Unrelated organisms that share similar niches often exhibit patterns of convergent evolution in functional traits.
Johnson and Raguso study long-tongued hawkmoths and flowers with very long (>8 cm) tubes for both native and invasive species in Africa and determine that the hawkmoth Agrius convolvuli, and to a much lesser extent the related species Coelonia fulvinotata, comprise a distinct long-tongued pollinator niche that is occupied by a large guild of plant species. From the patterns of convergent evolution among guild members, it seems likely that white floral colouration and copious amounts of nectar are important for establishing mutualisms with long-tongued hawkmoths. The study highlights the value of a niche perspective for understanding the geographical context and functional significance of floral traits.
Johnson, S. D., & Raguso, R. A. (2015). The long-tongued hawkmoth pollinator niche for native and invasive plants in Africa. Annals of Botany, 117(1), 25–36. https://doi.org/10.1093/aob/mcv137