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Pollock HS, Rutt CL, Cooper WJ, Brawn JD, Cheviron ZA, Luther DA. Equivocal support for the climate variability hypothesis within a Neotropical bird assemblage. Ecology 2024; 105:e4206. [PMID: 37950619 DOI: 10.1002/ecy.4206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 07/03/2023] [Accepted: 10/05/2023] [Indexed: 11/13/2023]
Abstract
The climate variability hypothesis posits that an organism's exposure to temperature variability determines the breadth of its thermal tolerance and has become an important framework for understanding variation in species' susceptibilities to climate change. For example, ectotherms from more thermally stable environments tend to have narrower thermal tolerances and greater sensitivity to projected climate warming. Among endotherms, however, the relationship between climate variability and thermal physiology is less clear, particularly with regard to microclimate variation-small-scale differences within or between habitats. To address this gap, we explored associations between two sources of temperature variation (habitat type and vertical forest stratum) and (1) thermal physiological traits and (2) temperature sensitivity metrics within a diverse assemblage of Neotropical birds (n = 89 species). We used long-term temperature data to establish that daily temperature regimes in open habitats and forest canopy were both hotter and more variable than those in the forest interior and forest understory, respectively. Despite these differences in temperature regime, however, we found little evidence that species' thermal physiological traits or temperature sensitivity varied in association with either habitat type or vertical stratum. Our findings provide two novel and important insights. First, and in contrast to the supporting empirical evidence from ectotherms, the thermal physiology of birds at our study site appears to be largely decoupled from local temperature variation, providing equivocal support for the climate variability hypothesis in endotherms. Second, we found no evidence that the thermal physiology of understory forest birds differed from that of canopy or open-habitat species-an oft-invoked, yet previously untested, mechanism for why these species are so vulnerable to environmental change.
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Affiliation(s)
- Henry S Pollock
- Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Cameron L Rutt
- Department of Biology, George Mason University, Fairfax, Virginia, USA
- American Bird Conservancy, The Plains, Virginia, USA
| | | | - Jeffrey D Brawn
- Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - David A Luther
- Department of Biology, George Mason University, Fairfax, Virginia, USA
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2
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Wall CE, Hanna JB, O'Neill MC, Toler M, Laird MF. Energetic costs of feeding in 12 species of small-bodied primates. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220553. [PMID: 37839441 PMCID: PMC10577031 DOI: 10.1098/rstb.2022.0553] [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: 03/01/2023] [Accepted: 06/25/2023] [Indexed: 10/17/2023] Open
Abstract
There are no comparative, empirical studies of the energetic costs of feeding in mammals. As a result, we lack physiological data to better understand the selection pressures on the mammalian feeding apparatus and the influence of variables such as food geometric and material properties. This study investigates interspecific scaling of the net energetic costs of feeding in relation to body size, jaw-adductor muscle mass and food properties in a sample of 12 non-human primate species ranging in size from 0.08 to 4.2 kg. Net energetic costs during feeding were measured by indirect calorimetry for a variety of pre-cut and whole raw foods varying in geometric and material properties. Net feeding costs were determined in two ways: by subtracting either the initial metabolic rate prior to feeding or subtracting the postprandial metabolic rate. Interspecific scaling relationships were evaluated using pGLS and OLS regression. Net feeding costs scale negatively relative to both body mass and jaw-adductor mass. Large animals incur relatively lower feeding costs indicating that small and large animals experience and solve mechanical challenges in relation to energetics in different ways. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
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Affiliation(s)
- Christine E. Wall
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
- Department of Anatomy, College of Osteopathic Medicine, New York Institute of Technology, New York Institute of Technology, Old Westbury, NY 11568, USA
- Duke Lemur Center, Duke University, Durham, NC 27705, USA
| | - Jandy B. Hanna
- Duke Lemur Center, Duke University, Durham, NC 27705, USA
| | | | - Maxx Toler
- Jerry M. Wallace School of Osteopathic Medicine, Campbell University, Buies Creek, NC 27506, USA
| | - Myra F. Laird
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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3
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Abbas W, Withers PC, Evans TA. Gas exchange patterns for a small, stored-grain insect pest, Tribolium castaneum. BULLETIN OF ENTOMOLOGICAL RESEARCH 2023; 113:361-367. [PMID: 36820514 DOI: 10.1017/s0007485322000657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Insects breathe using one or a combination of three gas exchange patterns; continuous, cyclic and discontinuous, which vary in their rates of exchange of oxygen, carbon dioxide and water. In general, there is a trade-off between lowering gas exchange using discontinuous exchange that limits water loss at the cost of lower metabolic rate. These patterns and hypotheses for the evolution of discontinuous exchange have been examined for relatively large insects (>20 mg) over relatively short periods (<4 h), but smaller insects and longer time periods have yet to be examined. We measured gas exchange patterns and metabolic rates for adults of a small insect pest of grain, the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), using flow-through respirometry in dry air for 48 h. All adults survived the desiccating measurement period; initially they used continuous gas exchange, then after 24 h switched to cyclic gas exchange with a 27% decrease in metabolic rate, and then after 48 h switched to discontinuous gas exchange with increased interburst duration and further decrease in metabolic rate. The successful use of the Qubit, a lower cost and so more common gas analyser, to measure respiration in the very small T. castaneum, may prompt more flow-through respirometry studies of small insects. Running such studies over long durations may help to better understand the evolution of respiration physiology and thus suggest new methods of pest management.
