1
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Zhang Y, Lauder GV. Energy conservation by collective movement in schooling fish. eLife 2024; 12:RP90352. [PMID: 38375853 PMCID: PMC10942612 DOI: 10.7554/elife.90352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
Many animals moving through fluids exhibit highly coordinated group movement that is thought to reduce the cost of locomotion. However, direct energetic measurements demonstrating the energy-saving benefits of fluid-mediated collective movements remain elusive. By characterizing both aerobic and anaerobic metabolic energy contributions in schools of giant danio (Devario aequipinnatus), we discovered that fish schools have a concave upward shaped metabolism-speed curve, with a minimum metabolic cost at ~1 body length s-1. We demonstrate that fish schools reduce total energy expenditure (TEE) per tail beat by up to 56% compared to solitary fish. When reaching their maximum sustained swimming speed, fish swimming in schools had a 44% higher maximum aerobic performance and used 65% less non-aerobic energy compared to solitary individuals, which lowered the TEE and total cost of transport by up to 53%, near the lowest recorded for any aquatic organism. Fish in schools also recovered from exercise 43% faster than solitary fish. The non-aerobic energetic savings that occur when fish in schools actively swim at high speed can considerably improve both peak and repeated performance which is likely to be beneficial for evading predators. These energetic savings may underlie the prevalence of coordinated group locomotion in fishes.
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Affiliation(s)
- Yangfan Zhang
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridgeUnited States
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridgeUnited States
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2
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Mignano AP, Kadapa S, Drago AC, Lauder GV, Kwatny HG, Tangorra JL. Fish robotics: multi-fin propulsion and the coupling of fin phase, spacing, and compliance. Bioinspir Biomim 2024; 19:026006. [PMID: 38211345 DOI: 10.1088/1748-3190/ad1dba] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
Fish coordinate the motion of their fins and body to create the time-varying forces required for swimming and agile maneuvers. To effectively adapt this biological strategy for underwater robots, it is necessary to understand how the location and coordination of interacting fish-like fins affect the production of propulsive forces. In this study, the impact that phase difference, horizontal and vertical spacing, and compliance of paired fins had on net thrust and lateral forces was investigated using two fish-like robotic swimmers and a series of computational fluid dynamic simulations. The results demonstrated that the propulsive forces created by pairs of fins that interact through wake flows are highly dependent on the fins' spacing and compliance. Changes to fin separation of less than one fin length had a dramatic effect on forces, and on the phase difference at which desired forces would occur. These findings have clear implications when designing multi-finned swimming robots. Well-designed, interacting fins can potentially produce several times more propulsive force than a poorly tuned robot with seemingly small differences in the kinematic, geometric, and mechanical properties.
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Affiliation(s)
- Anthony P Mignano
- Laboratory for Biological Systems Analysis, Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, United States of America
| | - Shraman Kadapa
- Laboratory for Biological Systems Analysis, Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, United States of America
| | - Anthony C Drago
- Laboratory for Biological Systems Analysis, Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, United States of America
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America
| | - Harry G Kwatny
- Laboratory for Biological Systems Analysis, Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, United States of America
| | - James L Tangorra
- Laboratory for Biological Systems Analysis, Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, United States of America
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3
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Matthews DG, Maciejewski MF, Wong GA, Lauder GV, Bolnick DI. Locomotor effects of a fibrosis-based immune response in stickleback fish. J Exp Biol 2023; 226:jeb246684. [PMID: 37947155 DOI: 10.1242/jeb.246684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023]
Abstract
The vertebrate immune system provides an impressively effective defense against parasites and pathogens. However, these benefits must be balanced against a range of costly side-effects including energy loss and risks of auto-immunity. These costs might include biomechanical impairment of movement, but little is known about the intersection between immunity and biomechanics. Here, we show that a fibrosis immune response to Schistocephalus solidus infection in freshwater threespine stickleback (Gasterosteus aculeatus) has collateral effects on their locomotion. Although fibrosis is effective at reducing infection, some populations of stickleback actively suppress this immune response, possibly because the costs of fibrosis outweigh the benefits. We quantified the locomotor effects of the fibrosis immune response in the absence of parasites to investigate whether there are incidental costs of fibrosis that could help explain why some fish forego this effective defense. To do this, we induced fibrosis in stickleback and then tested their C-start escape performance. Additionally, we measured the severity of fibrosis, body stiffness and body curvature during the escape response. We were able to estimate performance costs of fibrosis by including these variables as intermediates in a structural equation model. This model revealed that among control fish without fibrosis, there is a performance cost associated with increased body stiffness. However, fish with fibrosis did not experience this cost but rather displayed increased performance with higher fibrosis severity. This result demonstrates that the adaptive landscape of immune responses can be complex with the potential for wide-reaching and unexpected fitness consequences.
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Affiliation(s)
- David G Matthews
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Meghan F Maciejewski
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Greta A Wong
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Daniel I Bolnick
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
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Zhang Y, Lauder GV. Energetics of collective movement in vertebrates. J Exp Biol 2023; 226:jeb245617. [PMID: 37905670 DOI: 10.1242/jeb.245617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The collective directional movement of animals occurs over both short distances and longer migrations, and is a critical aspect of feeding, reproduction and the ecology of many species. Despite the implications of collective motion for lifetime fitness, we know remarkably little about its energetics. It is commonly thought that collective animal motion saves energy: moving alone against fluid flow is expected to be more energetically expensive than moving in a group. Energetic conservation resulting from collective movement is most often inferred from kinematic metrics or from computational models. However, the direct measurement of total metabolic energy savings during collective motion compared with solitary movement over a range of speeds has yet to be documented. In particular, longer duration and higher speed collective motion must involve both aerobic and non-aerobic (high-energy phosphate stores and substrate-level phosphorylation) metabolic energy contributions, and yet no study to date has quantified both types of metabolic contribution in comparison to locomotion by solitary individuals. There are multiple challenging questions regarding the energetics of collective motion in aquatic, aerial and terrestrial environments that remain to be answered. We focus on aquatic locomotion as a model system to demonstrate that understanding the energetics and total cost of collective movement requires the integration of biomechanics, fluid dynamics and bioenergetics to unveil the hydrodynamic and physiological phenomena involved and their underlying mechanisms.
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Affiliation(s)
- Yangfan Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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5
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Matthews DG, Dial TR, Lauder GV. Genes, Morphology, Performance, and Fitness: Quantifying Organismal Performance to Understand Adaptive Evolution. Integr Comp Biol 2023; 63:843-859. [PMID: 37422435 DOI: 10.1093/icb/icad096] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 06/06/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023] Open
Abstract
To understand the complexities of morphological evolution, we must understand the relationships between genes, morphology, performance, and fitness in complex traits. Genomicists have made tremendous progress in finding the genetic basis of many phenotypes, including a myriad of morphological characters. Similarly, field biologists have greatly advanced our understanding of the relationship between performance and fitness in natural populations. However, the connection from morphology to performance has primarily been studied at the interspecific level, meaning that in most cases we lack a mechanistic understanding of how evolutionarily relevant variation among individuals affects organismal performance. Therefore, functional morphologists need methods that will allow for the analysis of fine-grained intraspecific variation in order to close the path from genes to fitness. We suggest three methodological areas that we believe are well suited for this research program and provide examples of how each can be applied within fish model systems to build our understanding of microevolutionary processes. Specifically, we believe that structural equation modeling, biological robotics, and simultaneous multi-modal functional data acquisition will open up fruitful collaborations among biomechanists, evolutionary biologists, and field biologists. It is only through the combined efforts of all three fields that we will understand the connection between evolution (acting at the level of genes) and natural selection (acting on fitness).
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Affiliation(s)
- David G Matthews
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Terry R Dial
- Department of Biology and Ecology Center, Utah State University, Moab, UT 84322, USA
- Department of Environment and Society, Utah State University, Moab, UT 84322, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
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6
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Matthews DG, Maciejewski MF, Wong GA, Lauder GV, Bolnick DI. Locomotor effects of a fibrosis-based immune response in stickleback fish. bioRxiv 2023:2023.06.24.546342. [PMID: 37425734 PMCID: PMC10326981 DOI: 10.1101/2023.06.24.546342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The vertebrate immune system provides an impressively effective defense against parasites and pathogens. However, these benefits must be balanced against a range of costly side-effects including energy loss and risks of auto-immunity. These costs might include biomechanical impairment of movement, but little is known about the intersection between immunity and biomechanics. Here, we show that a fibrosis immune response in threespine stickleback (Gasterosteus aculeatus) has collateral effects on their locomotion. When freshwater stickleback are infected with the tapeworm parasite Schistocephalus solidus, they face an array of fitness consequences ranging from impaired body condition and fertility to an increased risk of mortality. To fight the infection, some stickleback will initiate a fibrosis immune response in which they produce excess collagenous tissue in their coelom. Although fibrosis is effective at reducing infection, some populations of stickleback actively suppress this immune response, possibly because the costs of fibrosis outweigh the benefits. Here we quantify the locomotor effects of the fibrosis immune response in the absence of parasites to investigate whether there are collateral costs of fibrosis that could help explain why some fish forego this effective defense. To do this, we induce fibrosis in stickleback and then test their C-start escape performance. Additionally, we measure the severity of fibrosis, body stiffness, and body curvature during the escape response. We were able to estimate performance costs of fibrosis by including these variables as intermediates in a structural equation model. This model reveals that among control fish without fibrosis, there is a performance cost associated with increased body stiffness. However, fish with fibrosis did not experience this cost but rather displayed increased performance with higher fibrosis severity. This result demonstrates that the adaptive landscape of immune responses can be complex with the potential for wide reaching and unexpected fitness consequences.
