Chironomidae (Insecta: Diptera) of Ecuadorian high altitude streams: a survey and illustrated key

Abstract

Chironomidae (Diptera) are among the most diverse and widespread aquatic insects, with roughly 5,500 described species inhabiting an enormous variety of aquatic ecosystems, ranging from moist soils to lakes and rivers, and even marine ecosystems. Despite its ubiquity, the group remains underrepresented in studies addressing aquatic insect assemblages of high-altitude systems, either glacier-fed or non-glacial, particularly in South America. Glacier-fed streams possibly are one of the harshest ecosystems in nature, and present a distinct downstream pattern in species distribution and diversity away from the constraining influence of the glacier. In this context, the goal of our study was to provide data on the chironomid fauna of glacier-fed streams, together with neighboring non-glacial streams in Ecuador, in order to contribute to the overall knowledge of tropical fauna in high Andean regions. Also, we sought to provide an identification key and photography material for future studies. Collections of non-biting midges were made in Ecuador during Jan 2008. In total, 1,412 specimens belonging to 16 genera and at least 23 species within the subfamilies Chironominae (3 taxa), Diamesinae (3 taxa), Podonominae (3 taxa), Orthocladiinae (13 taxa), and Tanypodinae (1 taxon) were found. The subfamilies Podonominae and Orthocladiinae predominated in terms of abundance. Parochlus was the most widespread genus of Chironomidae, while Cricotopus was the most diverse. This study contributes to the knowledge of the chironomid fauna in the high-altitude streams in Ecuador, and hopefully will motivate further studies in the area.