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Affiliation(s)
- Waseem Abbas
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
- Department of Entomology, University of Agriculture, Faisalabad 38040, Pakistan
| | - Philip C Withers
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Theodore A Evans
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
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Tan S, Li J, Yang Q, Fu J, Chen J. Light/dark phase influences intra-individual plasticity in maintenance metabolic rate and exploratory behavior independently in the Asiatic toad. BMC ZOOL 2022; 7:39. [PMID: 37170388 PMCID: PMC10127016 DOI: 10.1186/s40850-022-00139-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 06/28/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
It is well-known that light/dark phase can affect energy expenditure and behaviors of most organisms; however, its influences on individuality (inter-individual variance) and plasticity (intra-individual variance), as well as their associations remain unclear. To approach this question, we repeatedly measured maintenance metabolic rate (MR), exploratory and risk-taking behaviors across light/dark phase four times using wild-caught female Asiatic toads (Bufo gargarizans), and partitioned their variance components with univariate and bivariate mixed-effects models.
Results
The group means of maintenance MR and risk-taking behavior increased at night, while the group mean of exploratory behavior remained constant throughout the day. At night, the intra-individual variances were elevated in maintenance MR but reduced in exploration, suggesting that phenotypic plasticity was enhanced in the former but constrained in the latter. In addition, maintenance MR was not coupled with exploratory or risk-taking behaviors in daytime or at night, neither at the inter-individual nor intra-individual levels.
Conclusions
Our findings suggest that these traits are independently modulated by the light/dark phase, and an allocation energy management model may be applicable in this species. This study sheds new insights into how amphibians adapt nocturnal lifestyle across multiple hierarchy levels via metabolic and behavioral adjustments.
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Sirsat TS, Sirsat SKG, Price ER, Pineda M, Dzialowski EM. Manipulating plasma thyroid hormone levels alters development of endothermy and ventilation in nestling red-winged blackbirds. Front Physiol 2022; 13:1027257. [PMID: 36523554 PMCID: PMC9745037 DOI: 10.3389/fphys.2022.1027257] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/14/2022] [Indexed: 03/14/2024] Open
Abstract
Thyroid hormones are key regulators of development and metabolism in vertebrates. During the nestling period, young of altricial species transition from an ectothermic phenotype to an endothermic phenotype. Red-winged blackbirds are an altricial species that exhibit an increase in plasma 3,3', 5-triiodo-L-thyronine (T3) levels during the first 5 days post-hatch (dph), begin to develop endothermic metabolic responses by 7 dph, and fledge within 10 days of hatching. We propose that thyroid hormones play an important role in regulating development of endothermy during the nestling period in altricial birds. To better understand the effects of thyroid hormones on endothermic metabolic development in an altricial species, we treated nestling red-winged blackbirds on 2, 3, and 5 dph with either methimazole (MMI) to induce hypothyroidism or supplemental T3 to induce hyperthyroidism. We then measured on 5, 7, and 9 dph morphology and whole animal O2 consumption (V ˙ o 2 ) and ventilation in the thermal neutral zone and during gradual cooling. Treatment of nestlings with MMI resulted in lower plasma T3 levels on 5 dph that recovered by 7 dph, while supplementing with T3 did not affect plasma T3 levels on 5, 7 and 9 dph. Treatment with MMI resulted in smaller nestlings with smaller hearts and structural characters such as wing chord and femur length, but larger lungs and kidneys. Treatment with T3 produced smaller nestlings with smaller body masses and shorter femur and tarsus lengths. The development ofV ˙ o 2 and ventilation endothermic responses to gradual cooling in MMI treated nestlings were delayed when compared with control nestlings. In 9 dph nestlings, hypothyroidism resulted in alterations in the responses of ventilation frequency and tidal volume to cooling when compared with the control nestlings. Supplemental T3 had no effect on the development ofV ˙ o 2 and ventilation in the thermal neutral zone or in response to cooling. Our data suggest plasma thyroid hormone levels play an active role in the systemic development of endothermic capacity and the development of ventilatory control. In the nestling avian, multiple systems develop in concert to produce an endothermic phenotype, but reduced thyroid hormone delays maturation of endothermic capacity.
