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Hay EM, McGee MD, White CR, Chown SL. Body size shapes song in honeyeaters. Proc Biol Sci 2024; 291:20240339. [PMID: 38654649 PMCID: PMC11040244 DOI: 10.1098/rspb.2024.0339] [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: 02/08/2024] [Accepted: 03/22/2024] [Indexed: 04/26/2024] Open
Abstract
Birdsongs are among the most distinctive animal signals. Their evolution is thought to be shaped simultaneously by habitat structure and by the constraints of morphology. Habitat structure affects song transmission and detectability, thus influencing song (the acoustic adaptation hypothesis), while body size and beak size and shape necessarily constrain song characteristics (the morphological constraint hypothesis). Yet, support for the acoustic adaptation and morphological constraint hypotheses remains equivocal, and their simultaneous examination is infrequent. Using a phenotypically diverse Australasian bird clade, the honeyeaters (Aves: Meliphagidae), we compile a dataset consisting of song, environmental, and morphological variables for 163 species and jointly examine predictions of these two hypotheses. Overall, we find that body size constrains song frequency and pace in honeyeaters. Although habitat type and environmental temperature influence aspects of song, that influence is indirect, likely via effects of environmental variation on body size, with some evidence that elevation constrains the evolution of song peak frequency. Our results demonstrate that morphology has an overwhelming influence on birdsong, in support of the morphological constraint hypothesis, with the environment playing a secondary role generally via body size rather than habitat structure. These results suggest that changing body size (a consequence of both global effects such as climate change and local effects such as habitat transformation) will substantially influence the nature of birdsong.
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Affiliation(s)
- Eleanor M. Hay
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Matthew D. McGee
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Craig R. White
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Steven L. Chown
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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2
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Bourke JM, Witmer LM. Soft tissues influence nasal airflow in diapsids: Implications for dinosaurs. J Morphol 2023; 284:e21619. [PMID: 37585224 DOI: 10.1002/jmor.21619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 08/17/2023]
Abstract
The nasal passage performs multiple functions in amniotes, including olfaction and thermoregulation. These functions would have been present in extinct animals as well. However, fossils preserve only low-resolution versions of the nasal passage due to loss of soft-tissue structures after death. To test the effects of these lower resolution models on interpretations of nasal physiology, we performed a broadly comparative analysis of the nasal passages in extant diapsid representatives, e.g., alligator, turkey, ostrich, iguana, and a monitor lizard. Using computational fluid dynamics, we simulated airflow through 3D reconstructed models of the different nasal passages and compared these soft-tissue-bounded results to similar analyses of the same airways under the lower-resolution limits imposed by fossilization. Airflow patterns in these bony-bounded airways were more homogeneous and slower flowing than those of their soft-tissue counterparts. These data indicate that bony-bounded airway reconstructions of extinct animal nasal passages are far too conservative and place overly restrictive physiological limitations on extinct species. In spite of the diverse array of nasal passage shapes, distinct similarities in airflow were observed, including consistent areas of nasal passage constriction such as the junction of the olfactory region and main airway. These nasal constrictions can reasonably be inferred to have been present in extinct taxa such as dinosaurs.
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Affiliation(s)
- Jason M Bourke
- Department of Biological Sciences, Ohio University, Athens, Ohio, USA
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA
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Modeling of the respiratory system of the long-necked Triassic reptile Tanystropheus (Archosauromorpha). THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2022; 109:55. [DOI: 10.1007/s00114-022-01824-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 09/18/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
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Rose KA, Wilson RP, Ramenda C, Robotka H, Wikelski M, Shepard EL. Wake respirometry allows breath-by-breath assessment of ventilation and CO 2 production in unrestrained animals. iScience 2022; 25:104878. [PMID: 36060068 PMCID: PMC9437847 DOI: 10.1016/j.isci.2022.104878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/12/2022] [Accepted: 07/30/2022] [Indexed: 11/20/2022] Open
Abstract
Quantifying stress and energetic responses in animals are major challenges, as existing methods lack temporal resolution and elevate animal stress. We propose "wake respirometry," a new method of quantifying fine-scale changes in CO2 production in unrestrained animals, using a nondispersive infrared CO2 sensor positioned downwind of the animal, i.e., in its wake. We parameterize the dispersion of CO2 in wakes using known CO2 flow rates and wind speeds. Tests with three bird species in a wind tunnel demonstrated that the system can resolve breath-by-breath changes in CO2 concentration, with clear exhalation signatures increasing in period and integral with body size. Changes in physiological state were detectable following handling, flight, and exposure to a perceived threat. We discuss the potential of wake respirometry to quantify stress and respiratory patterns in wild animals and provide suggestions for estimating behavior-specific metabolic rates via full integration of CO2 production across the wake.
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Affiliation(s)
| | - Rory P. Wilson
- Biosciences, Swansea University, Singleton Park, Swansea, UK
| | - Claudia Ramenda
- Max Planck Institute of Animal Behaviour, Radolfzell, Germany
| | - Hermina Robotka
- Max Planck Institute of Animal Behaviour, Radolfzell, Germany
| | - Martin Wikelski
- Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Centre for the Advanced Study of Collective Behavior, University of Konstanz, Konstanz, Germany
| | - Emily L.C. Shepard
- Biosciences, Swansea University, Singleton Park, Swansea, UK
- Max Planck Institute of Animal Behavior, Radolfzell, Germany
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Domnik NJ, Vincent SG, Fisher JT. Mechanosensitivity of Murine Lung Slowly Adapting Receptors: Minimal Impact of Chemosensory, Serotonergic, and Purinergic Signaling. Front Physiol 2022; 13:833665. [PMID: 35250636 PMCID: PMC8889033 DOI: 10.3389/fphys.2022.833665] [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: 12/12/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Murine slowly adapting receptors (SARs) within airway smooth muscle provide volume-related feedback; however, their mechanosensitivity and morphology are incompletely characterized. We explored two aspects of SAR physiology: their inherent static mechanosensitivity and a potential link to pulmonary neuroepithelial bodies (NEBs). SAR mechanosensitivity displays a rate sensitivity linked to speed of inflation; however, to what extent static SAR mechanosensitivity is tuned for the very rapid breathing frequency (B f ) of small mammals (e.g., mouse) is unclear. NEB-associated, morphologically described smooth muscle-associated receptors (SMARs) may be a structural analog for functionally characterized SARs, suggesting functional linkages between SARs and NEBs. We addressed the hypotheses that: (1) rapid murine B f is associated with enhanced in vivo SAR static sensitivity; (2) if SARs and NEBs are functionally linked, stimuli reported to impact NEB function would alter SAR mechanosensitivity. We measured SAR action potential discharge frequency (AP f, action potentials/s) during quasi-static inflation [0-20 cmH2O trans-respiratory pressure (PTR)] in NEB-relevant conditions of hypoxia (FIO2 = 0.1), hypercarbia (FICO2 = 0.1), and pharmacologic intervention (serotonergic 5-HT3 receptor antagonist, Tropisetron, 4.5 mg/kg; P2 purinergic receptor antagonist, Suramin, 50 mg/kg). In all protocols, we obtained: (1) AP f vs. PTR; (2) PTR threshold; and (3) AP f onset at PTR threshold. The murine AP f vs. PTR response comprises high AP f (average maximum AP f: 236.1 ± 11.1 AP/s at 20 cmH2O), a low PTR threshold (mean 2.0 ± 0.1 cmH2O), and a plateau in AP f between 15 and 20 cmH2O. Murine SAR mechanosensitivity (AP f vs. PTR) is up to 60% greater than that reported for larger mammals. Even the maximum difference between intervention and control conditions was minimally impacted by NEB-related alterations: Tropisetron -7.6 ± 1.8% (p = 0.005); Suramin -10.6 ± 1.5% (p = 0.01); hypoxia +9.3 ± 1.9% (p < 0.001); and hypercarbia -6.2 ± 0.9% (p < 0.001). We conclude that the high sensitivity of murine SARs to inflation provides enhanced resolution of operating lung volume, which is aligned with the rapid B f of the mouse. We found minimal evidence supporting a functional link between SARs and NEBs and speculate that the <10% change in SAR mechanosensitivity during altered NEB-related stimuli is not consistent with a meaningful physiologic role.
