species competent for virus and filariae, wings of males and females were compared using geometric morphometrics and multivariate statistics. We sampled populations from Sao Paulo and Pariquera-Acu municipalities (State of Sao Paulo). Concerning wing shape, the sexual dimorphism was evident from blind reclassification tests which were 100% accurate, independently of the geographical origin of samples. On the other hand, wing size was sexually dimorphic only in the population from Sao Paulo. Presumably, wing shape is evolutionarily more stable than its size, an interpretation which is in accordance with the theory posed by Dujardin (2008b). That theory indicates wing shape would be composed of genetically-determined quantitative characters, and marginally influenced by non-genetic factors, whereas wing size would be more labile and predominantly influenced by the environment.