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Amador GJ, van Oorschot BK, Liao C, Wu J, Wei D. Functional fibrillar interfaces: Biological hair as inspiration across scales. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:664-677. [PMID: 38887525 PMCID: PMC11181169 DOI: 10.3762/bjnano.15.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/17/2024] [Indexed: 06/20/2024]
Abstract
Hair, or hair-like fibrillar structures, are ubiquitous in biology, from fur on the bodies of mammals, over trichomes of plants, to the mastigonemes on the flagella of single-celled organisms. While these long and slender protuberances are passive, they are multifunctional and help to mediate interactions with the environment. They provide thermal insulation, sensory information, reversible adhesion, and surface modulation (e.g., superhydrophobicity). This review will present various functions that biological hairs have been discovered to carry out, with the hairs spanning across six orders of magnitude in size, from the millimeter-thick fur of mammals down to the nanometer-thick fibrillar ultrastructures on bateriophages. The hairs are categorized according to their functions, including protection (e.g., thermal regulation and defense), locomotion, feeding, and sensing. By understanding the versatile functions of biological hairs, bio-inspired solutions may be developed across length scales.
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Affiliation(s)
- Guillermo J Amador
- Experimental Zoology Group, Department of Animal Sciences, Wageningen University & Research, De Elst 1, 6708 WD Wageningen, Netherlands
| | - Brett Klaassen van Oorschot
- Experimental Zoology Group, Department of Animal Sciences, Wageningen University & Research, De Elst 1, 6708 WD Wageningen, Netherlands
| | - Caiying Liao
- School of Aeronautics and Astronautics, Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Jianing Wu
- School of Aeronautics and Astronautics, Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Da Wei
- Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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2
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Ishihara D, Onishi M, Sugikawa K. Vein-Membrane Interaction in Cambering of Flapping Insect Wings. Biomimetics (Basel) 2023; 8:571. [PMID: 38132510 PMCID: PMC10741490 DOI: 10.3390/biomimetics8080571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/20/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
It is still unclear how elastic deformation of flapping insect wings caused by the aerodynamic pressure results in their significant cambering. In this study, we present that a vein-membrane interaction (VMI) can clarify this mechanical process. In order to investigate the VMI, we propose a numerical method that consists of (a) a shape simplification model wing that consists of a few beams and a rectangular shell structure as the structural essence of flapping insect wings for the VMI, and (b) a monolithic solution procedure for strongly coupled beam and shell structures with large deformation and large rotation to analyze the shape simplification model wing. We incorporate data from actual insects into the proposed numerical method for the VMI. In the numerical analysis, we demonstrate that the model wing can generate a camber equivalent to that of the actual insects. Hence, the VMI will be a mechanical basis of the cambering of flapping insect wings. Furthermore, we present the mechanical roles of the veins in cambering. The intermediate veins increase the out-of-plane deflection of the wing membrane due to the aerodynamic pressure in the central area of the wing, while they decrease it in the vicinity of the trailing edge. As a result, these veins create the significant camber. The torsional flexibility of the leading-edge veins increases the magnitude of cambering.
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Affiliation(s)
- Daisuke Ishihara
- Department of Intelligent and Control Systems, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Fukuoka, Japan; (M.O.); (K.S.)
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3
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Maya R, Lerner N, Ben-Dov O, Pons A, Beatus T. A hull reconstruction-reprojection method for pose estimation of free-flying fruit flies. J Exp Biol 2023; 226:jeb245853. [PMID: 37795876 PMCID: PMC10629692 DOI: 10.1242/jeb.245853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 09/18/2023] [Indexed: 10/06/2023]
Abstract
Understanding the mechanisms of insect flight requires high-quality data of free-flight kinematics, e.g. for comparative studies or genetic screens. Although recent improvements in high-speed videography allow us to acquire large amounts of free-flight data, a significant bottleneck is automatically extracting accurate body and wing kinematics. Here, we present an experimental system and a hull reconstruction-reprojection algorithm for measuring the flight kinematics of fruit flies. The experimental system can automatically record hundreds of flight events per day. Our algorithm resolves a significant portion of the occlusions in this system by a reconstruction-reprojection scheme that integrates information from all cameras. Wing and body kinematics, including wing deformation, are then extracted from the hulls of the wing boundaries and body. This model-free method is fully automatic, accurate and open source, and can be readily adjusted for different camera configurations or insect species.
