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Buckley J, Chikere N, Ozkan-Aydin Y. The effect of tail stiffness on a sprawling quadruped locomotion. Front Robot AI 2023; 10:1198749. [PMID: 37692530 PMCID: PMC10484481 DOI: 10.3389/frobt.2023.1198749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 08/09/2023] [Indexed: 09/12/2023] Open
Abstract
A distinctive feature of quadrupeds that is integral to their locomotion is the tail. Tails serve many purposes in biological systems, including propulsion, counterbalance, and stabilization while walking, running, climbing, or jumping. Similarly, tails in legged robots may augment the stability and maneuverability of legged robots by providing an additional point of contact with the ground. However, in the field of terrestrial bio-inspired legged robotics, the tail is often ignored because of the difficulties in design and control. In this study, we test the hypothesis that a variable stiffness robotic tail can improve the performance of a sprawling quadruped robot by enhancing its stability and maneuverability in various environments. In order to validate our hypothesis, we integrated a cable-driven, flexible tail with multiple segments into the underactuated sprawling quadruped robot, where a single servo motor working alongside a reel and cable mechanism regulates the tail's stiffness. Our results demonstrated that by controlling the stiffness of the tail, the stability of locomotion on rough terrain and the climbing ability of the robot are improved compared to the movement with a rigid tail and no tail. Our findings highlight that constant ground support provided by the flexible tail is key to maintaining stable locomotion. This ensured a predictable gait cycle, eliminating unexpected turning and slipping, resulting in an increase in locomotion speed and efficiency. Additionally, we observed the robot's enhanced climbing ability on surfaces inclined up to 20°. The flexibility of the tail enabled the robot to overcome obstacles without external sensing, exhibiting significant adaptability across various terrains.
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Affiliation(s)
- Josh Buckley
- Department of Biomedical Engineering, University of Galway, County Galway, Ireland
| | - Nnamdi Chikere
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, United States
| | - Yasemin Ozkan-Aydin
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, United States
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2
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Rennolds CW, Bely AE. Integrative biology of injury in animals. Biol Rev Camb Philos Soc 2023; 98:34-62. [PMID: 36176189 PMCID: PMC10087827 DOI: 10.1111/brv.12894] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 07/29/2022] [Accepted: 08/02/2022] [Indexed: 01/12/2023]
Abstract
Mechanical injury is a prevalent challenge in the lives of animals with myriad potential consequences for organisms, including reduced fitness and death. Research on animal injury has focused on many aspects, including the frequency and severity of wounding in wild populations, the short- and long-term consequences of injury at different biological scales, and the variation in the response to injury within or among individuals, species, ontogenies, and environmental contexts. However, relevant research is scattered across diverse biological subdisciplines, and the study of the effects of injury has lacked synthesis and coherence. Furthermore, the depth of knowledge across injury biology is highly uneven in terms of scope and taxonomic coverage: much injury research is biomedical in focus, using mammalian model systems and investigating cellular and molecular processes, while research at organismal and higher scales, research that is explicitly comparative, and research on invertebrate and non-mammalian vertebrate species is less common and often less well integrated into the core body of knowledge about injury. The current state of injury research presents an opportunity to unify conceptually work focusing on a range of relevant questions, to synthesize progress to date, and to identify fruitful avenues for future research. The central aim of this review is to synthesize research concerning the broad range of effects of mechanical injury in animals. We organize reviewed work by four broad and loosely defined levels of biological organization: molecular and cellular effects, physiological and organismal effects, behavioural effects, and ecological and evolutionary effects of injury. Throughout, we highlight the diversity of injury consequences within and among taxonomic groups while emphasizing the gaps in taxonomic coverage, causal understanding, and biological endpoints considered. We additionally discuss the importance of integrating knowledge within and across biological levels, including how initial, localized responses to injury can lead to long-term consequences at the scale of the individual animal and beyond. We also suggest important avenues for future injury biology research, including distinguishing better between related yet distinct injury phenomena, expanding the subjects of injury research to include a greater variety of species, and testing how intrinsic and extrinsic conditions affect the scope and sensitivity of injury responses. It is our hope that this review will not only strengthen understanding of animal injury but will contribute to building a foundation for a more cohesive field of 'injury biology'.
