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Older nymphs and adults of Paulinia are larger than Salvinia leaves and develop a somatolytic pattern: the animal is optically divided into two portions by the dark wink rudiments mimicing two. Salvinia leaves with the dark water surface between the leaves.
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Context 1
... solitary ventral leaf is deeply sub- merged, strongly divided and overtakes the function of roots. The floating two dorsal leaves are entire, simple and visible on the water surface (Figs. 1, 2). The floating leaves are covered by dense multicellular hairs and epicuticular waxes which cause an extreme water repellency (Figs. 3, 4). ...
Context 2
... and biology of P. acuminata While the younger nymphal stages of P. acuminata are smaller than leaves of Salvinia and possess the same green coloration (Fig. I), later stages are clearly larger than the 0.5 cm long and 0.3 cm broad leaves (Fig. 2). However, even the older animals are difficult to detect because they now posess dark wing rudiments which can be confused with gaps between the Salvinia leaves ( Fig. 2). This somatolytic effect is strengthened by an extraordinary slow movement of the grasshoppers. P. acuminata is sedentary and stays on its food plant for long periods ...
Context 3
... of P. acuminata are smaller than leaves of Salvinia and possess the same green coloration (Fig. I), later stages are clearly larger than the 0.5 cm long and 0.3 cm broad leaves (Fig. 2). However, even the older animals are difficult to detect because they now posess dark wing rudiments which can be confused with gaps between the Salvinia leaves ( Fig. 2). This somatolytic effect is strengthened by an extraordinary slow movement of the grasshoppers. P. acuminata is sedentary and stays on its food plant for long periods of time. Especially nymphs jump off only after strong irritation and evidently rely on their mimetic coloration as an efficient anti-predator defence which explains the ...
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Citations
... The floating water fern Salvinia has hierarchical architectures dominated by elastic eggbeater-shaped hairs, which has a long-term air retention effect (Figure 5d). These hairs are about 300 to 2200 μm in height, and they are covered with hydrophobic nanoscopic wax crystals appearing as thin rodlets perpendicular to the surface [63][64][65][66]. However, the terminal cells of the hair are not covered with wax crystals, but form hydrophilic tips. ...
In recent years, various biomimetic materials capable of forming gaseous plastron on their surfaces have been fabricated and widely used in various disciplines and fields. In particular, on submerged surfaces, gaseous plastron has been widely studied for antifouling applications due to its ecological and economic advantages. Gaseous plastron can be formed on the surfaces of various natural living things, including plants, insects, and animals. Gaseous plastron has shown inherent anti-biofouling properties, which has inspired the development of novel theories and strategies toward resisting biofouling formation on different surfaces. In this review, we focused on the research progress of gaseous plastron and its antifouling applications.
... Ein Beispiel eines solchen bionischen Übertrags ist die Fähigkeit einiger wasserlebender Tiere und Pflanzen, eine Luftschicht an ihrer Oberfläche zu halten, wenn sie unter Wasser getaucht werden ). In der Natur dient diese Fähigkeit mehreren Funktionen, sei es Atmen unter Wasser, Reibungsreduktion oder Auftrieb (Barthlott et al. 1994, Bhushan 2012) -aufweisen. Notonecta und Salvinia molesta erwiesen sich als optimale Untersuchungsobjekte (Bild 1) im Rahmen des BIONA-Projekts "Luft haltende Schiffsbeschichtungen nach biologischem Vorbild zur Reibungsreduktion", das in den Jahren 2008 -2012 am Nees-Institut der Universität Bonn und dem Lehrstuhl für Strömungsmechanik der Universität Rostock durch-geführt wurde. ...
Die Natur als Vorbild. Bioniker, Biologen,Technologen, Künstler, Philosophen, Entrepreneure, Architekten und Gestalter zeigen, was sie von der Natur lernen, wie sie ihren Geheimnissen auf die Spur kommen und letztlich als Inspiration für eigene Innovationen nutzen.