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Affiliation(s)
- Roni Maya
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center of Bioengineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Noam Lerner
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center of Bioengineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Omri Ben-Dov
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center of Bioengineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Arion Pons
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center of Bioengineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Tsevi Beatus
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center of Bioengineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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4
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Pons A. The self-oscillation paradox in the flight motor of Drosophila melanogaster. J R Soc Interface 2023; 20:20230421. [PMID: 37963559 PMCID: PMC10645510 DOI: 10.1098/rsif.2023.0421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/23/2023] [Indexed: 11/16/2023] Open
Abstract
Tiny flying insects, such as Drosophila melanogaster, fly by flapping their wings at frequencies faster than their brains are able to process. To do so, they rely on self-oscillation: dynamic instability, leading to emergent oscillation, arising from muscle stretch-activation. Many questions concerning this vital natural instability remain open. Does flight motor self-oscillation necessarily lead to resonance-a state optimal in efficiency and/or performance? If so, what state? And is self-oscillation even guaranteed in a motor driven by stretch-activated muscle, or are there limiting conditions? In this work, we use data-driven models of wingbeat and muscle behaviour to answer these questions. Developing and leveraging novel analysis techniques, including symbolic computation, we establish a fundamental condition for motor self-oscillation common to a wide range of motor models. Remarkably, D. melanogaster flight apparently defies this condition: a paradox of motor operation. We explore potential resolutions to this paradox, and, within its confines, establish that the D. melanogaster flight motor is probably not resonant with respect to exoskeletal elasticity: instead, the muscular elasticity plays a dominant role. Contrary to common supposition, the stiffness of stretch-activated muscle is an obstacle to, rather than an enabler of, the operation of the D. melanogaster flight motor.
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Affiliation(s)
- Arion Pons
- Division of Fluid Dynamics, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg, Sweden
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5
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Luna Lin Y, Pezzulla M, Reis PM. Fluid-structure interactions of bristled wings: the trade-off between weight and drag. J R Soc Interface 2023; 20:20230266. [PMID: 37700710 PMCID: PMC10498347 DOI: 10.1098/rsif.2023.0266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
The smallest flying insects often have bristled wings resembling feathers or combs. We combined experiments and three-dimensional numerical simulations to investigate the trade-off between wing weight and drag generation. In experiments of bristled strips, a reduced physical model of the bristled wing, we found that the elasto-viscous number indicates when reconfiguration occurs in the bristles. Analysis of existing biological data suggested that bristled wings of miniature insects lie below the reconfiguration threshold, thus avoiding drag reduction. Numerical simulations of bristled strips showed that there exist optimal numbers of bristles that maximize the weighted drag when the additional volume due to the bristles is taken into account. We found a scaling relationship between the rescaled optimal numbers and the dimensionless bristle length. This result agrees qualitatively with and provides an upper bound for the bristled wing morphological data analysed in this study.
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Affiliation(s)
- Yuexia Luna Lin
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Flexible Structures Laboratory, Lausanne 1015, Switzerland
| | - Matteo Pezzulla
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Flexible Structures Laboratory, Lausanne 1015, Switzerland
| | - Pedro M. Reis
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Flexible Structures Laboratory, Lausanne 1015, Switzerland
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Hürkey S, Niemeyer N, Schleimer JH, Ryglewski S, Schreiber S, Duch C. Gap junctions desynchronize a neural circuit to stabilize insect flight. Nature 2023:10.1038/s41586-023-06099-0. [PMID: 37225999 DOI: 10.1038/s41586-023-06099-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/18/2023] [Indexed: 05/26/2023]
Abstract
Insect asynchronous flight is one of the most prevalent forms of animal locomotion used by more than 600,000 species. Despite profound insights into the motor patterns1, biomechanics2,3 and aerodynamics underlying asynchronous flight4,5, the architecture and function of the central-pattern-generating (CPG) neural network remain unclear. Here, on the basis of an experiment-theory approach including electrophysiology, optophysiology, Drosophila genetics and mathematical modelling, we identify a miniaturized circuit solution with unexpected properties. The CPG network consists of motoneurons interconnected by electrical synapses that, in contrast to doctrine, produce network activity splayed out in time instead of synchronized across neurons. Experimental and mathematical evidence support a generic mechanism for network desynchronization that relies on weak electrical synapses and specific excitability dynamics of the coupled neurons. In small networks, electrical synapses can synchronize or desynchronize network activity, depending on the neuron-intrinsic dynamics and ion channel composition. In the asynchronous flight CPG, this mechanism translates unpatterned premotor input into stereotyped neuronal firing with fixed sequences of cell activation that ensure stable wingbeat power and, as we show, is conserved across multiple species. Our findings prove a wider functional versatility of electrical synapses in the dynamic control of neural circuits and highlight the relevance of detecting electrical synapses in connectomics.