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Affiliation(s)
- Nicolle J. Domnik
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Sandra G. Vincent
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
| | - John T. Fisher
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
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Recovery, body mass and buoyancy: a detailed analysis of foraging dive cycles in the European shag. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Williams CL, Czapanskiy MF, John JS, St Leger J, Scadeng M, Ponganis PJ. Cervical air sac oxygen profiles in diving emperor penguins: parabronchial ventilation and the respiratory oxygen store. J Exp Biol 2021; 224:jeb230219. [PMID: 33257430 DOI: 10.1242/jeb.230219] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/18/2020] [Indexed: 11/20/2022]
Abstract
Some marine birds and mammals can perform dives of extraordinary duration and depth. Such dive performance is dependent on many factors, including total body oxygen (O2) stores. For diving penguins, the respiratory system (air sacs and lungs) constitutes 30-50% of the total body O2 store. To better understand the role and mechanism of parabronchial ventilation and O2 utilization in penguins both on the surface and during the dive, we examined air sac partial pressures of O2 (PO2 ) in emperor penguins (Aptenodytes forsteri) equipped with backpack PO2 recorders. Cervical air sac PO2 values at rest were lower than in other birds, while the cervical air sac to posterior thoracic air sac PO2 difference was larger. Pre-dive cervical air sac PO2 values were often greater than those at rest, but had a wide range and were not significantly different from those at rest. The maximum respiratory O2 store and total body O2 stores calculated with representative anterior and posterior air sac PO2 data did not differ from prior estimates. The mean calculated anterior air sac O2 depletion rate for dives up to 11 min was approximately one-tenth that of the posterior air sacs. Low cervical air sac PO2 values at rest may be secondary to a low ratio of parabronchial ventilation to parabronchial blood O2 extraction. During dives, overlap of simultaneously recorded cervical and posterior thoracic air sac PO2 profiles supported the concept of maintenance of parabronchial ventilation during a dive by air movement through the lungs.
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Affiliation(s)
- Cassondra L Williams
- National Marine Mammal Foundation, 2240 Shelter Island Dr. #200, San Diego, CA 92106, USA
| | - Max F Czapanskiy
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950, USA
| | - Jason S John
- Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 McAlister Way, Santa Cruz, CA 95060, USA
| | - Judy St Leger
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA
| | - Miriam Scadeng
- Department of Anatomy and Medical Imaging, Faculty of Health and Medical Sciences, University of Auckland, Auckland 1142, New Zealand
- Center for Functional Magnetic Resonance Imaging, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paul J Ponganis
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA
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Souza RBBD, Bonfim VMG, Rios VP, Klein W. Allometric relations of respiratory variables in Amniota: Effects of phylogeny, form, and function. Comp Biochem Physiol A Mol Integr Physiol 2020; 252:110845. [PMID: 33197562 DOI: 10.1016/j.cbpa.2020.110845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 10/23/2022]
Abstract
Biological variables are frequently described by analyzing scaling relationships of the variable against body mass (MB). Respiratory variables are no exception and allometric relations for oxygen consumption, pulmonary ventilation, tidal volume, breathing frequency, and lung volume have been described in the literature. While the allometric relations of respiratory variables given for mammals and birds are very consistent among different studies, scaling relationships for non-avian reptiles have only been scarcely described and show considerable variation between studies. Since no comprehensive study of allometric relations of respiratory variables has been carried out comparing the different groups of non-avian reptiles, we analyzed morphological and physiological variables of the respiratory system of crocodilians, chelonians, lizards, snakes, birds, and mammals, regarding the allometric relations of each variable from a phylogenetic perspective as well as related to lung morphology. Our results indicated that few respiratory variables possess significant phylogenetic signals and that tidal volume, breathing frequency (except mammals), and air convection requirement were independent of phylogeny. Contrary to the literature, lung volume of amniotes scaled isometrically to MB, with the exception of lizards (MB0.78). Air convection requirement scaled isometrically in mammals and birds, but was more variable among non-avian reptiles, from a taxonomic perspective and in regard to different lung structures. In conclusion, respiratory variables among non-avian reptiles scaled more variably than previously expected, both according to phylogeny and to lung type, warranting future studies to explore structure-function relations of the reptilian respiratory system, especially regarding snakes and crocodilians, since these groups had very few data available for analysis.
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Affiliation(s)
- Ray Brasil Bueno de Souza
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Vanessa Maria Gomes Bonfim
- Programa de Pós-graduação em Biologia Comparada, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Vitor Passos Rios
- Programa de Pós-graduação em Biologia Comparada, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil; Universidade do Estado de Minas Gerais, Passos 37900-106, Minas Gerais, Brazil
| | - Wilfried Klein
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil.
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9
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Class B, Brommer J. Contrasting multilevel relationships between behavior and body mass in blue tit nestlings. Behav Ecol 2020. [DOI: 10.1093/beheco/araa014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Abstract
Repeatable behaviors (i.e., animal personality) are pervasive in the animal kingdom and various mechanisms have been proposed to explain their existence. Genetic and nongenetic mechanisms, which can be equally important, predict correlations between behavior and body mass on different levels (e.g., genetic and environmental) of variation. We investigated multilevel relationships between body mass measured on weeks 1, 2, and 3 and three behavioral responses to handling, measured on week 3, which form a behavioral syndrome in wild blue tit nestlings. Using 7 years of data and quantitative genetic models, we find that all behaviors and body mass on week 3 are heritable (h2 = 0.18–0.23) and genetically correlated, whereas earlier body masses are not heritable. We also find evidence for environmental correlations between body masses and behaviors. Interestingly, these environmental correlations have different signs for early and late body masses. Altogether, these findings indicate genetic integration between body mass and behavior and illustrate the impacts of early environmental factors and environmentally mediated growth trajectory on behaviors expressed later in life. This study, therefore, suggests that the relationship between personality and body mass in developing individuals is due to various underlying mechanisms, which can have opposing effects. Future research on the link between behavior and body mass would benefit from considering these multiple mechanisms simultaneously.
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Affiliation(s)
- Barbara Class
- Department of Biology, University of Turku, University Hill, Turku, Finland
| | - Jon Brommer
- Department of Biology, University of Turku, University Hill, Turku, Finland
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Berg KS, Delgado S, Mata-Betancourt A. Phylogenetic and kinematic constraints on avian flight signals. Proc Biol Sci 2019; 286:20191083. [PMID: 31530147 DOI: 10.1098/rspb.2019.1083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many birds vocalize in flight. Because wingbeat and respiratory cycles are often linked in flying vertebrates, birds in these cases must satisfy the respiratory demands of vocal production within the physiological limits imposed by flight. Using acoustic triangulation and high-speed video, we found that avian vocal production in flight exhibits a largely phasic and kinematic relationship with the power stroke. However, the sample of species showed considerable flexibility, especially those from lineages known for vocal plasticity (songbirds, parrots and hummingbirds), prompting a broader phylogenetic analysis. We thus collected data from 150 species across 12 avian orders and examined the links between wingbeat period, flight call duration and body mass. Overall, shorter wingbeat periods, controlling for ancestry and body mass, were correlated with shorter flight call durations. However, species from vocal learner lineages produced flight signals that, on average, exceeded multiple phases of their wingbeat cycle, while vocal non-learners had signal periods that were, on average, closer to the duration of their power stroke. These results raise an interesting question: is partial emancipation from respiratory constraints a necessary step in the evolution of vocal learning or an epiphenomenon? Our current study cannot provide the answer, but it does suggest several avenues for future research.
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Affiliation(s)
- K S Berg
- Department of Biology, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - S Delgado
- Department of Biology, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - A Mata-Betancourt
- Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
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Bourke JM, Porter WR, Witmer LM. Convoluted nasal passages function as efficient heat exchangers in ankylosaurs (Dinosauria: Ornithischia: Thyreophora). PLoS One 2018; 13:e0207381. [PMID: 30566469 PMCID: PMC6300222 DOI: 10.1371/journal.pone.0207381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 10/30/2018] [Indexed: 11/18/2022] Open
Abstract
Convoluted nasal passages are an enigmatic hallmark of Ankylosauria. Previous research suggested that these convoluted nasal passages functioned as heat exchangers analogous to the respiratory turbinates of mammals and birds. We tested this hypothesis by performing a computational fluid dynamic analysis on the nasal passages of two ankylosaurs: Panoplosaurus mirus and Euoplocephalus tutus. Our models predicted that Panoplosaurus and Euoplocephalus would have required 833 and 1568 thermal calories, respectively, to warm a single breath of air by 20°C. Heat recovery during exhalation resulted in energy savings of 65% for Panoplosaurus and 84% for Euoplocephalus. Our results fell well within the range of values for heat and water savings observed in extant terrestrial amniotes. We further tested alternate airway reconstructions that removed nasal passage convolutions or reduced nasal vestibule length. Our results revealed that the extensive elaboration observed in the nasal vestibules of ankylosaurs was a viable alternative to respiratory turbinates with regards to air conditioning. Of the two dinosaurs tested, Euoplocephalus repeatedly exhibited a more efficient nasal passage than Panoplosaurus. We suggest that the higher heat loads associated with the larger body mass of Euoplocephalus necessitated these more efficient nasal passages. Our findings further indicate that the evolution of complicated airways in dinosaurs may have been driven by the thermal requirements of maintaining cerebral thermal homeostasis.
