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Wold ES, Liu E, Lynch J, Gravish N, Sponberg S. The Weis-Fogh Number Describes Resonant Performance Tradeoffs in Flapping Insects. Integr Comp Biol 2024; 64:632-643. [PMID: 38816217 DOI: 10.1093/icb/icae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/29/2024] [Accepted: 05/06/2024] [Indexed: 06/01/2024] Open
Abstract
Dimensionless numbers have long been used in comparative biomechanics to quantify competing scaling relationships and connect morphology to animal performance. While common in aerodynamics, few relate the biomechanics of the organism to the forces produced on the environment during flight. We discuss the Weis-Fogh number, N, as a dimensionless number specific to flapping flight, which describes the resonant properties of an insect and resulting tradeoffs between energetics and control. Originally defined by Torkel Weis-Fogh in his seminal 1973 paper, N measures the ratio of peak inertial to aerodynamic torque generated by an insect over a wingbeat. In this perspectives piece, we define N for comparative biologists and describe its interpretations as a ratio of torques and as the width of an insect's resonance curve. We then discuss the range of N realized by insects and explain the fundamental tradeoffs between an insect's aerodynamic efficiency, stability, and responsiveness that arise as a consequence of variation in N, both across and within species. N is therefore an especially useful quantity for comparative approaches to the role of mechanics and aerodynamics in insect flight.
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Affiliation(s)
- Ethan S Wold
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Ellen Liu
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - James Lynch
- Mechanical and Aerospace Engineering, University of California San Diego, San Diego, CA 92161, USA
| | - Nick Gravish
- Mechanical and Aerospace Engineering, University of California San Diego, San Diego, CA 92161, USA
| | - Simon Sponberg
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
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2
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Darveau CA. Insect Flight Energetics and the Evolution of Size, Form, and Function. Integr Comp Biol 2024; 64:586-597. [PMID: 38688867 PMCID: PMC11406158 DOI: 10.1093/icb/icae028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/17/2024] [Accepted: 04/20/2024] [Indexed: 05/02/2024] Open
Abstract
Flying insects vary greatly in body size and wing proportions, significantly impacting their flight energetics. Generally, the larger the insect, the slower its flight wingbeat frequency. However, variation in frequency is also explained by differences in wing proportions, where larger-winged insects tend to have lower frequencies. These associations affect the energy required for flight. The correlated evolution of flight form and function can be further defined using a lineage of closely related bee species varying in body mass. The decline in flight wingbeat frequency with increasing size is paralleled by the flight mass-specific metabolic rate. The specific scaling exponents observed can be predicted from the wing area allometry, where a greater increase (hyperallometry) leads to a more pronounced effect on flight energetics, and hypoallometry can lead to no change in frequency and metabolic rate across species. The metabolic properties of the flight muscles also vary with body mass and wing proportions, as observed from the activity of glycolytic enzymes and the phospholipid compositions of muscle tissue, connecting morphological differences with muscle metabolic properties. The evolutionary scaling observed across species is recapitulated within species. The static allometry observed within the bumblebee Bombus impatiens, where the wing area is proportional and isometric, affects wingbeat frequency and metabolic rate, which is predicted to decrease with an increase in size. Intraspecific variation in flight muscle tissue properties is also related to flight metabolic rate. The role of developmental processes and phenotypic plasticity in explaining intraspecific differences is central to our understanding of flight energetics. These studies provide a framework where static allometry observed within species gives rise to evolutionary allometry, connecting the evolution of size, form, and function associated with insect flight.
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Affiliation(s)
- Charles-A Darveau
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
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Treidel LA, Deem KD, Salcedo MK, Dickinson MH, Bruce HS, Darveau CA, Dickerson BH, Ellers O, Glass JR, Gordon CM, Harrison JF, Hedrick TL, Johnson MG, Lebenzon JE, Marden JH, Niitepõld K, Sane SP, Sponberg S, Talal S, Williams CM, Wold ES. Insect Flight: State of the Field and Future Directions. Integr Comp Biol 2024; 64:icae106. [PMID: 38982327 PMCID: PMC11406162 DOI: 10.1093/icb/icae106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024] Open
Abstract
The evolution of flight in an early winged insect ancestral lineage is recognized as a key adaptation explaining the unparalleled success and diversification of insects. Subsequent transitions and modifications to flight machinery, including secondary reductions and losses, also play a central role in shaping the impacts of insects on broadscale geographic and ecological processes and patterns in the present and future. Given the importance of insect flight, there has been a centuries-long history of research and debate on the evolutionary origins and biological mechanisms of flight. Here, we revisit this history from an interdisciplinary perspective, discussing recent discoveries regarding the developmental origins, physiology, biomechanics, and neurobiology and sensory control of flight in a diverse set of insect models. We also identify major outstanding questions yet to be addressed and provide recommendations for overcoming current methodological challenges faced when studying insect flight, which will allow the field to continue to move forward in new and exciting directions. By integrating mechanistic work into ecological and evolutionary contexts, we hope that this synthesis promotes and stimulates new interdisciplinary research efforts necessary to close the many existing gaps about the causes and consequences of insect flight evolution.
