1
|
Hischen F, Reiswich V, Kupsch D, De Mecquenem N, Riedel M, Himmelsbach M, Weth A, Heiss E, Armbruster O, Heitz J, Baumgartner W. Adaptive camouflage: what can be learned from the wetting behaviour of the tropical flat bugs Dysodius lunatus and Dysodiusmagnus. Biol Open 2017; 6:1209-1218. [PMID: 28811303 PMCID: PMC5576082 DOI: 10.1242/bio.026070] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The neotropical flat bug species Dysodius lunatus and Dysodius magnus show a fascinating camouflage principle, as their appearance renders the animal hardly visible on the bark of trees. However, when getting wet due to rain, bark changes its colour and gets darker. In order to keep the camouflage effect, it seems that some Dysodius species benefit from their ability to hold a water film on their cuticle and therefore change their optical properties when also wetted by water. This camouflage behaviour requires the insect to have a hydrophilic surface and passive surface structures which facilitate the liquid spreading. Here we show morphological and chemical characterisations of the surface, especially the cuticular waxes of D. magnus Scanning electron microscopy revealed that the animal is covered with pillar-like microstructures which, in combination with a surprising chemical hydrophilicity of the cuticle waxes, render the bug almost superhydrophilic: water spreads immediately across the surface. We could theoretically model this behaviour assuming the effect of hemi-wicking (a state in which a droplet sits on a rough surface, partwise imbibing the structure around). Additionally the principle was abstracted and a laser-patterned polymer surface, mimicking the structure and contact angle of Dysodius wax, shows exactly the behaviour of the natural role model - immediate spreading of water and the formation of a thin continuous water film changing optical properties of the surface.
Collapse
Affiliation(s)
- Florian Hischen
- Institute of Biomedical Mechatronics, Johannes Kepler University of Linz, Altenbergerstr. 69, 4040 Linz, Austria .,Department of Cellular Neurobionics, Institute of Biology II, RWTH-Aachen University, Worringerweg 3, 52056 Aachen, Germany
| | - Vladislav Reiswich
- Department of Cellular Neurobionics, Institute of Biology II, RWTH-Aachen University, Worringerweg 3, 52056 Aachen, Germany
| | - Desirée Kupsch
- Department of Cellular Neurobionics, Institute of Biology II, RWTH-Aachen University, Worringerweg 3, 52056 Aachen, Germany
| | - Ninon De Mecquenem
- University of Bordeaux, Campus Talence, 351 Cours de la Libération, 33400 Talence, France
| | - Michael Riedel
- Department of Botany II, University of Würzburg, Julius-von-Sachs-Platz 3, D - 97082 Würzburg, Germany
| | - Markus Himmelsbach
- Institute of Analytical Chemistry, Johannes Kepler University of Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Agnes Weth
- Institute of Biomedical Mechatronics, Johannes Kepler University of Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Ernst Heiss
- Tiroler Landesmuseum, Josef-Schraffl-Straße 2a, A-6020 Innsbruck, Austria
| | - Oskar Armbruster
- Institute of Applied Physics, Johannes Kepler University of Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Johannes Heitz
- Institute of Applied Physics, Johannes Kepler University of Linz, Altenbergerstr. 69, 4040 Linz, Austria
| | - Werner Baumgartner
- Institute of Biomedical Mechatronics, Johannes Kepler University of Linz, Altenbergerstr. 69, 4040 Linz, Austria
| |
Collapse
|