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Affiliation(s)
- David G. Matthews
- Organismic and Evolutionary Biology, Harvard University, Cambridge, 02138, MA, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, 02138, MA, USA
| | - Meghan F. Maciejewski
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, Champaign, 61820, IL, USA
- Department of Ecology Evolutionary Biology, University of Connecticut, Storrs, 06269, CT, USA
| | - Greta A. Wong
- Museum of Comparative Zoology, Harvard University, Cambridge, 02138, MA, USA
| | - George V. Lauder
- Organismic and Evolutionary Biology, Harvard University, Cambridge, 02138, MA, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, 02138, MA, USA
| | - Daniel I. Bolnick
- Department of Ecology Evolutionary Biology, University of Connecticut, Storrs, 06269, CT, USA
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7
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Akanyeti O, Di Santo V, Goerig E, Wainwright DK, Liao JC, Castro-Santos T, Lauder GV. Fish-inspired segment models for undulatory steady swimming. Bioinspir Biomim 2022; 17:046007. [PMID: 35487201 DOI: 10.1088/1748-3190/ac6bd6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/29/2022] [Indexed: 06/14/2023]
Abstract
Many aquatic animals swim by undulatory body movements and understanding the diversity of these movements could unlock the potential for designing better underwater robots. Here, we analyzed the steady swimming kinematics of a diverse group of fish species to investigate whether their undulatory movements can be represented using a series of interconnected multi-segment models, and if so, to identify the key factors driving the segment configuration of the models. Our results show that the steady swimming kinematics of fishes can be described successfully using parsimonious models, 83% of which had fewer than five segments. In these models, the anterior segments were significantly longer than the posterior segments, and there was a direct link between segment configuration and swimming kinematics, body shape, and Reynolds number. The models representing eel-like fishes with elongated bodies and fishes swimming at high Reynolds numbers had more segments and less segment length variability along the body than the models representing other fishes. These fishes recruited their anterior bodies to a greater extent, initiating the undulatory wave more anteriorly. Two shape parameters, related to axial and overall body thickness, predicted segment configuration with moderate to high success rate. We found that head morphology was a good predictor of its segment length. While there was a large variation in head segments, the length of tail segments was similar across all models. Given that fishes exhibited variable caudal fin shapes, the consistency of tail segments could be a result of an evolutionary constraint tuned for high propulsive efficiency. The bio-inspired multi-segment models presented in this study highlight the key bending points along the body and can be used to decide on the placement of actuators in fish-inspired robots, to model hydrodynamic forces in theoretical and computational studies, or for predicting muscle activation patterns during swimming.
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Affiliation(s)
- Otar Akanyeti
- Department of Computer Science, Aberystwyth University, Ceredigion, SY23 3FL, United Kingdom
| | - Valentina Di Santo
- Division of Functional Morphology, Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Elsa Goerig
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America
- S.O. Conte Anadromous Fish Research Center, USGS, Turners Falls, MA, United States of America
| | - Dylan K Wainwright
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States of America
| | - James C Liao
- Department of Biology, The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States of America
| | - Theodore Castro-Santos
- S.O. Conte Anadromous Fish Research Center, USGS, Turners Falls, MA, United States of America
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America
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8
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Abstract
Fish display a versatile array of swimming patterns, and frequently demonstrate the ability to switch between these patterns altering kinematics as necessary. Many hard and soft robotic systems have sought to understand a variety of aspects pertaining to undulatory swimming, but most have been built to focus solely on a subset of those swimming patterns. We have expanded upon a previous soft robotic model, the pneufish, so that it can now simulate a variety of swimming patterns, much like a real fish. We explore the performance space available for this longer soft robotic model, which we call the quad-pneufish, with particular attention to the effects on lateral forces and z-torques produced during locomotion. We show that the quad-pneufish is capable of achieving a variety of midline patterns - including more realistic, fish-like patterns - and introducing a slight amount of co-activation between the left and right sides maintains forward thrust while decreasing lateral forces, indicating an increase in swimming efficiency. Robotic systems that are capable of producing an array of swimming movement patterns hold promise as experimental platforms for studying the diversity of fish locomotor patterns.
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Affiliation(s)
- Zane Wolf
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, 02138, Massachusetts, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, 02138, Massachusetts, USA
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, 02138, Massachusetts, USA
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9
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Abstract
Comparative biologists have typically used one or more of the following methods to assist in evaluating the proposed functional and performance significance of individual traits: comparative phylogenetic analysis, direct interspecific comparison among species, genetic modification, experimental alteration of morphology (for example by surgically modifying traits), and ecological manipulation where individual organisms are transplanted to a different environment. But comparing organisms as the endpoints of an evolutionary process involves the ceteris paribus assumption: that all traits other than the one(s) of interest are held constant. In a properly controlled experimental study, only the variable of interest changes among the groups being compared. The theme of this paper is that the use of robotic or mechanical models offers an additional tool in comparative biology that helps to minimize the effect of uncontrolled variables by allowing direct manipulation of the trait of interest against a constant background. The structure and movement pattern of mechanical devices can be altered in ways not possible in studies of living animals, facilitating testing hypotheses of the functional and performance significant of individual traits. Robotic models of organismal design are particularly useful in three arenas: (1) controlling variation to allow modification only of the trait of interest, (2) the direct measurement of energetic costs of individual traits, and (3) quantification of the performance landscape. Obtaining data in these three areas is extremely difficult through the study of living organisms alone, and the use of robotic models can reveal unexpected effects. Controlling for all variables except for the length of a swimming flexible object reveals substantial non-linear effects that vary with stiffness. Quantification of the swimming performance surface reveals that there are two peaks with comparable efficiency, greatly complicating the inference of performance from morphology alone. Organisms and their ecological interactions are complex, and dissecting this complexity to understand the effects of individual traits is a grand challenge in ecology and evolutionary biology. Robotics has great promise as a "comparative method," allowing better-controlled comparative studies to analyze the many interacting elements that make up complex behaviors, ecological interactions, and evolutionary histories.
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Affiliation(s)
- George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
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10
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Lee KY, Park SJ, Matthews DG, Kim SL, Marquez CA, Zimmerman JF, Ardoña HAM, Kleber AG, Lauder GV, Parker KK. An autonomously swimming biohybrid fish designed with human cardiac biophysics. Science 2022; 375:639-647. [PMID: 35143298 PMCID: PMC8939435 DOI: 10.1126/science.abh0474] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biohybrid systems have been developed to better understand the design principles and coordination mechanisms of biological systems. We consider whether two functional regulatory features of the heart-mechanoelectrical signaling and automaticity-could be transferred to a synthetic analog of another fluid transport system: a swimming fish. By leveraging cardiac mechanoelectrical signaling, we recreated reciprocal contraction and relaxation in a muscular bilayer construct where each contraction occurs automatically as a response to the stretching of an antagonistic muscle pair. Further, to entrain this closed-loop actuation cycle, we engineered an electrically autonomous pacing node, which enhanced spontaneous contraction. The biohybrid fish equipped with intrinsic control strategies demonstrated self-sustained body-caudal fin swimming, highlighting the role of feedback mechanisms in muscular pumps such as the heart and muscles.
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Affiliation(s)
- Keel Yong Lee
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Sung-Jin Park
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA.,Biohybrid Systems Group, Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David G. Matthews
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Sean L. Kim
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Carlos Antonio Marquez
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - John F. Zimmerman
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Herdeline Ann M. Ardoña
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA
| | - Andre G. Kleber
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - George V. Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Kevin Kit Parker
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA 02134, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.,Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA.,Corresponding author.
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11
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Gabler-Smith MK, Wainwright DK, Wong GA, Lauder GV. Dermal Denticle Diversity in Sharks: Novel Patterns on the Interbranchial Skin. Integr Org Biol 2022; 3:obab034. [PMID: 34988371 PMCID: PMC8694198 DOI: 10.1093/iob/obab034] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 10/13/2021] [Accepted: 11/18/2021] [Indexed: 11/17/2022] Open
Abstract
Shark skin is covered in dermal denticles—tooth-like structures consisting of enameloid, dentine, and a central pulp cavity. Previous studies have demonstrated differences in denticle morphology both among species and across different body regions within a species, including one report of extreme morphological variation within a 1 cm distance on the skin covering the branchial pouches, a region termed “interbranchial skin.” We used gel-based profilometry, histology, and scanning electron microscopy to quantify differences in denticle morphology and surface topography of interbranchial skin denticles among 13 species of sharks to better understand the surface structure of this region. We show that (1) interbranchial skin denticles differ across shark species, and (2) denticles on the leading edge of the skin covering each gill pouch have different morphology and surface topography compared with denticles on the trailing edge. Across all species studied, there were significant differences in denticle length (P = 0.01) and width (P = 0.002), with shorter and wider leading edge denticles compared with trailing edge denticles. Surface skew was also higher in leading edge denticles (P = 0.009), though most values were still negative, indicating a surface texture more dominated by valleys than peaks. Overall, leading edge denticles were smoother-edged than trailing edge denticles in all of the species studied. These data suggest two hypotheses: (1) smoother-edged leading edge denticles protect the previous gill flap from abrasion during respiration, and (2) ridged denticle morphology at the trailing edge might alter water turbulence exiting branchial pouches after passing over the gills. Future studies will focus on determining the relationship between denticle morphology and water flow by visualizing fluid motion over interbranchial denticles during in vivo respiration.
