Biological microtribology: anisotropy in frictional forces of orthopteran attachment pads reflects the ultrastructure of a highly deformable material

Gorb, Stanislav N.; Scherge, Matthias

doi:10.1098/rspb.2000.1133

Cited by 137 publications

(100 citation statements)

References 23 publications

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“…1. Although inspired by biological setal adhesion, it is distinct from any that we are aware of in nature, although the geometry of the setal system found in the insect Tettigonia viridissima is quite similar (31)(32)(33).…”

Section: Resultsmentioning

confidence: 99%

Biologically inspired crack trapping for enhanced adhesion

Glassmaker

Jagota

Hui

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

245

270

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We present a synthetic adaptation of the fibrillar adhesion surfaces found in nature. The structure consists of protruding fibrils topped by a thin plate and shows an experimentally measured enhancement in adhesion energy of up to a factor of 9 over a flat control. Additionally, this structure solves the robustness problems of previous mimic structures and has preferred contact properties (i.e., a large surface area and a highly compliant structure). We show that this geometry enhances adhesion because of its ability to trap interfacial cracks in highly compliant contact regimes between successive fibril detachments. This results in the requirement that the externally supplied energy release rate for interfacial separation be greater than the intrinsic work of adhesion, in a manner analogous to lattice trapping of cracks in crystalline solids.interface ͉ fracture ͉ fibrillar ͉ lattice trapping ͉ biomechanics T he ability to adhere two surfaces strongly together and then reversibly separate them, repeatedly, is a desirable capability that is rarely achievable using conventional fabrication techniques and materials. Nevertheless, fibrillar surfaces with these properties have evolved in nature on the adhesive surfaces of the feet of many lizards and insects. With such natural surfaces as inspiration, we have developed a fibrillar structure that produces a robust, reusable material with strongly enhanced adhesion compared with a flat control of the same material, with the enhancement resulting only from the modification of surface geometry.The essential feature that our surfaces borrow from biology is the seta, a hair-like bristle having a diameter of 0.5-10 m and terminating in one or more flattened, expanded tips (''spatulas'') at its contacting end. A number of biological studies (1-16) have found that arrays of setae are a common feature on the adhesion surfaces of many lizards and insects. In the biological literature, the shape, dimensions, and composition of setae from various species are described (1-5, 9-16). Also, the mechanical properties and adhesion force of a single gecko seta (7) and even a single spatula (17,18) were the subjects of recent investigations. An important conclusion to emerge from these two studies is that setal arrays use noncovalent surface forces to achieve adhesion, and evidence suggests that geckos rely primarily on van der Waals and capillary forces (8, 18). As a result, the surface architecture is the primary design variable that has been adjusted in biological systems by evolution.Because of the extraordinary adhesion ability of animals that possess setal arrays, several researchers have recently made an effort to mimic the biological setal geometry by using synthetic materials (19)(20)(21)(22)(23)(24)(25)(26). It has been established theoretically that a fibrillar interface can increase both strength and interfacial toughness, compared with a flat control (21, 27-30). However, simple arrays of micropillars (19-21) have not exhibited stronger adhesion than flat control surfaces o...

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Section: Resultsmentioning

confidence: 99%

Biologically inspired crack trapping for enhanced adhesion

Glassmaker

Jagota

Hui

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

245

270

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“…in flies [3] and beetles [4]. Smooth pads can be encountered, for example, in adult representatives of Hymenoptera [5], Hemiptera [6], Lepidoptera [7] and Orthoptera [8,9]. Like hairy pads they are supported by adhesion-mediating fluid, and use the combined effect of van der Waals forces, capillarity and friction in their functioning, but their surface structure is composed of a very thin and easily deformable cuticle underlain by thin filaments instead of individual setae [10].…”

Section: Introductionmentioning

confidence: 99%

Locomotion and attachment of leaf beetle larvaeGastrophysa viridula(Coleoptera, Chrysomelidae)

2015

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While adult green dock leaf beetles Gastrophysa viridula use tarsal adhesive setae to attach to and walk on smooth vertical surfaces and ceilings, larvae apply different devices for similar purposes: pretarsal adhesive pads on thoracic legs and a retractable pygopod at the 10th abdominal segment. Both are soft smooth structures and capable of wet adhesion. We studied attachment ability of different larval instars, considering the relationship between body weight and real contact area between attachment devices and the substrate. Larval gait patterns were analysed using high-speed video recordings. Instead of the tripod gait of adults, larvae walked by swinging contralateral legs simultaneously while adhering by the pygopod. Attachment ability of larval instars was measured by centrifugation on a spinning drum, revealing that attachment force decreases relative to weight. Contributions of different attachment devices to total attachment ability were investigated by selective disabling of organs by covering them with melted wax. Despite their smaller overall contact area, tarsal pads contributed to a larger extent to total attachment ability, probably because of their distributed spacing. Furthermore, we observed different behaviour in adults and larvae when centrifuged: while adults gradually slipped outward on the centrifuge drum surface, larvae stayed at the initial position until sudden detachment.

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“…Moreover, Tettigoniidae move fast, and the palm fronds are often wet from tropical rain. In the attachment pads the exocuticle is absent (Gorb & Scherge 2000). This would enable the ¢rst-instar larva to enter the host tettigoniid more quickly at this point than at any other point on the body.…”

Section: Resultsmentioning

confidence: 99%

“…The unique structure of the attachment pads (euplantulae) of the bush cricket, Tettigonia viridissima (Orthoptera: Tettigoniidae), was described by Gorb & Scherge (2000). As in all other Tettigoniidae, there are four euplantulae in each tarsus, the terminal one being the largest.…”

Section: Resultsmentioning

confidence: 99%

Stand tall and they still get you in your Achilles foot-pad

Kathirithamby¹

2001

Proc. R. Soc. Lond. B

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The free-living ¢rst-instar larvae of Strepsiptera (Insecta) are the infective stage of the parasitoid. They normally enter the host via the abdominal cuticle, and there have also been reports of entry via the egg of the host. The ¢rst-instar larvae of Stichotrema dallatorreanum Hofeneder in Papua New Guinea were found to enter the host orthopteran via the tarsi. This is, to my knowledge, the ¢rst report of entry of ¢rst-instar larvae of Strepsiptera via the attachment pads (euplantulae) of the host.

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Biological microtribology: anisotropy in frictional forces of orthopteran attachment pads reflects the ultrastructure of a highly deformable material

Cited by 137 publications

References 23 publications

Biologically inspired crack trapping for enhanced adhesion

Biologically inspired crack trapping for enhanced adhesion

Locomotion and attachment of leaf beetle larvaeGastrophysa viridula(Coleoptera, Chrysomelidae)

Stand tall and they still get you in your Achilles foot-pad

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