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Affiliation(s)
- Silvan Hürkey
- Institute of Developmental Biology and Neurobiology (iDN), Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Nelson Niemeyer
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Stefanie Ryglewski
- Institute of Developmental Biology and Neurobiology (iDN), Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Susanne Schreiber
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany.
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany.
| | - Carsten Duch
- Institute of Developmental Biology and Neurobiology (iDN), Johannes Gutenberg-University Mainz, Mainz, Germany.
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7
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Goczał J, Beutel RG. Beetle elytra: evolution, modifications and biological functions. Biol Lett 2023; 19:20220559. [PMID: 36855857 PMCID: PMC9975656 DOI: 10.1098/rsbl.2022.0559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Conversion of forewings into hardened covers, elytra, was a ground-breaking morphological adaptation that has contributed to the extraordinary evolutionary success of beetles. Nevertheless, the knowledge of the functional aspects of these structures is still fragmentary and scattered across a large number of studies. Here, we have synthesized the presently available information on the evolution, development, modifications and biological functions of this crucial evolutionary novelty. The formation of elytra took place in the earliest evolution of Coleoptera, very likely already in the Carboniferous, and was achieved through the gradual process of progressive forewing sclerotization and the formation of inward directed epipleura and a secluded sub-elytral space. In many lineages of modern beetles, the elytra have been distinctly modified. This includes multiple surface modifications, a rigid connection or fusion of the elytra, or partial or complete reduction. Beetle elytra can be involved in a very broad spectrum of functions: mechanical protection of hind wings and body, anti-predator strategies, thermoregulation and water saving, water harvesting, flight, hind wing folding, diving and swimming, self-cleaning and burrow cleaning, phoresy of symbiotic organisms, mating and courtship, and acoustic communication. We postulate that the potential of the elytra to take over multiple tasks has enormously contributed to the unparalleled diversification of beetles.
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Affiliation(s)
- Jakub Goczał
- Department of Forest Ecosystems Protection, University of Agriculture in Krakow, 29 Listopada 54, 31-425 Krakow, Poland
| | - Rolf G Beutel
- Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung, 07743 Jena, Germany
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8
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Li YD, Yamamoto S, Newton AF, Cai CY. Kekveus brevisulcatus sp. nov., a new featherwing beetle from mid-Cretaceous amber of northern Myanmar (Coleoptera: Ptiliidae). PeerJ 2023; 11:e15306. [PMID: 37193020 PMCID: PMC10183168 DOI: 10.7717/peerj.15306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 04/06/2023] [Indexed: 05/18/2023] Open
Abstract
Ptiliidae (featherwing beetles) is a group of minute staphylinoid beetles with a scarce fossil record. Here a second member of the Mesozoic genus Kekveus Yamamoto et al. is reported from mid-Cretaceous Burmese amber, with detailed morphology obtained through confocal microscopy. Kekveus brevisulcatus Li, Yamamoto, Newton & Cai sp. nov. shares with K. jason Yamamoto et al. the unpaired medial pronotal fovea and narrowly separated transverse metacoxae, but can be separated from the latter based on its less elongate body, shorter pronotal foveae, and much weaker transverse depression on the head. Our phylogenetic analyses support the discheramocephalin affinity of Kekveus, although its relationship with other members of Discheramocephalini cannot be confidently resolved.