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Affiliation(s)
- Corey W Rennolds
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
| | - Alexandra E Bely
- Department of Biology, University of Maryland, College Park, MD, 20742, USA
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3
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Yuan J, Wang Z, Song Y, Dai Z. Peking geckos (Gekko swinhonis) traversing upward steps: the effect of step height on the transition from horizontal to vertical locomotion. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:421-433. [PMID: 35362821 DOI: 10.1007/s00359-022-01548-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/13/2022] [Accepted: 03/15/2022] [Indexed: 11/25/2022]
Abstract
The ability to transition between surfaces (e.g., from the ground to vertical barriers, such as walls, tree trunks, or rock surfaces) is important for the Peking gecko's (Gekko swinhonis Günther 1864) survival. However, quantitative research on gecko's kinematic performance and the effect of obstacle height during transitional locomotion remains scarce. In this study, the transitional locomotion of geckos facing different obstacle heights was assessed. Remarkably, geckos demonstrated a bimodal locomotion ability, as they could climb and jump. Climbing was more common on smaller obstacles and took longer than jumping. The jumping type depended on the obstacle height: when geckos could jump onto the obstacle, the vertical velocity increased with obstacle height; however, geckos jumped from a closer position when the obstacle height exceeded this range and would get attached to the vertical surface. A stability analysis of vertical surface landing using a collision model revealed that geckos can reduce their restraint impulse by increasing the landing angle through limb extension close to the body, consequently dissipating collision energy and reducing their horizontal and vertical velocities. The findings of this study reveal the adaptations evolved by geckos to move in their environments and may have applicability in the robotics field.
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Affiliation(s)
- Jiwei Yuan
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China
| | - Zhouyi Wang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China.
| | - Yi Song
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China
| | - Zhendong Dai
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing, 210016, People's Republic of China
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4
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Fernández‐Rodríguez I, Braña F. Short‐term and long‐term consequences of regeneration on the reproductive investment of a multivoltine lizard. J Zool (1987) 2022. [DOI: 10.1111/jzo.12959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- I. Fernández‐Rodríguez
- Department of Organisms and Systems Biology (Zoology) University of Oviedo Oviedo Spain
- Biodiversity Research Institute (IMIB, CSIC/UO/PA) University of Oviedo Mieres Spain
| | - F. Braña
- Department of Organisms and Systems Biology (Zoology) University of Oviedo Oviedo Spain
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5
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Fernández-Rodríguez I, Braña F. Allocation costs of regeneration: tail regeneration constrains body growth under low food availability in juvenile lizards. Oecologia 2021; 198:853-864. [PMID: 34907460 PMCID: PMC9056467 DOI: 10.1007/s00442-021-05084-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 11/19/2021] [Indexed: 11/27/2022]
Abstract
The balance of energy allocated to development and growth of different body compartments may incur allocation conflicts and can thereby entail physiological and evolutionary consequences. Regeneration after autotomy restores the functionality lost after shedding a body part but requires a strong energy investment that may trade-off with other processes, like reproduction or growth. Caudal autotomy is a widespread antipredator strategy in lizards, but regeneration may provoke decreased growth rates in juveniles that could have subsequent consequences. Here, we assessed the growth of intact and regenerating hatchling wall lizards (Podarcis muralis) exposed to different food regimens. Regenerating juveniles presented slightly but significantly lower body growth rates than individuals with intact tails when facing low food availability, but there were no differences when food was supplied ad libitum. Regenerating individuals fed ad libitum increased their ingestion rates compared to intact ones during the period of greatest tail growth, which also reveals a cost of tail regeneration. When resources were scarce, hatchlings invested more in tail regeneration in relation to body growth, rather than delay regeneration to give priority to body growth. We propose that, in juvenile lizards, regeneration could be prioritized even at the expense of body growth to restore the functionality of the lost tail, likely increasing survivorship and the probability to reach reproductive maturity. Our study indicates that food availability is a key factor for the occurrence of trade-offs between regeneration and other growth processes, so that environmental conditions would be determinant for the severity of the costs of regeneration.
