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The study ponds are part of a peatland located in the Elqui river basin of the Andes. They turned out to be heliotropic (homoeother-mic), mesotrophic and mesopoikilohaline microlimnotopes. The ponds showed high content of dissolved metals, mainly Ca (mean ~205 mg/l), Na (~60 mg/l), Mg (~60 mg/l) and K (~13 mg/l), and the inorganic non-metals sulfate (~976 mg/l), chloride (~34.2 mg/l), phosphate (~23 mg/l), bicarbonate (~11 mg/l) and nitrate (~3.3 mg/l). Excluding Hg, Se and nitrite, trace elements were represented by Al, As, Cd, CN, Cu, Cr, Fe, Ba, Be, Co, Zn, Mo, Ni, Pb, Li, Ag, and V. The cationic pattern of ponds was Ca > Na > Mg > K >Mn; whereas the anionic pattern was sulfate > chloride > phosphate > carbonate > Fl. Although we did not study, the hydrochemical characteristics of these water bodies seem to reflect the characteristics of the geological substrate of the mountains through which the water drains into the peatland. Las pozas estudiadas forman parte de una vega ubicada en el piso altoandino de la hoya hidrográfica del río Elqui. Estas resultaron ser microlimnotopos heliotópicos (homeotérmicos), mesotróficos y mesopoikilohalinos. Las pozas mostraron niveles elevados de metales disueltos, principalmente Ca (promedio: ~205 mg/l), Na (~60 mg/l), Mg (~60 mg/l) y K (~13 mg/l), y los inorgánicos no metálicos sulfato (~976 mg/l), cloruro (~34,2 mg/l), fosfato (~23 mg/l), bicarbonato mg/l) y nitrato (~3,3 mg/l). Excluyendo Hg, Se y nitrito, las pozas presentaron niveles traza de Al, As total, Cd, CN, Cu, Cr, Fe, Ba, Be, Co, Zn, Mo, Ni, Pb, Li, Ag y V. El patrón catiónico de las pozas fue Ca > Na > Mg > K > Mn; a su vez, el patrón aniónico fue sulfato > cloruro > fosfato > carbonato > Fl. Aunque no fue estudiado por nosotros, las características hidroquímicas de estos cuerpos de agua parecen reflejar las características del sustrato geológico de las montañas por medio del que el agua fluye hacia la vega.

Diptera are one of the dominant taxonomic groups of animal invertebrates to be found in the highland wet pastures of the transitional desert of Chile. In wetlands, these insects play important roles as pollinators, decomposers and trophic resources for aquatic vertebrates. Additionally, Diptera are recognized to have the potentiality to be used as indicators of the health condition of wet terrestrial environments, important attribute in the case of Andean highland wet pastures given the water stress under which they are presently subjected. By using Barber and Malaise traps, the Diptera-assemblage associated to a highland wet pasture located in a transitional desert basin was investigated. This study was conducted during the growing season for the area. Its aims were to a) document the taxonomic structure of the assemblage in terms of the composition of Diptera-families and the relative abundance of its members, and b) evaluate the effect of the summer phenological phase on F-richness, relative abundance relationships, F-diversity and evenness. The PERMANOVA and t-pairwise tests were used to evaluate the effect of the summer phenological phase on the numerical relationships among families. The Simpsons D, Brillouin D, Berger-Parker dominance, and Fisher indices were used to estimate the F-diversity; in turn, the Simpson E, Camargo, Smith-Wilson B, and NHC indices estimated the F-evenness. Similarity between assemblages was compared by ANOSIM. The percent contribution by family to the observed differences between assemblages was computed by the SIMPER-routine. All analyses were done on the log-transformed data (x+1; log 10). 44524 Diptera-representatives were collected throughout the study, with a record of 27 families. The tests and the indices support the idea that the middle-summer phase provided the best environmental conditions for the diptero-fauna of the wet pasture. Apparently, this effect would be more related to the thermal pattern of the area than to the micro-habitat availability, Esta publicación fue financiada por la Dirección de Investigación de la Universidad de La Serena

Se describe la morfología y microestructura coriónica del huevo y la morfología del primer estadio larvario de Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae, Nycteliini). También se exponen antecedentes bionómicos y distribucionales de la especie. Para la obtención de huevos y larvas, se recolectaron parejas en el terreno que fueron mantenidas en cajas de cria hasta la ovoposición y posterior eclosión. La estructura y ornamentación del exocorion del huevo y características morfológicas externas de la larva fueron analizadas mediante microscopía electrónica de barrido. Los resultados muestran que los huevos de G. luczotii presentan un micropilo redondeado y exocorion liso, con células hexagonales sin aeropilos. Las larvas de G. luczotii presentan características morfológicas adaptativas para la vida edáfica del tipo Pedobionta: cápsula cefálica con gran cantidad de sensillas, patas protorácicas de función cavadora, y pigopodio bien desarrollado. Se analiza la importancia de algunos caracteres morfológicos de la larva de primer estadio como criterio de diagnóstico específico y se establece que las diferencias interespecíficas referidas a las sensillas frontales, la forma del clípeo y el margen anterior del labro tienen valor taxonómico y probablemente filogenético. Palabras clave: Tenebrionidae, Gyriosomus, Morfología, Estadios preimaginales, Desierto costero, Chile., Preimaginal characters and bionomical aspects of Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae) We describe the morphology and microstructure of the egg chorion, and the morphology of the first instar larva of Gyriosomus luczotii Laporte, 1840 (Coleoptera, Tenebrionidae, Nycteliini). Bionomical and distributional data on this species are also provided. To obtain eggs and larvae, couples were collected in the field and kept in rearing cages until oviposture and ecclosion. The structure and adornment of the egg exochorion, and the exterior morphological features of larvae were examined with electron scanning microscopy. The eggs of G. luczotii showed a rounded micropyle and a smooth exochorion, composed of hexagonal cells without aeropyles. The larvae of G. luczotii showed morphological characteristics suited for an edaphic life similar to that of Pedobionta: digging prothoracic legs, cephalic capsule with abundant sensilla, and well–developed pygopodium. We analysed the importance of larval morphology as an element for specific diagnosis and found that interspecific differences regarding frontal sensilla, clypeus shape, and anterior part of labrum, had a taxonomic value and possibly a phylogenetic value. Key words: Tenebrionidae, Gyriosomus, Morphology, Preimaginal stages, Coastal desert, Chile.