Abundance and diversity of black flies (Diptera: Simuliidae) in rivers of the Andean Eastern Hills of Bogotá (Colombia), and its relationship with water stream physicochemical variables

Abstract

Black flies are abundant benthic organisms in well-oxygenated running water and are considered effective bioindicators of water quality. Information on the ecology of these organisms at the species level is important, since up to now information has mainly been available on a family level. The aim of this study was to evaluate the composition of black flies and their relationships to a group of physical and chemical factors in four small rivers of the Eastern Hills around Bogotá, Colombia. These headwaters are protected by the Empresa de Acueducto y Alcantarillado de Bogotá. Black fly larvae and pupae were collected during four sampling periods during the dry season to the early rainy season of 2012. Multivariate methods were used to determine the presence of each species in relation to dissolved oxygen, nitrates, pH, temperature, and water velocity. PCA ordination revealed a physicochemical environment with a tendency towards a certain homogeneity in the fourrivers studied. The DCA ordination confirmed that in La Vieja River the G. ortizi complex dominated while S. muiscorum was dominant in the other three rivers. Similarly, according to the NMDS, the composition of black flies in Arzobispo and Chorro de Padilla rivers was similar, while that of El Delirio and La Vieja rivers were different, especially in this last river. The rivers hadlow species richness (four species and one species complex). Simulium muiscorum was negatively correlated with dissolved oxygen, temperature and current velocity while S. ignescens was associated with slightly more oxygenated waters and S. furcilatum with fastercurrents.The low species diversity and richness for the four rivers is consistent with previous report sof low Neotropical diversity of black flies. Results showed that simuliid species could possibly be good indicators of the environmental conditions of Eastern Hills rivers around Bogotá.

Keywords

• bioindicators
• macroinvertebrates
• rivers
• water quality
• black flies