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Lapsansky AB, Warrick DR, Tobalske BW. High Wing-Loading Correlates with Dive Performance in Birds, Suggesting a Strategy to Reduce Buoyancy. Integr Comp Biol 2022; 62:878-889. [PMID: 35810134 DOI: 10.1093/icb/icac117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 11/14/2022] Open
Abstract
Diving birds are regarded as a classic example of morphological convergence (Darwin 1859). Divers tend to have small wings extending from rotund bodies, requiring many volant species to fly with rapid wingbeats, and rendering others flightless (Darwin 1839; Simpson 1946). The high wing-loading of diving birds is frequently associated with the challenge of using forelimbs adapted for flight for locomotion in a "draggier" fluid, but this does not explain why species that rely exclusively on their feet to dive should have relatively small wings, as well. Therefore, others have hypothesized that ecological factors shared by wing-propelled and foot-propelled diving birds drive the evolution of high wing-loading. Following a reexamination of the aquatic habits of birds, we tested between hypotheses seeking to explain high wing-loading in divers using new comparative data and phylogenetically informed analyses. We found little evidence that wing-propelled diving selects for small wings, as wing-propelled and foot-propelled species share similar wing-loadings. Instead, our results suggest that selection to reduce buoyancy has driven high wing-loading in divers, offering insights for the development of bird-like aquatic robots.
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Affiliation(s)
- Anthony B Lapsansky
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, MT, USA.,Department of Zoology, University of British Columbia, BC, Canada
| | | | - Bret W Tobalske
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, MT, USA
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Bartol IK, Ganley AM, Tumminelli AN, Krueger PS, Thompson JT. Vectored jets power arms-first and tail-first turns differently in brief squid with assistance from fins and keeled arms. J Exp Biol 2022; 225:275902. [PMID: 35786780 DOI: 10.1242/jeb.244151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/29/2022] [Indexed: 11/20/2022]
Abstract
Squids maneuver to capture prey, elude predators, navigate complex habitats, and deny rivals access to mates. Despite the ecological importance of this essential locomotive function, limited quantitative data on turning performance and wake dynamics of squids are available. To better understand the contribution of the jet, fins, and arms to turns, the role of orientation (i.e., arms-first vs tail-first) in maneuvering, and relationship between jet flow and turning performance, kinematic and 3D velocimetry data were collected in tandem from brief squid Lolliguncula brevis. The pulsed jet, which can be vectored to direct flows, was the primary driver of most turning behaviors, producing flows with the highest impulse magnitude and angular impulse about the main axis of the turn (yaw) and secondary axes (roll and pitch). The fins and keeled arms played subordinate but important roles in turning performance, contributing to angular impulse, stabilizing the maneuver along multiple axes, and/or reducing rotational resistance. Orientation affected turning performance and dynamics, with tail-first turns being associated with greater impulse and angular impulse, longer jet structures, higher jet velocities, and greater angular turning velocities than arms-first turns. Conversely, arms-first turns involved shorter, slower jets with less impulse, but these directed short pulses resulted in lower minimum length-specific turning radii. Although the length-to-diameter ratio (L/D) of ejected jet flow was a useful metric for characterizing vortical flow features, it, by itself, was not a reliable predictor of angular velocity or turning radii, which reflects the complexity of the squid multi-propulsor system.
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Affiliation(s)
- Ian K Bartol
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Alissa M Ganley
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Amanda N Tumminelli
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Paul S Krueger
- Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75275, USA
| | - Joseph T Thompson
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17604, USA
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Turner ML, Falkingham PL, Gatesy SM. What is Stance Phase On Deformable Substrates? Integr Comp Biol 2022; 62:icac009. [PMID: 35325150 DOI: 10.1093/icb/icac009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The stance phase of walking is when forces are applied to the environment to support, propel, and maneuver the body. Unlike solid surfaces, deformable substrates yield under load, allowing the foot to sink to varying degrees. For bipedal birds and their dinosaurian ancestors, a shared response to walking on these substrates has been identified in the looping path the digits follow underground. Because a volume of substrate preserves a 3-D record of stance phase in the form of footprints or tracks, understanding how the bipedal stride cycle relates to this looping motion is critical for building a track-based framework for the study of walking in extinct taxa. Here we used biplanar X-ray imaging to record and analyze 161 stance phases from 81 trials of three Helmeted Guineafowl (Numida meleagris) walking on radiolucent substrates of different consistency (solid, dry granular, firm to semi-liquid muds). Across all substrates, the feet sank to a range of depths up to 78% of hip height. With increasing substrate hydration, the majority of foot motion shifted from above to below ground. Walking kinematics sampled across all stride cycles revealed six sequential gait-based events originating from both feet, conserved throughout the spectrum of substrate consistencies during normal alternating walking. On all substrates that yielded, five sub-phases of gait were drawn out in space and formed a loop of varying shape. We describe the two-footed coordination and weight distribution that likely contributed to the observed looping patterns of an individual foot. Given such complex subsurface foot motion during normal alternating walking and some atypical walking behaviors, we discuss the definition of "stance phase" on deformable substrates. We also discuss implications of the gait-based origins of subsurface looping on the interpretation of locomotory information preserved in fossil dinosaur tracks.
