Influência da urbanização sobre características sexuais de uma espécie invasora de Poeciliidae

Abstract

Urbanization is increasing over the years and, therefore, it is necessary to understand the urban influence on species. Populations residing in urban locations tend to show changes in morphological and behavioral characteristics that allow them to thrive in these environments. Such changes can affect evolutionary processes. Guppies (Poecilia reticulata) are freshwater fish, invasive in Brazil, which thrive in streams highly impacted by urban pressure. They have a short life cycle and phenotypic changes due to the environment are noticeable within a few generations. The pattern of body color and the size of the male reproductive organ guarantee their reproductive success. It is known that the populations of guppies in urban streams in addition to occurring in high population densities are exposed to changes in the diet due to the scarcity of algae, and the high turbidity of the water by the release of sewage from different sources. However, it is not known how these factors influence their reproductive characteristics. In the present study, guppies were used as a model to understand the influence of urbanization on sexual characteristics. Through the measurement and comparison of the reproductive organ (gonopodium) and colored spots (orange and iridescent areas) in males, we observed that urbanization influences only the size of iridescent areas, which are larger for males of urban streams. However, density, turbidity and diet did not explain the observed difference