... Unfortunately biology and ecology of these aquatic species are mainly unknown. However the semi-aquatic grasshopper Paulinia acuminata and its food plant Salvinia auricularia exhibit mimicry and ultrastructural analogy in order to achieve water-repellent surfaces (Barthlott et al. 1994). Generally among Orthoptera a lot of primary and secondary defensive mechanisms such as crypsis, aposematism, jumping, biting, flight, stridulation, or autotomy are realized (Dettner 2015). ...
This chapter compiles active and passive defensive mechanisms of aquatic and semiaquatic developmental stages of all insect orders against various predators. Mainly escape reactions, mechanical defense, defensive stridulation, and especially chemical defenses are described, illustrated, and tabulated. Apart from the large aquatic groups of ephemeropteran, Odonata or Trichoptera larvae especially aquatic bugs and water beetles are considered by even including small groups from Collembola up to Mecoptera. Differences between defensive mechanisms and strategies in aquatic and terrestrial insects are described. Aquatic insects especially rely on escape, mechanical defenses, defensive stridulation, and chemical defenses. Exocrine glands are mainly restricted to large taxa with both terrestrial and aquatic representatives (adephagan beetles, Heteroptera) and not invented in aquatic groups. Chemically aquatic insects especially evolved biosynthesis of aromatic and few aliphatic compounds against microorganisms. In contrast mainly steroids are targeted against cold-blooded vertebrates such as fishes and amphibians. As compared with terrestrial insects, aquatic representatives lack many mechanisms of defense such as reflex bleeding, incorporation of toxic compounds from plants, freshwater animals, or microorganisms. Exocrine secretions of water insects are usually externalized by secretion grooming in order to receive a clean body surface, to achieve an optimal breathing, and to modify the wettability of the body surface. Generally there exists a considerable lack of knowledge concerning bionomy and especially defenses of aquatic insects.
... Floating species like Salvinia or Pistia are usually superhydrophobic. A striking example is illustrated in Fig. 23b: the grasshopper Paulinia acuminate feeds exclusively on Salvinia and optical mimics its color and surface (camouflage)-but it also is superhydrophobic based on wax crystals, the same adaption to its semiaquatic habitat as its host plant [1,127]. ...
An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion years biological species evolved highly complex multifunctional surfaces for interacting with their environments: some 10 million living prototypes (i.e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structures and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step with the invasion of terrestrial habitats some 350–450 million years ago in plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it the biological role models. Plants, the dominating group of organisms on our planet, are sessile organisms with large multifunctional surfaces and thus exhibit particular intriguing features. Superhydrophilicity and superhydrophobicity are focal points in this work. We estimate that superhydrophobic plant leaves (e.g., grasses) comprise in total an area of around 250 million km², which is about 50% of the total surface of our planet. A survey of structures and functions based on own examinations of almost 20,000 species is provided, for further references we refer to Barthlott et al. (Philos. Trans. R. Soc. A 374: 20160191, 1). A basic difference exists between aquatic non-vascular and land-living vascular plants; the latter exhibit a particular intriguing surface chemistry and architecture. The diversity of features is described in detail according to their hierarchical structural order. The first underlying and essential feature is the polymer cuticle superimposed by epicuticular wax and the curvature of single cells up to complex multicellular structures. A descriptive terminology for this diversity is provided. Simplified, the functions of plant surface characteristics may be grouped into six categories: (1) mechanical properties, (2) influence on reflection and absorption of spectral radiation, (3) reduction of water loss or increase of water uptake, moisture harvesting, (4) adhesion and non-adhesion (lotus effect, insect trapping), (5) drag and turbulence increase, or (6) air retention under water for drag reduction or gas exchange (Salvinia effect). This list is far from complete. A short overview of the history of bionics and the impressive spectrum of existing and anticipated biomimetic applications are provided. The major challenge for engineers and materials scientists, the durability of the fragile nanocoatings, is also discussed.
... We expect the majority of 'bionic products' currently on the market are in fact parabionic: Bionics is purely a marketing tool. Sources: (a) from [17] and (b) photo taken from the package bought in a department store. (Online version in colour.) ...