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Affiliation(s)
- Jason M. Bourke
- Department of Biological Sciences, Ohio University, Athens, Ohio, United States of America
- * E-mail:
| | - Wm. Ruger Porter
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
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Mayhew PD, Pascoe PJ, Giuffrida MA, Mitchell J, Steffey MA, Culp WTN. Cardiorespiratory effects of variable pressure thoracic insufflation in cats undergoing video-assisted thoracic surgery. Vet Surg 2018; 48:O130-O137. [PMID: 30431172 DOI: 10.1111/vsu.13130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 07/27/2018] [Accepted: 08/09/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To evaluate the effects of intrathoracic insufflation on cardiorespiratory variables and working space in cats undergoing video-assisted thoracic surgery. STUDY DESIGN Prospective randomized study. ANIMALS Six healthy cats. METHODS Cats were anesthetized using a standardized protocol. A Swan-Ganz catheter was positioned in the pulmonary artery under fluoroscopic guidance for measurement of cardiac output. Intrathoracic pressures (ITP) of 0 (baseline), 3, and 5 mm Hg were induced with CO2 and maintained for 30 minutes. Statistical comparison of cardiorespiratory variables was performed. After the procedures, all cats were recovered from anesthesia. Videos of thoracic working space at each ITP level were scored in a blinded fashion by 3 board-certified surgeons using a numerical scale from 0-10. RESULTS All cats tolerated insufflation with 3 and 5 mm Hg for 30 minutes without oxygen desaturation, although ventilatory levels had to be increased substantially to maintain eucapnia and oxygenation. Cardiac index was not significantly different from baseline after 30 minutes at 3 mm Hg but was significantly lower after 30 minutes at 5 mm Hg compared with 3 mm Hg. Oxygen delivery was unaffected by 3 or 5 mm Hg compared with baseline. Scores for working space increased between baseline and 3 and 5 mm Hg but were not different between 3 and 5 mm Hg. CONCLUSION CO2 insufflation to 5 mm Hg seems well tolerated in healthy cats, provided ventilatory settings are substantially increased as ITP increases. CLINICAL SIGNIFICANCE Thoracic CO2 insufflation of 3 mm Hg in cats during video-assisted thoracic surgery is associated with less hemodynamic perturbation than 5 mm Hg insufflation and may provide the benefit of improved working space compared with baseline.
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Affiliation(s)
- Philipp D Mayhew
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California
| | - Peter J Pascoe
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California
| | - Michelle A Giuffrida
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California
| | - Jeffrey Mitchell
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California
| | - Michele A Steffey
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California
| | - William T N Culp
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California
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Bushuev A, Tolstenkov O, Zubkova E, Solovyeva E, Kerimov A. Basal metabolic rate in free-living tropical birds: the influence of phylogenetic, behavioral, and ecological factors. Curr Zool 2018; 64:33-43. [PMID: 29492036 PMCID: PMC5809028 DOI: 10.1093/cz/zox018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/17/2017] [Indexed: 11/30/2022] Open
Abstract
The majority of our knowledge of avian energetics is based on studies of birds from temperate and high latitudes. Using the largest existing sample of wild-caught Old World tropical species, we showed that birds from Southern Vietnam had lower basal metabolic rate (BMR) than temperate species. The strongest dissimilarity between tropical and temperate species was the low scaling exponent in the allometric relation between BMR and body mass in tropical birds (the regression slope was 0.573). The passerine migrants to temperate and high latitudes had higher BMR than tropical sedentary passerines. Body mass alone accounted for 93% of the variation in BMR (body mass ranged from 5 to 252 g). Contrary to some other studies, we did not find evidence besides the above mentioned that phylogeny, taxonomy, behavior, or ecology have a significant influence on BMR variation among tropical birds.
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Affiliation(s)
- Andrey Bushuev
- Department of Vertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Leninskie Gory 1/12, Moscow, Russia
- Joint Russian-Vietnamese Tropical Research and Technological Center, South Branch, Street 3/2 3, 10 District, Ho Chi Minh City, Vietnam
| | - Oleg Tolstenkov
- Joint Russian-Vietnamese Tropical Research and Technological Center, South Branch, Street 3/2 3, 10 District, Ho Chi Minh City, Vietnam
- Laboratory of Experimental Parasitology, Center of Parasitology, A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninskij prospekt 33, Moscow, Russia
| | - Ekaterina Zubkova
- Department of Vertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Leninskie Gory 1/12, Moscow, Russia
- Joint Russian-Vietnamese Tropical Research and Technological Center, South Branch, Street 3/2 3, 10 District, Ho Chi Minh City, Vietnam
| | - Eugenia Solovyeva
- Zoological Museum of Lomonosov Moscow State University, Bolshaya Nikitskaya 6, Moscow, Russia
| | - Anvar Kerimov
- Department of Vertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Leninskie Gory 1/12, Moscow, Russia
- Joint Russian-Vietnamese Tropical Research and Technological Center, South Branch, Street 3/2 3, 10 District, Ho Chi Minh City, Vietnam
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Nascimento ST, Maia AS, Gebremedhin KG, Nascimento CC. Metabolic heat production and evaporation of poultry. Poult Sci 2017; 96:2691-2698. [DOI: 10.3382/ps/pex094] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 03/22/2017] [Indexed: 11/20/2022] Open
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15
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Bourke JM, Witmer LM. Nasal conchae function as aerodynamic baffles: Experimental computational fluid dynamic analysis in a turkey nose (Aves: Galliformes). Respir Physiol Neurobiol 2016; 234:32-46. [PMID: 27612585 DOI: 10.1016/j.resp.2016.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 07/30/2016] [Accepted: 09/05/2016] [Indexed: 11/16/2022]
Abstract
We tested the aerodynamic function of nasal conchae in birds using CT data from an adult male wild turkey (Meleagris gallopavo) to construct 3D models of its nasal passage. A series of digital "turbinectomies" were performed on these models and computational fluid dynamic analyses were performed to simulate resting inspiration. Models with turbinates removed were compared to the original, unmodified control airway. Results revealed that the four conchae found in turkeys, along with the crista nasalis, alter the flow of inspired air in ways that can be considered baffle-like. However, these baffle-like functions were remarkably limited in their areal extent, indicating that avian conchae are more functionally independent than originally hypothesized. Our analysis revealed that the conchae of birds are efficient baffles that-along with potential heat and moisture transfer-serve to efficiently move air to specific regions of the nasal passage. This alternate function of conchae has implications for their evolution in birds and other amniotes.
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Affiliation(s)
- Jason M Bourke
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA.
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Bourke JM, Porter WMR, Ridgely RC, Lyson TR, Schachner ER, Bell PR, Witmer LM. Breathing life into dinosaurs: tackling challenges of soft-tissue restoration and nasal airflow in extinct species. Anat Rec (Hoboken) 2015; 297:2148-86. [PMID: 25312371 DOI: 10.1002/ar.23046] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/10/2022]
Abstract
The nasal region plays a key role in sensory, thermal, and respiratory physiology, but exploring its evolution is hampered by a lack of preservation of soft-tissue structures in extinct vertebrates. As a test case, we investigated members of the "bony-headed" ornithischian dinosaur clade Pachycephalosauridae (particularly Stegoceras validum) because of their small body size (which mitigated allometric concerns) and their tendency to preserve nasal soft tissues within their hypermineralized skulls. Hypermineralization directly preserved portions of the olfactory turbinates along with an internal nasal ridge that we regard as potentially an osteological correlate for respiratory conchae. Fossil specimens were CT-scanned, and nasal cavities were segmented and restored. Soft-tissue reconstruction of the nasal capsule was functionally tested in a virtual environment using computational fluid dynamics by running air through multiple models differing in nasal soft-tissue conformation: a bony-bounded model (i.e., skull without soft tissue) and then models with soft tissues added, such as a paranasal septum, a scrolled concha, a branched concha, and a model combining the paranasal septum with a concha. Deviations in fluid flow in comparison to a phylogenetically constrained sample of extant diapsids were used as indicators of missing soft tissue. Models that restored aspects of airflow found in extant diapsids, such as appreciable airflow in the olfactory chamber, were judged as more likely. The model with a branched concha produced airflow patterns closest to those of extant diapsids. These results from both paleontological observation and airflow modeling indicate that S. validum and other pachycephalosaurids could have had both olfactory and respiratory conchae. Although respiratory conchae have been linked to endothermy, such conclusions require caution in that our re-evaluation of the reptilian nasal apparatus indicates that respiratory conchae may be more widespread than originally thought, and other functions, such as selective brain temperature regulation, could be important.