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Affiliation(s)
- Lisa A Treidel
- School of Biological Sciences, University of Nebraska, Lincoln, Lincoln NE, 68588, USA
| | - Kevin D Deem
- Department of Biology, University of Rochester, Rochester NY, 14627, USA
| | - Mary K Salcedo
- Department of Biological and Environmental Engineering, Cornell University, Ithaca NY, 14853, USA
| | - Michael H Dickinson
- Department of Bioengineering, California Institute of Technology, Pasadena CA 91125, USA
| | | | - Charles-A Darveau
- Department of Biology, University of Ottawa, Ottawa Ontario, K1N 6N5, Canada
| | - Bradley H Dickerson
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Olaf Ellers
- Biology Department, Bowdoin College, Brunswick, ME 04011, USA
| | - Jordan R Glass
- Department of Zoology & Physiology, University of Wyoming, Laramie, WY 82070, USA
| | - Caleb M Gordon
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520-8109, USA
| | - Jon F Harrison
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Tyson L Hedrick
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Meredith G Johnson
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Jacqueline E Lebenzon
- Department of Integrative Biology, University of California, Berkeley, Berkeley CA, 94720, USA
| | - James H Marden
- Department of Biology, Pennsylvania State University, University Park, PA 16803, USA
| | | | - Sanjay P Sane
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065 India
| | - Simon Sponberg
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Stav Talal
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Caroline M Williams
- Department of Integrative Biology, University of California, Berkeley, Berkeley CA, 94720, USA
| | - Ethan S Wold
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Wold ES, Aiello B, Harris M, Bin Sikandar U, Lynch J, Gravish N, Sponberg S. Moth resonant mechanics are tuned to wingbeat frequency and energetic demands. Proc Biol Sci 2024; 291:20240317. [PMID: 38920055 DOI: 10.1098/rspb.2024.0317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/15/2024] [Indexed: 06/27/2024] Open
Abstract
An insect's wingbeat frequency is a critical determinant of its flight performance and varies by multiple orders of magnitude across Insecta. Despite potential energetic benefits for an insect that matches its wingbeat frequency to its resonant frequency, recent work has shown that moths may operate off their resonant peak. We hypothesized that across species, wingbeat frequency scales with resonance frequency to maintain favourable energetics, but with an offset in species that use frequency modulation as a means of flight control. The moth superfamily Bombycoidea is ideal for testing this hypothesis because their wingbeat frequencies vary across species by an order of magnitude, despite similar morphology and actuation. We used materials testing, high-speed videography and a model of resonant aerodynamics to determine how components of an insect's flight apparatus (stiffness, wing inertia, muscle strain and aerodynamics) vary with wingbeat frequency. We find that the resonant frequency of a moth correlates with wingbeat frequency, but resonance curve shape (described by the Weis-Fogh number) and peak location vary within the clade in a way that corresponds to frequency-dependent biomechanical demands. Our results demonstrate that a suite of adaptations in muscle, exoskeleton and wing drive variation in resonant mechanics, reflecting potential constraints on matching wingbeat and resonant frequencies.