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Affiliation(s)
| | | | - Greta A Wong
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138 USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138 USA
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12
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Santo VD, Blevins EL, Lauder GV. Correction: Batoid locomotion: effects of speed on pectoral fin deformation in the little skate, Leucoraja erinacea. J Exp Biol 2021; 224:272610. [PMID: 34698835 DOI: 10.1242/jeb.243018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Matthews DG, Lauder GV. Fin-fin interactions during locomotion in a simplified biomimetic fish model. Bioinspir Biomim 2021; 16:046023. [PMID: 34015781 DOI: 10.1088/1748-3190/ac03a8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Fish median fins are extremely diverse, but their function is not yet fully understood. Various biological studies on fish and engineering studies on flapping foils have revealed that there are hydrodynamic interactions between fins arranged in tandem and that these interactions can lead to improved performance by the posterior fin. This performance improvement is often driven by the augmentation of a leading-edge vortex on the trailing fin. Past experimental studies have necessarily simplified fish anatomy to enable more detailed engineering analyses, but such simplifications then do not capture the complexities of an undulating fish-like body with fins attached. We present a flexible fish-like robotic model that better represents the kinematics of swimming fishes while still being simple enough to examine a range of morphologies and motion patterns. We then create statistical models that predict the individual effects of each kinematic and morphological variable. Our results demonstrate that having fins arranged in tandem on an undulating body can lead to more steady production of thrust forces determined by the distance between the fins and their relative motion. We find that these same variables also affect swimming speed. Specifically, when swimming at high frequencies, self-propelled speed decreases by 12%-26% due to out of phase fin motion. Flow visualization reveals that variation within this range is caused in part by fin-fin flow interactions that affect leading edge vortices. Our results indicate that undulatory swimmers should optimize both the positioning and relative motion of their median fins in order to reduce force oscillations and improve overall performance while swimming.
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Affiliation(s)
- David G Matthews
- The Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, United States of America
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States of America
| | - George V Lauder
- The Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, United States of America
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States of America
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14
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Saadat M, Berlinger F, Sheshmani A, Nagpal R, Lauder GV, Haj-Hariri H. Hydrodynamic advantages of in-line schooling. Bioinspir Biomim 2021; 16:046002. [PMID: 33513591 DOI: 10.1088/1748-3190/abe137] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Fish benefit energetically when swimming in groups, which is reflected in lower tail-beat frequencies for maintaining a given speed. Recent studies further show that fish save the most energy when swimming behind their neighbor such that both the leader and the follower benefit. However, the mechanisms underlying such hydrodynamic advantages have thus far not been established conclusively. The long-standing drafting hypothesis-reduction of drag forces by judicious positioning in regions of reduced oncoming flow-fails to explain advantages of in-line schooling described in this work. We present an alternate hypothesis for the hydrodynamic benefits of in-line swimming based on enhancement of propulsive thrust. Specifically, we show that an idealized school consisting of in-line pitching foils gains hydrodynamic benefits via two mechanisms that are rooted in the undulatory jet leaving the leading foil and impinging on the trailing foil: (i) leading-edge suction on the trailer foil, and (ii) added-mass push on the leader foil. Our results demonstrate that the savings in power can reach as high as 70% for a school swimming in a compact arrangement. Informed by these findings, we designed a modification of the tail propulsor that yielded power savings of up to 56% in a self-propelled autonomous swimming robot. Our findings provide insights into hydrodynamic advantages of fish schooling, and also enable bioinspired designs for significantly more efficient propulsion systems that can harvest some of their energy left in the flow.
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Affiliation(s)
- Mehdi Saadat
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, United States of America
- Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States of America
| | - Florian Berlinger
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States of America
| | - Artan Sheshmani
- Center for Mathematical Sciences and Applications, Harvard University, Department of Mathematics, Cambridge, MA, 02139, United States of America
- Department of Mathematics, Aarhus University, Ny Munkegade 118, building 1530, 319, 8000 Aarhus C, Denmark
- National Research University Higher School of Economics, Russian Federation, Laboratory of Mirror Symmetry, NRU HSE, 6 Usacheva str., Moscow, Russia, 119048
| | - Radhika Nagpal
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States of America
| | - George V Lauder
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, United States of America
| | - Hossein Haj-Hariri
- Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States of America
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15
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Fish FE, Rybczynski N, Lauder GV, Duff CM. The Role of the Tail or Lack Thereof in the Evolution of Tetrapod Aquatic Propulsion. Integr Comp Biol 2021; 61:398-413. [PMID: 33881525 DOI: 10.1093/icb/icab021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Synopsis Secondary aquatic vertebrates exhibit a diversity of swimming modes that use paired limbs and/or the tail. Various secondarily aquatic tetrapod clades, including amphibians, reptiles, and mammals employ transverse undulations or oscillations of the tail for swimming. These movements have often been classified according to a kinematic gradient that was established for fishes, but may not be appropriate to describe the swimming motions of tetrapods. To understand the evolution of movements and design of the tail in aquatic tetrapods, we categorize the types of tails used for swimming and examine swimming kinematics and hydrodynamics. From a foundation of a narrow, elongate ancestral tail, the tails used for swimming by aquatic tetrapods are classified as tapered, keeled, paddle, and lunate. Tail undulations are associated with tapered, keeled, and paddle tails for a diversity of taxa. Propulsive undulatory waves move down the tail with increasing amplitude toward the tail tip, while moving posteriorly at a velocity faster than the anterior motion of the body indicating that the tail is used for thrust generation. Aquatic propulsion is associated with the transfer of momentum to the water from the swimming movements of the tail, particularly at the trailing edge. The addition of transverse extensions and flattening of the tail increases the mass of water accelerated posteriorly and affects vorticity shed into the wake for more aquatically adapted animals. DPIV (Digital Particle Image Velocimetry) reveals differences were exhibited in the vortex wake between the morphological and kinematic extremes of the alligator with a tapering undulating tail and the dolphin with oscillating wing-like flukes that generate thrust. In addition to exploring the relationship between shape of undulating tails and swimming performance across aquatic tetrapods, the role of tail reduction or loss of a tail in aquatic-tetrapod swimming was also explored. For aquatic tetrapods, reduction would have been due to factors including locomotor and defensive specializations and phylogenetic and physiological constraints. Possession of a thrust-generating tail for swimming, or lack thereof, guided various lineages of secondarily aquatic vertebrates into different evolutionary trajectories for effective aquatic propulsion (i.e., speed, efficiency, acceleration).
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Affiliation(s)
- Frank E Fish
- Department of Biology, West Chester University, West Chester, Pennsylvania 19383, USA
| | - Natalia Rybczynski
- Department of Palaeobiology, Canadian Museum of Nature, Ottawa, K1P 6P4, Ontario, Canada
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Christina M Duff
- Department of Biology, West Chester University, West Chester, Pennsylvania 19383, USA
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16
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White CH, Lauder GV, Bart-Smith H. Tunabot Flex: a tuna-inspired robot with body flexibility improves high-performance swimming. Bioinspir Biomim 2021; 16:026019. [PMID: 32927442 DOI: 10.1088/1748-3190/abb86d] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Tunas are flexible, high-performance open ocean swimmers that operate at high frequencies to achieve high swimming speeds. Most fish-like robotic systems operate at low frequencies (≤3 Hz) resulting in low swim speeds (≤1.5 body lengths per second), and the cost of transport (COT) is often one to four orders of magnitude higher than that of tunas. Furthermore, the impact of body flexibility on high-performance fish swimming remains unknown. Here we design and test a research platform based on yellowfin tuna (Thunnus albacares) to investigate the role of body flexibility and to close the performance gap between robotic and biological systems. This single-motor platform, termed Tunabot Flex, measures 25.5 cm in length. Flexibility is varied through joints in the tail to produce three tested configurations. We find that increasing body flexibility improves self-propelled swimming speeds on average by 0.5 body lengths per second while reducing the minimum COT by 53%. The most flexible configuration swims 4.60 body lengths per second with a tail beat frequency of 8.0 Hz and a COT measuring 18.4 J kg-1m-1. We then compare these results in addition to the midline kinematics, stride length, and Strouhal number with yellowfin tuna data. The COT of Tunabot Flex's most flexible configuration is less than a half-order of magnitude greater than that of yellowfin tuna across all tested speeds. Tunabot Flex provides a new baseline for the development of future bio-inspired underwater vehicles that aim to explore a fish-like, high-performance space and close the gap between engineered robotic systems and fish swimming ability.
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Affiliation(s)
- Carl H White
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, United States of America
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, United States of America
| | - Hilary Bart-Smith
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, United States of America
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17
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Abstract
Fish routinely accelerate during locomotor manoeuvres, yet little is known about the dynamics of acceleration performance. Thunniform fish use their lunate caudal fin to generate lift-based thrust during steady swimming, but the lift is limited during acceleration from rest because required oncoming flows are slow. To investigate what other thrust-generating mechanisms occur during this behaviour, we used the robotic system termed Tunabot Flex, which is a research platform featuring yellowfin tuna-inspired body and tail profiles. We generated linear accelerations from rest of various magnitudes (maximum acceleration of [Formula: see text] at [Formula: see text] tail beat frequency) and recorded instantaneous electrical power consumption. Using particle image velocimetry data, we quantified body kinematics and flow patterns to then compute surface pressures, thrust forces and mechanical power output along the body through time. We found that the head generates net drag and that the posterior body generates significant thrust, which reveals an additional propulsion mechanism to the lift-based caudal fin in this thunniform swimmer during linear accelerations from rest. Studying fish acceleration performance with an experimental platform capable of simultaneously measuring electrical power consumption, kinematics, fluid flow and mechanical power output provides a new opportunity to understand unsteady locomotor behaviours in both fishes and bioinspired aquatic robotic systems.