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Affiliation(s)
- Irene Fernández-Rodríguez
- Department of Organisms and Systems Biology (Zoology), University of Oviedo, 33071, Oviedo, Spain. .,Biodiversity Research Institute (IMIB, UO/CSIC/PA), University of Oviedo, Mieres, Spain.
| | - Florentino Braña
- Department of Organisms and Systems Biology (Zoology), University of Oviedo, 33071, Oviedo, Spain.,Biodiversity Research Institute (IMIB, UO/CSIC/PA), University of Oviedo, Mieres, Spain
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6
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Jumping with adhesion: landing surface incline alters impact force and body kinematics in crested geckos. Sci Rep 2021; 11:23043. [PMID: 34845262 PMCID: PMC8630229 DOI: 10.1038/s41598-021-02033-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 10/29/2021] [Indexed: 11/20/2022] Open
Abstract
Arboreal habitats are characterized by a complex three-dimensional array of branches that vary in numerous characteristics, including incline, compliance, roughness, and diameter. Gaps must often be crossed, and this is frequently accomplished by leaping. Geckos bearing an adhesive system often jump in arboreal habitats, although few studies have examined their jumping biomechanics. We investigated the biomechanics of landing on smooth surfaces in crested geckos, Correlophus ciliatus, asking whether the incline of the landing platform alters impact forces and mid-air body movements. Using high-speed videography, we examined jumps from a horizontal take-off platform to horizontal, 45° and 90° landing platforms. Take-off velocity was greatest when geckos were jumping to a horizontal platform. Geckos did not modulate their body orientation in the air. Body curvature during landing, and landing duration, were greatest on the vertical platform. Together, these significantly reduced the impact force on the vertical platform. When landing on a smooth vertical surface, the geckos must engage the adhesive system to prevent slipping and falling. In contrast, landing on a horizontal surface requires no adhesion, but incurs high impact forces. Despite a lack of mid-air modulation, geckos appear robust to changing landing conditions.
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7
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García-Hernández S, Machado G. Short- and long-term effects of an extreme case of autotomy: does "tail" loss and subsequent constipation decrease the locomotor performance of male and female scorpions? Integr Zool 2021; 17:672-688. [PMID: 34741423 DOI: 10.1111/1749-4877.12604] [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] [Indexed: 11/29/2022]
Abstract
In many taxa, individuals voluntarily detach a body part as a form to increase their chances of escaping predation. This defense mechanism, known as autotomy, has several consequences, such as changes in locomotor performance that may affect fitness. Scorpions of the genus Ananteris autotomize the "tail", which in fact corresponds to the last abdominal segments. After autotomy, individuals lose nearly 25% of their body mass and the last portion of the digestive tract, including the anus, which prevents defecation and leads to constipation, because regeneration does not occur. Here, we experimentally investigated the short- and long-term effects of tail loss on the locomotor performance of Ananteris balzani. In a short-term experiment, the maximum running speed (MRS) of males and females did not change after autotomy. Moreover, the relative mass of the lost tail did not affect the change in MRS after autotomy. In a long-term experiment, autotomy had a negative effect on the MRS of males, but not of females. Autotomized over-fed individuals suffered from severe constipation but were not slower than autotomized normally fed individuals. In conclusion, tail loss has no immediate effect on the locomotor performance of scorpions. The long-term decrease in the locomotor performance of autotomized males may impair mate searching. However, because death by constipation takes several months, males have a long time to find mates and reproduce. Thus, the prolonged period between autotomy and death by constipation is crucial for understanding the evolution of one of the most extreme cases of autotomy in nature.