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Affiliation(s)
- Ethan S Wold
- School of Biological Sciences, Georgia Institute of Technology , Atlanta, GA 30332, USA
| | - Brett Aiello
- School of Natural and Health Sciences, Seton Hill University , Greensburg, PA 15601, USA
| | - Manon Harris
- School of Physics, Georgia Institute of Technology , Atlanta, GA 30332, USA
| | - Usama Bin Sikandar
- School of Electrical and Computer Engineering, Georgia Institute of Technology , Atlanta, GA 30332, USA
| | - James Lynch
- Mechanical and Aerospace Engineering, University of California San Diego , San Diego, CA 92161, USA
| | - Nick Gravish
- Mechanical and Aerospace Engineering, University of California San Diego , San Diego, CA 92161, USA
| | - Simon Sponberg
- School of Biological Sciences, Georgia Institute of Technology , Atlanta, GA 30332, USA
- School of Physics, Georgia Institute of Technology , Atlanta, GA 30332, USA
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Yu K, Reddy GVP, Schrader J, Guo X, Li Y, Jiao Y, Shi P. A nondestructive method of calculating the wing area of insects. Ecol Evol 2022; 12:e8792. [PMID: 35386866 PMCID: PMC8975793 DOI: 10.1002/ece3.8792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/10/2022] [Accepted: 03/17/2022] [Indexed: 12/30/2022] Open
Abstract
Most insects engage in winged flight. Wing loading, that is, the ratio of body mass to total wing area, has been demonstrated to reflect flight maneuverability. High maneuverability is an important survival trait, allowing insects to escape natural enemies and to compete for mates. In some ecological field experiments, there is a need to calculate the wing area of insects without killing them. However, fast, nondestructive estimation of wing area for insects is not available based on past work. The Montgomery equation (ME), which assumes a proportional relationship between leaf area and the product of leaf length and width, is frequently used to calculate leaf area of plants, in crops with entire linear, lanceolate leaves. Recently, the ME was proved to apply to leaves with more complex shapes from plants that do not have any needle leaves. Given that the wings of insects are similar in shape to broad leaves, we tested the validity of the ME approach in calculating the wing area of insects using three species of cicadas common in eastern China. We compared the actual area of the cicadas' wings with the estimates provided by six potential models used for wing area calculation, and we found that the ME performed best, based on the trade-off between model structure and goodness of fit. At the species level, the estimates for the proportionality coefficients of ME for three cicada species were 0.686, 0.693, and 0.715, respectively. There was a significant difference in the proportionality coefficients between any two species. Our method provides a simple and powerful approach for the nondestructive estimation of insect wing area, which is also valuable in quantifying wing morphological features of insects. The present study provides a nondestructive approach to estimating the wing area of insects, allowing them to be used in mark and recapture experiments.
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Affiliation(s)
- Kexin Yu
- College of Biology and the EnvironmentBamboo Research InstituteNanjing Forestry UniversityNanjingChina
| | - Gadi V. P. Reddy
- USDA‐ARS‐Southern Insect Management Research UnitStonevilleMississippiUSA
| | - Julian Schrader
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
- Biodiversity, Macroecology and BiogeographyUniversity of GöttingenGöttingenGermany
| | - Xuchen Guo
- College of Biology and the EnvironmentBamboo Research InstituteNanjing Forestry UniversityNanjingChina
| | - Yirong Li
- College of Biology and the EnvironmentBamboo Research InstituteNanjing Forestry UniversityNanjingChina
| | - Yabing Jiao
- College of Biology and the EnvironmentBamboo Research InstituteNanjing Forestry UniversityNanjingChina
| | - Peijian Shi
- College of Biology and the EnvironmentBamboo Research InstituteNanjing Forestry UniversityNanjingChina
- Tropical Silviculture and Forest EcologyUniversity of GöttingenGöttingenGermany
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Zheng YX, Wang Y, Dai BY, Li Z, Huo QR, Cui JX, Liu H, Li XH, Hughes AC, Zhang AB. Flight Mill Experiments and Computer Simulations Indicate Islands Recruit More Capable Flyers of Moths. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.771719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Understanding the traits related to species colonization and invasion, is a key question for both pest management and evolution. One of the key components is flight, which has been measured for a number of insect species through radar and tethered flight mill systems, but a general understanding of insect flight at a community level is lacking. In this study, we used flight mill experiments to quantify flight abilities of moth species, and simulation experiments to study which moths in mainland China have the potential for cross-island dispersal. We found that moths from superfamily Geometroidea (family Geometridae) have the weakest flight ability among the seven Lepidoptera superfamilies, which is characterized by the shortest longest single flight (LSF), the shortest time corresponding to the longest single flight (TLSF) (timecorrespondingtothelongestsingleflight), the lowest total distance flown (TDF), and the lowest average speed during the flight (VTDF). Surprisingly, the family Pyralidae (superfamily Pyraloidea) has the highest flight endurance of all 186 species of 12 families in this study, which is unexpected, given its small size and morphological traits yet it shows the longest LSF and TLSF. The comparison between species common to mainland and islands shows that flight distance (LSF) may be more important for species spread than flight speed. The results of mainland-island simulations show that when P(LSF>CD) (the proportion of individuals whose LSF is greater than the closest distance (CD) between mainland and island to the total number of individuals in the population) is less than 0.004, it is difficult for moth species to disperse to across islands without relying on external factors such as airflow. Over extended periods, with the immigration of species with strong flight abilities, islands are more likely to recruit species with stronger flight abilities.
