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Naturwissenschaften

, Volume 89, Issue 7, pp 281–294 | Cite as

Cycads: their evolution, toxins, herbivores and insect pollinators

  • Dietrich Schneider
  • Michael Wink
  • Frank Sporer
  • Philip Lounibos
Review Article

Abstract.

Palaeobiological evidence indicates that gymnosperms were wind-pollinated and that insect pollination began in angiosperms in the Lower Cretaceous (ca. 135 mya) leading to close associations between higher plants and their pollinators. Cycads, which were widespread and pervasive throughout the Mesozoic (250–65 mya) are among the most primitive living seed-plants found today. Because pollination by beetles and by thrips has now been detected in several modern cycads, it is attractive to speculate that some insects and cycads had already developed similar mutualistic interactions in the Triassic (250–205 mya), long before the advent of angiosperms. We also draw attention to another key factor in this insect–plant relationship, namely secondary, defensive plant substances which must always have controlled interspecific interactions. Cycads mainly produce toxic azoglucosides and neurotoxic non-protein amino acids (e.g. BMAA), which apparently are crucial elements in the development and maintenance of mutualism (pollination) and parasitism (herbivory) by cycad-linked herbivores. We now add new results on the uptake and storage of the main toxin, cycasin, of the Mexican cycad Zamia furfuracea by its pollinator, the weevil Rhopalotria mollis, and by a specialist herbivore of Zamia integrifolia, the aposematic Atala butterfly Eumaeus atala.

Keywords

Cretaceous Lower Cretaceous Mutualistic Interaction Crucial Element Plant Substance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Dietrich Schneider
    • 1
  • Michael Wink
    • 2
  • Frank Sporer
    • 2
  • Philip Lounibos
    • 3
  1. 1.Max-Planck-lnstitut, 82319 Seewiesen/Starnberg, Germany
  2. 2.Institut für Pharmazeutische Biologie der Universität Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
  3. 3.University of Florida, Florida Medical Entomology Laboratory, 200 9th Street SE, Vero Beach, FL 32962, USA

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