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Affiliation(s)
- Robin Thandiackal
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Carl H White
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA
| | - Hilary Bart-Smith
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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18
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Berlinger F, Saadat M, Haj-Hariri H, Lauder GV, Nagpal R. Fish-like three-dimensional swimming with an autonomous, multi-fin, and biomimetic robot. Bioinspir Biomim 2021; 16:026018. [PMID: 33264757 DOI: 10.1088/1748-3190/abd013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
Fish migrate across considerable distances and exhibit remarkable agility to avoid predators and feed. Fish swimming performance and maneuverability remain unparalleled when compared to robotic systems, partly because previous work has focused on robots and flapping foil systems that are either big and complex, or tethered to external actuators and power sources. By contrast, we present a robot-the Finbot-that combines high degrees of autonomy, maneuverability, and biomimicry with miniature size (160 cm3). Thus, it is well-suited for controlled three-dimensional experiments on fish swimming in confined laboratory test beds. Finbot uses four independently controllable fins and sensory feedback for precise closed-loop underwater locomotion. Different caudal fins can be attached magnetically to reconfigure Finbot for swimming at top speed (122 mm s-1≡ 1 BL s-1) or minimal cost of transport (CoT = 8.2) at Strouhal numbers as low as 0.53. We conducted more than 150 experiments with 12 different caudal fins to measure three key characteristics of swimming fish: (i) linear speed-frequency relationships, (ii) U-shaped CoT, and (iii) reverse Kármán wakes (visualized with particle image velocimetry). More fish-like wakes appeared where the CoT was low. By replicating autonomous multi-fin fish-like swimming, Finbot narrows the gap between fish and fish-like robots and can address open questions in aquatic locomotion, such as optimized propulsion for new fish robots, or the hydrodynamic principles governing the energy savings in fish schools.
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Affiliation(s)
- F Berlinger
- Harvard University, John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA 02138, United States of America
| | - M Saadat
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States of America
| | - H Haj-Hariri
- College of Engineering and Computing, University of South Carolina, Columbia, SC 29208, United States of America
| | - G V Lauder
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States of America
| | - R Nagpal
- Harvard University, John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA 02138, United States of America
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19
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Thandiackal R, Lauder GV. How zebrafish turn: analysis of pressure force dynamics and mechanical work. J Exp Biol 2020; 223:jeb223230. [PMID: 32616548 DOI: 10.1242/jeb.223230] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/26/2020] [Indexed: 11/20/2022]
Abstract
Whereas many fishes swim steadily, zebrafish regularly exhibit unsteady burst-and-coast swimming, which is characterized by repeated sequences of turns followed by gliding periods. Such a behavior offers the opportunity to investigate the hypothesis that negative mechanical work occurs in posterior regions of the body during early phases of the turn near the time of maximal body curvature. Here, we used a modified particle image velocimetry (PIV) technique to obtain high-resolution flow fields around the zebrafish body during turns. Using detailed swimming kinematics coupled with body surface pressure computations, we estimated fluid-structure interaction forces and the pattern of forces and torques along the body during turning. We then calculated the mechanical work done by each body segment. We used estimated patterns of positive and negative work along the body to evaluate the hypothesis (based on fish midline kinematics) that the posterior body region would experience predominantly negative work. Between 10% and 20% of the total mechanical work was done by the fluid on the body (negative work), and negative work was concentrated in the anterior and middle areas of the body, not along the caudal region. Energetic costs of turning were calculated by considering the sum of positive and negative work and were compared with previous metabolic estimates of turning energetics in fishes. The analytical workflow presented here provides a rigorous way to quantify hydrodynamic mechanisms of fish locomotion and facilitates the understanding of how body kinematics generate locomotor forces in freely swimming fishes.
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Affiliation(s)
- Robin Thandiackal
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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20
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Dial TR, Lauder GV. Longer development provides first-feeding fish time to escape hydrodynamic constraints. J Morphol 2020; 281:956-969. [PMID: 32557795 DOI: 10.1002/jmor.21224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/20/2020] [Accepted: 05/27/2020] [Indexed: 11/08/2022]
Abstract
What is the functional effect of prolonged development? By controlling for size, we quantify first-feeding performance and hydrodynamics of zebrafish and guppy offspring (5 ± 0.5 mm in length), which differ fivefold in developmental time and twofold in ontogenetic state. By manipulating water viscosity, we control the hydrodynamic regime, measured as Reynolds number. We predicted that if feeding performance were strictly the result of hydrodynamics, and not development, feeding performance would scale with Reynolds number. We find that guppy offspring successfully feed at much greater distances to prey (1.0 vs. 0.2 mm) and with higher capture success (90 vs. 20%) compared with zebrafish larvae, and that feeding performance was not a result of Reynolds number alone. Flow visualization shows that zebrafish larvae produce a bow wave ~0.2 mm in length, and that the flow field produced during suction does not extend beyond this bow wave. Due to well-developed oral jaw protrusion, the similar-sized suction field generated by guppy offspring extends beyond the horizon of their bow wave, leading to successful prey capture from greater distances. These findings suggest that prolonged development and increased ontogenetic state provides first-feeding fish time to escape the pervasive hydrodynamic constraints (bow wave) of being small.
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Affiliation(s)
- Terry R Dial
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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21
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Abstract
Fish locomotion is characterized by waves of muscle electrical activity that proceed from head to tail, and result in an undulatory pattern of body bending that generates thrust during locomotion. Isolating the effects of parameters like body stiffness, co-activation between the right and left sides of the body, and frequency on thrust generation has proven to be difficult in live fishes. We use a pneumatically-actuated fish-like model to investigate how these parameters affect locomotor force generation. We measure thrust as well as side forces and torques generated during propulsion. Using a statistical linear model we examine the effects of input parameter combinations on thrust generation. We show that both stiffness and frequency substantially affect swimming kinematics, and that there are complex interactive effects of these two parameters on thrust. The stiffer the backbone the more impact that increasing frequency has on thrust production. For stiffer models, increasing frequency resulted in higher values for both thrust and lateral forces. Large side forces reduce swimming efficiency but this effect could be mitigated by decreasing undulatory wavelength and allowing appropriate phasing of left and right body movements to reduce amplitudes of side force.
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Affiliation(s)
- Z Wolf
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, United States of America
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22
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Popp M, White CF, Bernal D, Wainwright DK, Lauder GV. The denticle surface of thresher shark tails: Three-dimensional structure and comparison to other pelagic species. J Morphol 2020; 281:938-955. [PMID: 32515875 DOI: 10.1002/jmor.21222] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/14/2020] [Accepted: 05/21/2020] [Indexed: 11/06/2022]
Abstract
Shark skin denticles (scales) are diverse in morphology both among species and across the body of single individuals, although the function of this diversity is poorly understood. The extremely elongate and highly flexible tail of thresher sharks provides an opportunity to characterize gradients in denticle surface characteristics along the length of the tail and assess correlations between denticle morphology and tail kinematics. We measured denticle morphology on the caudal fin of three mature and two embryo common thresher sharks (Alopias vulpinus), and we compared thresher tail denticles to those of eleven other shark species. Using surface profilometry, we quantified 3D-denticle patterning and texture along the tail of threshers (27 regions in adults, and 16 regions in embryos). We report that tails of thresher embryos have a membrane that covers the denticles and reduces surface roughness. In mature thresher tails, surfaces have an average roughness of 5.6 μm which is smoother than some other pelagic shark species, but similar in roughness to blacktip, porbeagle, and bonnethead shark tails. There is no gradient down the tail in roughness for the middle or trailing edge regions and hence no correlation with kinematic amplitude or inferred magnitude of flow separation along the tail during locomotion. Along the length of the tail there is a leading-to-trailing-edge gradient with larger leading edge denticles that lack ridges (average roughness = 9.6 μm), and smaller trailing edge denticles with 5 ridges (average roughness = 5.7 μm). Thresher shark tails have many missing denticles visible as gaps in the surface, and we present evidence that these denticles are being replaced by new denticles that emerge from the skin below.
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Affiliation(s)
- Meagan Popp
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Connor F White
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Diego Bernal
- Department of Biology, University of Massachusetts Dartmouth, Dartmouth, Massachusetts, USA
| | - Dylan K Wainwright
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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23
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Wang J, Wainwright DK, Lindengren RE, Lauder GV, Dong H. Tuna locomotion: a computational hydrodynamic analysis of finlet function. J R Soc Interface 2020; 17:20190590. [PMID: 32264740 PMCID: PMC7211474 DOI: 10.1098/rsif.2019.0590] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 03/19/2020] [Indexed: 11/12/2022] Open
Abstract
Finlets are a series of small non-retractable fins common to scombrid fishes (mackerels, bonitos and tunas), which are known for their high swimming speed. It is hypothesized that these small fins could potentially affect propulsive performance. Here, we combine experimental and computational approaches to investigate the hydrodynamics of finlets in yellowfin tuna (Thunnus albacares) during steady swimming. High-speed videos were obtained to provide kinematic data on the in vivo motion of finlets. High-fidelity simulations were then carried out to examine the hydrodynamic performance and vortex dynamics of a biologically realistic multiple-finlet model with reconstructed kinematics. It was found that finlets undergo both heaving and pitching motion and are delayed in phase from anterior to posterior along the body. Simulation results show that finlets were drag producing and did not produce thrust. The interactions among finlets helped reduce total finlet drag by 21.5%. Pitching motions of finlets helped reduce the power consumed by finlets during swimming by 20.8% compared with non-pitching finlets. Moreover, the pitching finlets created constructive forces to facilitate posterior body flapping. Wake dynamics analysis revealed a unique vortex tube matrix structure and cross-flow streams redirected by the pitching finlets, which supports their hydrodynamic function in scombrid fishes. Limitations on modelling and the generality of results are also discussed.
