'Nectar guides' are patterns seen in some
flowers that guide pollinators to the
nectar and
pollen. These patterns may be visible to humans; for instance, the Dalmatian
toadflax (''Linaria genistifolia'') has yellow flowers with orange nectar guides.
[1] However in some plants, such as
sunflowers, they are visible only under
ultraviolet light. Under ultraviolet, the flowers have a darker center, where the nectaries are located, and often specific patterns upon the petals as well. This is believed to make the flowers more attractive to
pollinators such as
honey bees and other
insects that can see ultraviolet.
This page on butterflies shows an animated comparison of
black-eyed Susan (''Rudbeckia hirta'') flowers in visible and UV light.
External links
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Dalmatian Toadflax from the Southwest Exotic Plant Information Clearinghouse
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What do butterflies see? (speculation)