Functional morphology of tarsal adhesive pads and attachment ability in ticksIxodes ricinus(Arachnida, Acari, Ixodidae)

Dagmar Voigt; Stanislav Gorb

doi:10.1242/jeb.152942

Insect wet steps: loss of fluid from insect feet adhering to a substrate

Journal of The Royal Society Interface ◽

10.1098/rsif.2012.0639 ◽

2013 ◽

Vol 10 (78) ◽

pp. 20120639 ◽

Cited By ~ 11

Author(s):

Alexander E. Kovalev ◽

Alexander E. Filippov ◽

Stanislav N. Gorb

Keyword(s):

Surface Roughness ◽

Fluid Flows ◽

Solid Substrate ◽

Fluid Loss ◽

Adhesion Forces ◽

Roughness Parameters ◽

Fluid Absorption ◽

Remarkable Effect ◽

Adhesive Pads ◽

Attachment Ability

Reliable attachment ability of insect adhesive pads is proposed to be due to pad secretion. It has been shown that surface roughness strongly reduces adhesion forces of insect pads. This effect has been explained by decreased contact area and rapid fluid absorption from the pad surface by rough surfaces. However, it remains unclear how the fluid flows on rough substrates having different roughness parameters and surface energy. In this paper, we numerically studied the fluid flow on rough substrates during contact formation. The results demonstrate that an increase in the density of the substrate structures leads to an increase in fluid loss from the pad: substrates with a fine roughness absorb pad fluid faster. Decreased affinity of the solid substrate to the fluid has a more remarkable effect on the fluid loss and leads to a decrease in the fluid loss. With an increase in the aspect ratio of the substrate irregularities (porosity), the fluid loss is decreased. The numerical results obtained agree well with previous observations on insects and experimental results on nanoporous substrata. The significance of the obtained results for understanding biological wet adhesives is discussed.

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The same but different: setal arrays of anoles and geckos indicate alternative approaches to achieving similar adhesive effectiveness

10.1101/2020.11.03.366864 ◽

2020 ◽

Author(s):

Austin M. Garner ◽

Michael C. Wilson ◽

Caitlin Wright ◽

Anthony P. Russell ◽

Peter H. Niewiarowski ◽

...

Keyword(s):

Functional Morphology ◽

Empirical Work ◽

Field Configuration ◽

Clinal Variation ◽

Adhesive Systems ◽

Adhesive Pads ◽

The Difference ◽

Biological Adhesive ◽

Pattern Of Variation ◽

Adhesive Performance

AbstractThe functional morphology of squamate fibrillar adhesive systems has been extensively investigated and has indirectly and directly influenced the design of synthetic counterparts. Not surprisingly, the structure and geometry of exemplar fibrils (setae) have been the subject of the bulk of the attention in such research, although variation in setal morphology along the length of subdigital adhesive pads has been implicated in the effective functioning of these systems. Adhesive setal field configuration has been described for several geckos, but that of the convergent Anolis lizards, comprised of morphologically simpler fibrils, remains largely unexplored. Here we examine setal morphology along the proximodistal axis of the digits of Anolis equestris and compare our findings to those for a model gecko, Gekko gecko. Consistent with previous work, we found that the setae of A. equestris are generally thinner, shorter, and present at higher densities than those of G. gecko and terminate in a single spatulate tip. Contrastingly, the setae of G. gecko are hierarchically branched in structure and carry hundreds of spatulate tips. Although the splitting of contacts into multiple smaller tips is predicted to increase the adhesive performance of a fiber compared to an unbranched one, we posited that the adhesive performance of G. gecko and A. equestris would be relatively similar when the configuration of the setal fields of each was accounted for. We found that, as in geckos, setal morphology of A. equestris follows a predictable pattern along the proximodistal axis of the pad, although there are several critical differences in the configuration of the setal fields of these two groups. Most notably, the pattern of variation in setal length of A. equestris is effectively opposite to that exhibited by G. gecko. This difference in clinal variation mirrors the difference in the direction in which the setal fields of anoles and geckos are peeled from the substrate, consistent with the hypothesis that biomechanical factors are the chief determinants of these patterns of variation. Future empirical work, however, is needed to validate this. Our findings introduce Anolis lizards as an additional source of inspiration for bio-inspired design and set the stage for comparative studies investigating the functional morphology of these convergent adhesive apparatuses. Such investigations will lead to an enhanced understanding of the interactions between form, function, and environment of fibril-based biological adhesive systems.

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The synergy between the insect-inspired claws and adhesive pads increases the attachment ability on various rough surfaces

Scientific Reports ◽

10.1038/srep26219 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 31

Author(s):

Yi Song ◽

Zhendong Dai ◽

Zhouyi Wang ◽

Aihong Ji ◽

Stanislav N. Gorb

Keyword(s):

Rough Surfaces ◽

Adhesive Pads ◽

Attachment Ability

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Porous substrate affects a subsequent attachment ability of the beetle Harmonia axyridis (Coleoptera, Coccinellidae)

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0696 ◽

2019 ◽

Vol 16 (150) ◽

pp. 20180696 ◽

Cited By ~ 3

Author(s):

Elena V. Gorb ◽

Wiebke Lemke ◽

Stanislav N. Gorb

Keyword(s):

