Evolution of Tropical Heliconia: Temporal and Spatial Diversification at the Species Level

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

An award has been made to the University of California at Berkeley under the direction of Dr. Chelsea Specht to study the diversification of floral form and the classification of a family of tropical plants known as heliconias. The goal of the proposed research is to develop an understanding of the evolutionary history of Heliconiaceae, an ecologically and economically important family of tropical plants. The family Heliconiaceae (heliconias) comprises approximately 215 species (190 currently recognized with an estimated 25 remaining to be described) in the single genus Heliconia, distributed primarily in the neotropics. While heliconias are grown as tropical ornamentals throughout the world, the native range extends from central Mexico to central South America including the Caribbean, with a group of six closely related species native to Indonesia, New Guinea, and several South Pacific islands. Although heliconias are frequently cultivated as ornamentals, there have been no well-supported hypotheses on relationships among species of Heliconia, primarily due to similarities in flower traits that are specific to hummingbird pollination. Species have been divided taxonomically into subgenera based on morphology, but this classification has not been tested. Heliconia species each maintain intricate and specialized evolutionary relationships with pollinating hummingbirds and herbivorous rolled-leaf hispine beetles, as well as other mutualistic, parasitic, and predatory partnerships. A comprehensive, well-supported phylogeny is necessary to determine species-level relationships within the family and to understand the evolution of floral and vegetative characters involved in such complex interspecies interactions. This phylogeny will be used to (a) reconcile and revise the taxonomy of the family using evolutionary relationships to determine specialized features of subgeneric groupings and (b) interpret evolutionary trends in pollination relationships, herbivore interactions, and tropical biogeography. Training will take place at both graduate and undergraduate levels, incorporating students into all aspects of the research, including field collections, phylogenetic and biogeographic analyses, and the description of new species and higher-level taxonomic groupings.