1. Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, D-24118 Kiel, Germany
2. Dipartimento di Meccanica-Matematica-Management DMMM, Campus, Via Orabona 4, 70125 Bari, Italy
3. Plant Biomechanics Group, Botanic Garden, Faculty of Biology, University of Freiburg, Schänzlestraße 1, D-79104 Freiburg, Germany
4. Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Golm, Germany