Rodulfo Ospina-Torres

Deriva de macroinvertebrados acuáticos en dos sitios con diferente grado de perturbación, río Gaira, Santa Marta - Colombia

The aim of this work was to evaluate the spatial variation of the macroinvertebrate biomass and density drift on two stations with different degree of disturbance (flow regulated and higher sediment amount in one of them) in the lower basin of Gaira River (Santa Marta, Colombia). We carried out three surveys per station using drift nets during 24-hour periods, collecting samples each four hours. We found differences on abundance-, biomass- and drift density between sites and samples, where the less disturbed station had the higher values. The daily variation of drift was highest at night. Leptohyphidae, Chironomidae, Hydropsychidae and Elmidae were the most abundant drifting taxa. The differences can be related to river flow variability and sediment transport, in spite of the marginal value of both magnitude and frequency of the disturbance.

Contribution to the Trichoptera fauna of the river La Vieja, Bogotá, Colombia (Insecta: Trichoptera)

Investigation of the Trichoptera fauna from the small river La Vieja on the city border of Bogotá yielded a total of 17 species. Nine new species of Trichoptera are described from La Vieja: Atopsyche viejae spec. nov., A. flavoantennata spec. nov., Metrichia trisignata spec. nov., M. longiphallata spec. nov., Smicridea colombosaucia spec. nov., Xiphocentron laviejae spec. nov., Phylloicus monserratensis spec. nov., Marilia bogotaensis spec. nov., and Oecetis chapinera spec. nov. Images of the adults of some species are provided, and the male genitalia are illustrated. The genitalia of three additional species (Hydroptila constricta Bueno-Soria 1984, Polycentropus joergenseni Ulmer 1909, Contulma spec.) are depicted to facilitate their future identifications.

Pollination of Granadilla (Passiflora ligularis) Benefits From Large Wild Insects

Abstract The contribution of wild pollinators to food production has recently been assessed for many crops, although it remains unclear for several tropical crops. Granadilla (Passiflora ligularis Juss), a crop native to the tropical Andes, is one such crop where a gap exists regarding comprehensive knowledge about its pollination system. In a field experiment in the Colombian Andes, we 1) describe flower visitors in terms of visit quantity (visitation rate) and quality (touches of flower-reproductive structures), 2) assess the pollination system by comparing fruit set and fruit weight per flower in three pollination treatments: pollinator exclusion, open pollination, and supplementary pollination, and 3) evaluate pollination deficits (difference between open and supplementary pollination) in relation to pollinator density. We observed 12 bee species visiting granadilla flowers, with Apis mellifera Linnaeus being the most frequent species. However, large bees such as Xylocopa lachnea Moure and Epicharis rustica Olivier touched stigmata and anthers more often. Fruit set and fruit weight per flower were significantly lower in the pollinator exclusion treatment compared to open and supplementary pollination, while the latter treatments showed nonsignificant differences. Pollination deficit significantly decreased with the increasing density of large bees and wasps. Our results illustrate the high dependency of granadilla on wild pollinating insects and highlight the crucial role of large insects to granadilla production.This stresses the need to maintain or increase the density of large pollinators in granadilla production areas, which in turn will necessitate better knowledge on their ecological requirements to inform landscape planning and population-management programs.