<p>The aquatic insects are important bioindicators of water quality in rivers and streams. The order Trichoptera is part of this group, plays an important role in aquatic systems and because of the multiple functions they fulfill, it is essential to know about their biodiversity. This study aimed to know the Trichoptera composition, and its spatial and temporal distribution, in close relationship with the available microhabitats, and some physical and chemical variables, in the middle and lower sections of the Manzanares river basin (Sierra Nevada of Santa Marta, Colombia). A total of eight microhabitats were sampled in three sites from August 2002 to February 2003, and during the rainy and dry seasons. A total sample of 3 316 Trichoptera larvae were collected, belonging to 10 family and 14 genera; six of these genera and one family are new records for the Magdalena department. The caddisflies presented the greatest abundance and richness on leaves in pool, leave in riffles and stones in riffle, where <em>Nectopsyche</em> (28%), <em>Leptonema</em> (17%) and <em>Smicridea</em> (15%) were the more predominant genus. Structure and composition of Trichoptera genus in each site changed in function to the rainfall pattern, and physical and chemical variables presented in the basin, showing the lowest abundance and richness during high rainfall period (October and November), and the greatest abundance and richness in low rainfall period (December, January and February). Likewise, stations with higher values of dissolved oxygen and lower in temperature and conductivity reported the greatest abundance of Trichoptera. The Trichoptera showed affinity to the specific microhabitats, variations in their composition in relationship whit climatic periods and pollution levels of the river. To know others aspects about the Trichoptera distribution, we recommended continuing these studies including annual cycles and increasing the altitudinal gradients.</p>

Feeding habits of immature individuals of Ephemeroptera, Plecoptera, and Trichoptera from middle reaches of a tropical mountain stream. Morphological and behavioral aspects of insects allow their grouping in trophic guilds and represent their dependence on food resources. We determined the feeding habits of immature organisms of Ephemeroptera, Plecoptera, and Trichoptera (EPT) from the middle reaches of Gaira stream (Sierra Nevada de Santa Marta, Colombia), using gut content analysis. We identified 13 EPT genera, but only ten were analyzed for a total of 100 organisms. We describe six food items: animal parts (AP), vascular plant tissue (VPT), microalgae (M), fungi (F), coarse particulate organic matter (CPOM) and fine particulate organic matter (FPOM). Baetodes was determined to be a collector-scraper, since FPOM represented 46.6% of food content, followed by F (38.4%). Chimarra, Leptohyphes, Lachlania, and Thraulodes were categorized as collectors with average proportions of FPOM 86.8%, 93.1%, 93.1% and 93.7%, respectively. Phylloicus, Smicridea and Leptonema were main consumers of VPT and CPOM with proportions of 76.3%, 54.6%, and 62.4%, respectively; while ratios of FPOM were 22.3%, 38.8%, and 32.9%, respectively. While all are detritivores, Phylloicus is functionally classified as shredders and Smicridea and Leptonema as collectors. Atopsyche and Anacroneuria were the only taxa in which AP were observed in high proportions, 57.9% and 58.2%, respectively, for that reason they were classified as predators. The organisms examined consume a wide variability of resources. Rev. Biol. Trop. 62 (Suppl. 2): 169-178. Epub 2014 April 01.

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La evaluación de la calidad del agua de fuentes fluviales a través del estudio de variables físicas, químicas y microbiológicas es considerada como una herramienta que permite conocer el estado de contaminación. Una de las formas de evaluar estos sistemas a través de la integración de variables ambientales mediante índices como el ICA-NSF. Por tanto, el objetivo de este trabajo fue evaluar la calidad fisicoquímica de las aguas en del río Córdoba en su parte baja a través ICA-NSF y analizar los plaguicidas organoclorados más comunes. Se definieron seis sitios se muestreo, en cada una de ellas se midieron parámetros físicos, químicos y microbiológicos. Además, se determinó el nivel de concentración de los principales contaminantes, considerando el impacto que causan en el río y se estableció la calidad del agua por medio del ICA-NSF durante los periodos de sequía y lluvias entre el 2010 y el 2011. El ICA-NSF varió entre 52,6 durante las lluvias en “Muelle carbonífero” y 72,4 en el periodo seco en “Paso de los anillos” indican que la calidad del agua categorizó entre regular y buena, respectivamente. De las variables evaluadas, los coliformes fecales mostraron altos valores en los seis sitios (entre 2974 y 4940 NMP/100 ml), registros que sobrepasaron los límites permisibles para el consumo humano y la protección de flora y la fauna por la legislación colombiana. Los resultados mostraron una variación temporal (entre periodos climáticos) y una alta uniformidad espacial del río en los sitios de muestreo. En ninguno de los muestreos se encontraron residuos de plaguicidas organoclorados. Los resultados evidenciaron que la variación temporal (periodos de lluvias vs. sequías) reflejó de mejor manera los cambios en la calidad del agua del río Córdoba en su parte baja.