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Affiliation(s)
- Tushar S. Sirsat
- Department of Physician Assistant Studies, Clarkson University, Potsdam, NY, United States
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Sarah K. G. Sirsat
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
- Department of Biology, SUNY Potsdam, Potsdam, NY, United States
| | - Edwan R. Price
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
- Green Godwit Consulting, Cleveland, OH, United States
| | - Megan Pineda
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
- FUJIFILM Diosynth Biotechnologies Texas, College Station, TX, United States
| | - Edward M. Dzialowski
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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Dickinson E, Hanna CS, Fischer HM, Davoli EC, Currier AA, Granatosky MC. Locomotor energetics in the Indonesian blue-tongued skink (Tiliqua gigas) with implications for the cost of belly-dragging in early tetrapods. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:329-336. [PMID: 34914867 DOI: 10.1002/jez.2569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/17/2021] [Accepted: 11/24/2021] [Indexed: 12/19/2022]
Abstract
During the last decade, biomechanical and kinematic studies have suggested that a belly-dragging gait may have represented a critical locomotor stage during tetrapod evolution. This form of locomotion is hypothesized to facilitate animals to move on land with relatively weaker pectoral muscles. The Indonesian blue-tongued skink (Tiliqua gigas) is known for its belly-dragging locomotion and is thought to employ many of the same spatiotemporal gait characteristics of stem tetrapods. Conversely, the savannah monitor (Varanus exanthematicus) employs a raised quadrupedal gait. Thus, differences in the energetic efficiency of locomotion between these taxa may elucidate the role of energetic optimization in driving gait shifts in early tetrapods. Five Tiliqua and four Varanus were custom-fitted for 3D printed helmets that, combined with a Field Metabolic System, were used to collect open-flow respirometry data including O2 consumption, CO2 production, water vapor pressure, barometric pressure, room temperature, and airflow rates. Energetic data were collected for each species at rest, and when walking at three different speeds. Energetic consumption in each taxon increased at greater speeds. On a per-stride basis, energetic costs appear similar between taxa. However, significant differences were observed interspecifically in terms of net cost of transport. Overall, energy expenditure was ~20% higher in Tiliqua at equivalent speeds, suggesting that belly-dragging does impart a tangible energetic cost during quadrupedal locomotion. This cost, coupled with the other practical constraints of belly-dragging (e.g., restricting top-end speed and reducing maneuverability in complex terrains) may have contributed to the adoption of upright quadrupedal walking throughout tetrapod locomotor evolution.
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Affiliation(s)
- Edwin Dickinson
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Christopher S Hanna
- New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Hannah M Fischer
- New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Elizabeth C Davoli
- New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Allen A Currier
- New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Michael C Granatosky
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA.,Center for Biomedical Innovation, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, USA
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7
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Relative Water Economy Is a Useful Index of Aridity Tolerance for Australian Poephiline Finches. BIRDS 2022. [DOI: 10.3390/birds3020012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We evaluate if the iconic Australian Zebra Finch (Taeniopygia guttata) has a unique physiology or if its metabolic, thermal and hygric physiology are similar to other Australian poephiline finches, by comparing it with three other species, the arid-habitat Painted Finch (Emblema pictum) and the mesic-habitat Double-barred (Taeniopygia bichenovii) and Red-browed (Neochmia temporalis) Finches. All physiological variables responded to ambient temperature as expected. There were no species differences for any of the standard physiological variables, consistent with the hypotheses that birds are pre-adapted to arid habitats, the recent development of Australian deserts has limited opportunity for physiological adaptation, and all four species share similar behavioural and ecological traits. Nevertheless, the ambient temperature where metabolic water production equals evaporative water loss (point of relative water economy) was highest for the Zebra (19.1 °C), lower for Double-barred (16.4 °C) and Painted (15.2 °C) and lowest for Red-Browed (4.1 °C) Finches, corresponding with their general patterns of habitat aridity. The point of relative water economy may be a sensitive index for assessing a species’ tolerance of aridity because it integrates individual physiological variables. We conclude that the Zebra Finch is not a physiological outlier amongst Australian finches, but is at the end of a continuum of aridity tolerance for the four study species.
