The plants are of considerable biological and evolutionary interest because of their adaptions to particular pollinators, such as flies in the families Tabanidae, Acroceridae, Bombyliidae, and most spectacularly, Nemestrinidae.
Research is in progress on the ecological and evolutionary relationships between some members of the genus and specialist long-tongued pollinators, particularly night flying hawk moths (Family Sphingidae) and flies in the families Nemestrinidae, Tabanidae, and Bombyliidae.