These data strengthen the statement that the bat syndrome in Sinningieae originated independently in Sinningia brasiliensis and in Paliavana species. Paliavana sericiflora may be another example of a plant 'in transition' from the hummingbird to the bat pollination, but a reversion in the direction of bat to hummingbird might not be excluded. It is also possible that this is a case of speciation on both bat and hummingbird pollination. Studies on Paliavana sister species may provide insights about origins and the evolutionary directions of the pollination systems of these species.

-(Species of Vanhouttea Lem. and Sinningia Nees (Gesneriaceae) pollinated by hummingbirds: interactions related with plant habitat and nectar). 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.Key words -frequency of visits, Gesneriaceae, hummingbirds, nectar, Sinningieae RESUMO -(Espécies de VanhoutteaLem. e Sinningia Nees (Gesneriaceae) polinizadas por beija-flores: interações relacionadas ao hábitat da planta e ao néctar). Com base nas características florais tem sido inferida a polinização por beija-flores na maioria das espécies de Sinningia e Vanhouttea, entretanto, informações detalhadas sobre a biologia da polinização são restritas a poucas espécies. Neste estudo são apresentadas as observações sobre a biologia da polinização e as espécies de beija-flores polinizadores, relacionando as características do néctar com o comportamento desses beija-flores em três espécies de Vanhouttea e três de Sinningia. As flores são tubulosas, avermelhadas e inodoras. Em relação ao tamanho da corola estas espécies formam dois grupos morfológicos, sendo as corolas em V. hilariana, V. brueggeri e S. gigantifolia significativamente maiores que em V. calcarata, S. cochlearis e S. tuberosa. O volume de néctar secretado durante 24 horas pelas espécies de Vanhouttea (21,8 ± 13,2 µL) é maior que nas espécies de Sinningia (6,3 ± 5,7 µL). Assim também, a quantidade de açúcares produzida pelas espécies de Vanhouttea é mais alta (6,1 ± 3,9 mg) e difere significativamente das espécies de Sinningia (1,8 ± 1,6 mg). Estas diferenças nas características do néctar podem estar relacionadas com a variação do tamanho das glândulas nectaríferas entre os dois gêneros. Cinco espécies de beija-flores, Leucochloris albicollis, Stephanoxis la...

Pollination by male and female Euglossini bees, euglossophily, was suggested for a number of neotropical Gesneriaceae species. Information on bee species other than Euglossini as pollinators of neotropical members of this family is limited, and in the tribe Sinningieae data about bee pollination are still lacking. Here, we report on floral biology and bee pollination of four Sinningia species: S. schiffneri, S. eumorpha, S. villosa, and Sinningia "canastrensis". The flower features, such as corolla size, shape, and colour, are very different among the four species, but all conform to the melittophilous syndrome. The average nectar volume and sugar amount is low in S. schiffneri, S. eumorpha, and Sinningia "canastrensis", when compared to that of S. villosa, but low nectar amounts is a general feature of Sinningia species. The main pollinators of the four species are: small Tapinotaspidini (Trigonopedia ferruginea) of S. schiffneri, large Bombini (Bombus morio) and large Centridini (Epicharis morio) of S. eumorpha, large Euglossini (Eulaema cingulata and Eufriesea surinamensis) of S. villosa, and large Euglossini (Eufriesea violascens) and Megachilini (Megachile sp.) of Sinningia "canastrensis". Out of the four species, only S. villosa is exclusively Euglossini-pollinated. The marked differences in flower features and nectar production of these Sinningia species may reflect their pollination by distinct groups of bees. These results strengthen the idea of multiple origins for the pollination systems involving bees within this genus, which is highly supported by molecular phylogenetic analyses.