The present study is a comparison of the flower biology and pollination of some thermogenic species of palms and Annonaceae. In the palms eleven representatives of the genera Astrocaryum, Attalea, Bactris, and Oenocarpus, and in the Annonaceae nine representatives of the genera Anaxagorea, Duguetia, and Xylopia were studied in the region of Manaus (AM). All the studied palm species are monoecious and the anthesis of their inflorescences occurs at night during a period which varies from two days to five weeks. The investigated species of the Annonaceae are protogynous with the anthesis of a single flower lasting for two days and occurring at night or during the day. Flower visiting insects are attracted by strong odours which are intensified through thermogenesis. The species-specific odours range from fruit-like to unpleasant and pungent. Most of the flower visiting insects are beetles of the families Scarabaeidae, Nitidulidae, Staphylinidae, Curculionidae, and Chrysomelidae, and additionally thrips and drosophilid flies. Further insects which visit the flowers are bees, wasps, ants, and other fly groups. However, palms and Annonaceae with thermogenic flowers most frequently showed beetle pollination. It is notable that flowers of some species of both families were visited bythe same families and even species of beetles, which might be due to similar morphological and physiological adaptations of the flowers, including production of similar odour components.
Arecaceae; Annonaceae; flower biology; pollination; beetles; thermogenesis