Exploring the Ecology and Indicator Value of Some Larvae of Odonata Genera in Colombia

Bioindication is a method to assess environmental conditions using indicator organisms. In Colombia, water quality evaluation is mostly performed following the Biological Monitoring Working Party/Colombia method (BMWP/Col), which uses aquatic macroinvertebrates at the taxonomic family level. Studies on potential bioindicators are important to produce comprehensive information on the requirements of macroinvertebrates and their value for water quality bioindication. We studied the larval ecology of several common genera of Odonata from Colombian freshwater ecosystems and assigned an indicator value to each genus. The physical and chemical water characteristics of 1,022 sites surveyed in Colombia from 2005 to 2016 were analyzed using a principal component analysis (PCA). The relationship between environmental conditions and Odonata genera found was studied using multiple logistic regressions between sample coordinates of the first three axes of the PCA and occurrence of the respective genus. We assigned an indicator value for each genus using the logistic regression and the water quality of samples. The highest indicator values were assigned to genera, which were mainly explained by the PCA axis associated with water quality, showed a high odds ratio to this axis, and were found in ecosystems with excellent water quality. The indicator values suggested for each taxon are, Brechmorhoga Kirby, 1894, 8; Macrothemis Hagen, 1868, 4; Micrathyria Kirby, 1889, 4 (Libellulidae); Progomphus Selys, 1854, 7 (Gomphidae); Acanthagrion Selys, 1876, 4; and Argia Rambur, 1842, 7 (Coenagrionidae). Differences in water quality preferences in genera of the same family suggest that higher taxonomic resolution may allow more detailed environmental assessments.