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8
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Withers PC, Cooper CE, Körtner G, Geiser F. Small Alpine Marsupials Regulate Evaporative Water Loss Suggesting a Thermoregulatory Rather than Water Conservation Role. Physiol Biochem Zool 2022; 95:212-228. [DOI: 10.1086/719735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Berntsen HH, Bech C. Incubation temperature and physiological aging in the zebra finch. PLoS One 2021; 16:e0260037. [PMID: 34843532 PMCID: PMC8629242 DOI: 10.1371/journal.pone.0260037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 10/30/2021] [Indexed: 11/19/2022] Open
Abstract
In birds, incubation temperature has received increased attention as an important source of phenotypic variability in offspring. A lower than optimal incubation temperature may negatively affect aspects of nestling physiology, such as body growth and energy metabolism. However, the long-term effects of sub-optimal incubation temperature on morphology and physiology are not well understood. In a previous study, we showed that zebra finches from eggs incubated at a low temperature (35.9°C) for 2/3 of the total incubation time suffered a lower post-fledging survival compared to individuals that had been incubated at higher temperatures (37.0 and 37.9°C). In the present study, we investigated whether these variations in incubation temperature could cause permanent long-lasting differences in body mass, body size, or basal metabolic rate. Furthermore, we tested whether the observed differences in survival between treatment groups would be reflected in the rate of physiological deterioration, assessed through oxidative damage and decreased metabolic rate with age (i.e. 'metabolic aging'). Incubation temperature did not significantly affect embryonic or nestling body growth and did not influence final adult body mass or body size. Nor was there any long-term effect on basal metabolic rate. Birds from eggs incubated at the lowest temperature experienced an accumulation of oxidative damage with age, although this was not accompanied by an accelerated rate of metabolic aging. The present results suggest that the low survival in these birds was possibly mediated by increased oxidative stress, but independent of body growth and the basal metabolic rate.
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Affiliation(s)
- Henrik H. Berntsen
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Norwegian Institute for Nature Research, Trondheim, Norway
| | - Claus Bech
- Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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10
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Young A, Anderson RO, Naimo A, Alton LA, Goulet CT, Chapple DG. How do the physiological traits of a lizard change during its invasion of an oceanic island? Oecologia 2021; 198:567-578. [PMID: 34725729 DOI: 10.1007/s00442-021-05054-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 09/28/2021] [Indexed: 11/30/2022]
Abstract
Physiology is crucial for the survival of invasive species in new environments. Yet, new climatic conditions and the limited genetic variation found within many invasive populations may influence physiological responses to new environmental conditions. Here, we studied the case of the delicate skinks (Lampropholis delicata) invading Lord Howe Island (LHI), Australia. On LHI, the climate is different from the mainland source of the skinks, and independent introduction events generated invasive populations with distinct genetic backgrounds. To understand how climate and genetic background may shape physiological responses along biological invasions, we compared the physiological traits of a source and two invasive (single-haplotype and multi-haplotype) populations of the delicate skink. For each population, we quantified physiological traits related to metabolism, sprint speed, and thermal physiology. We found that, for most physiological traits analysed, population history did not influence the ecophysiology of delicate skinks. However, invasive populations showed higher maximum speed than the source population, which indicates that locomotor performance might be a trait under selection during biological invasions. As well, the invasive population with a single haplotype was less cold-tolerant than the multi-haplotype and source populations. Our results suggest that limited genetic variability and climate may influence physiological responses of invasive organisms in novel environments. Incorporating the interplay between genetic and physiological responses into models predicting species invasions can result in more accurate understanding of the potential habitats those species can occupy.