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Affiliation(s)
- Solimary García-Hernández
- Programa de Pós-graduação em Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Glauco Machado
- LAGE do Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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8
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Schwaner MJ, Hsieh ST, Braasch I, Bradley S, Campos CB, Collins CE, Donatelli CM, Fish FE, Fitch OE, Flammang BE, Jackson BE, Jusufi A, Mekdara PJ, Patel A, Swalla BJ, Vickaryous M, McGowan CP. Future Tail Tales: A Forward-Looking, Integrative Perspective on Tail Research. Integr Comp Biol 2021; 61:521-537. [PMID: 33999184 PMCID: PMC8680820 DOI: 10.1093/icb/icab082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Synopsis Tails are a defining characteristic of chordates and show enormous diversity in function and shape. Although chordate tails share a common evolutionary and genetic-developmental origin, tails are extremely versatile in morphology and function. For example, tails can be short or long, thin or thick, and feathered or spiked, and they can be used for propulsion, communication, or balancing, and they mediate in predator-prey outcomes. Depending on the species of animal the tail is attached to, it can have extraordinarily multi-functional purposes. Despite its morphological diversity and broad functional roles, tails have not received similar scientific attention as, for example, the paired appendages such as legs or fins. This forward-looking review article is a first step toward interdisciplinary scientific synthesis in tail research. We discuss the importance of tail research in relation to five topics: (1) evolution and development, (2) regeneration, (3) functional morphology, (4) sensorimotor control, and (5) computational and physical models. Within each of these areas, we highlight areas of research and combinations of long-standing and new experimental approaches to move the field of tail research forward. To best advance a holistic understanding of tail evolution and function, it is imperative to embrace an interdisciplinary approach, re-integrating traditionally siloed fields around discussions on tail-related research.
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Affiliation(s)
- M J Schwaner
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA 92697, USA
| | - S T Hsieh
- Department of Biology, Temple University, Philadelphia, PA 19122, USA
| | - I Braasch
- Department of Integrative Biology and Program in Ecology, Evolution, and Behavior (EEB), Michigan State University, East Lansing, MI 48824, USA
| | - S Bradley
- Department of Biomedical Science, University of Guelph, Guelph N1G 2W1, Canada
| | - C B Campos
- Department of Biological Sciences, Sacramento State University, Sacramento, CA 95819, USA
| | - C E Collins
- Department of Biological Sciences, Sacramento State University, Sacramento, CA 95819, USA
| | - C M Donatelli
- Department of Biology, University of Ottawa, Ontario K1N 6N5, Canada
| | - F E Fish
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - O E Fitch
- Department of Integrative Biology and Program in Ecology, Evolution, and Behavior (EEB), Michigan State University, East Lansing, MI 48824, USA
| | - B E Flammang
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - B E Jackson
- Department of Biological and Environmental Sciences, Longwood University, Farmville, VA 23909, USA
| | - A Jusufi
- Max Planck Institute for Intelligent Systems, Stuttgart 70569, Germany
| | - P J Mekdara
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - A Patel
- Department of Electrical Engineering, University of Cape Town, Cape Town 7701, South Africa
| | - B J Swalla
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - M Vickaryous
- Department of Biomedical Science, University of Guelph, Guelph N1G 2W1, Canada
| | - C P McGowan
- Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, CA 90033, USA
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9
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Smith SK, Hilliard Young VK. Balancing on a Limb: Effects of Gravidity on Locomotion in Arboreal, Limbed Vertebrates. Integr Comp Biol 2021; 61:573-578. [PMID: 33885749 DOI: 10.1093/icb/icab035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Reproduction is linked to a plethora of costs in gravid females, not least of which is a reduction in locomotor performance. Locomotor constraints due to gravidity are apparent across aquatic, terrestrial, and arboreal habitats. Decrements to speed and maneuverability are the most often cited performance consequences of gravidity, regardless of habitat. Arboreal habitats present additional challenges, as they often are composed of unstable and varying substrates that affect locomotor performance. Many arboreal taxa exhibit morphological adaptations, such as grasping extremities and tails, that function to aid in stability during locomotion. Tail length has been found to correlate with lifestyle: arboreal mammals tend to have relatively longer tails compared with terrestrial counterparts. Balancing on a limb is hard on its own, but when combined with increased mass and shifts in center of mass due to pregnancy, it becomes even more challenging. However, few studies have explored the constraints that govern the intersection of arboreal locomotion, reproductive cost, and morphology. In this review, we identify fruitful areas for expansion of research and knowledge (i.e., the role of the tail) when it comes to arboreal balance during gestation.
