Flowers visited by hummingbirds in an urban Cerrado fragment, Mato Grosso do Sul, Brazil

Abstract

Hummingbirds are the main vertebrate pollinators in the Neotropics, but little is known about the interactions between hummingbirds and flowers in areas of Cerrado. This paper aims to describe the interactions between flowering plants (ornithophilous and non-ornithophilous species) and hummingbirds in an urban Cerrado remnant. For this purpose, we investigated which plant species are visited by hummingbirds, which hummingbird species occur in the area, their visiting frequency and behavior, their role as legitimate or illegitimate visitors, as well as the number of agonistic interactions among these visitors. Sampling was conducted throughout 18 months along a track located in an urban fragment of Cerrado vegetation in Campo Grande, Mato Grosso do Sul, Brasil. We found 15 species of plants visited by seven species of hummingbirds. The main habit for ornithophilous species was herbaceous, with the predominance of Bromeliaceae; among non-ornithophilous most species were trees from the families Vochysiaceae and Malvaceae. Hylocharis chrysura was the hummingbird that visited the largest number of plant species and also attended the greater number of agonistic events. The high proportion (66.7%) of non-ornithophilous species visited by hummingbirds in the present study was similar to that found in other communities analyzed in Brazil. The fact that ornithophilous species in the area does not offer resources continuously throughout the year should induce hummingbirds to search for alternative resources, and contribute to the high proportion of non-ornithophilous species visited. In general, the floral form was not a barrier to floral visits by hummingbirds, although morphological characteristics of flowers from some plant species may be restrictive. Tabebuia aurea, for example, presents flowers with long corollas, hindering the access to floral resources by the pollinators, what may favor the occurrence of illegitimate visits by hummingbirds. Despite of being a small fragment of Cerrado vegetation, the studied remnant can be considered an important refuge, sheltering a great richness of hummingbird species comparable to several forested areas in Brazil.