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Affiliation(s)
- Morgan L Turner
- Department of Ecology, Evolution, and Organismal Biology, Division of Biology and Medicine, Brown University, Providence, RI, 02912, USA
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Peter L Falkingham
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Stephen M Gatesy
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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Höfling E, Abourachid A. The skin of birds' feet: Morphological adaptations of the plantar surface. J Morphol 2020; 282:88-97. [PMID: 33098345 DOI: 10.1002/jmor.21284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/24/2020] [Accepted: 10/08/2020] [Indexed: 11/09/2022]
Abstract
The skin of the foot provides the interface between the bird and the substrate. The foot morphology involves the bone shape and the integument that is in contact with the substrate. The podotheca is a layer of keratinized epidermis forming scales that extends from the tarsometatarsus to the toe extremities. It varies in size, shape, amount of overlap and interacts with the degree of fusion of the toes (syndactyly). A study of toe shape and the podotheca provides insights on the adaptations of perching birds. Our analysis is based on micro-CT scans and scanning electron microscopy images of 21 species from 17 families, and includes examples with different orientations of the toes: zygodactyl (toes II and III forward), anisodactyl (toes II, III, and IV forward), and heterodactyl (toes III and IV forward). We show that in these three groups, the skin forms part of a perching adaptation that involves syndactyly to different degrees. However, syndactyly does not occur in Psittacidae that use their toes also for food manipulation. The syndactyly increases the sole surface and may reinforce adherence with the substrate. Scale shape and toe orientation are involved in functional adaptations to perch. Thus, both bone and skin features combine to form a pincer-like foot.
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Affiliation(s)
- Elizabeth Höfling
- Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.,Museu de História Natural de Taubaté, Taubaté, SP, Brazil
| | - Anick Abourachid
- Mécanismes adapatatifs et évolution, Muséum National d'Histoire Naturelle - CNRS, 57 rue Cuvier, Paris, France, 75005, France
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Lapsansky AB, Zatz D, Tobalske BW. Alcids 'fly' at efficient Strouhal numbers in both air and water but vary stroke velocity and angle. eLife 2020; 9:55774. [PMID: 32602463 PMCID: PMC7332295 DOI: 10.7554/elife.55774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/20/2020] [Indexed: 12/01/2022] Open
Abstract
Birds that use their wings for ‘flight’ in both air and water are expected to fly poorly in each fluid relative to single-fluid specialists; that is, these jacks-of-all-trades should be the masters of none. Alcids exhibit exceptional dive performance while retaining aerial flight. We hypothesized that alcids maintain efficient Strouhal numbers and stroke velocities across air and water, allowing them to mitigate the costs of their ‘fluid generalism’. We show that alcids cruise at Strouhal numbers between 0.10 and 0.40 – on par with single-fluid specialists – in both air and water but flap their wings ~ 50% slower in water. Thus, these species either contract their muscles at inefficient velocities or maintain a two-geared muscle system, highlighting a clear cost to using the same morphology for locomotion in two fluids. Additionally, alcids varied stroke-plane angle between air and water and chord angle during aquatic flight, expanding their performance envelope.
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Affiliation(s)
- Anthony B Lapsansky
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, United States
| | | | - Bret W Tobalske
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, United States
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Crandell KE, Howe RO, Falkingham PL. Repeated evolution of drag reduction at the air-water interface in diving kingfishers. J R Soc Interface 2020; 16:20190125. [PMID: 31088257 DOI: 10.1098/rsif.2019.0125] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Piscivorous birds have a unique suite of adaptations to forage under the water. One method aerial birds use to catch fish is the plunge dive, wherein birds dive from a height to overcome drag and buoyancy in the water. The kingfishers are a well-known clade that contains both terrestrially foraging and plunge-diving species, allowing us to test for morphological and performance differences between foraging guilds in an evolutionary context. Diving species have narrower bills in the dorsoventral and sagittal plane and longer bills (size-corrected data, n = 71 species, p < 0.01 for all). Although these differences are confounded by phylogeny (phylogenetically corrected ANOVA for dorsoventral p = 0.26 and length p = 0.14), beak width in the sagittal plane remains statistically different ( p < 0.001). We examined the effects of beak morphology on plunge performance by physically simulating dives with three-dimensional printed models of beaks coupled with an accelerometer, and through computational fluid dynamics (CFD). From physically simulated dives of bill models, diving species have lower peak decelerations, and thus enter the water more quickly, than terrestrial and mixed-foraging species (ANOVA p = 0.002), and this result remains unaffected by phylogeny (phylogenetically corrected ANOVA p = 0.05). CFD analyses confirm these trends in three representative species and indicate that the morphology between the beak and head is a key site for reducing drag in aquatic species.