... Mimicry is well defined and discussed in biology since its introduction into science in 1862 and means the imitation of a biological role model ('living prototype' of bionics) by another species, but with a different function. An intriguing example is illustrated in figure 8: the leafhopper (Paulinia acuminata) imitates the protective coloration and surface appearance of its host plant Salvinia: a phenomenon called camouflage, a form of mimicry, to deceive predators [17]. Mimicry (in this case, camouflage) is just the opposite of what bionics is meant to be-mimicry is per definition the story of cheats and deceits. ...
A comprehensive survey of the construction principles and occurrences of superhydrophobic surfaces in plants, animals and other organisms is provided and is based on our own scanning electron microscopic examinations of almost 20 000 different species and the existing literature. Properties such as self-cleaning (lotus effect), fluid drag reduction (Salvinia effect) and the introduction of new functions (air layers as sensory systems) are described and biomimetic applications are discussed: self-cleaning is established, drag reduction becomes increasingly important, and novel air-retaining grid technology is introduced. Surprisingly, no evidence for lasting superhydrophobicity in non-biological surfaces exists (except technical materials). Phylogenetic trees indicate that superhydrophobicity evolved as a consequence of the conquest of land about 450 million years ago and may be a key innovation in the evolution of terrestrial life. The approximate 10 million extant species exhibit a stunning diversity of materials and structures, many of which are formed by self-assembly, and are solely based on a limited number of molecules. A short historical survey shows that bionics (today often called biomimetics) dates back more than 100 years. Statistical data illustrate that the interest in biomimetic surfaces is much younger still. Superhydrophobicity caught the attention of scientists only after the extreme superhydrophobicity of lotus leaves was published in 1997. Regrettably, parabionic products play an increasing role in marketing.
This article is part of the themed issue ‘Bioinspired hierarchically structured surfaces for green science’.
... Ein Beispiel eines solchen bionischen Übertrags ist die Fähigkeit einiger wasserlebender Tiere und Pflanzen, eine Luftschicht an ihrer Oberfläche zu halten, wenn sie unter Wasser getaucht werden ). In der Natur dient diese Fähigkeit mehreren Funktionen, sei es Atmen unter Wasser, Reibungsreduktion oder Auftrieb (Barthlott et al. 1994, Bhushan 2012) -aufweisen. Notonecta und Salvinia molesta erwiesen sich als optimale Untersuchungsobjekte (Bild 1) im Rahmen des BIONA-Projekts "Luft haltende Schiffsbeschichtungen nach biologischem Vorbild zur Reibungsreduktion", das in den Jahren 2008 -2012 am Nees-Institut der Universität Bonn und dem Lehrstuhl für Strömungsmechanik der Universität Rostock durch-geführt wurde. ...
... These hairs with heights between approximately 300 and 2200 mm cover the major part of the upper side of the leaf (Fig. 1). Both the hairs and the remaining cell surface are hydrophobically covered with waxes in the shape of thin rodlets perpendicular to the surface (Barthlott and Wollenweber 1981;Barthlott et al. 1994Barthlott et al. , 2009Barthlott et al. , 2010. As a special characteristic of Salvinia molesta, the topmost cells of its hairs lack the wax cover and are thereby hydrophilic whereas the remaining part is hydrophobic. ...
Superhydrophobic, hierarchically structured, technical surfaces (Lotus-effect) are of high scientific and economic interest because of their remarkable properties. Recently, the immense potential of air-retaining superhydrophobic surfaces, for example, for low-friction transport of fluids and drag-reducing coatings of ships has begun to be explored. A major problem of superhydrophobic surfaces mimicking the Lotus-effect is the limited persistence of the air retained, especially under rough conditions of flow. However, there are a variety of floating or diving plant and animal species that possess air-retaining surfaces optimized for durable water-repellency (Salvinia-effect). Especially floating ferns of the genus Salvinia have evolved superhydrophobic surfaces capable of maintaining layers of air for months. Apart from maintaining stability under water, the layer of air has to withstand the stresses of water pressure (up to 2.5 bars). Both of these aspects have an application to create permanent air layers on ships' hulls. We investigated the effect of pressure on air layers in a pressure cell and exposed the air layer to pressures of up to 6 bars. We investigated the suppression of the air layer at increasing pressures as well as its restoration during decreases in pressure. Three of the four examined Salvinia species are capable of maintaining air layers at pressures relevant to the conditions applying to ships' hulls. High volumes of air per surface area are advantageous for retaining at least a partial Cassie-Baxter-state under pressure, which also helps in restoring the air layer after depressurization. Closed-loop structures such as the baskets at the top of the "egg-beater hairs" (see main text) also help return the air layer to its original level at the tip of the hairs by trapping air bubbles.
