Harmless nectar source or deadly trap: Nepenthes pitchers are activated by rain, condensation and nectar.

Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.68). 03/2008; 275(1632):259-65. DOI: 10.1098/rspb.2007.1402
Source: PubMed

ABSTRACT The leaves of Nepenthes pitcher plants are specialized pitfall traps which capture and digest arthropod prey. In many species, insects become trapped by 'aquaplaning' on the wet pitcher rim (peristome). Here we investigate the ecological implications of this capture mechanism in Nepenthes rafflesiana var. typica. We combine meteorological data and continuous field measurements of peristome wetness using electrical conductance with experimental assessments of the pitchers' capture efficiency. Our results demonstrate that pitchers can be highly effective traps with capture rates as high as 80% but completely ineffective at other times. These dramatic changes are due to the wetting condition of the peristome. Variation of peristome wetness and capture efficiency was perfectly synchronous, and caused by rain, condensation and nectar secreted from peristome nectaries. The presence of nectar on the peristome increased surface wetness mainly indirectly by its hygroscopic properties. Experiments confirmed that pitchers with removed peristome nectaries remained generally drier and captured prey less efficiently than untreated controls. This role of nectar in prey capture represents a novel function of plant nectar. We propose that the intermittent and unpredictable activation of Nepenthes pitcher traps facilitates ant recruitment and constitutes a strategy to maximize prey capture.

1 Bookmark
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Trichomes are a common feature of plants and perform important and diverse functions. Here, we show that the inward-pointing hairs on the inner wall of insect-trapping Heliamphora nutans pitchers are highly wettable, causing water droplets to spread rapidly across the surface. Wetting strongly enhanced the slipperiness and increased the capture rate for ants from 29 to 88 per cent. Force measurements and tarsal ablation experiments revealed that wetting affected the insects' adhesive pads but not the claws, similar to the 'aquaplaning' mechanism of (unrelated) Asian Nepenthes pitcher plants. The inward-pointing trichomes provided much higher traction when insects were pulled outwards. The wetness-dependent capture mechanisms of H. nutans and Nepenthes pitchers present a striking case of functional convergence, whereas the use of wettable trichomes constitutes a previously unknown mechanism to make plant surfaces slippery.
    Proceedings of the Royal Society B: Biological Sciences 01/2013; 280(1753):20122569. · 5.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Through evolution, nature has arrived at what is optimal. Inspired by the biomaterials with special wettability, superhydrophobic materials have been well-investigated and -covered by several excellent reviews. The construction of superoleophobicity is more difficult than that of superhydrophobicity because the surface tension of oil or other organic liquids is lower than that of water. However, superoleophobic surfaces have drawn a great deal of attention for both fundamental research and practical applications in a variety of fields. In this contribution, we focus on recent research progress in the design, fabrication, and application of bio-inspired superoleophobic and smart surfaces, including superoleophobic–superhydrophobic surfaces, oleophobic–hydrophilic surfaces, underwater superoleophobic surfaces, and smart surfaces. Although the research of bio-inspired superoleophobicity is in its infancy, it is a rapidly growing and enormously promising field. The remaining challenges and future outlook of this field are also addressed. Multifunctional integration is a inherent characteristic for biological materials. Learning from nature has long been a source of bio-inspiration for scientists and engineers. Therefore, further cross-disciplinary cooperation is essential for the construction of multifunctional advanced superoleophobic surfaces through learning the optimized biological solutions from nature. We hope this review will provide some inspirations to the researchers in the field of material science, chemistry, physics, biology, and engineering.
    Progress in Materials Science 05/2013; 58(4):503–564. · 23.19 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The review reports most of the works realized in the field of the surface wettability based on conducting polymers. The surface wettability is highly depending on the intrinsic hydrophobicity of materials and the roughness geometry. Conducting polymers have unique properties allowing to tune the surface wettability, for example, by reversibly incorporating various hydrophobic/hydrophilic doping ions, by changing the nature of the polymerizable core or by functionalization with various hydrophobic/hydrophilic substituents. Conducting polymers are obtained by monomer oxidation using various strategies such as the chemical oxidative polymerization in solution, the electrochemical polymerization on conductive substrates or the vapor-phase polymerization, leading to have an easy control of the surface morphology at micro- or a nanoscale with a surface wettability going from superhydrophilicity to superoleophobicity.
    Progress in Polymer Science 01/2014; 39:656–682. · 26.38 Impact Factor

Full-text (2 Sources)

Available from
Jun 3, 2014

Holger Bohn