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Affiliation(s)
- Junshi Wang
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Dylan K. Wainwright
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Royce E. Lindengren
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - George V. Lauder
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Haibo Dong
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA
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24
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Wainwright DK, Lauder GV. Tunas as a high-performance fish platform for inspiring the next generation of autonomous underwater vehicles. Bioinspir Biomim 2020; 15:035007. [PMID: 32053798 DOI: 10.1088/1748-3190/ab75f7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Tunas of the genus Thunnus are a group of high-performance pelagic fishes with many locomotor traits that are convergently shared with other high-performance fish groups. Because of their swimming abilities, tunas continue to be an inspiration for both comparative biomechanics and the design of biomimetic autonomous underwater vehicles (AUVs). Despite the strong history of studies in tuna physiology and current interest in tuna biomechanics and bio-inspired design, we lack quantitative data on the function of many features of tunas. Here we present data on the morphology, behavior, and function of tunas, focusing especially on experimentally examining the function of tuna lateral keels, finlets, and pectoral fins by using simple physical models. We find that both triangular lateral keels and flexible finlets decrease power requirements during swimming, likely by reducing lateral forces and yaw torques (compared to models either without keels or with rectangular keels, and models with stiff finlets or strip fins of equal area, respectively). However, both triangular keels and flexible finlets generate less thrust than other models either without these features or with modified keels or finlets, leading to a tradeoff between power consumption and thrust. In addition, we use micro computed tomography (µCT) to show that the flexible lateral keels possess a lateral line canal, suggesting these keels have a sensory function. The curved and fully-attached base of tuna pectoral fins provides high lift-to-drag ratio at low angles of attack, and generates the highest torques across speeds and angles of attack. Therefore, curved, fully-attached pectoral fins grant both better gliding and maneuvering performance compared to flat or curved, partially-attached designs. We provide both 3D models of tuna morphology derived from µCT scans and conclusions about the performance effects of tuna-like features as a resource for future biological and engineering work for next-generation tuna-inspired AUV designs.
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Affiliation(s)
- Dylan K Wainwright
- Harvard University, Museum of Comparative Zoology, 26 Oxford Street, Cambridge MA 02143, United States of America. Yale University, Peabody Museum of Natural History, 21 Sachem Street, New Haven CT 06511, United States of America. Author to whom any correspondence should be addressed
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25
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Zhu J, White C, Wainwright DK, Di Santo V, Lauder GV, Bart-Smith H. Tuna robotics: A high-frequency experimental platform exploring the performance space of swimming fishes. Sci Robot 2019; 4:4/34/eaax4615. [PMID: 33137777 DOI: 10.1126/scirobotics.aax4615] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/20/2019] [Indexed: 11/02/2022]
Abstract
Tuna and related scombrid fishes are high-performance swimmers that often operate at high frequencies, especially during behaviors such as escaping from predators or catching prey. This contrasts with most fish-like robotic systems that typically operate at low frequencies (< 2 hertz). To explore the high-frequency fish swimming performance space, we designed and tested a new platform based on yellowfin tuna (Thunnus albacares) and Atlantic mackerel (Scomber scombrus). Body kinematics, speed, and power were measured at increasing tail beat frequencies to quantify swimming performance and to study flow fields generated by the tail. Experimental analyses of freely swimming tuna and mackerel allow comparison with the tuna-like robotic system. The Tunabot (255 millimeters long) can achieve a maximum tail beat frequency of 15 hertz, which corresponds to a swimming speed of 4.0 body lengths per second. Comparison of midline kinematics between scombrid fish and the Tunabot shows good agreement over a wide range of frequencies, with the biggest discrepancy occurring at the caudal fin, primarily due to the rigid propulsor used in the robotic model. As frequency increases, cost of transport (COT) follows a fish-like U-shaped response with a minimum at ~1.6 body lengths per second. The Tunabot has a range of ~9.1 kilometers if it swims at 0.4 meter per second or ~4.2 kilometers at 1.0 meter per second, assuming a 10-watt-hour battery pack. These results highlight the capabilities of high-frequency biological swimming and lay the foundation to explore a fish-like performance space for bio-inspired underwater vehicles.
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Affiliation(s)
- J Zhu
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA
| | - C White
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA
| | - D K Wainwright
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - V Di Santo
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - G V Lauder
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - H Bart-Smith
- Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA.
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26
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Kenaley CP, Marecki MC, Lauder GV. The role of an overlooked adductor muscle in the feeding mechanism of ray-finned fishes: Predictions from simulations of a deep-sea viperfish. ZOOLOGY 2019; 135:125678. [PMID: 31383297 DOI: 10.1016/j.zool.2019.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/13/2019] [Accepted: 02/25/2019] [Indexed: 10/27/2022]
Abstract
In a majority of ray-finned fishes (Actinopterygii), effective acquisition of food resources is predicated on rapid jaw adduction. Although the musculoskeletal architecture of the feeding system has been the subject of comparative research for many decades, individual contributions of the major adductor divisions to closing dynamics have not been elucidated. While it is understood that the dorsal divisions that arise from the head and insert on the posterior of the lower jaw are major contributors to closing dynamics, the contribution of the ventral components of the adductor system has been largely overlooked. In many ray-finned fishes, the ventral component is comprised of a single division, the Aω, that originates on an intersegmental aponeurosis of the facialis divisions and inserts on the medial face of the dentary, anterior to the Meckelian tendon. This configuration resembles a sling applied at two offset points of attachment on a third-order lever. The goal of this study was to elucidate the contributions of the Aω to jaw adduction by modeling jaw closing in the deep-sea viperfish Chauliodus sloani. To do this, we simulated adduction with a revised computational model that incorporates the geometry of the Aω. By comparing results between simulations that included and excluded Aω input, we show that the Aω adds substantially to lower-jaw adduction dynamics in C. sloani by acting as a steering motor and displacing the line of action of the dorsal facialis adductor muscles and increasing the mechanical advantage and input moment arms of the jaw lever system. We also explored the effect of the Aω on muscle dynamics and found that overall facialis muscle shortening velocities are higher and normalized force production is lower in simulations including the Aω. The net effect of these changes in muscle dynamics results in similar magnitudes of peak power in the facialis divisions between simulations, however, peak power is achieved earlier in adduction Modifications of muscle mechanics and posture result in significant increases in closing performance, including static bite force, angular velocity, and adduction time. We compare this configuration to a similar design in crocodilians and suggest that the Aω configuration and similar sling configurations across the vertebrate tree of life indicate the importance of this musculoskeletal design in feeding.
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Affiliation(s)
- Christopher P Kenaley
- Department of Biology, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA.
| | - Mikhaila C Marecki
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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Wainwright DK, Fish FE, Ingersoll S, Williams TM, St Leger J, Smits AJ, Lauder GV. How smooth is a dolphin? The ridged skin of odontocetes. Biol Lett 2019; 15:20190103. [PMID: 31311484 DOI: 10.1098/rsbl.2019.0103] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dolphin skin has long been an inspiration for research on drag reduction mechanisms due to the presence of skin ridges that could reduce fluid resistance. We gathered in vivo three-dimensional surface data on the skin from five species of odontocetes to quantitatively examine skin texture, including the presence and size of ridges. We used these data to calculate k+ values, which relate surface geometry to changes in boundary layer flow. Our results showed that while ridge size differs among species, odontocete skin was surprisingly smooth compared to the skin of other swimmers (average roughness = 5.3 µm). In addition, the presence of ridges was variable among individuals of the same species. We predict that odontocete skin ridges do not alter boundary layer flows at cruising swimming speeds. By combining k+ values and morphological data, our work provides evidence that skin ridges are unlikely to be an adaptation for drag reduction and that odontocete skin is exceptionally smooth compared to other pelagic swimmers.
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Affiliation(s)
- Dylan K Wainwright
- Organismic and Evolutionary Biology, Harvard University, Museum of Comparative Zoology, Cambridge, MA 02138, USA
| | - Frank E Fish
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - Sam Ingersoll
- Organismic and Evolutionary Biology, Harvard University, Museum of Comparative Zoology, Cambridge, MA 02138, USA
| | - Terrie M Williams
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | | | - Alexander J Smits
- Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - George V Lauder
- Organismic and Evolutionary Biology, Harvard University, Museum of Comparative Zoology, Cambridge, MA 02138, USA
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28
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Domel AG, Saadat M, Weaver JC, Haj-Hariri H, Bertoldi K, Lauder GV. Shark skin-inspired designs that improve aerodynamic performance. J R Soc Interface 2019; 15:rsif.2017.0828. [PMID: 29436512 DOI: 10.1098/rsif.2017.0828] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/17/2018] [Indexed: 11/12/2022] Open
Abstract
There have been significant efforts recently aimed at improving the aerodynamic performance of aerofoils through the modification of their surfaces. Inspired by the drag-reducing properties of the tooth-like denticles that cover the skin of sharks, we describe here experimental and simulation-based investigations into the aerodynamic effects of novel denticle-inspired designs placed along the suction side of an aerofoil. Through parametric modelling to query a wide range of different designs, we discovered a set of denticle-inspired surface structures that achieve simultaneous drag reduction and lift generation on an aerofoil, resulting in lift-to-drag ratio improvements comparable to the best-reported for traditional low-profile vortex generators and even outperforming these existing designs at low angles of attack with improvements of up to 323%. Such behaviour is enabled by two concurrent mechanisms: (i) a separation bubble in the denticle's wake altering the flow pressure distribution of the aerofoil to enhance suction and (ii) streamwise vortices that replenish momentum loss in the boundary layer due to skin friction. Our findings not only open new avenues for improved aerodynamic design, but also provide new perspective on the role of the complex and potentially multifunctional morphology of shark denticles for increased swimming efficiency.