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Affiliation(s)
- Alyse Young
- Faculty of Science, School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Rodolfo O Anderson
- Faculty of Science, School of Biological Sciences, Monash University, Clayton, VIC, Australia.
| | - Annalise Naimo
- Faculty of Science, School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Lesley A Alton
- Faculty of Science, School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Celine T Goulet
- Faculty of Science, School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - David G Chapple
- Faculty of Science, School of Biological Sciences, Monash University, Clayton, VIC, Australia
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11
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Tan S, Li P, Yao Z, Liu G, Yue B, Fu J, Chen J. Metabolic cold adaptation in the Asiatic toad: intraspecific comparison along an altitudinal gradient. J Comp Physiol B 2021; 191:765-776. [PMID: 34089366 DOI: 10.1007/s00360-021-01381-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/07/2021] [Accepted: 05/19/2021] [Indexed: 11/26/2022]
Abstract
The metabolic cold adaptation (MCA) hypothesis predicts an increase in metabolic rate and thermal sensitivity of poikilotherms from cold environments as compared to those from warm environments, when measured under standardized conditions. This compensatory response is also expected to evolve in life history and behavioral traits if the reductions in these phenotypic traits at low temperature involves in a reduction in fitness. We investigated the extent to which the level of energy intake (measured as feeding rate), energy turnover (measured as standard metabolic rate, SMR) and the energy budget (energy allocation to growth and physical activity) are influenced by climatic conditions in three populations of the Asiatic toad (Bufo gargarizans) distributed across an altitudinal gradient of 1350 m in the Qionglai Mountains of Western China. We found a similar thermal reaction norm of SMR at both population and individual levels; therefore, the data did not support the MCA hypothesis. However, there was a co-gradient variation (CoGV) for mass change rate in which the high and medium altitudinal populations displayed slower mass change rates than their counterparts from low altitudes. Moreover, this CoGV pattern was accompanied by a low feeding rate and high physical activity for the high- and medium-altitude populations. Our results highlight that adjustments in energy intake and energy allocation to behaviors, but not energy allocation to metabolism of maintenance, could act as an energetic strategy to accommodate the varied growth efficiency in Asiatic toads along an altitudinal gradient.
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Affiliation(s)
- Song Tan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- College of Life Sciences, Sichuan University, Chengdu, 610064, China
- University of Chinese Academy of Sciences, No.19 (A) Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Ping Li
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- University of Chinese Academy of Sciences, No.19 (A) Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Zhongyi Yao
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- College of Life Sciences, Sichuan University, Chengdu, 610064, China
- University of Chinese Academy of Sciences, No.19 (A) Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Gaohui Liu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- Chinese Research Academy of Environmental Sciences, No.8, Dayangfang, Beiyuan, Beijing, 100012, China
| | - Bisong Yue
- College of Life Sciences, Sichuan University, Chengdu, 610064, China
| | - Jinzhong Fu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
- Department of Integrative Biology, University of Guelph, Guelph, N1G 2W1, Canada.
| | - Jingfeng Chen
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
- University of Chinese Academy of Sciences, No.19 (A) Yuquan Road, Shijingshan District, Beijing, 100049, China.
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12
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Ton R, Stier A, Cooper CE, Griffith SC. Effects of Heat Waves During Post-natal Development on Mitochondrial and Whole Body Physiology: An Experimental Study in Zebra Finches. Front Physiol 2021; 12:661670. [PMID: 33986695 PMCID: PMC8110927 DOI: 10.3389/fphys.2021.661670] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022] Open
Abstract
Human-induced climate change is increasing the frequency, duration, and intensity of heat waves and exposure to these extreme temperatures impacts individual physiology and performance (e.g., metabolism, water balance, and growth). These traits may be susceptible to thermal conditions experienced during embryonic development, but experiments focusing on post-natal development are scant. Documented effects of heat waves on whole-body metabolism may reflect changes in mitochondrial function, but most studies do not measure physiological traits at both the cellular and whole organism levels. Here, we exposed nests of zebra finches to experimentally simulated heat waves for 18 days after hatching and measured body mass, growth rate, whole-body metabolic rate, body temperature, wet thermal conductance, evaporative water loss, and relative water economy of chicks at three ages corresponding to ectothermic (day 5), poikilothermic (day 12), and homoeothermic (day 50) stages. Additionally, we measured mitochondrial bioenergetics of blood cells 80 days post-hatch. While early-life exposure to heat wave conditions did not impact whole body metabolic and hygric physiology, body temperature was lower for birds from heated compared with control nests at both 12 and 50 days of age. There was also an effect of nest heating at the cellular level, with mitochondria from heated birds having higher endogenous and proton-leak related respiration, although oxidative phosphorylation, maximum respiratory capacity, and coupling efficiency were not impacted. Our results suggest that early-life exposure to high ambient temperature induces programming effects on cellular-level and thermal physiology that may not be apparent for whole-animal metabolism.