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Affiliation(s)
- Yan-Da Li
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, United Kingdom
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China
| | - Shûhei Yamamoto
- The Hokkaido University Museum, Hokkaido University, Sapporo, Japan
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, United States of America
| | - Alfred F. Newton
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, United States of America
| | - Chen-Yang Cai
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, United Kingdom
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China
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9
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Chi Y, Hong Y, Zhao Y, Li Y, Yin J. Snapping for high-speed and high-efficient butterfly stroke-like soft swimmer. SCIENCE ADVANCES 2022; 8:eadd3788. [PMID: 36399554 PMCID: PMC9674291 DOI: 10.1126/sciadv.add3788] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Natural selection has tuned many flying and swimming animals to share the same narrow design space for high power efficiency, e.g., their dimensionless Strouhal numbers St that relate flapping frequency and amplitude and forward speed fall within the range of 0.2 < St < 0.4 for peak propulsive efficiency. It is rather challenging to achieve both comparably fast-speed and high-efficient soft swimmers to marine animals due to the naturally selected narrow design space and soft body compliance. Here, bioinspired by the flapping motion in swimming animals, we report leveraging snapping instabilities for soft flapping-wing swimmers with comparable high performance to biological counterparts. The lightweight, butterfly stroke-like soft swimmer (2.8 g) demonstrates a record-high speed of 3.74 body length/s (4.8 times faster than the reported fastest flapping soft swimmer), high power efficiency (0.2 < St = 0.25 < 0.4), low energy consumption cost, and high maneuverability (a high turning speed of 157°/s).
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10
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Zhang J, Zhao N, Qu F. Bio-inspired flapping wing robots with foldable or deformable wings: a review. BIOINSPIRATION & BIOMIMETICS 2022; 18:011002. [PMID: 36317380 DOI: 10.1088/1748-3190/ac9ef5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Traditional flapping-wing robots (FWRs) obtain lift and thrust by relying on the passive deformation of their wings which cannot actively fold or deform. In contrast, flying creatures such as birds, bats, and insects can maneuver agilely through active folding or deforming their wings. Researchers have developed many bio-inspired foldable or deformable wings (FDWs) imitating the wings of flying creatures. The foldable wings refer to the wings like the creatures' wings that can fold in an orderly manner close to their bodies. Such wings have scattered feathers or distinct creases that can be stacked and folded to reduce the body envelope, which in nature is beneficial for these animals to prevent wing damage and ensure agility in crossing bushes. The deformable wings refer to the active deformation of the wings using active driving mechanisms and the passive deformation under the aerodynamic force, which functionally imitates the excellent hydrodynamic performance of the deformable body and wings of the creatures. However, the shape and external profile changes of deformable wings tend to be much smaller than that of folding wings. FDWs enable the FWRs to improve flight degree of flexibility, maneuverability, and efficiency and reduce flight energy consumption. However, FDWs still need to be studied, and a comprehensive review of the state-of-the-art progress of FDWs in FWR design is lacking. This paper analyzes the wing folding and deformation mechanisms of the creatures and reviews the latest progress of FWRs with FDWs. Furthermore, we summarize the current limitations and propose future directions in FDW design, which could help researchers to develop better FWRs for safe maneuvering in obstacle-dense environments.
