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Brazilian Journal of Botany
On-line version ISSN 1806-9959
LONGO, José Milton and FISCHER, Erich. Effect of nectar secretion rate on pollination and seed production by Passiflora speciosa Gardn. flowers (Passifloraceae) in the Pantanal. Rev. bras. Bot. [online]. 2006, vol.29, n.3, pp. 481-488. ISSN 1806-9959. http://dx.doi.org/10.1590/S0100-84042006000300015.
We verified the effect of nectar secretion rate (NSR) on the pollinator frequency and the number of seeds per Passiflora speciosa Gardn. flowers in the Pantanal Wetlands. The plant was pollinated by hummingbirds and presented self-incompatibility. The NSR varied as a function of flower diameter, and number of hummingbird visits was a function of flower diameter. The number of seeds per flower of P. speciosa increased with the number of pollinator visits. The frequency of nectar thieves had no significant effect on seed set, but total number of hummingbird visits was negatively correlated with the total number of visits by nectar and/or pollen thieves. The overall results indicate that flower size affects NSR, which could determine the number of pollinator visits and the success of seed set per Passiflora speciosa flowers.
Keywords : flower size; foraging; hummingbird; nectar secretion; seed set.