Biotemas (Nov 2004)
A contribution to the pollination ecology of Tabebuia pulcherrima (Bignoniaceae) in a sandbank area of the south of Santa Catarina State, Brazil
Abstract
Studies on pollination mechanisms in Bignoniaceae have show some evidence of co-evolution with its pollen vectors. Floral biology and flower visitors of Tabebuia pulcherrima were investigated in a sandbank area. Flower phenology, the nectar production, pollen/ovule ratio, and identification of the flower visitors, as well as their behavior, were studied. Tabebuia pulcherrima displays typical melitophilous flowers, due to its morphology, diurnal anthesis and day-long nectar secretion. In the morning, the nectar volume is smaller, which is associated with a higher frequency of visitors. The pollen/ovule ratio indicates facultative xenogamy. We collected 88 insects on the flowers, 52% of which were bees; the rest were wasps, flies, ants end beetles. The most abundant species were Niltonia virgilii (42%), Bombus morio (20%) and Xylocopa brasilianorum (18%). According to their frequency, abundance and visiting behavior, Bombus morio and Niltonia virgilii were considered to be the potencial pollinators of T. pulcherrima and Epicharis dejeanii, a secondary pollinator. The carpenter bee Xylocopa brasilianorum is a nectar robber of T. pulcherrima. The flowers of T. pulcherrima are an important food source for the entomofauna of the restinga, offering nectar and pollen as floral rewards.