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Affiliation(s)
- Jason M Bourke
- Department of Biological Sciences, Ohio University, Athens, Ohio
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White CR, Kearney MR. Metabolic scaling in animals: methods, empirical results, and theoretical explanations. Compr Physiol 2014; 4:231-56. [PMID: 24692144 DOI: 10.1002/cphy.c110049] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Life on earth spans a size range of around 21 orders of magnitude across species and can span a range of more than 6 orders of magnitude within species of animal. The effect of size on physiology is, therefore, enormous and is typically expressed by how physiological phenomena scale with mass(b). When b ≠ 1 a trait does not vary in direct proportion to mass and is said to scale allometrically. The study of allometric scaling goes back to at least the time of Galileo Galilei, and published scaling relationships are now available for hundreds of traits. Here, the methods of scaling analysis are reviewed, using examples for a range of traits with an emphasis on those related to metabolism in animals. Where necessary, new relationships have been generated from published data using modern phylogenetically informed techniques. During recent decades one of the most controversial scaling relationships has been that between metabolic rate and body mass and a number of explanations have been proposed for the scaling of this trait. Examples of these mechanistic explanations for metabolic scaling are reviewed, and suggestions made for comparing between them. Finally, the conceptual links between metabolic scaling and ecological patterns are examined, emphasizing the distinction between (1) the hypothesis that size- and temperature-dependent variation among species and individuals in metabolic rate influences ecological processes at levels of organization from individuals to the biosphere and (2) mechanistic explanations for metabolic rate that may explain the size- and temperature-dependence of this trait.
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Affiliation(s)
- Craig R White
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
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Mortola JP, Toro-Velasquez PA. Breathing pattern and ventilatory chemosensitivity of the 1-day old Muscovy duck (Cairina moschata) in relation to its metabolic demands. Comp Biochem Physiol A Mol Integr Physiol 2014; 167:35-9. [PMID: 24055760 DOI: 10.1016/j.cbpa.2013.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/11/2013] [Accepted: 09/11/2013] [Indexed: 10/26/2022]
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Abstract
In mammals and birds, all oxygen used (VO2) must pass through the lungs; hence, some degree of coupling between VO2 and pulmonary ventilation (VE) is highly predictable. Nevertheless, VE is also involved with CO2 elimination, a task that is often in conflict with the convection of O2. In hot or cold conditions, the relationship between VE and VO2 includes the participation of the respiratory apparatus to the control of body temperature and water balance. Some compromise among these tasks is achieved through changes in breathing pattern, uncoupling changes in alveolar ventilation from VE. This article examines primarily the relationship between VE and VO2 under thermal stimuli. In the process, it considers how the relationship is influenced by hypoxia, hypercapnia or changes in metabolic level. The shuffling of tasks in emergency situations illustrates that the constraints on VE-VO2 for the protection of blood gases have ample room for flexibility. However, when other priorities do not interfere with the primary goal of gas exchange, VE follows metabolic rate quite closely. The fact that arterial CO2 remains stable when metabolism is changed by the most diverse circumstances (moderate exercise, cold, cold and exercise combined, variations in body size, caloric intake, age, time of the day, hormones, drugs, etc.) makes it unlikely that VE and metabolism are controlled in parallel by the condition responsible for the metabolic change. Rather, some observations support the view that the gaseous component of metabolic rate, probably CO2, may provide the link between the metabolic level and VE.
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Paula VV, Otsuki DA, Auler JOC, Nunes TL, Ambrósio AM, Fantoni DT. The effect of premedication with ketamine, alone or with diazepam, on anaesthesia with sevoflurane in parrots (Amazona aestiva). BMC Vet Res 2013; 9:142. [PMID: 23867018 PMCID: PMC3724746 DOI: 10.1186/1746-6148-9-142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 07/12/2013] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Premedication is rarely used in avian species. The aim of this study was to evaluate the effect of premedication on the quality of sevoflurane induction and anaesthesia in parrots. We hypothesised that premedication would facilitate handling and decrease the minimum anaesthetic dose (MAD). Thirty-six adult parrots were randomly distributed in three groups: group S (n = 12) was premedicated with NaCl 0.9%; group KS (n = 12) was premedicated with 10 mg.kg-1 ketamine; and group KDS (n = 12) was premedicated with 10 mg.kg-1 ketamine and 0.5 mg.kg-1 diazepam, delivered intramuscularly. After induction using 4.5% sevoflurane introduced through a facemask, the MAD was determined for each animal. The heart rate (HR), respiratory rate (RR), systolic arterial blood pressure (SAP), and cloacal temperature (CT) were recorded before premedication (T0), 15 minutes after premedication (T1), and after MAD determination (T2). Arterial blood gas analyses were performed at T0 and T2. The quality of anaesthesia was evaluated using subjective scales based on animal behaviour and handling during induction, maintenance, and recovery. Statistical analyses were performed using analysis of variance or Kruskal-Wallis tests followed by Tukey's or Dunn's tests. RESULTS The minimal anaesthetic doses obtained were 2.4 ± 0.37%, 1.7 ± 0.39%, and 1.3 ± 0.32% for groups S, KS, and KDS, respectively. There were no differences in HR, RR, or CT among groups, but SAP was significantly lower in group S. Sedation was observed in both the premedicated S-KS and S-KDS groups. There were no differences in the quality of intubation and recovery from anaesthesia among the three groups, although the induction time was significantly shorter in the pre-medicated groups, and the KS group showed less muscle relaxation. CONCLUSIONS Ketamine alone or the ketamine/diazepam combination decreased the MAD of sevoflurane in parrots (Amazona aestiva). Ketamine alone or in combination with diazepam promoted a good quality of sedation, which improved handling and reduced the stress of the birds. All protocols provided safe anaesthesia in this avian species.
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Affiliation(s)
- Valéria Veras Paula
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, Av. Francisco Mota, 572, Bairro Costa e Silva, CEP: 59.625-900, Mossoró, RN, Brazil
| | - Denise Aya Otsuki
- Laboratory of Medical Investigation/Anesthesiology (LIM/08), Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo, 455, Cerqueira César, CEP 01246903, São Paulo, SP, Brazil
| | - José Otávio Costa Auler
- Laboratory of Medical Investigation/Anesthesiology (LIM/08), Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo, 455, Cerqueira César, CEP 01246903, São Paulo, SP, Brazil
| | - Talyta Lins Nunes
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, Av. Francisco Mota, 572, Bairro Costa e Silva, CEP: 59.625-900, Mossoró, RN, Brazil
| | - Aline Magalhães Ambrósio
- Department of Surgery, Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87 CEP 05508 270, Cidade Universitária, São Paulo, SP, Brazil
| | - Denise Tabacchi Fantoni
- Department of Surgery, Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87 CEP 05508 270, Cidade Universitária, São Paulo, SP, Brazil
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Hawkins MG, Malka S, Pascoe PJ, Solano AM, Kass PH, Ohmura H, Jones JH. Evaluation of the effects of dorsal versus lateral recumbency on the cardiopulmonary system during anesthesia with isoflurane in red-tailed hawks (Buteo jamaicensis). Am J Vet Res 2013; 74:136-43. [DOI: 10.2460/ajvr.74.1.136] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Determinants of inter-specific variation in basal metabolic rate. J Comp Physiol B 2012; 183:1-26. [DOI: 10.1007/s00360-012-0676-5] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 05/02/2012] [Accepted: 05/09/2012] [Indexed: 10/27/2022]
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Clark TD, Farrell AP. Effects of body mass on physiological and anatomical parameters of mature salmon: evidence against a universal heart rate scaling exponent. ACTA ACUST UNITED AC 2011; 214:887-93. [PMID: 21346114 DOI: 10.1242/jeb.051607] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The influence of body mass (M(b)) on the physiology of large, adult fish is poorly understood, in part because of the logistical difficulties of studying large individuals. For the first time, this study quantified the influence of M(b) on the resting heart rate (f(H)), blood properties and organ masses of adults of a large-growing fish species, the Chinook salmon (Oncorhynchus tshawytscha). Surgically implanted biologgers measured f(H) and acceleration activity in sexually mature, male fish ranging in M(b) from 2.7 to 16.8 kg while they roamed freely in a controlled water body at ∼8°C. Blood parameters (at surgery and at death) and body organ masses (at death) were measured to investigate interrelationships with M(b). The scaling exponents for both f(H) and acceleration activity were not significantly different from zero. The lack of scaling of f(H) with M(b) contrasts with the situation for birds and mammals. All blood parameters were independent of M(b), while the masses of the compact myocardium, ventricle and spleen each scaled near-isometrically with M(b). These data raise the possibility that blood oxygen carrying capacity, mass-specific cardiac output and cardiac power output are maintained across M(b) in adult Chinook salmon. Biologging and biotelemetry should advance investigations into the effects of M(b) on the physiology and behaviour of large fish, where current knowledge lags far behind that of birds and mammals.