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Affiliation(s)
- Riccardo Ton
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Antoine Stier
- Department of Biology, University of Turku, Turku, Finland
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Christine E. Cooper
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- School of Molecular and Life Sciences, Curtin University, Perth, WA, Australia
| | - Simon C. Griffith
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
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13
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Pretzlaff I, Radchuk V, Turner JM, Dausmann KH. Flexibility in thermal physiology and behaviour allows body mass maintenance in hibernating hazel dormice. J Zool (1987) 2021. [DOI: 10.1111/jzo.12862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- I. Pretzlaff
- Institute for Zoology University of Hamburg Hamburg Germany
| | - V. Radchuk
- Department of Ecological Dynamics Leibniz Institute for Zoo and Wildlife Research (IZW) Berlin Germany
| | - J. M. Turner
- Institute for Land, Water and Society Charles Sturt University Albury NSW Australia
| | - K. H. Dausmann
- Institute for Zoology University of Hamburg Hamburg Germany
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Cooper CE, Withers PC. Two lines of evidence for physiological control of insensible evaporative water loss by a tiny marsupial. J Exp Biol 2020; 223:jeb234450. [PMID: 33097571 DOI: 10.1242/jeb.234450] [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: 08/01/2020] [Accepted: 10/16/2020] [Indexed: 11/20/2022]
Abstract
We present two independent lines of evidence that a tiny dasyurid marsupial, the ningaui (Ningaui spp.), has acute physiological control of its insensible evaporative water loss below and within thermoneutrality. Perturbation of the driving force for evaporation by varying relative humidity, and therefore the water vapour pressure deficit between the animal and the ambient air, does not have the expected physical effect on evaporative water loss. Exposure to a helox atmosphere also does not have the expected physical effect of increasing evaporative water loss for live ningauis (despite it having the expected effect of increasing heat loss for live ningauis), but increases evaporative water loss for dead ningauis. We discuss the relative advantages and disadvantages of both experimental approaches for demonstrating physiological control of insensible evaporative water loss. An appreciation of physiological control is important because insensible evaporative water loss contributes to both water and heat balance, is clearly under environmental selection pressure, and potentially impacts the distribution of endotherms and their response to environmental change.
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Affiliation(s)
- Christine Elizabeth Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6845, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Philip Carew Withers
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6845, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
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15
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Sirsat TS, Dzialowski EM. Manipulating plasma thyroid hormone levels at hatching alters development of endothermy and ventilation in Pekin duck ( Anas platyrhynchos domestica). J Exp Biol 2020; 223:jeb237701. [PMID: 33046566 DOI: 10.1242/jeb.237701] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 08/25/2023]
Abstract
At hatching in precocial birds, there are rapid physiological and metabolic phenotypic changes associated with attaining endothermy. During the transition to ex ovo life, thyroid hormone levels naturally increase, peaking at hatching, and then decline. To better understand the role of the natural increase in thyroid hormone at hatching in regulating the developmental trajectory of the Pekin duck's endothermic phenotype, we examined development of O2 consumption (V̇O2 ) and ventilation (frequency, tidal volume and minute ventilation) while inhibiting the developmental increase in thyroid hormones that occurs at hatching via administration of the thyroid-peroxidase inhibitor methimazole (MMI) or accelerating the developmental increase via triiodothyronine (T3) supplementation. Animals were dosed only on day 24 of a 28-day incubation period and studied on incubation day 25, during external pipping (EP) and 1 day post-hatching (dph). On day 25, there was an increase in V̇O2 in the hyperthyroid treatment compared with the other two treatments. During the EP stage, there was a significant effect of thyroid status on V̇O2 , with hyperthyroid V̇O2 being highest and hypothyroid V̇O2 the lowest. By 1 dph, the supplemented T3 and control animals had similar V̇O2 responses to cooling with comparable thermal neutral zones followed by increased V̇O2 Hypothyroid 1 dph hatchlings had a lower resting V̇O2 that did not increase to the same extent as the supplemented T3 and control animals during cooling. During EP, inhibiting the rise in T3 resulted in embryos with lower ventilation frequency and tidal volume than control and supplemented T3 embryos. At 1 dph, ventilation frequency of all animals increased during cooling, but tidal volume only increased in supplemented T3 and control hatchlings. Our data support the role of the late incubation increase in T3 in regulating the systemic development of endothermic metabolic capacity and associated control of ventilation occurring at hatching of the Pekin duck.
