Reproductive biology of Prepusa hookeriana (Gentianaceae): an endangered species of high-altitude grasslands in Brazil

Abstract

The genus Prepusa Martius is endemic to montane regions of Brazil and comprises only six species, most of them endangered. Although studies on reproductive biology are necessary to increase knowledge of this genus and to implement conservation plans, to date, no such studies have been conducted. This study assessed the floral biology, breeding system, and pollinators of Prepusa hookeriana, an endangered species of high-altitude grasslands. We perform field observations and manual pollination experiments. Certain floral traits of this species appear to be associated with hummingbird pollination, although ornithophily is unusual in Gentianaceae. Even though cross-pollination is favoured by the presence of movement herkogamy and protandry, both prior and delayed autonomous self-pollination were observed. The only pollinator observed was the hummingbird Amazilia versicolor. Prepusa hookeriana did not show pollen limitation in the year of study. The absence of pollen limitation is related to the high reproductive success of pollination due to visits, not to autonomous self-pollination. However, we share the idea that the ability of autonomous selfing can provide a backup to cope with occasional pollination failures.