Morphological Specializations in Central European Bees for the Uptake of Pollen from Flowers with Anthers Hidden in Narrow Corolla Tubes (Hymenoptera: Apoidea)

13 species of the Central European bee fauna belonging to 4 familiae and 5 genera were found to have evolved stout, curved bristles either on the tarsomera of pedes-I [P-I-ta] or on the proboscis which serve to extract pollen from plants having their anthers enclosed in narrow flower tubes, viz representatives of the Boraginaceae and Primulaceae. Pollen from narrow-tubed flowers plays an important role in the larval nourishment of these bees. The development of hooked bristles on the P-I-ta of one bee species is accompanied by a distinct elongation of the pedes-I which is interpreted as an additional adaptation to anthers concealed in deep corolla tubes. A literature survey reveals that morphological specializations enabling female bees to collect pollen efficiently at narrow-tubed flowers are widespread and must have evolved many times during bee evolution. The currently known morphological specializations of bees for the uptake of pollen from flowers are reviewed.