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Affiliation(s)
- Shaylee K Smith
- Department of Biology, Saint Mary's College, Notre Dame, IN 46556, USA
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10
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Telheiro A, Coelho P, van der Meijden A. The effect of change in mass distribution due to defensive posture on gait in fat-tailed scorpions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:117-125. [PMID: 33751181 DOI: 10.1007/s00359-021-01467-5] [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: 08/27/2020] [Revised: 02/11/2021] [Accepted: 02/15/2021] [Indexed: 10/22/2022]
Abstract
In terrestrial legged locomotion, the distribution of mass can influence the gait characteristics. This can be due to a change in the magnitude or distribution of the load. The latter occurs in scorpions when they lift their large metasoma from a trailing position in ambulatory posture to the well-known arched forward position in the defensive posture. We measured how locomotion changes between these two postures by recording scorpions walking using high-speed video. We found that the metasoma in the fat-tailed scorpion (Androctonus australis) represents about a quarter of the total mass. Moving this mass anteriorly over the body changes the position of the center of mass forward 8.15 ± 1.86 mm. We found this increases the overall duty factor, and particularly that of the second leg pair, even when taking the reduced speed in defensive posture into account. In the five scorpions we recorded, also the ipsilateral phase of leg pairs 3 and 4 differed in defensive posture. We found that the trajectory the 4th foot describes during a single stride also differed significantly between postures, showing this to be a sensitive measure of changes in gait. The change from an ambulatory to a defensive posture places different demands on the gait of scorpions, possibly largely due to the forward displacement of the center of mass.
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Affiliation(s)
- Ana Telheiro
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, Vila do Conde, 4485-661, Vairão, Portugal
| | - Pedro Coelho
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, Vila do Conde, 4485-661, Vairão, Portugal
| | - Arie van der Meijden
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, Vila do Conde, 4485-661, Vairão, Portugal.
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11
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FernÁndez-RodrÍguez I, BraÑa F. The movement dynamics of autotomized lizards and their tails reveal functional costs of caudal autotomy. Integr Zool 2020; 15:511-521. [PMID: 32297699 DOI: 10.1111/1749-4877.12443] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Autotomy has evolved independently several times in different animal lineages. It frequently involves immediate functional costs, so regeneration evolved in many instances to restore the functionality of that body part. Caudal autotomy is a widespread antipredator strategy in lizards, although it may affect energy storage, locomotion dynamics, or survival in future encounters with predators. Here, we assessed the effect of tail loss on the locomotor performance of wall lizards (Podarcis muralis), as well as the recovery of locomotor functionality of lizards with regenerated tails, and the movement dynamics of shed tails that were either intact or having regenerated portions. Tail loss had no effect on locomotion over unhindered spaces, possibly due to compensation between a negative effect on the stride of front limbs, and a positive effect of losing mass and friction force. We found a clear negative impact of tail loss on locomotion in spaces with interspersed obstacles, in which tailed lizards jumped larger distances when leaving the obstacles. Besides, lizards that used the tail to push off the ground were able to approach the obstacles from further, so that the tail seemed to be useful when used during jumping. Regeneration fully restores lizard's locomotor capacities, but tail antipredator value, as indicated by the intensity of post-autotomic movements, is only partially retrieved. From these results, we propose that, together with the recovery of post-autotomy antipredator capacities, the restoration of the organismal locomotor performance may have been an important, yet frequently neglected factor in the evolution of lizard's regeneration ability.
