Function of epidermal surfaces in the trapping efficiency of Nepenthes alata pitchers

Authors

  • Laurence Gaume,

    Corresponding author
    1. Botanique et bioinformatique de l’architecture des plantes, UMR CNRS 5120, Boulevard de la Lironde – TA 40/PS 2, F–34398 Montpellier, cedex 5, France;
    Search for more papers by this author
  • Stanislav Gorb,

    1. Biological Microtribology Group, Max-Planck-Institute of Development Biology, Spenmannstrasse 35, D–72076 Tübingen, Germany
    Search for more papers by this author
  • Nick Rowe

    1. Botanique et bioinformatique de l’architecture des plantes, UMR CNRS 5120, Boulevard de la Lironde – TA 40/PS 2, F–34398 Montpellier, cedex 5, France;
    Search for more papers by this author

Author for correspondence: Laurence Gaume Tel: +33 4 67617166 Fax: +33 4 67615668 Email: lgaume@cirad.fr

Summary

  • •   Several epidermal microstructures characterize surfaces of pitcher plants and are presumably involved in their trapping function. Here we report the effects of Nepenthes alata surfaces on insect locomotion and trapping efficiency.
  • •   The architectural designs of pitcher surfaces were characterized using scanning electron microscopy. Two insect species – fruitfly (Drosophila melanogaster) and ant (Iridomyrmex humilis) – were tested for their ability to remain and walk on them. The relative contributions of various epidermal structures to trapping ability were quantified.
  • •   Pitchers were very effective traps for both insect species. They were slightly more efficient in capturing the ants, but slightly more effective in retaining captured flies. Trapping efficiency was attributed to the combined effects of several surfaces displaying different functions. The waxy zone played a key role in the slippery syndrome: in addition to the wax itself, the subjacent layer of convex lunate cells interfered considerably with insect locomotion. The unsubmersed glandular zone displayed an important retentive effect and secretions of the digestive glands are suspected to be adhesive.
  • •   Pad performances of the hairy and smooth system of attachment are discussed to explain the differences between the two insect species. This study aims to encourage biomechanical studies of plant–insect surface mechanisms.

Ancillary