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Affiliation(s)
- August G Domel
- Harvard University John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA 02138, USA
| | - Mehdi Saadat
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.,College of Engineering and Computing, University of South Carolina, Columbia, SC 29208, USA
| | - James C Weaver
- Wyss Institute for Biologically Inspired Engineering, Cambridge, MA 02138, USA
| | - Hossein Haj-Hariri
- College of Engineering and Computing, University of South Carolina, Columbia, SC 29208, USA
| | - Katia Bertoldi
- Harvard University John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA 02138, USA
| | - George V Lauder
- Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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29
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Wen L, Ren Z, Di Santo V, Hu K, Yuan T, Wang T, Lauder GV. Understanding Fish Linear Acceleration Using an Undulatory Biorobotic Model with Soft Fluidic Elastomer Actuated Morphing Median Fins. Soft Robot 2018; 5:375-388. [DOI: 10.1089/soro.2017.0085] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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30
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Domel AG, Domel G, Weaver JC, Saadat M, Bertoldi K, Lauder GV. Hydrodynamic properties of biomimetic shark skin: effect of denticle size and swimming speed. Bioinspir Biomim 2018; 13:056014. [PMID: 30018184 DOI: 10.1088/1748-3190/aad418] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Biomechanists and biologists alike have yet to fully understand the complex morphology and function of shark denticles, morphologically intricate tooth-like structures embedded into the skin of sharks. Denticles vary in many ways (such as size and shape) depending on shark species, and studies on denticle hydrodynamics have suggested that they may aid in drag reduction as well as increase both lift and thrust. Although previous studies have analyzed the effect of different denticle patterns on hydrodynamic performance, no previous work has focused on the effects of denticle size. Here, we report on the hydrodynamic properties of 3D printed shark skin foils with rigid denticles embedded into a flexible substrate. The patterning of these denticles was based on previously reported designs exhibiting the greatest hydrodynamic performance (which also most closely mimics real shark skin). The size of the denticles and the speed of the flow were varied, and the foils were evaluated under both static and dynamic conditions. Static tests showed drag reduction compared to a smooth control foil (without denticles) for the smallest denticle size, while medium and large denticles exhibited increased drag. Under dynamic testing conditions, the smallest denticles increased the self-propelled swimming speed, while the largest denticles reduced swimming performance. At higher speeds, the smallest denticles were also able to reduce power consumption compared to the control, demonstrating that their hydrodynamic effect depends on both denticle size and swimming speed. Our results thus provide new insights into the role of denticle size in shark swimming hydrodynamics across a range of locomotory modes, while simultaneously providing new design guidelines for the production of high performance low drag surface coatings for aquatic and aerospace applications.
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Affiliation(s)
- August G Domel
- Harvard University John A Paulson School of Engineering and Applied Sciences, Cambridge, MA 02138, United States of America
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31
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Abstract
Aquatic vertebrates display a variety of control surfaces that are used for propulsion, stabilization, trim and maneuvering. Control surfaces include paired and median fins in fishes, and flippers and flukes in secondarily aquatic tetrapods. These structures initially evolved from embryonic fin folds in fishes and have been modified into complex control surfaces in derived aquatic tetrapods. Control surfaces function both actively and passively to produce torque about the center of mass by the generation of either lift or drag, or both, and thus produce vector forces to effect rectilinear locomotion, trim control and maneuvers. In addition to fins and flippers, there are other structures that act as control surfaces and enhance functionality. The entire body can act as a control surface and generate lift for stability in destabilizing flow regimes. Furthermore, control surfaces can undergo active shape change to enhance their performance, and a number of features act as secondary control structures: leading edge tubercles, wing-like canards, multiple fins in series, finlets, keels and trailing edge structures. These modifications to control surface design can alter flow to increase lift, reduce drag and enhance thrust in the case of propulsive fin-based systems in fishes and marine mammals, and are particularly interesting subjects for future research and application to engineered systems. Here, we review how modifications to control surfaces can alter flow and increase hydrodynamic performance.
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Affiliation(s)
- Frank E Fish
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
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Ankhelyi MV, Wainwright DK, Lauder GV. Diversity of dermal denticle structure in sharks: Skin surface roughness and three‐dimensional morphology. J Morphol 2018; 279:1132-1154. [DOI: 10.1002/jmor.20836] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/07/2018] [Accepted: 04/14/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Madeleine V. Ankhelyi
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridge Massachusetts 02138
| | - Dylan K. Wainwright
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridge Massachusetts 02138
| | - George V. Lauder
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridge Massachusetts 02138
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Abstract
ABSTRACT
For centuries, designers and engineers have looked to biology for inspiration. Biologically inspired robots are just one example of the application of knowledge of the natural world to engineering problems. However, recent work by biologists and interdisciplinary teams have flipped this approach, using robots and physical models to set the course for experiments on biological systems and to generate new hypotheses for biological research. We call this approach robotics-inspired biology; it involves performing experiments on robotic systems aimed at the discovery of new biological phenomena or generation of new hypotheses about how organisms function that can then be tested on living organisms. This new and exciting direction has emerged from the extensive use of physical models by biologists and is already making significant advances in the areas of biomechanics, locomotion, neuromechanics and sensorimotor control. Here, we provide an introduction and overview of robotics-inspired biology, describe two case studies and suggest several directions for the future of this exciting new research area.
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Affiliation(s)
- Nick Gravish
- Dept. of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - George V. Lauder
- Dept. of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, MA 02138, USA
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Abstract
Tunas of the genus Thunnus possess many morphological and physiological adaptations for their high-performance epipelagic ecology. Although Thunnus anatomy has been studied, there are no quantitative studies on the structure of their scales. We investigated the scales of bigeye tuna (Thunnus obesus) from ten regions of the body using micro computed tomography (µCT)-scanning and histology to quantitatively and qualitatively compare regional scale morphology. We found a diversity of scale sizes and shapes across the body of bigeye tuna and discriminant function analysis on variables derived from µCT-data showed that scales across the body differ quantitatively in shape and size. We also report the discovery of a novel scale type in corselet, tail, and cheek regions. These modified scales are ossified shells supported by internal trabeculae, filled with fat, and possessing an internal blood supply. Histological analysis showed that the outer lamellar layers of these thickened scales are composed of cellular bone, unexpected for a perciform fish in which bone is typically acellular. In the fairing region of the anterior body, these fat-filled scales are stacked in layers up to five scales deep, forming a thickened bony casing. Cheek scales also possess a fat-filled internal trabecular structure, while most posterior body scales are more plate-like and similar to typical teleost scales. While the function of these novel fat-filled scales is unknown, we explore several possible hypotheses for their function.
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Affiliation(s)
- Dylan K Wainwright
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts
| | - Sam Ingersoll
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts
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35
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Higham TE, Rogers SM, Langerhans RB, Jamniczky HA, Lauder GV, Stewart WJ, Martin CH, Reznick DN. Speciation through the lens of biomechanics: locomotion, prey capture and reproductive isolation. Proc Biol Sci 2017; 283:rspb.2016.1294. [PMID: 27629033 DOI: 10.1098/rspb.2016.1294] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/24/2016] [Indexed: 11/12/2022] Open
Abstract
Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical traits. We investigate the role of biomechanics in speciation using fish predator-prey interactions, a primary driver of fitness for both predators and prey. We highlight specific groups of fishes, or specific species, that have been particularly valuable for understanding these dynamic interactions and offer the best opportunities for future studies that link genetic architecture to biomechanics and reproductive isolation (RI). In addition to emphasizing the key biomechanical techniques that will be instrumental, we also propose that the movement towards linking biomechanics and speciation will include (i) establishing the genetic basis of biomechanical traits, (ii) testing whether similar and divergent selection lead to biomechanical divergence, and (iii) testing whether/how biomechanical traits affect RI. Future investigations that examine speciation through the lens of biomechanics will propel our understanding of this key process.