El objetivo de este trabajo fue evaluar el cuerpo de agua y los sedimentos de una charca estacional, además de describir el ciclo de vida y proporciones de sexo de Dendrocephalus affinis en condiciones de laboratorio. La charca se muestreó desde 2010 hasta 2012, la cual se caracterizó la fisicoquímica del agua y la granulometría y metales pesados del sedimento. Simultáneamente se tomaron muestras de sedimento para recolectar los quistes usados para la descripción del ciclo de vida, la supervivencia y proporción de sexo de D. affinis en laboratorio. La charca mostró condiciones mesotróficas en época de lluvia y mayor carga orgánica en época seca. El suelo dominante fue lodoso, lo cual facilitó la retención de agua. Los metales pesados mostraron concentraciones dentro del rango habitual en estos ambientes. Los macroinvertebrados asociados estuvieron conformados por representantes de siete órdenes y 28 géneros, de los cuales los órdenes Hemiptera y Coleoptera fueron los más abundantes con el 39.7 y 31.8% respectivamente. El ensayo de laboratorio mostró que los nauplios de D. affinis vivieron 30 días, y tuvieron una supervivencia del 31.6%. Este trabajo también contribuyó con una descripción una charca estacional del ciclo de vida de D. affinis en condiciones de laboratorio. Dendrocephalus affinis mostró ser un organismo con corto ciclo de vida, de crecimiento rápido y alta tasa de supervivencia, lo cual favorece su uso como potencial alimento vivo en la acuicultura.

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Morphology of mouthparts and feeding habits of Leptonema and Smicridea (Trichoptera: Hydropsychidae) from Gaira river, Sierra Nevada de Santa Marta, Colombia. The genera Leptonema and Smicridea belong to the family Hidropsychidae and constitute one of the most important groups in the nutrient dynamics in the tropical aquatic ecosystems, which diversity of microhabitats is exploited by their larvae. However, there is lack of information concerning the detailed and comparative descriptions of mouthparts between these two genera, and their possible relation with their diet. The aim of this paper was to describe the morphology of the mouthparts and the feeding habits of both genera, in the middle basin of the Gaira River (Sierra Nevada de Santa Marta, Colombia). The samples were collected on a monthly basis, with a surber net, between October and December of 2014, and May of 2015. A total of 15 larvae per genus were taken and the Blue Zen Software was used to determine the morphometric measurements of the cephalic pieces. Measurements were taken on photographs obtained from an AxioCam ERc5s camera adapted to a Nikon SMZ 745T stereoscope. To describe the mouthparts a M205A microscope-stereoscope Leica was used. The dietary habits of 15 individuals in total were evaluated by means of the analysis of stomach contents. A discriminant analysis of Hotelling was applied to the morphometric measurements. There were significant differences in head area (HA), head width (HW3), head length (HL2) and left mandible length (LML). In the morphological descriptions were found differences in: head, labrum and submentum. Dietaries profiles were performed to the stomach contents for both genera and the items with highest percentage for Leptonema was MOPG and MOPF with 38 % and 32 %, respectively, and for Smicridea MOPF (38 %) and MOPG (34 %) with significant differences (F = 8.8298, p < 0.05). This study indicated that the evaluated individuals consume a wide variety of resources and the difference of the diet of both genera can be related to the detected morphological differences. Rev. Biol. Trop. 65 (4): 1231-1244. Epub 2017 December 01.