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Affiliation(s)
- Timothy Darren Clark
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada.
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24
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White CR. Allometric estimation of metabolic rates in animals. Comp Biochem Physiol A Mol Integr Physiol 2011; 158:346-57. [DOI: 10.1016/j.cbpa.2010.10.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 10/01/2010] [Accepted: 10/01/2010] [Indexed: 10/19/2022]
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Latif I, Karim A, Zuki A, Zamri-Saad M, Niu J, Noordin M. Pulmonary modulation of benzo[a]pyrene-induced hemato- and hepatotoxicity in broilers. Poult Sci 2010; 89:1379-88. [DOI: 10.3382/ps.2009-00622] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Codd JR. Uncinate processes in birds: morphology, physiology and function. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:303-8. [PMID: 20036338 DOI: 10.1016/j.cbpa.2009.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 10/20/2022]
Abstract
The avian respiratory system is remarkable in terms of its complexity and efficiency. The evolution of this system with its unique lung morphology and physiology has contributed to birds being one of the most successful vertebrate lineages. Despite holding the attention of the scientific community for a long time, much remains to be discovered about the complexities of this system. Recent advances have highlighted the important role that accessory breathing structures, the uncinate processes, play in understanding not only how this system functions but how it evolved. Almost all species of extant bird have uncinate processes extending from the midpoint of the vertebral ribs. These processes are integral to the mechanics of ventilation in birds, being active in both inspiration and expiration but also playing some role during locomotion. The morphological variation in the uncinate processes suggests that the constraints placed on the body by adaptations to different forms of locomotion are key to understanding differences in how birds breathe. These processes also occur in the theropod dinosaurs, providing further evidence that they are the ancestors of modern birds but also highlighting the intrinsic flexibility in the ventilatory systems of these animals.
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Affiliation(s)
- Jonathan R Codd
- 3.614 Stopford Bldg Faculty of Life Science University of Manchester, Manchester M139PT, UK.
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Universal model for water costs of gas exchange by animals and plants. Proc Natl Acad Sci U S A 2010; 107:8469-74. [PMID: 20404161 DOI: 10.1073/pnas.0905185107] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
For terrestrial animals and plants, a fundamental cost of living is water vapor lost to the atmosphere during exchange of metabolic gases. Here, by bringing together previously developed models for specific taxa, we integrate properties common to all terrestrial gas exchangers into a universal model of water loss. The model predicts that water loss scales to gas exchange with an exponent of 1 and that the amount of water lost per unit of gas exchanged depends on several factors: the surface temperature of the respiratory system near the outside of the organism, the gas consumed (oxygen or carbon dioxide), the steepness of the gradients for gas and vapor, and the transport mode (convective or diffusive). Model predictions were largely confirmed by data on 202 species in five taxa--insects, birds, bird eggs, mammals, and plants--spanning nine orders of magnitude in rate of gas exchange. Discrepancies between model predictions and data seemed to arise from biologically interesting violations of model assumptions, which emphasizes how poorly we understand gas exchange in some taxa. The universal model provides a unified conceptual framework for analyzing exchange-associated water losses across taxa with radically different metabolic and exchange systems.
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Affiliation(s)
- Douglas S Glazier
- Department of Biology, Juniata College, Huntingdon, Pennsylvania 16652, USA.
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Perry SF, Christian A, Breuer T, Pajor N, Codd JR. Implications of an avian-style respiratory system for gigantism in sauropod dinosaurs. ACTA ACUST UNITED AC 2009; 311:600-10. [PMID: 19189317 DOI: 10.1002/jez.517] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In light of evidence for avian-like lungs in saurischian dinosaurs, the physiological implications of cross-current gas exchange and voluminous, highly heterogeneous lungs for sauropod gigantism are critically examined. At 12 ton the predicted body temperature and metabolic rate of a growing sauropod would be similar to that of a bird scaled to the same body weight, but would increase exponentially as body mass increases. Although avian-like lung structure would be consistent with either a tachymetabolic-endothermic or a bradymetabolic-gigantothermic model, increasing body temperature requires adjustments to avoid overheating. We suggest that a unique sauropod structure/function unit facilitated the evolution of gigantism. This unit consisted of (1) a reduction in metabolic rate below that predicted by the body temperature, akin to thermal adaptation as seen in extant squamates, (2) presence of air-filled diverticula in the long neck and in the visceral cavity, and (3) low activity of respiratory muscles coupled with the high efficiency of cross-current gas exchange.
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Affiliation(s)
- Steven F Perry
- Institut für Zoologie, University of Bonn, Bonn, Germany.
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Mortola JP, Seguin J. Resting breathing frequency in aquatic birds: a comparative analysis with terrestrial species. J Zool (1987) 2009. [DOI: 10.1111/j.1469-7998.2009.00606.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Owerkowicz T, Elsey RM, Hicks JW. Atmospheric oxygen level affects growth trajectory, cardiopulmonary allometry and metabolic rate in the American alligator (Alligator mississippiensis). ACTA ACUST UNITED AC 2009; 212:1237-47. [PMID: 19376944 DOI: 10.1242/jeb.023945] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recent palaeoatmospheric models suggest large-scale fluctuations in ambient oxygen level over the past 550 million years. To better understand how global hypoxia and hyperoxia might have affected the growth and physiology of contemporary vertebrates, we incubated eggs and raised hatchlings of the American alligator. Crocodilians are one of few vertebrate taxa that survived these global changes with distinctly conservative morphology. We maintained animals at 30 degrees C under chronic hypoxia (12% O(2)), normoxia (21% O(2)) or hyperoxia (30% O(2)). At hatching, hypoxic animals were significantly smaller than their normoxic and hyperoxic siblings. Over the course of 3 months, post-hatching growth was fastest under hyperoxia and slowest under hypoxia. Hypoxia, but not hyperoxia, caused distinct scaling of major visceral organs-reduction of liver mass, enlargement of the heart and accelerated growth of lungs. When absorptive and post-absorptive metabolic rates were measured in juvenile alligators, the increase in oxygen consumption rate due to digestion/absorption of food was greatest in hyperoxic alligators and smallest in hypoxic ones. Hyperoxic alligators exhibited the lowest breathing rate and highest oxygen consumption per breath. We suggest that, despite compensatory cardiopulmonary remodelling, growth of hypoxic alligators is constrained by low atmospheric oxygen supply, which may limit their food utilisation capacity. Conversely, the combination of elevated metabolism and low cost of breathing in hyperoxic alligators allows for a greater proportion of metabolised energy to be available for growth. This suggests that growth and metabolic patterns of extinct vertebrates would have been significantly affected by changes in the atmospheric oxygen level.
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Affiliation(s)
- Tomasz Owerkowicz
- Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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White CR, Blackburn TM, Seymour RS. Phylogenetically informed analysis of the allometry of Mammalian Basal metabolic rate supports neither geometric nor quarter-power scaling. Evolution 2009; 63:2658-67. [PMID: 19519636 DOI: 10.1111/j.1558-5646.2009.00747.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The form of the relationship between the basal metabolic rate (BMR) and body mass (M) of mammals has been at issue for almost seven decades, with debate focusing on the value of the scaling exponent (b, where BMR is proportional to M(b)) and the relative merits of b= 0.67 (geometric scaling) and b= 0.75 (quarter-power scaling). However, most analyses are not phylogenetically informed (PI) and therefore fail to account for the shared evolutionary history of the species they consider. Here, we reanalyze the most rigorously selected and comprehensive mammalian BMR dataset presently available, and investigate the effects of data selection and phylogenetic method (phylogenetic generalized least squares and independent contrasts) on estimation of the scaling exponent relating mammalian BMR to M. Contrary to the results of a non-PI analysis of these data, which found an exponent of 0.67-0.69, we find that most of the PI scaling exponents are significantly different from both 0.67 and 0.75. Similarly, the scaling exponents differ between lineages, and these exponents are also often different from 0.67 or 0.75. Thus, we conclude that no single value of b adequately characterizes the allometric relationship between body mass and BMR.
