MACROEVOLUTIONARY DATA SUGGEST A ROLE FOR REINFORCEMENT IN POLLINATION SYSTEM SHIFTS

Authors

  • Timotheüs van der Niet,

    1. Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
    Search for more papers by this author
    • 3

      Present address: Nationaal Herbarium Nederland, Wageningen University Branch, and Biosystematics Group, Wageningen University and Research Centre, Generaal Foulkesweg 37, 6703 BL Wageningen, The Netherlands; E-mail: niet@systbot.unizh.ch.

  • Steven D. Johnson,

    1. School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01 Scottsville, Pietermaritzburg 3209, South Africa
    Search for more papers by this author
  • H. Peter Linder

    1. Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
    Search for more papers by this author

Abstract

Abstract . Reproductive isolation can evolve either as a by-product of divergent selection or through reinforcement. We used the Cape flora of South Africa, known for its high level of pollination specialization, as a model system to test the potential role of shifts in pollination system in the speciation process. Comparative analysis of 41 sisterspecies pairs (representing Geraniaceae, Iridaceae, and Orchidaceae) for which complete pollinator, edaphic, and distribution data are available showed that for sister species with overlapping distribution ranges, pollination system shifts are significantly associated with edaphic shifts. In contrast, there is no significant association between pollination system shifts and edaphic shifts for allopatric sister species. These results are interpreted as evidence for reinforcement.

Ancillary