Consumo de polen por sírfidos (Diptera: Syrphidae) en una cuenca urbana altoandina con influencia antrópica.

Flower flies are fundamental pollinators in high mountain habitats such as high Andean forests. We evaluated the plant-syrphid relationship associated with pollen consumption in three vegetation covers with different levels of anthropic influence in a micro-watershed near Bogotá. After extracting and performing acetolysis the digestive tracts of 22 syrphid species (n = 358 specimens), the pollen found was characterized and categorized according to its size and ornamentation, while the pollen spectra were analyzed by means of bipartite interaction networks to assess the degrees of specialization, connection, vulnerability, and nestedness of each network. The relationships of the syrphids in the studied covers appeared to be generalist in nature. Greater vulnerability was observed in tall secondary vegetation, and less stability was found in the discontinuous urban fabric's bipartite network when compared to that of the riparian forest. This suggests a lower resilience for the anthropized covers and intermediate successions in the face of extinction events. [ABSTRACT FROM AUTHOR]