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Affiliation(s)
- Craig R White
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, United Kingdom.
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Glazier DS. Effects of metabolic level on the body size scaling of metabolic rate in birds and mammals. Proc Biol Sci 2008; 275:1405-10. [PMID: 18348961 DOI: 10.1098/rspb.2008.0118] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Metabolic rate is traditionally assumed to scale with body mass to the 3/4-power, but significant deviations from the '3/4-power law' have been observed for several different taxa of animals and plants, and for different physiological states. The recently proposed 'metabolic-level boundaries hypothesis' represents one of the attempts to explain this variation. It predicts that the power (log-log slope) of metabolic scaling relationships should vary between 2/3 and 1, in a systematic way with metabolic level. Here, this hypothesis is tested using data from birds and mammals. As predicted, in both of these independently evolved endothermic taxa, the scaling slope approaches 1 at the lowest and highest metabolic levels (as observed during torpor and strenuous exercise, respectively), whereas it is near 2/3 at intermediate resting and cold-induced metabolic levels. Remarkably, both taxa show similar, approximately U-shaped relationships between the scaling slope and the metabolic (activity) level. These predictable patterns strongly support the view that variation of the scaling slope is not merely noise obscuring the signal of a universal scaling law, but rather is the result of multiple physical constraints whose relative influence depends on the metabolic state of the organisms being analysed.
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Mortola JP, Cooney E. Cost of growth and maintenance in chicken embryos during normoxic or hypoxic conditions. Respir Physiol Neurobiol 2008; 162:223-9. [DOI: 10.1016/j.resp.2008.07.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 07/18/2008] [Accepted: 07/21/2008] [Indexed: 11/17/2022]
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Frappell PB. Ontogeny and allometry of metabolic rate and ventilation in the marsupial: Matching supply and demand from ectothermy to endothermy. Comp Biochem Physiol A Mol Integr Physiol 2008; 150:181-8. [DOI: 10.1016/j.cbpa.2008.02.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 02/10/2008] [Accepted: 02/11/2008] [Indexed: 11/26/2022]
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Kilgore DL, Boggs DF, Kilgore TJ, Colby C, Williams BR, Bavis RW. Ventilatory and metabolic responses of burrowing owls, Athene cunicularia, to moderate and extreme hypoxia: Analysis of the hypoxic ventilatory threshold vs. hemoglobin oxygen affinity relationship in birds. Comp Biochem Physiol A Mol Integr Physiol 2008; 150:247-57. [PMID: 17561426 DOI: 10.1016/j.cbpa.2007.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 04/05/2007] [Accepted: 04/12/2007] [Indexed: 10/23/2022]
Abstract
We measured ventilation, oxygen consumption and blood gases in burrowing owls (Athene cunicularia) breathing moderate and extreme hypoxic gas mixtures to determine their hypoxic ventilatory threshold (HVT) and to assess if they, like other birds and mammals, exhibit a relationship between HVT and hemoglobin O2 affinity (P(50)) of their blood. An earlier report of an attenuated ventilatory responsiveness of this species to hypoxia was enigmatic given the low O2 affinity (high P(50)) of burrowing owl hemoglobin. In the current study, burrowing owls breathing 11% and 9% O2 showed a significantly elevated total ventilation. The arterial partial pressure of oxygen (PaO2) at which ventilation is elevated above normoxic values in burrowing owls was 58 mm Hg. This threshold value conforms well to expectations based on the high P(50) of their hemoglobin and the HVT vs. P(50) relationship for birds developed in this study. Correcting for phylogenetic relatedness in the multi-species analysis had no effect on the HVT vs. P(50) relationship. Also, because burrowing owls in this study did not show a hypometabolic response at any level of hypoxia (even at 9% O2); HVT described in terms of percent change in oxygen convection requirement is identical to that based on ventilation alone.
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Affiliation(s)
- Delbert L Kilgore
- Division of Biological Sciences, The University of Montana, Missoula, MT 59801, USA.
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Stephens PA, Carbone C, Boyd IL, McNamara JM, Harding KC, Houston AI. The scaling of diving time budgets: insights from an optimality approach. Am Nat 2008; 171:305-14. [PMID: 18199001 DOI: 10.1086/527491] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Simple scaling arguments suggest that, among air-breathing divers, dive duration should scale approximately with mass to the one-third power. Recent phylogenetic analyses appear to confirm this. The same analyses showed that duration of time spent at the surface between dives has scaling very similar to that of dive duration, with the result that the ratio of dive duration to surface pause duration is approximately mass invariant. This finding runs counter to other arguments found in the diving literature that suggest that surface pause duration should scale more positively with mass, leading to a negative scaling of the dive-pause ratio. We use a published model of optimal time allocation in the dive cycle to show that optimal decisions can predict approximate mass invariance in the dive-pause ratio, especially if metabolism scales approximately with mass to the two-thirds power (as indicated by some recent analyses) and oxygen uptake is assumed to have evolved to supply the body tissues at the required rate. However, emergent scaling rules are sensitive to input parameters, especially to the relationship between the scaling of metabolism and oxygen uptake rate at the surface. Our results illustrate the utility of an optimality approach for developing predictions and identifying key areas for empirical research on the allometry of diving behavior.
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Affiliation(s)
- Philip A Stephens
- Department of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, United Kingdom.
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38
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Halsey L, Butler P, Fahlman A, Woakes A, Handrich Y. Behavioral and Physiological Significance of Minimum Resting Metabolic Rate in King Penguins. Physiol Biochem Zool 2008; 81:74-86. [DOI: 10.1086/523318] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2007] [Indexed: 11/03/2022]
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Abstract
The debate about the value of the allometric scaling exponent (b) relating metabolic rate to body mass (metabolic rate = a x mass(b)) is ongoing, with published evidence both for and against a 3/4-power scaling law continuing to accumulate. However, this debate often revolves around a dichotomous distinction between the 3/4-power exponent predicted by recent models of nutrient distribution networks and a 2/3 exponent predicted by Euclidean surface-area-to-volume considerations. Such an approach does not allow for the possibility that there is no single "true" exponent. In the present study, we conduct a meta-analysis of 127 interspecific allometric exponents to determine whether there is a universal metabolic allometry or if there are systematic differences between taxa or between metabolic states. This analysis shows that the effect size of mass on metabolic rate is significantly heterogeneous and that, on average, the effect of mass on metabolic rate is stronger for endotherms than for ectotherms. Significant differences between scaling exponents were also identified between ectotherms and endotherms, as well as between metabolic states (e.g., rest, field, and exercise), a result that applies to b values estimated by ordinary least squares, reduced major axis, and phylogenetically correct regression models. The lack of support for a single exponent model suggests that there is no universal metabolic allometry and represents a significant challenge to any model that predicts only a single value of b.
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Affiliation(s)
- Craig R White
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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Farmer CG. On the origin of avian air sacs. Respir Physiol Neurobiol 2006; 154:89-106. [PMID: 16787763 DOI: 10.1016/j.resp.2006.04.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2005] [Revised: 04/19/2006] [Accepted: 04/20/2006] [Indexed: 11/27/2022]
Abstract
For many vertebrates the lung is the largest and lightest organ in the body cavity and for these reasons can greatly affect an organism's shape, density, and its distribution of mass; characters that are important to locomotion. In this paper non-respiratory functions of the lung are considered along with data on the respiratory capacities and gas exchange abilities of birds and crocodilians to infer the evolutionary history of the respiratory systems of dinosaurs, including birds. From a quadrupedal ancestry theropod dinosaurs evolved a bipedal posture. Bipedalism is an impressive balancing act, especially for tall animals with massive heads. During this transition selection for good balance and agility may have helped shape pulmonary morphology. Respiratory adaptations arising for bipedalism are suggested to include a reduction in costal ventilation and the use of cuirassal ventilation with a caudad expansion of the lung into the dorsal abdominal cavity. The evolution of volant animals from bipeds required yet again a major reorganization in body form. With this transition avian air sacs may have been favored because they enhanced balance and agility in flight. Finally, I propose that these hypotheses can be tested by examining the importance of the air sacs to balance and agility in extant animals and that these data will enhance our understanding of the evolution of the respiratory system in archosaurs.
