FLOWERS AND BEETLES IN THE SOUTH-AMERICAN TROPICS

Examples of beetle pollination in the South American tropics are given. The case histories refer to representatives of the families Cyclanthaceae, Annonaceae, and Araceae. In most cases the cantharophilous syndrome does not seem to be the result of coevolution but of a one-sided adaptation of flowers to the behavior, necessities, and sense-capacities of beetle species. It is emphasized that cantharophily may not necessarily be an indication of ancientness of a flower/insect relationship. Besides primitive angiosperms, there are derived and modern groups which, in their pollination, are specialized for beetles. Carludovica palmata (Cyclanthaceae) is pollinated by small curculionids which are attracted by odors in the early morning hours. Annona coriacea (Annonaceae) and Philodendron selloum (Araceae) are pollinated by large dynastid scarab beetles in the evening hours. In all three species thermogenesis occurs. Although belonging to widely separate systematic groups, Annona flowers and Philodendron inflorescences have a similar pollination biology, which indicates that their adaptations to beetles are the result of convergent evolutionary developments.