J Syst Evol ›› 2020, Vol. 58 ›› Issue (6): 805-822.DOI: 10.1111/jse.12704

• Research Articles • Previous Articles     Next Articles

Dispersal and adaptive radiation of Bidens (Compositae) across the remote archipelagoes of Polynesia

Matthew L. Knope1 * , Vicki A. Funk2 , Melissa A. Johnson3 , Warren L. Wagner2,4 , Erin M. Datlof1 , Gabriel Johnson2 , Daniel J. Crawford5 , J. Mauricio Bonifacino6 , Clifford W. Morden7 , David H. Lorence4 , Kenneth R. Wood4 , Jean-Yves Meyer8 , and Sherwin Carlquist9   

  1. 1 Department of Biology, University of Hawaiʻi at Hilo, Hilo, HI 96720, USA
    2 Department of Botany, MRC166, Smithsonian Institution, P.O. Box 37012 Washington, DC 20013‐7012, USA
    3 USDA‐ARS, Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center, 64 Nowelo St. Hilo, HI 96720, USA
    4 National Tropical Botanical Garden, 3530 Papalina Road, Kalāheo Kauaʻi, HI 96741, USA
    5 Department of Ecology & Evolutionary Biology, Biodiversity Institute University of Kansas, Lawrence, KS 66045‐7534, USA
    6 Laboratorio de Botánica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Av. Garzón 780 Montevideo, CP 12900, Uruguay
    7 School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
    8 Délégation à la Recherche, Government of French Polynesia, Papeete, Tahiti, French Polynesia
    9 Santa Barbara Botanic Garden, Herbarium, Santa Barbara Botanic Garden, 1212 Mission Canyon Road Santa Barbara, CA 93105, USA
  • Received:2020-09-04 Accepted:2020-10-29 Online:2020-11-09 Published:2020-11-01


The genus Bidens (Compositae) comprises c. 230 species distributed across five continents, with the 41 Polynesian species displaying the greatest ecomorphological variation in the group. However, the genus has had a long and complicated taxonomic history, and its phylogenetic and biogeographic history are poorly understood. To resolve the evolutionary history of the Polynesian Bidens, 152 individuals representing 91 species were included in this study, including 39 of the 41 described species from Polynesia. Four chloroplast and two nuclear DNA markers were utilized to estimate phylogenetic relationships, divergence times, and biogeographic history. Bidens was found to be polyphyletic within Coreopsis, consistent with previous assessments. The Polynesian radiation was resolved as monophyletic, with the initial dispersal into the Pacific possibly from South America to either the Hawaiian or Marquesas Islands. From the Marquesas, Bidens dispersed to the Society Islands, and ultimately to the Austral Islands. The initial diversification of the crown group in the Pacific is estimated to have occurred ~1.63 mya (0.74–2.72, 95% HPD), making Polynesian Bidens among the youngest and most rapid plant diversification events documented in the Pacific. Our findings suggest that relatively rare long‐distance dispersal and founder‐event speciation, coupled with subsequent loss of dispersal potential and within‐island speciation, can explain the repeated and explosive adaptive radiation of Bidens throughout the archipelagoes of Polynesia.

Key words: Asteraceae, Coreopsideae, ecology, evolution, extinction, geologic history, Heliantheae Alliance, Island biogeography, speciation