FLOWERING, POLLINATION, NECTAR STANDING CROP, AND NECTARIES OF EUTERPE PRECATORIA (ARECACEAE), AN AMAZONIAN RAIN-FOREST PALM

Flowering and pollination biology of the monoecious palm Euterpe preca toria was studied in the forest of the ''Reserva Ducke'' near Manaus, Brazil, during two annual flowering periods (middle of October to end of March) between 1991 and 1993. Individuals produced one to four bise xual inflorescences per flowering period. Inflorescences have staminat e and pistillate flowers in triads. The anthesis of the whole inflores cence averaged 26 days, with the male phase extending over the first 1 7 days, followed by six days without any open flowers, and the female phase covering the last three days. The distinct dichogamy of the infl orescence results in obligate outcrossing. The pollen-ovule ratio is h igh (42000). Both male and female flowers emit an almond oil-like scen t and produce nectar in septal nectaries. The concentration and total amount of sugar of the nectar of female flowers (37% and 0.021 mg) wer e significantly higher than that of male flowers (9% and 0.007 mg). Th e nectar is hexose-rich and with a moderately high amino acid concentr ation (68 mu g/ml). Euterpe precatoria seems to be a generally entomop hilous palm with a predominance of beetles and bees as potential polli nators. The most constant visitors were beetles of the families Curcul ionidae, Chrysomelidae, Staphylinidae, and bees of the family Halictid ae. The actual composition of the insect spectrum depends on climatic and biotic factors. Additionally, wind pollination may occur. Fruit de velopment lasted four months and ripe fruits are swallowed by toucans who thus disperse the seeds.