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Affiliation(s)
- K E Crandell
- 1 School of Natural Sciences, Bangor University , Bangor , UK
| | - R O Howe
- 1 School of Natural Sciences, Bangor University , Bangor , UK
| | - P L Falkingham
- 2 School of Natural Sciences, Liverpool John Moores University , Liverpool , UK
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Møller AP, Laursen K. Large feet are beneficial for eiders Somateria mollissima. Ecol Evol 2019; 9:8580-8586. [PMID: 31410263 PMCID: PMC6686295 DOI: 10.1002/ece3.5384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/25/2019] [Accepted: 05/28/2019] [Indexed: 11/08/2022] Open
Abstract
Many waterbirds have fully (totipalmate) or partially webbed (palmate) feet that are used for locomotion in aquatic environments.If webbed feet and wings both contribute to efficient diving, we predicted a positive association between the area of webbed feet and the size of the frontal locomotor apparatus (wing area, heart mass, and breast muscle, after adjusting for any partial effects of body size). We predicted that individuals able to acquire more and better quality food due to larger webbed feet should have larger livers with higher concentrations of fat-soluble antioxidants such as vitamin E, and invest more in immune function as reflected by the relative size of the uropygial gland than individuals with small webbed feet.Here, we examine if the area of webbed feet is correlated with locomotion, diet, and body condition in a sea-duck, the eider (Somateria mollissima). We analyzed an extensive database of 233 eiders shot in Danish waters and at Åland, Finland during winter and early spring.Eiders with larger webbed feet had a larger locomotor apparatus, but did not have larger body size, they had larger uropygial glands that waterproof the plumage, they had larger beak volume and larger gizzards, and they had higher body condition.These findings imply that eiders with large webbed feet benefitted in terms of locomotion, feeding, and reproduction.
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Affiliation(s)
- Anders Pape Møller
- Ecologie Systématique EvolutionUniversité Paris‐SudOrsay CedexFrance
- CNRS, AgroParisTechUniversité Paris‐SaclayOrsay CedexFrance
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life SciencesBeijing Normal UniversityBeijingChina
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Lapsansky AB, Tobalske BW. Upstroke-based acceleration and head stabilization are the norm for the wing-propelled swimming of alcid seabirds. ACTA ACUST UNITED AC 2019; 222:jeb.201285. [PMID: 31160426 DOI: 10.1242/jeb.201285] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/28/2019] [Indexed: 11/20/2022]
Abstract
Alcids, a family of seabirds including murres, guillemots and puffins, exhibit the greatest mass-specific dive depths and durations of any birds or mammals. These impressive diving capabilities have motivated numerous studies on the biomechanics of alcid swimming and diving, with one objective being to compare stroke-acceleration patterns of swimming alcids with those of penguins, where upstroke and downstroke are used for horizontal acceleration. Studies of free-ranging, descending alcids have found that alcids accelerate in the direction of travel during both their upstroke and downstroke, but only at depths <20 m, whereas studies of alcids swimming horizontally report upstroke-based acceleration to be rare (≤16% of upstrokes). We hypothesized that swimming trajectory, via its interaction with buoyancy, determines the magnitude of acceleration produced during the upstroke. Thus, we studied the stroke-acceleration relationships of five species of alcid swimming freely at the Alaska SeaLife Center using videography and kinematic analysis. Contrary to our prediction, we found that upstroke-based acceleration is very common (87% of upstrokes) during both descending and horizontal swimming. We reveal that head-damping - wherein an animal extends and retracts its head to offset periodic accelerations - is common in swimming alcids, underscoring the importance of head stabilization during avian locomotion.
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Affiliation(s)
- Anthony B Lapsansky
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Bret W Tobalske
- Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
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Moon JI, Jong-Gil Park, Nam DH, Lee DH. Complete mitochondrial genome of the Pacific Loon, Gavia pacifica (Gaviiformes: Gaviidae). Mitochondrial DNA B Resour 2019. [DOI: 10.1080/23802359.2019.1591229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
- Jae-I Moon
- Department of Biological Sciences, College of Natural Sciences and Research Center of Ecomimetics, Chonnam National University, Gwangju, Korea
| | - Jong-Gil Park
- Birds Research Center, Korea National Park Research Institute, Korea National Park Service, Jeollanam-do, Korea
| | - Dong-Ha Nam
- Department of Biological Sciences, College of Natural Sciences and Research Center of Ecomimetics, Chonnam National University, Gwangju, Korea
| | - Dong-Hyun Lee
- Department of Biological Sciences, College of Natural Sciences and Research Center of Ecomimetics, Chonnam National University, Gwangju, Korea
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