Microgeographic Wing-Shape Variation in Aedes albopictus and Aedes scapularis (Diptera: Culicidae) Populations.

Abstract

Simple SummaryAedes albopictus and Aedes scapularis have been incriminated as vectors of arboviruses that can cause human diseases. Geometric morphometric tools have been used in several epidemiological studies to investigate how each of these mosquito species behaves in urban areas in the city of São Paulo, Brazil, and how these species have adapted to anthropogenic changes in the environment. Since it is exotic to the Brazilian fauna, Ae. albopictus has received more attention from health agencies than Ae. scapularis, a native species. It is thus crucial to investigate and compare the two species simultaneously in the same geographic area to better understand how they adapt to urban environments. The aim of this work was to evaluate the population profile of these species in urban parks in the city of São Paulo using wing geometric morphometrics. Our results showed different levels of population structuring for both species, suggesting different adaptive responses to urbanization: Ae. albopictus populations collected in the urban parks displayed homogeneous wing patterns, whereas Ae. scapularis populations were shown to have more variation. This indicates the importance of maintaining surveillance of exotic and native mosquito vector species given the fundamental role that urbanization can play in the population dynamics of arbovirus vector species.Aedes albopictus and Aedes scapularis are vectors of several arboviruses, including the dengue, chikungunya, and Rocio virus infection. While Ae. albopictus is a highly invasive species native to Asia and has been dispersed by humans to most parts of the world, Ae. scapularis is native to Brazil and is widely distributed in the southeast of the country. Both species are highly anthropophilic and are often abundant in places with high human population densities. Because of the great epidemiological importance of these two mosquitoes and the paucity of knowledge on how they have adapted to different urban built environments, we investigated the microgeographic population structure of these vector species in the city of São Paulo, Brazil, using wing geometric morphometrics. Females of Ae. albopictus and Ae. scapularis were collected in seven urban parks in the city. The right wings of the specimens were removed and digitized, and eighteen landmarks based on vein intersections in the wing venation patterns were used to assess cross-sectional variation in wing shape and size. The analyses revealed distinct results for Ae. albopictus and Ae. scapularis populations. While the former had less wing shape variation, the latter had more heterogeneity, indicating a higher degree of intraspecific variation. Our results indicate that microgeographic selective pressures exerted by different urban built environments have a distinct effect on wing shape patterns in the populations of these two mosquito species studied here.