I’ve heard that plants attract insects and other pollinators using nectar guides (nature’s own user interface!), but I’ve never heard of this adaptation: the plants depicted above manipulate sound rather than light to attract attention, a bit of floral acoustics.
Ralph Simon at the University of Ulm in Germany and his colleagues analysed the leaf’s acoustic properties and found that its unique shape produces a strong, constant echo across a range of sound-source angles. They then trained bats to seek a feeder hidden in artificial foliage. The animals found feeders topped with the cup shape in an average of 12 seconds — around half the time it took them to locate unadorned feeders or those under other leaf shapes.