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Affiliation(s)
- Irene FernÁndez-RodrÍguez
- Department of Organisms and Systems Biology (Zoology), University of Oviedo, Oviedo, Spain.,Research Unit of Biodiversity (UMIB, UO/CSIC/PA), University of Oviedo, Mieres, Spain
| | - Florentino BraÑa
- Department of Organisms and Systems Biology (Zoology), University of Oviedo, Oviedo, Spain.,Research Unit of Biodiversity (UMIB, UO/CSIC/PA), University of Oviedo, Mieres, Spain
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12
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Michelangeli M, Melki-Wegner B, Laskowski K, Wong BB, Chapple DG. Impacts of caudal autotomy on personality. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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13
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Jagnandan K, Higham TE. Neuromuscular control of locomotion is altered by tail autotomy in geckos. J Exp Biol 2018; 221:jeb.179564. [DOI: 10.1242/jeb.179564] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 07/16/2018] [Indexed: 11/20/2022]
Abstract
Animal locomotion is driven by underlying axial and appendicular musculature. In order for locomotion to be effective, these muscles must be able to rapidly respond to changes in environmental and physiological demands. Although virtually unstudied, muscles must also respond to morphological changes, such as those that occur with tail autotomy in lizards. Tail autotomy in leopard geckos (Eublepharis macularius) results in a 25% loss of caudal mass and significant kinematic alterations to maintain stability. To elucidate how motor control of the locomotor muscles is modulated with these shifts, we used electromyography (EMG) to quantify patterns of in vivo muscle activity in fore- and hind limb muscles before and after autotomy. Forelimb muscles (biceps brachii and triceps brachii) exhibited no changes in motor recruitment, consistent with unaltered kinematics after autotomy. Amplitude of activity of propulsive muscles of the hind limbs (caudofemoralis and gastrocnemius) was significantly reduced and coincided with decreases in the propulsive phases of femur retraction and ankle extension, respectively. The puboischiotibialis did not exhibit these changes, despite significant reductions in femur depression and knee angle, suggesting that reduction in mass and vertical ground-reaction force by autotomy allows for the maintenance of a more sprawled and stable posture without increasing motor recruitment of the support muscles. These results highlight the significant neuromuscular shifts that occur to accommodate dramatic changes in body size and mass distribution, and illuminate the utility of tail autotomy as a system for studying the neuromuscular control of locomotion.
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Affiliation(s)
- Kevin Jagnandan
- Life Sciences Department, San Diego City College, 1313 Park Boulevard, San Diego, CA 92101, USA
| | - Timothy E. Higham
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, 900 University Avenue, Riverside, CA 92521, USA
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14
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Lateral movements of a massive tail influence gecko locomotion: an integrative study comparing tail restriction and autotomy. Sci Rep 2017; 7:10865. [PMID: 28883491 PMCID: PMC5589804 DOI: 10.1038/s41598-017-11484-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/22/2017] [Indexed: 11/27/2022] Open
Abstract
Tails are an intricate component of the locomotor system for many vertebrates. Leopard geckos (Eublepharis macularius) possess a large tail that is laterally undulated during steady locomotion. However, the tail is readily shed via autotomy, resulting in the loss of tail function, loss in body mass, and a cranial shift in the center of mass. To elucidate the function of tail undulations, we investigated changes in limb kinematics after manipulating the tail artificially by restricting tail undulations and naturally by removing the tail via autotomy. Restricting tail undulations resulted in kinematic adjustments similar to those that occur following tail autotomy, characterized by more flexed hind limb joints. These data suggest that effects of autotomy on locomotion may be linked to the loss of tail movements rather than the loss of mass or a shift in center of mass. We also provide empirical support for the link between lateral tail undulations and step length through the rotation of the pelvic girdle and retraction of the femur. Restriction and autotomy of the tail limits pelvic rotation, which reduces femur retraction and decreases step length. Our findings demonstrate a functional role for tail undulations in geckos, which likely applies to other terrestrial vertebrates.
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15
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Hessel AL, Ryerson WG, Whitenack LB. Doing Without: Jump Performance After Tail Autotomy in Three Species of Plethodontid Salamanders. HERPETOLOGICA 2017. [DOI: 10.1655/herpetologica-d-15-00067.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Anthony L. Hessel
- Department of Biological Sciences, Allegheny College, Meadville, PA 16335, USA
| | - William G. Ryerson
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Lisa B. Whitenack
- Department of Biological Sciences, Allegheny College, Meadville, PA 16335, USA
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Savvides P, Stavrou M, Pafilis P, Sfenthourakis S. Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard. Naturwissenschaften 2016; 104:3. [DOI: 10.1007/s00114-016-1425-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 11/29/2016] [Accepted: 12/07/2016] [Indexed: 11/30/2022]
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Gillis G, Higham TE. Consequences of lost endings: caudal autotomy as a lens for focusing attention on tail function during locomotion. J Exp Biol 2016; 219:2416-22. [DOI: 10.1242/jeb.124024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Autotomy has evolved in many animal lineages as a means of predator escape, and involves the voluntary shedding of body parts. In vertebrates, caudal autotomy (or tail shedding) is the most common form, and it is particularly widespread in lizards. Here, we develop a framework for thinking about how tail loss can have fitness consequences, particularly through its impacts on locomotion. Caudal autotomy is fundamentally an alteration of morphology that affects an animal's mass and mass distribution. These morphological changes affect balance and stability, along with the performance of a range of locomotor activities, from running and climbing to jumping and swimming. These locomotor effects can impact on activities critical for survival and reproduction, including escaping predators, capturing prey and acquiring mates. In this Commentary, we first review work illustrating the (mostly) negative effects of tail loss on locomotor performance, and highlight what these consequences reveal about tail function during locomotion. We also identify important areas of future study, including the exploration of new behaviors (e.g. prey capture), increased use of biomechanical measurements and the incorporation of more field-based studies to continue to build our understanding of the tail, an ancestral and nearly ubiquitous feature of the vertebrate body plan.