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Affiliation(s)
- Jun Zhang
- The State Key Laboratory of Bioelectronics, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, People's Republic of China
| | - Ning Zhao
- The State Key Laboratory of Bioelectronics, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, People's Republic of China
| | - Feiyang Qu
- The State Key Laboratory of Bioelectronics, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, People's Republic of China
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11
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Liu W, Sun M. Aerodynamics and three-dimensional effect of a translating bristled wing at low Reynolds numbers. Sci Rep 2022; 12:14966. [PMID: 36056054 PMCID: PMC9440148 DOI: 10.1038/s41598-022-18834-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/22/2022] [Indexed: 11/18/2022] Open
Abstract
The smallest insects fly with bristled wings at very low Reynolds numbers (Re) and use the drag of the wings to provide the weight-supporting force and thrust. Previous studies used two-dimensional (2-D) models to study the aerodynamic force and the detailed flow field of the bristled wings, neglecting the three-dimensional (3-D) effect caused by the finite span. At high Re, the 3-D effect is known to decrease the aerodynamic force on a body, compared with the 2-D case. However, the bristled wing operates at very low Re, for which the 3-D effect is unknown. Here, a 3-D model of the bristled wing is constructed to numerically investigate the detailed flow field and the aerodynamic force of the wing. Our findings are as follows: The 3-D effect at low Re increases the drag of the bristled wing compared with that of the corresponding 2-D wing, which is contrary to that of the high-Re case. The drag increase is limited to the tip region of the bristles and could be explained by the increase of the flow velocity around the tip region. The spanwise length of the drag-increasing region (measuring from the wing tip) is about 0.23 chord length and does not vary as the wing aspect ratio increases. The amount of the drag increment in the tip region does not vary as the wing aspect ratio increases either, leading to the decrease of the drag coefficient with increasing aspect ratio.
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Affiliation(s)
- Wenjie Liu
- Institute of Fluid Mechanics, Beihang University, Beijing, 100191, China.
| | - Mao Sun
- Institute of Fluid Mechanics, Beihang University, Beijing, 100191, China
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12
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Wu YK, Liu YP, Sun M. Aerodynamics of two parallel bristled wings in low Reynolds number flow. Sci Rep 2022; 12:10928. [PMID: 35764779 PMCID: PMC9239992 DOI: 10.1038/s41598-022-15068-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 06/17/2022] [Indexed: 11/18/2022] Open
Abstract
Most of the smallest flying insects use bristled wings. It was observed that during the second half of their upstroke, the left and right wings become parallel and close to each other at the back, and move upward at zero angle of attack. In this period, the wings may produce drag (negative vertical force) and side forces which tend to push two wings apart. Here we study the aerodynamic forces and flows of two simplified bristled wings experiencing such a motion, compared with the case of membrane wings (flat-plate wings), to see if there is any advantage in using the bristled wings. The method of computational fluid dynamics is used in the study. The results are as follows. In the motion of two bristled wings, the drag acting on each wing is 40% smaller than the case of a single bristled wing conducting the same motion, and only a very small side force is produced. But in the case of the flat-plate wings, although there is similar drag reduction, the side force on each wing is larger than that of the bristled wing by an order of magnitude (the underlying physical reason is discussed in the paper). Thus, if the smallest insects use membrane wings, their flight muscles need to overcome large side forces in order to maintain the intended motion for less negative lift, whereas using bristled wings do not have this problem. Therefore, the adoption of bristled wings can be beneficial during upward movement of the wings near the end of the upstroke, which may be one reason why most of the smallest insects adopt them.
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Affiliation(s)
- Yu Kai Wu
- Institute of Fluid Mechanics, Beihang University, Beijing, 100191, China.
| | - Yan Peng Liu
- Institute of Fluid Mechanics, Beihang University, Beijing, 100191, China
| | - Mao Sun
- Institute of Fluid Mechanics, Beihang University, Beijing, 100191, China
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13
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Li YD, Newton AF, Huang DY, Cai CY. The First Fossil of Nossidiinae From Mid-Cretaceous Amber of Northern Myanmar (Coleoptera: Ptiliidae). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.911512] [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] Open
Abstract
Ptiliidae is a group of distinctly miniaturized staphylinoid beetles with a scarce fossil record. Here, we report a new ptiliid genus and species, Crenossidium slipinskii Li, Newton and Cai gen. et sp. nov., from mid-Cretaceous amber from northern Myanmar. Crenossidium can be attributed to the subfamily Nossidiinae based on the hind wing morphology, which has also been confirmed through phylogenetic analyses. Crenossidium differs from other extant nossidiine genera in the combination of the wide apical maxillary palpomeres, posteriorly widest pronotal disk, (almost) contiguous procoxae, fewer setae along wing margin, and multidentate pygidium.urn:lsid:zoobank.org:pub:8038D763-6856-4AC5-972C-E20D636137EE.