... These multi-cellular hairs on the upper (adaxial) side of the leaves form complex hierarchical surface structures which are able to retain an air layer at the surface, even when leaves were fixed under water for several days [167,41]. The hairs have the shape of tiny crowns (Fig. 17b-d), and in SEM, small wax rodlets on the epidermis cells and hairs ( Fig. 17e and f) are visible [16]. ...
... These four hairs can either be unconnected (apically open) (e.g., Salvinia natans and Salvinia minima), or connected, forming eggbeater or crownlike structures (e.g., Salvinia auriculata and Salvinia molesta). Trichome sizes of different species range from 200 lm (S. oblongifolia) to 800 lm (S. minima), and earlier SEM examinations of Salvinia revealed these plants to have very small rodlet-shaped waxes on their surfaces (Fig. 20f) [16]. The combination of trichomes and waxes make the surfaces of Salvinia superhydrophobic and has a positive effect on their buoyancy through maintaining an air film when leaves are underwater. ...
The surfaces of plants represent multifunctional interfaces between the organisms and their biotic
(living) and the nonbiotic solid, liquid, and gaseous environment. The diversity of plant surface structures has evolved over several hundred million years of evolution. Evolutionary processes have led to a large variety of functional plant surfaces which exhibit, for example, superhydrophobicity, self-cleaning, superhydrophilicity, and reduction of adhesion and light reflection. The primary surface of nearly all parts of land plants is the epidermis. The outer part of epidermal cells is an extracellular membrane called the cuticle. The cuticle, with its associated waxes, is a stabilization element, has a barrier function, and is responsible for various kinds of surface structuring by cuticular folding or deposition of three-dimensional wax crystals on the cuticle. Surface properties, such as superhydrophobicity, self-cleaning, reduction of adhesion and light reflection, and absorption of harmful ultraviolet (UV) radiation, are based on the existence of three-dimensional waxes. Waxes form different morphologies, such as tubules, platelets or rodlets, by self-assembly. The ability of plant waxes to self-assemble into three-dimensional nanostructures can be used to create hierarchical roughness of various kinds of surfaces. The structures and principles which nature uses to develop functional surfaces are of special interest in biomimetics. Hierarchical structures play a key role in surface wetting and are discussed in the context of superhydrophobic and self-cleaning plants and for the development of biomimetic surfaces. Superhydrophobic biomimetic surfaces are introduced and their use for self-cleaning or development of air-retaining surfaces, for, e.g.,
drag reduction at surfaces moving in water, are discussed. This chapter presents an overview of plant structures, combines the structural basis of plant surfaces with their functions, and introduces
existing biomimetic superhydrophobic surfaces and their fabrication.
... The adaxial sides of the floating leaves are densely covered with peculiar trichomes, and their surfaces are extremely water repellent (Zawidzki 1911;Ziegenspeck 1942;Kaul 1976; Barthlott et al. 1994). The adaxial leaf surface is also covered by an extremely fine layer of epicuticular waxes (Barthlott and Wollenweber 1981;Barthlott et al. 1994). ...
... The adaxial sides of the floating leaves are densely covered with peculiar trichomes, and their surfaces are extremely water repellent (Zawidzki 1911;Ziegenspeck 1942;Kaul 1976; Barthlott et al. 1994). The adaxial leaf surface is also covered by an extremely fine layer of epicuticular waxes (Barthlott and Wollenweber 1981;Barthlott et al. 1994). The leaf architecture and hydrophobic wax coverage enables Salvinia to retain an air film when submersed in water for up to 17 d for some species (Zawidzki 1911;Ziegenspeck 1942;Kaul 1976; Barthlott et al. 1994;Cerman et al. 2009), and in some species up to 60 d (W. ...
