Nectar sugar composition and concentration in relation to pollination syndromes in Bromeliaceae.

A first comprehensive dataset of nectar sugar composition and concentration in Bromeliaceae is presented, covering 111 species belonging to all three subfamilies. Based on this dataset, we examined the relationship between nectar traits and pollination syndromes in the family. Sugars in samples were assayed by high pressure liquid chromatography. All sampled species were grouped into three broad categories (trochilophilous, chiropterophilous, or lepidopterophilous) according to their main pollination mode. Significant differences between the different pollination syndromes were found in nectar sugar composition as well as concentration. For a total of four genera (Guzmania, Pitcairnia, Tillandsia and Vriesea), a comparison of nectar composition showed significant differences between trochilophilous and chiropterophilous species. Data presented here indicate that the characteristics of nectar in Bromeliaceae are predominantly determined by putative adaptations of nectar sugars to preferences of the pollinators rather than by phylogenetic relations.