Slippery surfaces of pitcher plants: Nepenthes wax crystals minimize insect attachment via microscopic surface roughness
| Autor: | Florian Hischen, Lars Dolge, M. Bückins, Markus Riederer, T. Erlinghagen, Sarah L. Hoffmann, Ingo Scholz, Michael Riedel, Agnes Weth, Joachim Mayer, Werner Baumgartner |
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| Rok vydání: | 2010 |
| Předmět: |
Insecta
Materials science Surface Properties Physiology Surface finish Aquatic Science Microscopy Atomic Force Models Biological Epicuticular wax Botany Surface roughness Animals Composite material Molecular Biology Ecology Evolution Behavior and Systematics Wax biology Adhesiveness Adhesion biology.organism_classification Nepenthes alata Peristome Sarraceniaceae Waxes Insect Science visual_art visual_art.visual_art_medium Female Animal Science and Zoology Adhesive Crystallization |
| Zdroj: | Journal of Experimental Biology. 213:1115-1125 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.035618 |
| Popis: | SUMMARY Pitcher plants of the genus Nepenthes efficiently trap and retain insect prey in highly specialized leaves. Besides a slippery peristome which inhibits adhesion of insects they employ epicuticular wax crystals on the inner walls of the conductive zone of the pitchers to hamper insect attachment by adhesive devices. It has been proposed that the detachment of individual crystals and the resulting contamination of adhesive organs is responsible for capturing insects. However, our results provide evidence in favour of a different mechanism, mainly based on the stability and the roughness of the waxy surface. First, we were unable to detect a large quantity of crystal fragments on the pads of insects detached from mature pitcher surfaces of Nepenthes alata. Second, investigation of the pitcher surface by focused ion beam treatment showed that the wax crystals form a compact 3D structure. Third, atomic force microscopy of the platelet-shaped crystals revealed that the crystals are mechanically stable, rendering crystal detachment by insect pads unlikely. Fourth, the surface profile parameters of the wax layer showed striking similarities to those of polishing paper with low grain size. By measuring friction forces of insects on this artificial surface we demonstrate that microscopic roughness alone is sufficient to minimize insect attachment. A theoretical model shows that surface roughness within a certain length scale will prevent adhesion by being too rough for adhesive pads but not rough enough for claws. |
| Databáze: | OpenAIRE |
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