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Affiliation(s)
- C G Farmer
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
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41
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Hayes JP, Shonkwiler JS. Allometry, Antilog Transformations, and the Perils of Prediction on the Original Scale. Physiol Biochem Zool 2006; 79:665-74. [PMID: 16691531 DOI: 10.1086/502814] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2005] [Indexed: 11/03/2022]
Abstract
Biologists often use allometric equations that take the form of power functions (e.g., Y = aM(b), where M stands for mass and a and b are empirically fitted constants). Typically, these allometric equations are fitted by taking the antilog of log-log regressions. Predictions from these allometric equations are biased, and the bias my be appreciable. Methods for making predictions that correct for the bias are available, but they have rarely, if ever, been used by ecological and evolutionary physiologists. Just as physiologists would not use an instrument that was not properly calibrated, they should not use allometric equations to make predictions unless they account for the bias of those predictions. We analyzed 20 interspecific and 10 intraspecific data sets. We compared predictions from standard allometric equations with those from several alternative methods. Our analyses suggest that the bias of predictions from interspecific data sets may be substantial. For the intraspecific data sets we analyzed, the bias was likely to be small. Biologists, including ecological and evolutionary physiologists, should exercise care when using allometric equations to make predictions, particularly given that methods to adjust for bias are easily implemented.
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Affiliation(s)
- Jack P Hayes
- Department of Biology, University of Nevada, Reno, 89557, USA.
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Cooke SJ, Philipp DP, Wahl DH, Weatherhead PJ. Energetics of parental care in six syntopic centrarchid fishes. Oecologia 2006; 148:235-49. [PMID: 16485098 DOI: 10.1007/s00442-006-0375-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Accepted: 01/19/2006] [Indexed: 11/29/2022]
Abstract
We studied parental behavior in six syntopically breeding species of centrarchid fishes to determine whether energetic costs could contribute to our understanding of the diversity of parental care. We used a combination of underwater videography, radio telemetry and direct observation to examine how the cost of parental care varied with both its duration and intensity. Duration of parental care, activity patterns, and energetic costs varied widely among species. Overall, the duration of care increased with parental size between species. When energetic costs were adjusted for species-specific differences in the duration of parental care, the cost of parental care also increased with mean size of the species. Species with extended parental care exhibited stage-specific patterns of activity and energy expenditure consistent with parental investment theory, whereas fish with short duration parental care tended to maintain high levels of activity throughout the entire period of parental care. The only apparent exception (a species with brief parental care but stage-specific behavior) was a species with multiple breeding bouts, and thus effectively having protracted parental care. These data suggest that some species with short duration parental care can afford not to adjust parental investment over stages of offspring development. Using our empirical data on parental care duration and costs, we reevaluated the relationship between egg size and quality of parental care. Variation in egg size explained almost all of the observed variation in total energetic cost of parental care, and to a lesser degree, duration-the larger the eggs, the more costly the parental care. This research highlights the value of incorporating energetic information into the study of parental care behavior and testing of ecological theory.
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Affiliation(s)
- Steven J Cooke
- Department of Natural Resources and Environmental Sciences, University of Illinois, and Center for Aquatic Ecology and Conservation, Illinois Natural History Survey, Champaign, IL, USA.
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Hempleman SC, Kilgore DL, Colby C, Bavis RW, Powell FL. Spike firing allometry in avian intrapulmonary chemoreceptors: matching neural code to body size. ACTA ACUST UNITED AC 2006; 208:3065-73. [PMID: 16081605 DOI: 10.1242/jeb.01752] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Biological rates in small animals are usually higher than those in large animals, yet the maximal rate of action potential (spike) generation in sensory neurons encoding rate functions is similar in all animals, due to the conserved genetics of voltage-gated ion channels. Therefore, sensory signals that vary at rates approaching maximal spike generation rate, as might occur in animals of diminished body size, may require specialized spike coding to convey this information. To test whether spike coding scales allometrically in sensory neurons monitoring signals that change frequency with body size, we recorded action potentials from 70 avian intrapulmonary chemoreceptors (IPC), respiratory neurons that detect lung CO2 changes during breathing, in five different avian species ranging in size from body mass Mb=0.045 kg (lovebirds) to 5.23 kg (geese). Since breathing frequency scales approximately to Mb-1/4 (higher in small birds, lower in large birds), we reasoned that IPC discharge frequencies may also scale to maintain spike information transmission within each breath. We found that phasic action potential discharge pattern, as quantified by the peak discharge rate and the magnitude of spike frequency adaptation, scaled between Mb-0.22 and Mb-0.26, like breathing rate (P<0.05). Previously published values of peak discharge rate in IPC also fit this allometric relationship. We suggest that mass-dependent scaling of neural coding may be necessary for preserving information transmission with decreasing body size.
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Affiliation(s)
- S C Hempleman
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011-5640 USA.
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44
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Glazier DS. Beyond the '3/4-power law': variation in the intra- and interspecific scaling of metabolic rate in animals. Biol Rev Camb Philos Soc 2006; 80:611-62. [PMID: 16221332 DOI: 10.1017/s1464793105006834] [Citation(s) in RCA: 602] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Revised: 05/27/2005] [Accepted: 06/08/2005] [Indexed: 01/01/2023]
Abstract
In this review I show that the '3/4-power scaling law' of metabolic rate is not universal, either within or among animal species. Significant variation in the scaling of metabolic rate with body mass is described mainly for animals, but also for unicells and plants. Much of this variation, which can be related to taxonomic, physiological, and/or environmental differences, is not adequately explained by existing theoretical models, which are also reviewed. As a result, synthetic explanatory schemes based on multiple boundary constraints and on the scaling of multiple energy-using processes are advocated. It is also stressed that a complete understanding of metabolic scaling will require the identification of both proximate (functional) and ultimate (evolutionary) causes. Four major types of intraspecific metabolic scaling with body mass are recognized [based on the power function R=aMb, where R is respiration (metabolic) rate, a is a constant, M is body mass, and b is the scaling exponent]: Type I: linear, negatively allometric (b<1); Type II: linear, isometric (b=1); Type III: nonlinear, ontogenetic shift from isometric (b=1), or nearly isometric, to negatively allometric (b<1); and Type IV: nonlinear, ontogenetic shift from positively allometric (b>1) to one or two later phases of negative allometry (b<1). Ontogenetic changes in the metabolic intensity of four component processes (i.e. growth, reproduction, locomotion, and heat production) appear to be important in these different patterns of metabolic scaling. These changes may, in turn, be shaped by age (size)-specific patterns of mortality. In addition, major differences in interspecific metabolic scaling are described, especially with respect to mode of temperature regulation, body-size range, and activity level. A 'metabolic-level boundaries hypothesis' focusing on two major constraints (surface-area limits on resource/waste exchange processes and mass/volume limits on power production) can explain much, but not all of this variation. My analysis indicates that further empirical and theoretical work is needed to understand fully the physiological and ecological bases for the considerable variation in metabolic scaling that is observed both within and among species. Recommended approaches for doing this are discussed. I conclude that the scaling of metabolism is not the simple result of a physical law, but rather appears to be the more complex result of diverse adaptations evolved in the context of both physico-chemical and ecological constraints.
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Affiliation(s)
- Douglas S Glazier
- Department of Biology, Juniata College, Huntingdon, Pennsylvania 16652, USA.
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45
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White CR, Seymour RS. Sample size and mass range effects on the allometric exponent of basal metabolic rate. Comp Biochem Physiol A Mol Integr Physiol 2005; 142:74-8. [PMID: 16125988 DOI: 10.1016/j.cbpa.2005.07.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Revised: 06/18/2005] [Accepted: 07/28/2005] [Indexed: 10/25/2022]
Abstract
The controversial relationship between body mass and basal metabolic rate in animals revolves around two questions: what is the allometric scaling exponent and what is the functional basis for it? For mammals, the first question could be resolved if measurements from all 4600 extant species were available, but this study shows that data for only 150 species, spanning three to four orders of magnitude variation in body mass, are sufficient to accurately determine the exponent. Because the currently available data set includes about 600 species that vary over five orders of magnitude in body size, further increases in sample size are unlikely to change the estimate of the scaling exponent.
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Affiliation(s)
- Craig R White
- Environmental Biology, School of Earth and Environmental Sciences, The University of Adelaide, SA, Australia.