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14
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Pons A, Beatus T. Distinct forms of resonant optimality within insect indirect flight motors. J R Soc Interface 2022; 19:20220080. [PMID: 35582811 DOI: 10.1098/rsif.2022.0080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Insect flight motors are extraordinary natural structures that operate efficiently at high frequencies. Structural resonance is thought to play a role in ensuring efficient motor operation, but the details of this role are elusive. While the efficiency benefits associated with resonance may be significant, a range of counterintuitive behaviours are observed. In particular, the relationship between insect wingbeat frequencies and thoracic natural frequencies is uncertain, with insects showing wingbeat frequency modulation over both short and long time scales. Here, we offer new explanations for this modulation. We show how, in linear and nonlinear models of an indirect flight motor, resonance is not a unitary state at a single frequency, but a complex cluster of distinct and mutually exclusive states, each representing a different form of resonant optimality. Additionally, by characterizing the relationship between resonance and the state of negative work absorption within the motor, we demonstrate how near-perfect resonant energetic optimality can be maintained over significant wingbeat frequency ranges. Our analysis leads to a new conceptual model of flight motor operation: one in which insects are not energetically restricted to a precise wingbeat frequency, but instead are robust to changes in thoracic and environmental properties-an illustration of the extraordinary robustness of these natural motors.
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Affiliation(s)
- Arion Pons
- The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.,The Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Israel
| | - Tsevi Beatus
- The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.,The Benin School of Computer Science and Engineering, The Hebrew University of Jerusalem, Israel
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15
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Aerodynamic Effects of Ceiling and Ground Vicinity on Flapping Wings. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12084012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The combined ceiling and ground effect on the aerodynamics of a hovering flapping wing is investigated using numerical simulations. In the simulations, the wing was located between the ceiling and the ground. Simulations were carried out for different wall clearances at two Reynolds numbers (Re = 10 and 100). Special efforts were paid to whether there exists aerodynamic coupling between the ceiling effect and the ground effect. At Re = 10, the combined ceiling and ground effect increases the aerodynamic forces monotonically through two effects, namely the narrow-channel effect and the downwash-reducing effect. Additionally, there exists a coupling effect of the ceiling and the ground for the combined case at Re = 10, where the force enhancement of the combined effect is much more significant than the sum of the ceiling-only effect and the ground-only effect. At Re = 100, the combined effect of ceiling and ground causes three non-monotonic force regimes (force enhancement, reduction and recovery) with increasing wall clearance. The narrow-channel effect at Re = 100 leads to a monotonic force trend, while the downwash-reducing effect results in a non-monotonic force trend. The two effects eventually lead to the three force regimes at Re = 100. Unlike the Re = 10 case, the coupling effect at Re = 100 is small.
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Lesser E. Featherwing beetles fly with style. J Exp Biol 2022. [DOI: 10.1242/jeb.243450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Efficiency and Aerodynamic Performance of Bristled Insect Wings Depending on Reynolds Number in Flapping Flight. FLUIDS 2022. [DOI: 10.3390/fluids7020075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Insect wings are generally constructed from veins and solid membranes. However, in the case of the smallest flying insects, the wing membrane is often replaced by hair-like bristles. In contrast to large insects, it is possible for both bristled and membranous wings to be simultaneously present in small insect species. There is therefore a continuing debate about the advantages and disadvantages of bristled wings for flight. In this study, we experimentally tested bristled robotic wing models on their ability to generate vertical forces and scored aerodynamic efficiency at Reynolds numbers that are typical for flight in miniature insects. The tested wings ranged from a solid membrane to a few bristles. A generic lift-based wing kinematic pattern moved the wings around their root. The results show that the lift coefficients, power coefficients and Froude efficiency decreased with increasing bristle spacing. Skin friction significantly attenuates lift production, which may even result in negative coefficients at elevated bristle spacing and low Reynolds numbers. The experimental data confirm previous findings from numerical simulations. These had suggested that for small insects, flying with bristled instead of membranous wings involved less change in energetic costs than for large insects. In sum, our findings highlight the aerodynamic changes associated with bristled wing designs and are thus significant for assessing the biological fitness and dispersal of flying insects.
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