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Garner AM, Wilson MC, Wright C, Russell AP, Niewiarowski PH, Dhinojwala A. Parameters of the adhesive setae and setal fields of the Jamaican radiation of anoles (Dactyloidae: Anolis): potential for ecomorphology at the microscopic scale. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
The subdigital adhesive pads of Caribbean Anolis lizards are considered to be a key innovation that permits occupation of novel ecological niches. Although previous work has demonstrated that subdigital pad morphology and performance vary with habitat use, such investigations have only considered the macroscale aspects of these structures (e.g. pad area). The morphological agents of attachment, however, are arrays of hair-like fibres (setae) that terminate in an expanded tip (spatula) and have not been examined in a similar manner. Here we examine the setal morphology and setal field configuration of ecologically distinct species of the monophyletic Jamaican Anolis radiation from a functional and ecological perspective. We find that anoles occupying the highest perches possess greater setal densities and smaller spatulae than those exploiting lower perches. This finding is consistent with the concept of contact splitting, whereby subdivision of an adhesive area into smaller and more densely packed fibres results in an increase in adhesive performance. Micromorphological evidence also suggests that the biomechanics of adhesive locomotion may vary between Anolis ecomorphs. Our findings indicate that, in a similar fashion to macroscale features of the subdigital pad, its microstructure may vary in relation to performance and habitat use in Caribbean Anolis.
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Affiliation(s)
- Austin M Garner
- Integrated Bioscience Program, The University of Akron , Akron, OH , USA
- Department of Biology, The University of Akron , Akron, OH , USA
| | - Michael C Wilson
- School of Polymer Science and Polymer Engineering, The University of Akron , Akron, OH , USA
| | - Caitlin Wright
- Department of Biology, The University of Akron , Akron, OH , USA
| | - Anthony P Russell
- Department of Biological Sciences, University of Calgary , Calgary, AB, CA
| | - Peter H Niewiarowski
- Integrated Bioscience Program, The University of Akron , Akron, OH , USA
- Department of Biology, The University of Akron , Akron, OH , USA
| | - Ali Dhinojwala
- Integrated Bioscience Program, The University of Akron , Akron, OH , USA
- School of Polymer Science and Polymer Engineering, The University of Akron , Akron, OH , USA
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Shi W, Cheng X, Cheng K. Gecko-Inspired Adhesives with Asymmetrically Tilting-Oriented Micropillars. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:8890-8898. [PMID: 35830463 DOI: 10.1021/acs.langmuir.2c01002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The anisotropic adhesion behavior of the gecko is closely related to their feet and is comprised of keratinous hairs, setae, where van der Waals forces permit attachment and detachment during locomotion. Previous research either achieved only isotropic adhesion behaviors or involved the complicated photolithography method. Here, we reported a simple way to achieve the anisotropic adhesion behaviors of gecko-inspired adhesives, consisting of micropillars with asymmetrically tilted orientation via the 3D printing technique. The adhesive forces of structured polymer pillars achieved 4-fold stronger, compared to controls with the plain surface. The anisotropic adhesion behavior is presented on the patterned surface and is two times stronger along the gripping direction compared to the releasing direction on the adhesives, which is attributed to the asymmetric stress distributions at the edges, as well as the stresses resulting from the moment with the sheared top. The finite element analysis is applied to demonstrate the stress distributions and displacement variations. This work provides the insight into the design and fabrication of gecko-inspired adhesives with anisotropic adhesion behaviors in practical applications.
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Affiliation(s)
- Weiwei Shi
- Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu 215316, China
- Environmental Research Center, Duke Kunshan University, Kunshan, Jiangsu 215316, China
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina 27606, United States
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, United States
| | - Xiao Cheng
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina 27606, United States
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, United States
| | - Ke Cheng
- Department of Molecular Biomedical Sciences and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina 27606, United States
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, North Carolina 27514, United States
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Song Y, Weng Z, Yuan J, Zhang L, Wang Z, Dai Z, Full RJ. Incline-dependent adjustments of toes in geckos inspire functional strategies for biomimetic manipulators. BIOINSPIRATION & BIOMIMETICS 2022; 17:046010. [PMID: 35390775 DOI: 10.1088/1748-3190/ac6557] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 04/07/2022] [Indexed: 06/14/2023]
Abstract
Geckos show versatility by rapidly maneuvering on diverse complex terrain because they benefit from their distributed, setae-covered toes and thus have the ability to generate reliable and adaptive attachment. Significant attention has been paid to their adhesive microstructures (setae), but the effectiveness of the gecko's adaptive attachment at the level of toes and feet remains unclear. In order to better understand the geckos' attachment, we first focused on the deployment of toes while challenging geckos to locomote on varying inclines. When the slope angle was less than 30°, their feet mainly interacted with the substrate using the bases of the toes and generated anisotropic frictional forces. As the slope angle increased to 90°, the participation of the toe bases was reduced. Instead, the setae contribution increased for the middle three toes of the front feet and for the first three toes of the hind feet. As the incline changed from vertical to inverted, the adhesive contribution of the toes of the front feet became more equal, whereas the effective adhesion contact of the hind feet gradually shifted to the toes oriented rearwards. Second, a mathematical model was established and then suggested the potential advantages of distributed control among the toes to regulate foot force. Finally, a physical foot model containing five compliant, adjustable toes was constructed and validated the discoveries with regard to the animals. Using the gecko toes' control strategies, the artificial foot demonstrated diverse behavior regulating attachment forces. The success of the foot prototype not only tested our understanding of the mechanism of biological attachment, but also provided a demonstration for the design and control of gecko-inspired attachment devices, grippers and other manipulators.
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Affiliation(s)
- Yi Song
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China
| | - Zhiyuan Weng
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China
| | - Jiwei Yuan
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China
| | - Linghao Zhang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China
| | - Zhouyi Wang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China
| | - Zhendong Dai
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, People's Republic of China
| | - Robert J Full
- Department of Integrative Biology, University of California, Berkeley, Valley Life Science Building, Berkeley, CA 94702, United States of America
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Yuan J, Wang Z, Song Y, Dai Z. Peking geckos (Gekko swinhonis) traversing upward steps: the effect of step height on the transition from horizontal to vertical locomotion. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:421-433. [PMID: 35362821 DOI: 10.1007/s00359-022-01548-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/13/2022] [Accepted: 03/15/2022] [Indexed: 11/25/2022]
Abstract
The ability to transition between surfaces (e.g., from the ground to vertical barriers, such as walls, tree trunks, or rock surfaces) is important for the Peking gecko's (Gekko swinhonis Günther 1864) survival. However, quantitative research on gecko's kinematic performance and the effect of obstacle height during transitional locomotion remains scarce. In this study, the transitional locomotion of geckos facing different obstacle heights was assessed. Remarkably, geckos demonstrated a bimodal locomotion ability, as they could climb and jump. Climbing was more common on smaller obstacles and took longer than jumping. The jumping type depended on the obstacle height: when geckos could jump onto the obstacle, the vertical velocity increased with obstacle height; however, geckos jumped from a closer position when the obstacle height exceeded this range and would get attached to the vertical surface. A stability analysis of vertical surface landing using a collision model revealed that geckos can reduce their restraint impulse by increasing the landing angle through limb extension close to the body, consequently dissipating collision energy and reducing their horizontal and vertical velocities. The findings of this study reveal the adaptations evolved by geckos to move in their environments and may have applicability in the robotics field.
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Affiliation(s)
- Jiwei Yuan
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China
| | - Zhouyi Wang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China.
| | - Yi Song
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China
| | - Zhendong Dai
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China
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