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Affiliation(s)
- Timothy E Higham
- Department of Biology, University of California, Riverside, CA, USA
| | - Sean M Rogers
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - R Brian Langerhans
- Department of Biological Sciences and W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA
| | - Heather A Jamniczky
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | | | | | - David N Reznick
- Department of Biology, University of California, Riverside, CA, USA
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36
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Lucas KN, Dabiri JO, Lauder GV. A pressure-based force and torque prediction technique for the study of fish-like swimming. PLoS One 2017; 12:e0189225. [PMID: 29216264 PMCID: PMC5720764 DOI: 10.1371/journal.pone.0189225] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Many outstanding questions about the evolution and function of fish morphology are linked to swimming dynamics, and a detailed knowledge of time-varying forces and torques along the animal’s body is a key component in answering many of these questions. Yet, quantifying these forces and torques experimentally represents a major challenge that to date prevents a full understanding of fish-like swimming. Here, we develop a method for obtaining these force and torque data non-invasively using standard 2D digital particle image velocimetry in conjunction with a pressure field algorithm. We use a mechanical flapping foil apparatus to model fish-like swimming and measure forces and torques directly with a load cell, and compare these measured values to those estimated simultaneously using our pressure-based approach. We demonstrate that, when out-of-plane flows are relatively small compared to the planar flow, and when pressure effects sufficiently dominate shear effects, this technique is able to accurately reproduce the shape, magnitude, and timing of locomotor forces and torques experienced by a fish-like swimmer. We conclude by exploring of the limits of this approach and its feasibility in the study of freely-swimming fishes.
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Affiliation(s)
- Kelsey N Lucas
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, United States of America
| | - John O Dabiri
- Departments of Civil & Environmental Engineering and Mechanical Engineering, Stanford University, Stanford, California, United States of America
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, United States of America
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37
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Di Santo V, Kenaley CP, Lauder GV. High postural costs and anaerobic metabolism during swimming support the hypothesis of a U-shaped metabolism-speed curve in fishes. Proc Natl Acad Sci U S A 2017; 114:13048-13053. [PMID: 29158392 PMCID: PMC5724281 DOI: 10.1073/pnas.1715141114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Swimming performance is considered a key trait determining the ability of fish to survive. Hydrodynamic theory predicts that the energetic costs required for fishes to swim should vary with speed according to a U-shaped curve, with an expected energetic minimum at intermediate cruising speeds and increasing expenditure at low and high speeds. However, to date no complete datasets have shown an energetic minimum for swimming fish at intermediate speeds rather than low speeds. To address this knowledge gap, we used a negatively buoyant fish, the clearnose skate Raja eglanteria, and took two approaches: a classic critical swimming speed protocol and a single-speed exercise and recovery procedure. We found an anaerobic component at each velocity tested. The two approaches showed U-shaped, though significantly different, speed-metabolic relationships. These results suggest that (i) postural costs, especially at low speeds, may result in J- or U-shaped metabolism-speed curves; (ii) anaerobic metabolism is involved at all swimming speeds in the clearnose skate; and (iii) critical swimming protocols might misrepresent the true costs of locomotion across speeds, at least in negatively buoyant fish.
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Affiliation(s)
| | | | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138
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38
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Maia A, Lauder GV, Wilga CD. Hydrodynamic function of dorsal fins in spiny dogfish and bamboo sharks during steady swimming. ACTA ACUST UNITED AC 2017; 220:3967-3975. [PMID: 28883085 DOI: 10.1242/jeb.152215] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 08/28/2017] [Indexed: 11/20/2022]
Abstract
A key feature of fish functional design is the presence of multiple fins that allow thrust vectoring and redirection of fluid momentum to contribute to both steady swimming and maneuvering. A number of previous studies have analyzed the function of dorsal fins in teleost fishes in this context, but the hydrodynamic function of dorsal fins in freely swimming sharks has not been analyzed, despite the potential for differential functional roles between the anterior and posterior dorsal fins. Previous anatomical research has suggested a primarily stabilizing role for shark dorsal fins. We evaluated the generality of this hypothesis by using time-resolved particle image velocimetry to record water flow patterns in the wake of both the anterior and posterior dorsal fins in two species of freely swimming sharks: bamboo sharks (Chiloscyllium plagiosum) and spiny dogfish (Squalus acanthias). Cross-correlation analysis of consecutive images was used to calculate stroke-averaged mean longitudinal and lateral velocity components, and vorticity. In spiny dogfish, we observed a velocity deficit in the wake of the first dorsal fin and flow acceleration behind the second dorsal fin, indicating that the first dorsal fin experiences net drag while the second dorsal fin can aid in propulsion. In contrast, the wake of both dorsal fins in bamboo sharks displayed increased net flow velocity in the majority of trials, reflecting a thrust contribution to steady swimming. In bamboo sharks, fluid flow in the wake of the second dorsal fin had higher absolute average velocity than that for first dorsal fin, and this may result from a positive vortex interaction between the first and second dorsal fins. These data suggest that the first dorsal fin in spiny dogfish has primarily a stabilizing function, while the second dorsal fin has a propulsive function. In bamboo sharks, both dorsal fins can contribute thrust and should be considered as propulsive adjuncts to the body during steady swimming. The function of shark dorsal fins can thus differ considerably among fins and species, and is not limited to a stabilizing role.
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Affiliation(s)
- Anabela Maia
- Department of Biological Sciences, College of the Environmental and Life Sciences, University of Rhode Island, 120 Flagg Road, Kingston, RI 02881-0816, USA
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Cheryl D Wilga
- Department of Biological Sciences, College of the Environmental and Life Sciences, University of Rhode Island, 120 Flagg Road, Kingston, RI 02881-0816, USA
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39
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Weickhardt AF, Feilich KL, Lauder GV. Structure of supporting elements in the dorsal fin of percid fishes. J Morphol 2017; 278:1716-1725. [PMID: 28914460 DOI: 10.1002/jmor.20744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 07/01/2017] [Accepted: 07/31/2017] [Indexed: 11/11/2022]
Abstract
The dorsal fin is one of the most varied swimming structures in Acanthomorpha, the spiny-finned fishes. This fin can be present as a single contiguous structure supported by bony spines and soft lepidotrichia, or it may be divided into an anterior, spiny dorsal fin and a posterior, soft dorsal fin. The freshwater fish family Percidae exhibits especially great variation in dorsal fin spacing, including fishes with separated fins of varying gap length and fishes with contiguous fins. We hypothesized that fishes with separated dorsal fins, especially those with large gaps between fins, would have stiffened fin elements at the leading edge of the soft dorsal fin to resist hydrodynamic loading during locomotion. For 10 percid species, we measured the spacing between dorsal fins and calculated the second moment of area of selected spines and lepidotrichia from museum specimens. There was no significant relationship between the spacing between dorsal fins and the second moment of area of the leading edge of the soft dorsal fin.
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Affiliation(s)
- Alexander F Weickhardt
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, Massachusetts, 02138
| | - Kara L Feilich
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, Massachusetts, 02138
| | - George V Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, Massachusetts, 02138
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40
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Jusufi A, Vogt DM, Wood RJ, Lauder GV. Undulatory Swimming Performance and Body Stiffness Modulation in a Soft Robotic Fish-Inspired Physical Model. Soft Robot 2017; 4:202-210. [DOI: 10.1089/soro.2016.0053] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ardian Jusufi
- Centre for Autonomous Systems, Faculty of Engineering and Information Technology, University of Technology, Sydney
- Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts
| | - Daniel M. Vogt
- Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts
| | - Robert J. Wood
- Wyss Institute for Biologically Inspired Engineering, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts
| | - George V. Lauder
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
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41
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Shaffer HB, Lauder GV. PATTERNS OF VARIATION IN AQUATIC AMBYSTOMATID SALAMANDERS: KINEMATICS OF THE FEEDING MECHANISM. Evolution 2017; 39:83-92. [DOI: 10.1111/j.1558-5646.1985.tb04081.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/1983] [Accepted: 07/06/1984] [Indexed: 11/29/2022]
Affiliation(s)
- H. Bradley Shaffer
- Committee on Evolutionary Biology and Department of Anatomy University of Chicago Chicago IL 60637
| | - George V. Lauder
- Committee on Evolutionary Biology and Department of Anatomy University of Chicago Chicago IL 60637
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42
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Reilly SM, Lauder GV. THE EVOLUTION OF TETRAPOD FEEDING BEHAVIOR: KINEMATIC HOMOLOGIES IN PREY TRANSPORT. Evolution 2017; 44:1542-1557. [DOI: 10.1111/j.1558-5646.1990.tb03845.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/1989] [Accepted: 01/08/1990] [Indexed: 11/30/2022]
Affiliation(s)
- Stephen M. Reilly
- School of Biological Sciences University of California Irvine CA 92717 USA
| | - George V. Lauder
- School of Biological Sciences University of California Irvine CA 92717 USA
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43
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Schaefer SA, Lauder GV. TESTING HISTORICAL HYPOTHESES OF MORPHOLOGICAL CHANGE: BIOMECHANICAL DECOUPLING IN LORICARIOID CATFISHES. Evolution 2017; 50:1661-1675. [DOI: 10.1111/j.1558-5646.1996.tb03938.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/1994] [Accepted: 09/21/1995] [Indexed: 12/01/2022]
Affiliation(s)
- Scott A. Schaefer
- Department of Ichthyology Academy of Natural Sciences 1900 Ben Franklin Parkway Philadelphia Pennsylvania 19103‐1195
| | - George V. Lauder
- Department of Ecology and Evolution University of California Irvine California 92717
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44
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Affiliation(s)
- Dylan K. Wainwright
- Museum of Comparative Zoology, and Department of Organismic and Evolutionary Biology Harvard University Cambridge MA 02138 USA
| | - George V. Lauder
- Museum of Comparative Zoology, and Department of Organismic and Evolutionary Biology Harvard University Cambridge MA 02138 USA
| | - James C. Weaver
- Wyss Institute for Biologically Inspired Engineering Harvard University Cambridge MA 02138 USA
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Seth D, Flammang BE, Lauder GV, Tangorra JL. Development of a vortex generator to perturb fish locomotion. J Exp Biol 2017; 220:959-963. [PMID: 28082612 DOI: 10.1242/jeb.148346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/23/2016] [Indexed: 11/20/2022]
Abstract
Knowledge about the stiffness of fish fins, and whether stiffness is modulated during swimming, is important for understanding the mechanics of a fin's force production. However, the mechanical properties of fins have not been studied during natural swimming, in part because of a lack of instrumentation. To remedy this, a vortex generator was developed that produces traveling vortices of adjustable strength which can be used to perturb the fins of swimming fish. Experiments were conducted to understand how the generator's settings affected the resulting vortex rings. A variety of vortices (14-32 mm diameter traveling at 371-2155 mm s-1) were produced that elicited adequate responses from the fish fins to help us to understand the fin's mechanical properties at various swimming speeds (0-350 mm s-1).
