Floral scent and nectar production in Parkia biglobosa Jacq. (Leguminosae: Mimosoideae)

Abstract

Composition and variation in scent chemistry among individuals and populations, and nocturnal variation in scent composition and nectar production were studied in the African bat-pollinated species Parkia biglobosa. Floral scent was sampled using headspace techniques and chemical composition determined by GC-MS. Nectar production and sugar concentration were measured. The floral scent of P. biglobosa contained mainly benzenoids and isoprenoids. The total amount of volatiles produced and the chemical composition varied within and among the populations studied, as did nectar production. A nocturnal variation in the production of individual compounds and in nectar production was also found, but the sugar concentration of the nectar was fairly constant. Most of the floral scent compounds in P. biglobosa are common in the floral scent of plants pollinated by various groups of animals. The temporal scent and nectar production in P. biglobosa showed highest production early during anthesis and then declined following bat visitation. Published descriptions of floral scents in other species of Parkia imply the presence of sulphur compounds, as has been reported in several bat-pollinated species in the Neotropics. However, Parkia biglobosa did not contain any sulphur compounds, which shows that megabats, in this case, do not use sulphur compounds as foraging cues, as has been suggested for microbats in the New World.