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Affiliation(s)
- Tushar S Sirsat
- Developmental Integrative Biology Research Group, Department of Biological Sciences, 1155 Union Circle #305220, University of North Texas, Denton, TX 76203, USA
| | - Edward M Dzialowski
- Developmental Integrative Biology Research Group, Department of Biological Sciences, 1155 Union Circle #305220, University of North Texas, Denton, TX 76203, USA
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16
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Pollock HS, Brawn JD, Cheviron ZA. Heat tolerances of temperate and tropical birds and their implications for susceptibility to climate warming. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13693] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Henry S. Pollock
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Champaign IL USA
| | - Jeffrey D. Brawn
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Champaign IL USA
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17
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Cooper CE, Withers PC, Körtner G, Geiser F. Does control of insensible evaporative water loss by two species of mesic parrot have a thermoregulatory role? J Exp Biol 2020; 223:jeb229930. [PMID: 32747451 DOI: 10.1242/jeb.229930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/29/2020] [Indexed: 12/20/2022]
Abstract
Insensible evaporative water loss (EWL) at or below thermoneutrality is generally assumed to be a passive physical process. However, some arid zone mammals and a single arid zone bird can control their insensible water loss, so we tested the hypothesis that the same is the case for two parrot species from a mesic habitat. We investigated red-rumped parrots (Psephotus haematonotus) and eastern rosellas (Platycercus eximius), measuring their EWL, and other physiological variables, at a range of relative humidities at ambient temperatures of 20 and 30°C (below and at thermoneutrality). We found that, despite a decrease in EWL with increasing relative humidity, rates of EWL were not fully accounted for by the water vapour deficit between the animal and its environment, indicating that the insensible EWL of both parrots was controlled. It is unlikely that this deviation from physical expectations was regulation with a primary role for water conservation because our mesic-habitat parrots had equivalent regulatory ability as the arid habitat budgerigar (Melopsittacus undulatus). This, together with our observations of body temperature and metabolic rate, instead support the hypothesis that acute physiological control of insensible water loss serves a thermoregulatory purpose for endotherms. Modification of both cutaneous and respiratory avenues of evaporation may be involved, possibly via modification of expired air temperature and humidity, and surface resistance.
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Affiliation(s)
- Christine Elizabeth Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
- Centre for Behavioural and Physiology Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Philip Carew Withers
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
- Centre for Behavioural and Physiology Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Gerhard Körtner
- Centre for Behavioural and Physiology Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiology Ecology, Zoology, University of New England, Armidale, NSW 2351, Australia
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18
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Water Costs of Gas Exchange by a Speckled Cockroach and a Darkling Beetle. INSECTS 2020; 11:insects11090632. [PMID: 32937981 PMCID: PMC7563770 DOI: 10.3390/insects11090632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/26/2020] [Accepted: 09/10/2020] [Indexed: 11/16/2022]
Abstract
Simple Summary Evaporative water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. This respiratory water cost of gas exchange (the ratio of respiratory water loss to metabolic rate) is suggested to depend on several factors, such as the mode of gas exchange (convection vs. diffusion), species habitat, body size and measurement conditions. We measured this cost for a blaberid cockroach and a tenebrionid beetle using flow-through respirometry. We controlled the factors that affect respiratory water cost of gas exchange, i.e., both species are similar in their mode of gas exchange (dominantly convective), habitat (relatively moist) and body size, and were measured at the same temperature. The cockroaches showed both continuous and discontinuous gas exchange patterns, which had a significantly different metabolic rate and respiratory water loss but the same respiratory water cost of gas exchange. The darkling beetles showed a continuous gas exchange pattern only, and their metabolic rate, respiratory water loss and respiratory water cost of gas exchange were equivalent to those cockroaches using continuous gas exchange. This finding from our study highlights that the respiratory water cost of gas exchange is similar between species, regardless of the gas exchange pattern used, when the confounding factors affecting this cost are controlled. However, the total evaporative water cost of gas exchange is much higher than the respiratory cost because cuticular water loss contributes considerably more to the overall evaporative water loss than respiratory water. We suggest that the total water cost of gas exchange is likely to be a more useful indicator of species distribution with respect to environmental aridity than just the respiratory water cost. Abstract Respiratory water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. It has been suggested to depend on several factors, such as the mode of gas exchange (convective vs. diffusive), species habitat (aridity), body size and measurement conditions (temperature). We measured this cost in terms of respiratory water loss relative to metabolic rate (respiratory water cost of gas exchange; RWL/V˙CO2) for adults of two insect species, the speckled cockroach (Nauphoeta cinerea) and the darkling beetle (Zophobas morio), which are similar in their mode of gas exchange (dominantly convective), habitat (mesic), body size and measurement conditions, by measuring gas exchange patterns using flow-through respirometry. The speckled cockroaches showed both continuous and discontinuous gas exchange patterns, which had significantly a different metabolic rate and respiratory water loss but the same respiratory water cost of gas exchange. The darkling beetles showed continuous gas exchange pattern only, and their metabolic rate, respiratory water loss and respiratory cost of gas exchange were equivalent to those cockroaches using continuous gas exchange. This outcome from our study highlights that the respiratory water cost of gas exchange is similar between species, regardless of gas exchange pattern used, when the confounding factors affecting this cost are controlled. However, the total evaporative water cost of gas exchange is much higher than the respiratory cost because cuticular water loss contributes considerably more to the overall evaporative water loss than respiratory water. We suggest that the total water cost of gas exchange is likely to be a more useful index of environmental adaptation (e.g., aridity) than just the respiratory water cost.
