The aim of this study was to analyze the influence of floral architecture, the behavior of day visitors to the flowers and the influence of the location of pollen deposition on the bodies of the pollinators for the reproductive success of Helicteres sacarolha and H. lhotzkyana. Flowering of H. sacarolha occurred during the rainy season (January to April) and H. lhotzkyana between July and October (dry season and beginning of the rainy season). Flowers of both species are colorful and zygomorphic with characteristics of ornithophily. Hummingbirds were the main day visitors to the flowers. The species had no pollinators in common. The behavior of the hummingbirds that visited H. sacarolha flowers was territorial and the pollen was deposited on the head or forehead; the behavior of those that visited H. lhotzkyana flowers was traplining and the pollen was deposited on the tail or feet. Reproductive success was significantly different between the species; mean fruit set was 24.56 for H. sacarolha and 5.28 for H. lhotzkyana. Floral characteristics and pollinator behavior explain part of the differences in the reproductive success of the species studied.
flower morphology; ornithophily; pollination efficiency; reproductive biology
