FLORAL SYMMETRY AND NECTAR GUIDES - ONTOGENIC CONSTRAINTS FROM FLORALDEVELOPMENT, COLOR PATTERN RULES AND FUNCTIONAL-SIGNIFICANCE

The accord between symmetries of flower shape (external contours) and nectar guides (internal contours) was examined using the bulbous flora of South Africa, and in the general floras of Britain, Alpine Colorad o, Canadian Arctic and Israel. It was found that radially symmetrical flowers have radially symmetrical nectar guides whereas bilaterally sy mmetrical flowers have bilaterally symmetrical nectar guides. It is su ggested that the complementarity between the external and the internal contours of the newer increases the probability that, and efficiency with which, a bee moves into the newer's centre and towards the sporop hylls and access to floral rewards, regardless of the flower's form an d the bee's previous experience. patterns of coloration of tepals agai nst background and nectar guides against tepals also accord with behav ioural and sensory characteristics of pollinators. It is suggested tha t the complementarity of contours is probably constrained by floral de velopment, but patterns of coloration of tepals against background and nectar guides against tepals is constrained by pollinators' sensory p hysiology. (C) 1996 The Linnean Society of London