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46
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Boggs DF, Miller JH. Absence of an hypoxic depression of metabolism in preproenkephalin knockout mice. Respir Physiol Neurobiol 2005; 152:92-9. [PMID: 16095981 DOI: 10.1016/j.resp.2005.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2005] [Revised: 06/06/2005] [Accepted: 06/07/2005] [Indexed: 11/16/2022]
Abstract
Opioids inhibit breathing in mammals, especially in newborns, and are also implicated in the control of hypoxic anapyrexia. We measured breathing patterns and metabolic responses to 12% oxygen in six adult male wildtype C57B/6J mice and six preproenkephalin knockout (PPNK-/-) mice in a flow-through respirometer and barometric plethysmograph with ambient temperature maintained in the thermoneutral zone. Breathing air, there was no significant difference between the two groups of mice in ventilation ((.)V), oxygen consumption ((.)V(O(2)), convection requirement ((.)V/(.)V(O(2)), tidal volume (V(t)), frequency (f), or inspiratory time (T(i)); however, PPNK-/- mice had a significantly shorter expiratory time (T(e)). The breathing pattern response to 5% CO(2) was the same between wildtype and PPNK-/- in terms of absolute values, but the % change in V(t) was greater in the wildtype. Breathing 12% O(2), there was no significant difference in V , V(t), f, T(i), T(e) or body temperature between groups, but there was a significant difference in (.)V(O(2) (PPNK-/- 1.24+/-0.05 ml O(2)min(-1) versus 0.91+/-0.05 for wildtype, P<0.001) and % change in (.)V(O(2), (2.3+/-6.6% for PPNK-/- versus -28+/-3.8% for wildtype); in ((.)V/(.)V(O(2)), (54+/-4 versus 78+/-10, P<0.05) and the % change in (.)V/(.)V(O(2), (37+/-9 versus 131+/-28, P<0.01). These data implicate enkephalin as a signaling molecule in the control of hypoxic depression of metabolism in mice.
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Affiliation(s)
- Dona F Boggs
- Department of Biology, Eastern Washington University, Cheney, WA 99004-2431, USA.
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47
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Arens JR, Cooper SJ. Metabolic and Ventilatory Acclimatization to Cold Stress in House Sparrows (Passer domesticus). Physiol Biochem Zool 2005; 78:579-89. [PMID: 15957112 DOI: 10.1086/430235] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2004] [Indexed: 11/03/2022]
Abstract
Passerines that overwinter in temperate climates undergo seasonal acclimatization that is characterized by metabolic adjustments that may include increased basal metabolic rate (BMR) and cold-induced summit metabolism (M(sum)) in winter relative to summer. Metabolic changes must be supported by equivalent changes in oxygen transport. While much is known about the morphology of the avian respiratory system, little is known about respiratory function under extreme cold stress. We examined seasonal variation in BMR, M(sum), and ventilation in seasonally acclimatized house sparrows from Wisconsin. BMR and M(sum) increased significantly in winter compared with summer. In winter, BMR increased 64%, and M(sum) increased 29% over summer values. The 64% increase in winter BMR is the highest recorded for birds. Metabolic expansibility (M(sum)/BMR) was 9.0 in summer and 6.9 in winter birds. The metabolic expansibility of 9.0 in summer is the highest yet recorded for birds. Ventilatory accommodation under helox cold stress was due to changes in breathing frequency (f), tidal volume, and oxygen extraction efficiency in both seasons. However, the only significant difference between summer and winter ventilation measures in helox cold stress was f. Mean f in helox cold stress for winter birds was 1.23 times summer values.
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Affiliation(s)
- Jeremy R Arens
- Department of Biology and Microbiology, University of Wisconsin, Oshkosh, WI 54901-8640, USA
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Macleod M, McKone TE, Foster KL, Maddalena RL, Parkerton TF, Mackay D. Applications of contaminant fate and bioaccumulation models in assessing ecological risks of chemicals: a case study for gasoline hydrocarbons. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:6225-6233. [PMID: 15597875 DOI: 10.1021/es049752+] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mass balance models of chemical fate and transport can be applied in ecological risk assessments for quantitative estimation of concentrations in air, water, soil, and sediment. These concentrations can, in turn, be used to estimate organism exposures and ultimately internal tissue concentrations that can be compared to mode-of-action-based critical body residues that induce toxic effects. From this comparison, risks to the exposed organism can be evaluated. To demonstrate the use of fate models in ecological risk assessment, we combine the EQuilibrium Criterion (EQC) environmental fate model with a simple screening level biouptake model for three representative organisms: a bird, a mammal, and a fish. This effort yields estimates of internal body concentrations that can be compared with levels known to elicit toxic effects. As an illustration, we present an analysis of 24 hydrocarbon components of gasoline that differ in properties but are assumed to elicit toxicity by a common narcotic mode of action. Results demonstrate that differences in chemical properties and mode of entry into the environment lead to profound differences in the efficiency of transport from emission to target biota. We discussthe implications of these results and draw attention to the insights gained about regional fate and ecological risks associated with gasoline. This approach is suitable for assessing single chemicals or mixtures that have similar modes of action. We conclude that the model-based methodologies presented are widely applicable for screening level ecological risk assessments that support effective chemicals management.
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Affiliation(s)
- Matthew Macleod
- Lawrence Berkeley National Laboratory, Berkeley, California 94720-8132, USA.
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49
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Suarez RK, Darveau CA, Childress JJ. Metabolic scaling: a many-splendoured thing. Comp Biochem Physiol B Biochem Mol Biol 2004; 139:531-41. [PMID: 15544974 DOI: 10.1016/j.cbpc.2004.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2004] [Revised: 04/26/2004] [Accepted: 05/05/2004] [Indexed: 11/21/2022]
Abstract
Animals at rest and during exercise display rates of aerobic metabolism, VO2, that represent mainly the sum of mitochondrial respiration rates in various organs. The relative contributions of these organs change with physiological state such that internal organs such as liver, kidney and brain account for most of the whole-body VO2 at rest, while locomotory muscles account for >90% of the maximum rate, VO2max, during maximal aerobic exercise. Mechanisms that regulate VO2 are complex and the relative importance of each step in a series, estimated by metabolic control analysis, depends upon the level of biological organization under consideration as well as physiological state. Despite this complexity, prominent single-cause models propose that metabolic rates are supply-limited and that the scaling of supply systems provides a sufficient explanation for the allometric scaling of metabolism. We argue that some assumptions, as well as current interpretations of the meaning (or consequences) of these constraints are flawed, i.e., elephants do not have lower mass-specific basal or maximal rates of aerobic metabolism because their mitochondria are more supply-limited than those of shrews. Animals do not violate the laws of physics, and the allometric scaling of supply systems would be expected, to some extent, to be matched by capacities for (and rates of) energy expenditure. But life is not so simple. Animals are so diverse that to do justice to metabolic scaling, it is also necessary to consider the scaling of energy expenditure. It is by doing so that models of metabolic scaling can be consistent with current paradigms in metabolic regulation and accommodate the range of inter- and intraspecific exponents found in nature. The "allometric cascade," a first attempt at such an accounting, was a source of great satisfaction to Peter Hochachka. It was the last door that he helped open to comparative physiologists before he said goodbye.
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Affiliation(s)
- Raul K Suarez
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106-9610, USA.
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50
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White CR, Seymour RS. Does Basal Metabolic Rate Contain a Useful Signal? Mammalian BMR Allometry and Correlations with a Selection of Physiological, Ecological, and Life‐History Variables. Physiol Biochem Zool 2004; 77:929-41. [PMID: 15674767 DOI: 10.1086/425186] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2004] [Indexed: 11/03/2022]
Abstract
Basal metabolic rate (BMR, mL O2 h(-1)) is a useful measurement only if standard conditions are realised. We present an analysis of the relationship between mammalian body mass (M, g) and BMR that accounts for variation associated with body temperature, digestive state, and phylogeny. In contrast to the established paradigm that BMR proportional to M3/4, data from 619 species, representing 19 mammalian orders and encompassing five orders of magnitude variation in M, show that BMR proportional to M2/3. If variation associated with body temperature and digestive state are removed, the BMRs of eutherians, marsupials, and birds do not differ, and no significant allometric exponent heterogeneity remains between orders. The usefulness of BMR as a general measurement is supported by the observation that after the removal of body mass effects, the residuals of BMR are significantly correlated with the residuals for a variety of physiological and ecological variables, including maximum metabolic rate, field metabolic rate, resting heart rate, life span, litter size, and population density.
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Affiliation(s)
- Craig R White
- Department of Environmental Biology, School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.
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