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7
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Aiello BR, Sikandar UB, Minoguchi H, Bhinderwala B, Hamilton CA, Kawahara AY, Sponberg S. The evolution of two distinct strategies of moth flight. J R Soc Interface 2021; 18:20210632. [PMID: 34847789 DOI: 10.1098/rsif.2021.0632] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Across insects, wing shape and size have undergone dramatic divergence even in closely related sister groups. However, we do not know how morphology changes in tandem with kinematics to support body weight within available power and how the specific force production patterns are linked to differences in behaviour. Hawkmoths and wild silkmoths are diverse sister families with divergent wing morphology. Using three-dimensional kinematics and quasi-steady aerodynamic modelling, we compare the aerodynamics and the contributions of wing shape, size and kinematics in 10 moth species. We find that wing movement also diverges between the clades and underlies two distinct strategies for flight. Hawkmoths use wing kinematics, especially high frequencies, to enhance force and wing morphologies that reduce power. Silkmoths use wing morphology to enhance force, and slow, high-amplitude wingstrokes to reduce power. Both strategies converge on similar aerodynamic power and can support similar body weight ranges. However, inter-clade within-wingstroke force profiles are quite different and linked to the hovering flight of hawkmoths and the bobbing flight of silkmoths. These two moth groups fly more like other, distantly related insects than they do each other, demonstrating the diversity of flapping flight evolution and a rich bioinspired design space for robotic flappers.
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Affiliation(s)
- Brett R Aiello
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.,McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA
| | - Usama Bin Sikandar
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.,Department of Electrical Engineering, Information Technology University, Lahore, Pakistan
| | - Hajime Minoguchi
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Chris A Hamilton
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | - Akito Y Kawahara
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA.,Department of Biology, University of Florida, Gainesville, FL 32608, USA.,Department Entomology and Nematology, University of Florida, Gainesville, FL 32608, USA
| | - Simon Sponberg
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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8
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Hamilton CA, Winiger N, Rubin JJ, Breinholt J, Rougerie R, Kitching IJ, Barber JR, Kawahara AY. Hidden phylogenomic signal helps elucidate arsenurine silkmoth phylogeny and the evolution of body size and wing shape trade-offs. Syst Biol 2021; 71:859-874. [PMID: 34791485 DOI: 10.1093/sysbio/syab090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
One of the key objectives in biological research is understanding how evolutionary processes have produced Earth's diversity. A critical step towards revealing these processes is an investigation of evolutionary tradeoffs - that is, the opposing pressures of multiple selective forces. For millennia, nocturnal moths have had to balance successful flight, as they search for mates or host plants, with evading bat predators. However, the potential for evolutionary trade-offs between wing shape and body size are poorly understood. In this study, we used phylogenomics and geometric morphometrics to examine the evolution of wing shape in the wild silkmoth subfamily Arsenurinae (Saturniidae) and evaluate potential evolutionary relationships between body size and wing shape. The phylogeny was inferred based on 782 loci from target capture data of 42 arsenurine species representing all 10 recognized genera. After detecting in our data one of the most vexing problems in phylogenetic inference - a region of a tree that possesses short branches and no "support" for relationships (i.e., a polytomy), we looked for hidden phylogenomic signal (i.e., inspecting differing phylogenetic inferences, alternative support values, quartets, and phylogenetic networks) to better illuminate the most probable generic relationships within the subfamily. We found there are putative evolutionary trade-offs between wing shape, body size, and the interaction of fore- and hindwing shape. Namely, body size tends to decrease with increasing hindwing length but increases as forewing shape becomes more complex. Additionally, the type of hindwing (i.e., tail or no tail) a lineage possesses has a significant effect on the complexity of forewing shape. We outline possible selective forces driving the complex hindwing shapes that make Arsenurinae, and silkmoths as a whole, so charismatic.
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Affiliation(s)
- Chris A Hamilton
- Florida Museum of Natural History, McGuire Center for Lepidoptera and Biodiversity, University of Florida, Gainesville, FL 32611 USA.,Department of Entomology, Plant Pathology & Nematology, University of Idaho, Moscow, ID, 83844 USA
| | - Nathalie Winiger
- Florida Museum of Natural History, McGuire Center for Lepidoptera and Biodiversity, University of Florida, Gainesville, FL 32611 USA.,Wildlife Ecology and Management, Albert-Ludwigs-Universität Freiburg, 79106 Freiburg, Germany
| | - Juliette J Rubin
- Florida Museum of Natural History, McGuire Center for Lepidoptera and Biodiversity, University of Florida, Gainesville, FL 32611 USA
| | - Jesse Breinholt
- Florida Museum of Natural History, McGuire Center for Lepidoptera and Biodiversity, University of Florida, Gainesville, FL 32611 USA.,Division of Bioinformatics, Intermountain Healthcare, Precision Genomics, St. George, UT 84790 USA
| | - Rodolphe Rougerie
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris, France
| | - Ian J Kitching
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Jesse R Barber
- Department of Biological Sciences, Boise State University, Boise, ID, 83725 USA
| | - Akito Y Kawahara
- Florida Museum of Natural History, McGuire Center for Lepidoptera and Biodiversity, University of Florida, Gainesville, FL 32611 USA
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