... The adaxial leaf surface is also covered by an extremely fine layer of epicuticular waxes (Barthlott and Wollenweber 1981;Barthlott et al. 1994). The leaf architecture and hydrophobic wax coverage enables Salvinia to retain an air film when submersed in water for up to 17 d for some species (Zawidzki 1911;Ziegenspeck 1942;Kaul 1976; Barthlott et al. 1994;Cerman et al. 2009), and in some species up to 60 d (W. Barthlott, unpublished data). ...
Species of the water fern Salvinia are well known for their extremely water-repellent floating leaves. The architecture of Salvinia surfaces is of great interest for biomimetic applications, because submersed in water, they retain air films for a long period. Knowledge of these surfaces is also important for pest control, since one species (Salvinia molesta D.S. Mitch.) is a pantropic invasive aquatic weed. The micromorphology of the leaf surfaces of six representative species has been characterized by scanning electron microscopy. Based on their morphology, the trichomes are classified in four types, named after the typical species. Among the species examined, numbers, distribution, and sizes of the trichome types vary significantly. The simplest types, the Cucullata trichomes, are multicellular, uniseriate, and up to 800 mu m high. Groups of two multicellular, uniseriate trichomes are described as the Oblongifolia trichomes. The Natans trichomes are grouped as four multicellular, uniseriate trichomes. The Molesta trichomes are composed of four trichomes, which are connected by the second last apical cells of the trichome. The ontogeny of the Molesta trichome groups was puzzling and resulted in various names being applied to them ("Kronchenhaare," "egg-beater," or "coroniform" hairs). Their unique development from four solitary uniseriate trichomes to groups of four connected trichomes is described in detail.
... These multi-cellular hairs on the upper (adaxial) side of the leaves form complex hierarchical surface structures which are able to retain an air layer at the surface, even when leaves were fixed under water for several days [167,41]. The hairs have the shape of tiny crowns (Fig. 17b-d), and in SEM, small wax rodlets on the epidermis cells and hairs ( Fig. 17e and f) are visible [16]. ...
... These four hairs can either be unconnected (apically open) (e.g., Salvinia natans and Salvinia minima), or connected, forming eggbeater or crownlike structures (e.g., Salvinia auriculata and Salvinia molesta). Trichome sizes of different species range from 200 lm (S. oblongifolia) to 800 lm (S. minima), and earlier SEM examinations of Salvinia revealed these plants to have very small rodlet-shaped waxes on their surfaces (Fig. 20f) [16]. The combination of trichomes and waxes make the surfaces of Salvinia superhydrophobic and has a positive effect on their buoyancy through maintaining an air film when leaves are underwater. ...
Biological surfaces provide multifunctional interfaces to their environment. More than 400 million years of land plants evolution led to a large diversity of functional biological surface structures. This article provides an overview of the most frequently functional surface structures of plants. It focuses on functional adaptations of plant surface structures to environmental conditions. The structural and functional relationships of plants growing in deserts, water and wetlands are discussed. The article is written for both biologists and non-biologists and should stimulate the readers to initiate or intensify the study of functional biological surfaces and their potential for technical use, leading to, so called, biomimetic inspired smart surfaces. For a broader understanding of the structural diversity in plants, the origin of surface structuring is introduced from the sub-cellular level up to multi-cellular structures. Functional aspects of plant surface structures include the reduction of particle adhesion and the self-cleaning properties in the Lotus (Nelumbo nucifera) leaves. These surface properties are based on physico-chemical principles and can be transferred into technical “biomimetic” materials, as successfully done for the Lotus leaves. In plants, several other functional structures, e.g., for the absorption of water or light reflection, exist. Some, which might be useful models for the development of functional materials, are introduced here and some existing technical applications and fabrication techniques for the generation of biomimetic surfaces are discussed.
