Environmental factors associated with habitat preferences by caddisfly larvae in tropical dry forest watersheds (Tolima, Colombia). River ecosystems, mainly those draining tropical dry forests, are among the most endangered tropical ecosystems and a major conservation priority in South America, as elsewhere. In this study, we assessed the influence of environmental factors (e.g., precipitation) and riparian vegetation on Trichoptera larval assemblages colonizing four substrates (rock, gravel, sand, and litter) in the Venadillo and Opia watersheds (Tolima, Colombia). In each river, five 20m reaches nested into two 100m segments (one at ~550 and another at ~250masl), were surveyed for benthic invertebrates in the above mentioned substrates. In addition, water samples were collected for physicochemical analyses and the QBR index ("qualitat del bosc de ribera" or riparian forest quality) was applied in both rivers. A total of 6 282 larvae were collected, belonging to 11 families and 22 genera, representing 73.30% and 43.13% of the Trichoptera fauna reported to Colombia, respectively. The most abundant families were Hydropsychidae (49.86%) and Philopotamidae (25.44%) and the least abundant Odontoceridae (0.16%) and Hydrobiosidae (0.06%). The genera Smicridea, Chimarra, Protoptila, Neotrichia, and Leptonema, were common during dry and rainy seasons. The main factors related to changes in composition, richness, and abundance of larval Trichoptera were seasonality and riparian vegetation, which can influence organic matter supply, availability and stability of substrates, and colonization and population dynamics. Trichoptera assemblages showed no significant differences among substrates. However sampling points located at high elevation and in non-urbanized areas offered the largest variety of substrates and richness. Our results indicate that Trichoptera larvae are an important biotic element in freshwater ecosystems and that they are sensitive to environmental changes. Hence, our study suggests that caddisflies may be used as potential organisms for the biomonitoring of tropical dry forest rivers. The implementation of these studies is urgent, considering that degradation of freshwater ecosystems tends to be severe and persistent in dry forest. Rev. Biol. Trop. 62 (Suppl. 2): 21-40. Epub 2014 April 01.

ResumenEl presente listado taxonómico y de distribución de tricópteros inmaduros corresponde al material biológico depositado en la Colección Zoológica de la Universidad del Tolima-CZUT-Ma. Se registraron 14 de las 15 familias y 35 de los 45 géneros reportados para Colombia. Las familias más abundantes fueron Hydropsychidae, Hydroptilidae, Leptoceridae, y los géneros, Smicridea, Leptonema y Hydroptila. Con relación a la distribución altitudinal, los géneros con los mayores rangos de distribución fueron Neotrichia, Leucotrichia y Smicridea, recolectados desde los 244 m hasta los 3.533 m. Con el fin de establecer las relaciones entre los géneros de Trichoptera y las zonas de vida, se hizo un análisis de correspondencia cuyos resultados permitieron identificar que la mayor riqueza específica de este grupo faunístico en el departamento del Tolima se concentró en las zonas de vida correspondientes a bosque seco tropical, bosque húmedo premontano y bosque húmedo montano bajo. Palabras clave: Trichoptera, Tolima, zonas de vida, correspondencia, CZUT. Taxonomic list and distribution of immature caddisflies in the Department of Tolima AbstractThis taxonomic list of the Trichoptera larvae references data from the Zoological Voucher Collection at Universidad del Tolima, Colombia (Colección Zoológica de la Universidad del Tolima -CZUT-Ma). This collection includes 14 families and 35 genera of Trichoptera (out of the 15 families and 45 genera currently registered in Colombia). The most abundant families were Hydropsychidae, Hydroptilidae and Leptoceridae. The most abundant genera were Smicridea, Leptonema and Hydroptila. Regarding altitudinal distribution of the taxa found in the collection, Neotrichia, Leucotrichia and Smicridea exhibited the widest distribution, since they were found from 244m to 3533m. Results from a correspondence analysis performed on the taxa vs Holdridge life zones data, revealed that the highest species richness of the order Trichoptera in Tolima (Colombia) concentrated in the tropical dry forest, wet pre-mountain forest and lower wet mountain forest zones.

Los élmidos (Coleoptera) son organismos acuáticos de distribución mundial. Sus formas inmaduras y adultas ocupan una amplia gama de sustratos y hábitats, y son un grupo diverso. Este estudio tuvo como objetivo determinar la distribución espacial y temporal de los Elmidae, y su relación con los parámetros fisicoquímicos en el río Ocoa. Se establecieron 15 estaciones de muestreo y se revisaron 210 muestras de macroinvertebrados recolectadas en un sustrato de roca-guijarro utilizando una red Surber (250 μm) en dos periodos hidrológicos contrastantes (de baja y alta precipitación), correspondientes a octubre de 2014 y febrero de 2015. Se obtuvieron 37 organismos (larvas y adultos) de nueve géneros de Elmidae: Heterelmis, Huleechius, Macrelmis, Astrolimnius, Microcylloepus, Neoelmis, Hexacylloepus, Cylloepus, Notelmis y Phanocerus, de los cuales siete corresponden a nuevos registros para la región de la Orinoquia colombiana. En el periodo de baja precipitación hubo una mayor representatividad, con 35 registros de nueve géneros, en tanto que en el periodo de alta precipitación hubo una marcada disminución de la riqueza, con dos registros solamente, correspondientes a dos géneros. En general, la abundancia de Elmidae fue baja a lo largo del río, y en las estaciones ubicadas en el sector que atraviesa la ciudad de Villavicencio, con mayor deterioro del hábitat, se registró la menor abundancia y en algunas no se registraron élmidos. Los efectos ambientales de la urbanización, como la contaminación por materia orgánica y la proliferación de coliformes debida al vertimiento de aguas residuales, fueron los principales factores determinantes de la disminución de la riqueza y la abundancia de estos organismos. Esta es la primera exploración de Elmidae en la zona y contribuye al conocimiento ecológico de la fauna de coleópteros en cuencas urbanas de la Orinoquia colombiana. © 2019. Acad. Colomb. Cienc. Ex. Fis. Nat. Palabras clave: Bioindicador; Coleoptera; Elmidae; Cuenca urbana; Orinoco.

The mayflies are insects widely known as indicators of aquatic quality in freshwater systems, they are abundant and diverse in tropical streams. In this study, it was determined the influence of physical, chemical and bacteriological characteristics on the Ephemeroptera assembly in a period of low precipitation in the Ocoa river of Meta department. There were 5,332 nymphs belonging to 4 families, 10 genera and 3 species. Three new genera records and one species are presented for Meta: Cloeodes, Zelusia, Lumahyphes and Americabaetis alphus. The genera Camelobaetidius and Varipes were found associated with conditions of contamination by organic matter and water mineralization. Likewise, Americabaetis, Thraulodes, Lumahyphes and Tricorythodes were associated with contamination conditions, especially with nitrites and nitrates. Nanomis, Cloeodes and Zelusia showed greater sensitivity to the contamination condition and were related to high percentages of dissolved oxygen in the water and they were in the sampling stations of the upper part in the river. It is important to mention that there were not Ephemeroptera in most of the stations associated with the urban area. That reflects their high sensitivity to polluting conditions at low precipitation period.