Journalartikel

Jahr der Veröffentlichung: 1990

Seiten: 213-233

Zeitschrift: Phyton: Annales rei Botanicae

Bandnummer: 30

Heftnummer: 2

ISSN: 0079-2047

Verlag: Institut für Biologie, Universität Graz, Austria) und Verlag Ferdinand Berger

Abstract: 
It is hypothesized that the original pollination mode in palms was one of general entomophily and that cantharophily is a derived mode. Many extant palm species are pollinated by more than one insect group, often with predominance of either bees, flies, or beetles. Certain morphological and physiological differentiation patterns of inflorescences and flowers are correlated with the predominance of a certain insect group, but these modifications are not so specific that they exclude other insect groups from visiting and pollinating the flowers. Furthermore, wind is a potential pollen vector. On the other hand, several species are specialized in their pollination for beetles. These cantharophilous species show different syndromes with diurnal or nocturnal attraction. Species exhibiting cantharophily belong to primitive groups as well as to more derived ones. Curculionidae and Nitidulidae are the main pollinators of cantharophilous palms, but also Scarabaeidae (Dynastinae) or Staphylinidae are involved. Pollination of palm flowers by beetles is closely related with predation. Palms offer food and mating or breeding sites for the beetles. The interrelationship palms/beetles has apparently evolved towards a balance between parasitism and successful pollination. The fact that many palms breed their own pollinators and that they additionally can be pollinated by the wind, makes them more independent from the surrounding insect fauna. Wind pollination, although derived in palms, probably was a very early event in the evolutionary history of the family and occurs today in primitive and derived species. Some small acaulescent savanna palms are derived in their habit but not necessarily in their pollination modes. In palms, the inflorescence bracts can function as protective or visually attractive organs, and further as breeding sites, pollination chambers, or in the aerodynamics of pollen capture. Nectar secretion from external nectaries in the gynoecium in species with free carpels, is supposed to be original in palms. Internal septal nectaries apparently are derived. Most cantharophilous palms do not have any nectar secretion.

Harvard-Zitierstil: SILBERBAUERGOTTSBERGER, I. (1990) POLLINATION AND EVOLUTION IN PALMS, Phyton: Annales rei Botanicae , 30(2), pp. 213-233

APA-Zitierstil: SILBERBAUERGOTTSBERGER, I. (1990). POLLINATION AND EVOLUTION IN PALMS. Phyton: Annales rei Botanicae . 30(2), 213-233.