Hummingbird pollination was suggested for Sinningia and Vanhouttea species based on floral features. However, there is still a lack of information about pollination biology. Here we report observations about floral biology and hummingbird-pollination of three Vanhouttea and three Sinningia species. The flowers are tubular, red and scentless. The pairwise comparison of corolla size results in two groups formed by: V. hilariana, V. brueggeri and S. gigantifolia which have bigger corollas than those of V. calcarata, S. cochlearis, and S. tuberosa. The nectar volume secreted during 24 hours by Vanhouttea species (21.8 ± 13.2 µL) was higher than that of Sinningia species (6.3 ± 5.7 µL). As well, the sugar amount produced by Vanhouttea species (6.1 ± 3.9 mg) was higher than that produced by Sinningia species (1.8 ± 1.6 mg). These differences on nectar production may be correlated with the distinct size of nectar glands in both genera. The hummingbirds Clytolaema rubricauda, Leucochloris albicollis, Stephanoxis lalandi (Trochilinae), Phaethornis eurynome and P. pretrei (Phaethornithinae) were the main pollinators of Vanhouttea and Sinningia species. The group of hummingbird pollinators (Trochilinae or Phaethornithinae) seems to be determined by the habitat of each plant species, while the frequency of visits seems to be mainly determined by nectar features.
Article in Portuguese.