Annals of Botany 95(7): 1097-1103. (2005)
Chiropterophily in Sinningieae (Gesneriaceae):
Sinningia brasiliensis
and Paliavana prasinata are bat-pollinated, but P. sericiflora is not. Not yet?

Ivonne SanMartin-Gajardo and Marlies Sazima

Background and Aims Based on the bell shape and greenish colour of the flowers, bat-pollination was suggested for some Sinningieae species (Gesneriaceae). Actually, there are no reports on pollination biology and visitors for these species. This paper reports on pollination biology of Sinningia brasiliensis, Paliavana prasinata and P. sericiflora in south-eastern Brazil.

Methods Flowers were observed in situ to determine phases of anthesis, colour patterns and scent intensity. Corolla measures were taken from fresh flowers. Nectar production and concentration were measured in flowers bagged at the pre-anthesis phases. Direct visual observations of visitors were made during the day and night, and photographs were taken to analyse their visiting behaviour.

Key Results Some floral features of the three species fit the bat-pollination syndrome: large, robust and gullet-shaped corollas, colour patterns and large amount of nectar. However, other floral features—such as onset of anthesis, nectar attributes and odour intensity—differ among the species. Nectar volume and total sugar production increased significantly at midnight in S. brasiliensis and P. prasinata, but in P. sericiflora there were no significant differences in the total nectar and sugar production during anthesis. Scent intensity is much higher in S. brasiliensis and P. prasinata than P. sericiflora. Flowers of S. brasiliensis and P. prasinata, whose features fit the chiropterophilous syndrome, are pollinated by glossophagine bat species. Paliavana sericiflora, on the other hand, presents floral features intermediate between bat and hummingbird syndromes, but is visited and pollinated only by hummingbirds.

Conclusions 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.

Paliavana is a genus of 6 shrubby species from southern Brazil that are very closely related to (and probably should be included within) Sinningia, but lack tubers. They are generally of easy culture but are not commonly cultivated as they can grow quite large.

[CybeRose note: I wonder whether the Paliavana species could be crossed with the miniature Sinningias to produce shrubby plants of more convenient sizes.]