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Affiliation(s)
- Deeksha Seth
- Drexel University, Department of Mechanical Engineering and Mechanics, 3141 Chestnut Street, Randell 115, MEM Department, Philadelphia, PA 19104, USA
| | - Brooke E Flammang
- New Jersey Institute of Technology, Department of Biological Sciences, University Heights, Newark, NJ 07102, USA
| | - George V Lauder
- Harvard University, Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology Laboratory, 26 Oxford Street, Cambridge, MA 02138, USA
| | - James L Tangorra
- Drexel University, Department of Mechanical Engineering and Mechanics, 3141 Chestnut Street, Randell 115, MEM Department, Philadelphia, PA 19104, USA
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Rosic MLN, Thornycroft PJM, Feilich KL, Lucas KN, Lauder GV. Performance variation due to stiffness in a tuna-inspired flexible foil model. Bioinspir Biomim 2017; 12:016011. [PMID: 28094239 DOI: 10.1088/1748-3190/aa5113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Tuna are fast, economical swimmers in part due to their stiff, high aspect ratio caudal fins and streamlined bodies. Previous studies using passive caudal fin models have suggested that while high aspect ratio tail shapes such as a tuna's generally perform well, tail performance cannot be determined from shape alone. In this study, we analyzed the swimming performance of tuna-tail-shaped hydrofoils of a wide range of stiffnesses, heave amplitudes, and frequencies to determine how stiffness and kinematics affect multiple swimming performance parameters for a single foil shape. We then compared the foil models' kinematics with published data from a live swimming tuna to determine how well the hydrofoil models could mimic fish kinematics. Foil kinematics over a wide range of motion programs generally showed a minimum lateral displacement at the narrowest part of the foil, and, immediately anterior to that, a local area of large lateral body displacement. These two kinematic patterns may enhance thrust in foils of intermediate stiffness. Stiffness and kinematics exhibited subtle interacting effects on hydrodynamic efficiency, with no one stiffness maximizing both thrust and efficiency. Foils of intermediate stiffnesses typically had the greatest coefficients of thrust at the highest heave amplitudes and frequencies. The comparison of foil kinematics with tuna kinematics showed that tuna motion is better approximated by a zero angle of attack foil motion program than by programs that do not incorporate pitch. These results indicate that open questions in biomechanics may be well served by foil models, given appropriate choice of model characteristics and control programs. Accurate replication of biological movements will require refinement of motion control programs and physical models, including the creation of models of variable stiffness.
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Park SJ, Gazzola M, Park KS, Park S, Di Santo V, Blevins EL, Lind JU, Campbell PH, Dauth S, Capulli AK, Pasqualini FS, Ahn S, Cho A, Yuan H, Maoz BM, Vijaykumar R, Choi JW, Deisseroth K, Lauder GV, Mahadevan L, Parker KK. Phototactic guidance of a tissue-engineered soft-robotic ray. Science 2016; 353:158-62. [PMID: 27387948 DOI: 10.1126/science.aaf4292] [Citation(s) in RCA: 423] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/19/2016] [Indexed: 12/15/2022]
Abstract
Inspired by the relatively simple morphological blueprint provided by batoid fish such as stingrays and skates, we created a biohybrid system that enables an artificial animal--a tissue-engineered ray--to swim and phototactically follow a light cue. By patterning dissociated rat cardiomyocytes on an elastomeric body enclosing a microfabricated gold skeleton, we replicated fish morphology at 1/10 scale and captured basic fin deflection patterns of batoid fish. Optogenetics allows for phototactic guidance, steering, and turning maneuvers. Optical stimulation induced sequential muscle activation via serpentine-patterned muscle circuits, leading to coordinated undulatory swimming. The speed and direction of the ray was controlled by modulating light frequency and by independently eliciting right and left fins, allowing the biohybrid machine to maneuver through an obstacle course.
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Affiliation(s)
- Sung-Jin Park
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Mattia Gazzola
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Kyung Soo Park
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742, Korea. Sogang-Harvard Research Center for Disease Biophysics, Sogang University, Seoul 121-742, Korea
| | - Shirley Park
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Valentina Di Santo
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Erin L Blevins
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Johan U Lind
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Patrick H Campbell
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Stephanie Dauth
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Andrew K Capulli
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Francesco S Pasqualini
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Seungkuk Ahn
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Alexander Cho
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Hongyan Yuan
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Ben M Maoz
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Ragu Vijaykumar
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Jeong-Woo Choi
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742, Korea. Sogang-Harvard Research Center for Disease Biophysics, Sogang University, Seoul 121-742, Korea
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA. Department of Psychiatry and Behavioral Sciences and the Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - L Mahadevan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. Department of Organismic and Evolutionary Biology, Department of Physics, Wyss Institute for Biologically Inspired Engineering, Kavli Institute for Nanobio Science and Technology, Harvard University, Cambridge, MA 02138S, USA
| | - Kevin Kit Parker
- Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. Sogang-Harvard Research Center for Disease Biophysics, Sogang University, Seoul 121-742, Korea.
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Lim JL, Lauder GV. Mechanisms of anguilliform locomotion in fishes studied using simple three-dimensional physical models. Bioinspir Biomim 2016; 11:046006. [PMID: 27378052 DOI: 10.1088/1748-3190/11/4/046006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Physical models enable researchers to systematically examine complex and dynamic mechanisms of underwater locomotion in ways that would be challenging with freely swimming animals. Previous research on undulatory locomotion, for example, has used rectangular flexible panels that are effectively two-dimensional as proxies for the propulsive surfaces of swimming fishes, but these bear little resemblance to the bodies of elongate eel-like swimming animals. In this paper we use a polyurethane rod (round cross-section) and bar (square cross-section) to represent the body of a swimming Pacific hagfish (Eptatretus stoutii). We actuated the rod and bar in both heave and pitch using a mechanical controller to generate a propulsive wave at frequencies between 0.5 and 2.5 Hz. We present data on (1) how kinematic swimming patterns change with driving frequency in these elongate fish-like models, (2) the thrust-generating capability of these simple models, (3) how forces and work done during propulsion compare between cross-sectional shapes, (4) the wake flow patterns in these swimming models using particle image velocimetry. We also contrast kinematic and hydrodynamic patterns produced by bar and rod models to comparable new experimental data on kinematics and wake flow patterns from freely swimming hagfish. Increasing the driving frequency of bar and rod models reduced trailing edge amplitude and wavelength, and above 2 Hz a nodal point appeared in the kinematic wave. Above 1 Hz, both the rod and bar generated net thrust, with the work per cycle reaching a minimum at 1.5 Hz, and the bar always requiring more work per cycle than the rod. Wake flow patterns generated by the swimming rod and bar included clearly visible lateral jets, but not the caudolaterally directed flows seen in the wakes from freely swimming hagfish.
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Kenaley CP, Lauder GV. A biorobotic model of the suction-feeding system in largemouth bass: the roles of motor program speed and hyoid kinematics. J Exp Biol 2016; 219:2048-59. [PMID: 27122547 DOI: 10.1242/jeb.132514] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 04/21/2016] [Indexed: 11/20/2022]
Abstract
The vast majority of ray-finned fishes capture prey through suction feeding. The basis of this behavior is the generation of subambient pressure through rapid expansion of a highly kinetic skull. Over the last four decades, results from in vivo experiments have elucidated the general relationships between morphological parameters and subambient pressure generation. Until now, however, researchers have been unable to tease apart the discrete contributions of, and complex relationships among, the musculoskeletal elements that support buccal expansion. Fortunately, over the last decade, biorobotic models have gained a foothold in comparative research and show great promise in addressing long-standing questions in vertebrate biomechanics. In this paper, we present BassBot, a biorobotic model of the head of the largemouth bass (Micropterus salmoides). BassBot incorporates a 3D acrylic plastic armature of the neurocranium, maxillary apparatus, lower jaw, hyoid, suspensorium and opercular apparatus. Programming of linear motors permits precise reproduction of live kinematic behaviors including hyoid depression and rotation, premaxillary protrusion, and lateral expansion of the suspensoria. BassBot reproduced faithful kinematic and pressure dynamics relative to live bass. We show that motor program speed has a direct relationship to subambient pressure generation. Like vertebrate muscle, the linear motors that powered kinematics were able to produce larger magnitudes of force at slower velocities and, thus, were able to accelerate linkages more quickly and generate larger magnitudes of subambient pressure. In addition, we demonstrate that disrupting the kinematic behavior of the hyoid interferes with the anterior-to-posterior expansion gradient. This resulted in a significant reduction in subambient pressure generation and pressure impulse of 51% and 64%, respectively. These results reveal the promise biorobotic models have for isolating individual parameters and assessing their role in suction feeding.
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Affiliation(s)
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
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