Recovery Time ◽

Harmonia Axyridis ◽

Plant Protection ◽

Porous Membrane ◽

Porous Substrate ◽

Porous Sample ◽

Significant Difference ◽

Adhesive Pads ◽

Attachment Ability ◽

Insect Attachment

According to literature data, porous substrates can cause a reduction of insect attachment ability. We carried out traction experiments with adult ladybird beetles Harmonia axyridis on the smooth solid glass sample and rough porous Al 2 O 3 membrane to prove the primary effect of absorption of the insect pad secretion by porous media, rather than surface roughness, on the attachment force on the porous sample. With each insect individual, a set of five experiments was conducted: (1) on glass; (2) on the porous membrane; (3–5) on glass immediately after the test on the porous surface, then after 30 min and 1 h of recovery time. On the porous substrate, the forces, being similar in females and males, were greatly reduced compared to those measured on glass. A significant difference between the force values obtained in the first (before the test on the porous sample) and second (immediately after the experiment on the porous sample) tests on glass was observed. After 30 min recovery time, beetles completely regained their attachment ability. Females produced significantly lower forces than males in all experiments on glass: the differences are probably caused by the sexual dimorphism in the microstructure of their adhesive pads. The obtained results are of fundamental importance for further application in biomimetics of novel insect-repelling surfaces and in plant protection by using porous materials.

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Insect attachment on crystalline bioinspired wax surfaces formed by alkanes of varying chain lengths

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.5.116 ◽

2014 ◽

Vol 5 ◽

pp. 1031-1041 ◽

Cited By ~ 10

Author(s):

Elena Gorb ◽

Sandro Böhm ◽

Nadine Jacky ◽

Louis-Philippe Maier ◽

Kirstin Dening ◽

...

Keyword(s):

Surface Roughness ◽

Experimental Studies ◽

Three Dimensional ◽

Coccinella Septempunctata ◽

Fold Reduction ◽

Adhesive Pads ◽

Highly Hydrophobic ◽

Chain Lengths ◽

Attachment Ability ◽

Insect Attachment

The impeding effect of plant surfaces covered with three-dimensional wax on attachment and locomotion of insects has been shown previously in numerous experimental studies. The aim of this study was to examine the effect of different parameters of crystalline wax coverage on insect attachment. We performed traction experiments with the beetle Coccinella septempunctata and pull-off force measurements with artificial adhesive systems (tacky polydimethylsiloxane semi-spheres) on bioinspired wax surfaces formed by four alkanes of varying chain lengths (C36H74, C40H82, C44H90, and C50H102). All these highly hydrophobic coatings were composed of crystals having similar morphologies but differing in size and distribution/density, and exhibited different surface roughness. The crystal size (length and thickness) decreased with an increase of the chain length of the alkanes that formed these surfaces, whereas the density of the wax coverage, as well as the surface roughness, showed an opposite relationship. Traction tests demonstrated a significant, up to 30 fold, reduction of insect attachment forces on the wax surfaces when compared with the reference glass sample. Attachment of the beetles to the wax substrates probably relied solely on the performance of adhesive pads. We found no influence of the wax coatings on the subsequent attachment ability of beetles. The obtained data are explained by the reduction of the real contact between the setal tips of the insect adhesive pads and the wax surfaces due to the micro- and nanoscopic roughness introduced by wax crystals. Experiments with polydimethylsiloxane semi-spheres showed much higher forces on wax samples when compared to insect attachment forces measured on these surfaces. We explain these results by the differences in material properties between polydimethylsiloxane probes and tenent setae of C. septempunctata beetles. Among wax surfaces, force experiments showed stronger insect attachment and higher pull-off forces of polydimethylsiloxane probes on wax surfaces having a higher density of wax coverage, created by smaller crystals.

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Functional significance of preserved color patterns of mollusks from the Gosport Sand (Eocene) of Alabama

Journal of Paleontology ◽

10.1017/s0022336000058911 ◽

1988 ◽

Vol 62 (01) ◽

pp. 83-87 ◽

Cited By ~ 4

Author(s):

Patricia H. Kelley ◽

Charles T. Swann

Keyword(s):

Functional Morphology ◽

Functional Significance ◽

Intraspecific Variability ◽

Color Pattern ◽

Color Patterns ◽

Historical Factors ◽

Life Mode ◽

Molluscan Fauna ◽

Excellent Preservation ◽

Architectural Constraints

The excellent preservation of the molluscan fauna from the Gosport Sand (Eocene) at Little Stave Creek, Alabama, has made it possible to describe the preserved color patterns of 15 species. In this study the functional significance of these color patterns is tested in the context of the current adaptationist controversy. The pigment of the color pattern is thought to be a result of metabolic waste disposal. Therefore, the presence of the pigment is functional, although the patterns formed by the pigment may or may not have been adaptive. In this investigation the criteria proposed by Seilacher (1972) for testing the functionality of color patterns were applied to the Gosport fauna and the results compared with life mode as interpreted from knowledge of extant relatives and functional morphology. Using Seilacher's criteria of little ontogenetic and intraspecific variability, the color patterns appear to have been functional. However, the functional morphology studies indicate an infaunal life mode which would preclude functional color patterns. Particular color patterns are instead interpreted to be the result of historical factors, such as multiple adaptive peaks or random fixation of alleles, or of architectural constraints including possibly pleiotropy or allometry. The low variability of color patterns, which was noted within species and genera, suggests that color patterns may also serve a useful taxonomic purpose.

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