Article

Insect aquaplaning: Nepenthes pitcher plants capture prey with the peristome, a fully wettable water-lubricated anisotropic surface

Zoologie II, Biozentrum, Am Hubland, 97074 Würzburg, Germany.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 10/2004; 101(39):14138-43. DOI: 10.1073/pnas.0405885101
Source: PubMed

ABSTRACT Pitcher plants of the genus Nepenthes have highly specialized leaves adapted to attract, capture, retain, and digest arthropod prey. Several mechanisms have been proposed for the capture of insects, ranging from slippery epicuticular wax crystals to downward-pointing lunate cells and alkaloid secretions that anesthetize insects. Here we report that perhaps the most important capture mechanism has thus far remained overlooked. It is based on special surface properties of the pitcher rim (peristome) and insect "aquaplaning." The peristome is characterized by a regular microstructure with radial ridges of smooth overlapping epidermal cells, which form a series of steps toward the pitcher inside. This surface is completely wettable by nectar secreted at the inner margin of the peristome and by rain water, so that homogenous liquid films cover the surface under humid weather conditions. Only when wet, the peristome surface is slippery for insects, so that most ant visitors become trapped. By measuring friction forces of weaver ants (Oecophylla smaragdina) on the peristome surface of Nepenthes bicalcarata, we demonstrate that the two factors preventing insect attachment to the peristome, i.e., water lubrication and anisotropic surface topography, are effective against different attachment structures of the insect tarsus. Peristome water films disrupt attachment only for the soft adhesive pads but not for the claws, whereas surface topography leads to anisotropic friction only for the claws but not for the adhesive pads. Experiments on Nepenthes alata show that the trapping mechanism of the peristome is also essential in Nepenthes species with waxy inner pitcher walls.

0 Bookmarks
 · 
204 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Anisotropic wetting of machined surfaces is widely applied in industries which can be greatly affected by roughness and solid's chemical properties. However, there has not been much work on it. A free-energy thermodynamic model is presented by analyzing geometry morphology of machined surfaces (2-D model surfaces), which demonstrates the influence of roughness on anisotropic wetting. It can be concluded that the energy barrier is one of the main reasons for the anisotropic wetting existing in the direction perpendicular to the lay. In addition, experiments in investigating anisotropic wetting, which was characterized by the static contact angle and droplet's distortion, were performed on machined surfaces with different roughness on hydrophilic and hydrophobic materials. The droplet's anisotropy found on machined surfaces increased with mean slope of roughness profile Kr. It indicates that roughness on anisotropic wetting on hydrophilic materials has a stronger effect than that on hydrophobic materials. Furthermore, the contact angles predicted by the model are basically consistent with the experimentally ones.
    Applied Surface Science 03/2015; 331. DOI:10.1016/j.apsusc.2014.12.071 · 2.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Inspired by natural structures, great attention has been devoted to the study and development of surfaces with extreme wettable properties. The meticulous study of natural systems revealed that the micro/nano-topography of the surface is critical to obtaining unique wettability features, including superhydrophobicity. However, the surface chemistry also has an important role in such surface characteristics. As the interaction of biomaterials with the biological milieu occurs at the surface of the materials, it is expected that synthetic substrates with extreme and controllable wettability ranging from superhydrophilic to superhydrophobic regimes could bring about the possibility of new investigations of cell-material interactions on nonconventional surfaces and the development of alternative devices with biomedical utility. This first part of the review will describe in detail how proteins and cells interact with micro/nano-structured surfaces exhibiting extreme wettabilities.
    Nanomedicine 01/2015; 10(1):103-19. DOI:10.2217/nnm.14.174 · 5.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pitchers plants of Nepenthes specie growing in infertile habitats have developed highly specialized apparatus for trapping and digesting arthropods to obtain sufficient growing nutrients. Nepenthes pitchers are generally recognized by several distinguishably morphological zones, and different districts exhibit distinct functions in prey capturing, combined effect of the several zones results in great trapping efficiency. This prey ability of Nepenthes pitchers potentially inspires an idea for biomimetic development of slippery trapping plate used in controlling agricultural pests, especially plague locust. In this paper, we reviewed the recent researches of Nepenthes pitchers, including surface structures, physical properties, and anti-attachment functions. Apart from this, combined with our latest studies on mechanical controlling plague locust, the potential application of Nepenthes pitchers as establishing biomimetic models utilized in creating trapping plate was addressed, and several corresponding aspects requiring to be paid attention to in near future were also highlighted.
    Chinese Science Bulletin 07/2014; 59(21):2513-2523. DOI:10.1007/s11434-014-0383-6 · 1.37 Impact Factor

Full-text (2 Sources)

Download
50 Downloads
Available from
May 27, 2014

Holger Bohn