Pollination by Hummingbirds and Bees in Eight Syntopic Species and a Putative Hybrid of Ericaceae in Southeastern Brazil.

LEANDRO FREITAS,; LEONARDO GALETTO,; MARLIES SAZIMA,

PLANT SYSTEMATICS AND EVOLUTION

Año: 2006 vol. 258 p. 49 - 61

0378-2697

Distinct floral traits of sympatric and congener species may promote pollination by different agents and, consequently, contribute to the reproductive isolation of such species. The small, campanulate- to tubular-shaped flowers of eight species and a putative hybrid belonging to three Ericaceae genera -- that occur syntopically in a montane area of southeastern Brazil -- are primarily pollinated by either hummingbirds, large bees or small bees. Flowering overlaps in all species and slight differences on nectar production, sugar composition, and on floral shape, colour and dimensions seem to drive the pollination by each of the three agent groups. Moreover, some floral traits are similar among species of different genera pollinated by the same animal group, suggesting a possible morphological convergence selected by the pollinators. Otherwise, differences in floral traits are not enough to exclude occasional pollinators in addition to the main agents. Nectar composition seems to be a more conservative trait than flower morphology in these species of Gesneriaceae.  Pollinators may promote inter-specific crosses and, consequently, they are potential agents for production of natural hybrids, which seems to be a common phenomenon among neotropical Ericaceae species.   Key words: Agarista, Atlantic forest, bee, Ericaceae, floral biology, Gaultheria, Gaylussacia, hummingbird, hybrid, nectar, pollination, southeastern Brazil