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Affiliation(s)
- Gary Gillis
- Department of Biology, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Timothy E. Higham
- Department of Biology, University of California, Riverside, CA 92521, USA
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Russell AP, Lynn SE, Powell GL, Cottle A. The regenerated tail of juvenile leopard geckos (Gekkota: Eublepharidae: Eublepharis macularius) preferentially stores more fat than the original. ZOOLOGY 2015; 118:183-91. [PMID: 25935709 DOI: 10.1016/j.zool.2014.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/14/2014] [Accepted: 12/03/2014] [Indexed: 11/27/2022]
Abstract
The tail of many species of lizard is used as a site of fat storage, and caudal autotomy is a widespread phenomenon among lizards. This means that caudal fat stores are at risk of being lost if the tail is autotomized. For fat-tailed species, such as the leopard gecko, this may be particularly costly. Previous work has shown that tail regeneration in juveniles of this species is rapid and that it receives priority for energy allocation, even when dietary resources are markedly reduced. We found that the regenerated tails of juvenile leopard geckos are more massive than their original counterparts, regardless of dietary intake, and that they exhibit greater amounts of skeleton, inner fat, muscle and subcutaneous fat than original tails (as assessed through cross-sectional area measurements of positionally equivalent stations along the tail). Autotomy and regeneration result in changes in tail shape, mass and the pattern of tissue distribution within the tail. The regenerated tail exhibits enhanced fat storage capacity, even in the face of a diet that results in significant slowing of body growth. Body growth is thus sacrificed at the expense of rapid tail growth. Fat stores laid down rapidly in the regenerating tail may later be used to fuel body growth or reproductive investment. The regenerated tail thus seems to have adaptive roles of its own, and provides a potential vehicle for studying trade-offs that relate to life history strategy.
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Affiliation(s)
- Anthony P Russell
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4.
| | - Sabrina E Lynn
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
| | - G Lawrence Powell
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
| | - Andrew Cottle
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada T2N 1N4
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Jagnandan K, Russell AP, Higham TE. Tail autotomy and subsequent regeneration alter the mechanics of locomotion in lizards. J Exp Biol 2014; 217:3891-7. [DOI: 10.1242/jeb.110916] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Animals undergo significant weight change due to a variety of causes. Autotomy, the voluntary shedding of an appendage in response to a predator stimulus, provides an effective model for measuring the effects of rapid weight change on locomotor behavior and the responses to more gradual weight gain, particularly in lizards capable of both autotomizing and regenerating their tail. Although the general effects of autotomy on locomotor performance are commonly explored, we investigated changes in locomotor mechanics associated with tail loss and long-term regeneration for the first time by measuring morphology, 3D kinematics, and ground reaction forces (GRFs) in the leopard gecko, Eublepharis macularius. Tail autotomy resulted in a 13% anterior shift in the center of mass (CoM), which only partially recovered after full regeneration of the tail. Although no changes in body or forelimb kinematics were evident, decreases in hindlimb joint angles signify a more sprawled posture following autotomy. Changes in hindlimb GRFs resulted in an increase in weight-specific propulsive force, without a corresponding change in locomotor speed. Hindlimb kinematics and GRFs following autotomy recovered to pre-autotomy values as the tail regenerated. These results suggest an active locomotor response to tail loss that demonstrates the causal relationships between morphological, kinematic, and force variation.
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Higham TE, Russell AP, Zani PA. Integrative Biology of Tail Autotomy in Lizards. Physiol Biochem Zool 2013; 86:603-10. [DOI: 10.1086/673875] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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