Mucuna holtonii

About

Mucuna holtonii is a species of plant in the bean family, which is pollinated by bats. Bats are able to detect if the flowers have nectar using echolocation. After an initial bat visit during which nectar is removed, the petals are arranged in a different manner. As a result, the unique "echo fingerprint" of petal arrangement informs the bat whether nectar is present or absent.

Summary from Wikipedia