The aim of this study was to investigate the Syrphidae community in the area of the Green Belt of Santa Cruz do Sul, RS, Brazil, as well as to obtain information on the structure and composition of this community, its floral preferences and the interactions between the species in the food resource utilization. The specimens were collected with entomological net, from September/2001 to January/2005. A total of 1.283 syrphid specimens were collected, totaling 88 species distributed in 21 genera. Eristalinae presented the highest number of collected species, followed by Syrphinae and Microdontinae. The genus Palpada Macquart, 1834 and the species P. urotaenia (Curran) were the most abundant. 1.187 syrphids (74 species) were flower visitors of 51 plant species from 23 families, of which Apiaceae and Asteraceae presented the highest number of visitors. The feeding specialization degree varied according to the visited blooming types. The relative easy access to the floral resources with lighter coloration were the main factors regarding the syrphid attraction in the families Apiaceae, Asteraceae, Lauraceae, Malvaceae, Meliaceae, Oleaceae, Poaceae and Solanaceae. The diversity of the syrphid community is regulated by local interactions between the species, mainly between the environmental conditions and the food resources offering.
Asteraceae; flower-visiting; insect-plant interaction; Palpada