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19
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Geiser F, Willis CKR, Brigham RM. No evidence for hibernation in rockwrens. J Exp Biol 2020; 223:jeb229518. [PMID: 32788270 DOI: 10.1242/jeb.229518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/04/2020] [Indexed: 11/20/2022]
Affiliation(s)
- Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology CO2, University of New England, Armidale, NSW 2351, Australia
| | - Craig K R Willis
- Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, Canada, MB R3B 2E9
| | - R Mark Brigham
- Department of Biology, University of Regina, Regina, Canada, SK S4S 0A2
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20
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Cooper CE, Hurley LL, Deviche P, Griffith SC. Physiological responses of wild zebra finches ( Taeniopygia guttata) to heatwaves. J Exp Biol 2020; 223:jeb225524. [PMID: 32376711 DOI: 10.1242/jeb.225524] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 04/30/2020] [Indexed: 12/17/2022]
Abstract
Desert birds inhabit hot, dry environments that are becoming hotter and drier as a consequence of climate change. Extreme weather such as heatwaves can cause mass-mortality events that may significantly impact populations and species. There are currently insufficient data concerning physiological plasticity to inform models of species' response to extreme events and develop mitigation strategies. Consequently, we examine here the physiological plasticity of a small desert bird in response to hot (mean maximum ambient temperature=42.7°C) and cooler (mean maximum ambient temperature=31.4°C) periods during a single Austral summer. We measured body mass, metabolic rate, evaporative water loss and body temperature, along with blood parameters (corticosterone, glucose and uric acid) of wild zebra finches (Taeniopygia guttata) to assess their physiological state and determine the mechanisms by which they respond to heatwaves. Hot days were not significant stressors; they did not result in modification of baseline blood parameters or an inability to maintain body mass, provided drinking water was available. During heatwaves, finches shifted their thermoneutral zone to higher temperatures. They reduced metabolic heat production, evaporative water loss and wet thermal conductance, and increased hyperthermia, especially when exposed to high ambient temperature. A consideration of the significant physiological plasticity that we have demonstrated to achieve more favourable heat and water balance is essential for effectively modelling and planning for the impacts of climate change on biodiversity.
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Affiliation(s)
- Christine Elizabeth Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia 3102, Australia
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Laura Leilani Hurley
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Pierre Deviche
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Simon Charles Griffith
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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21
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Tomlinson S. The construction of small‐scale, quasi‐mechanistic spatial models of insect energetics in habitat restoration: A case study of beetles in Western Australia. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Sean Tomlinson
- School of Molecular and Life Sciences Curtin University of Technology Perth WA Australia
- Department of Biodiversity, Conservation an Attractions Kings Park Science Kings Park WA Australia
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22
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Lombardi EJ, Bywater CL, White CR. The effect of ambient oxygen on the thermal performance of a cockroach, Nauphoeta cinerea. J Exp Biol 2020; 223:jeb208306. [PMID: 32366686 DOI: 10.1242/jeb.208306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 04/17/2020] [Indexed: 11/20/2022]
Abstract
The oxygen and capacity-limited thermal tolerance (OCLTT) hypothesis proposes that the thermal tolerance of an animal is shaped by its capacity to deliver oxygen in relation to oxygen demand. Studies testing this hypothesis have largely focused on measuring short-term performance responses in animals under acute exposure to critical thermal maximums. The OCLTT hypothesis, however, emphasises the importance of sustained animal performance over acute tolerance. The present study tested the effect of chronic hypoxia and hyperoxia during development on moderate to long-term performance indicators at temperatures spanning the optimal temperature for growth in the speckled cockroach, Nauphoeta cinerea In contrast to the predictions of the OCLTT hypothesis, development under hypoxia did not significantly reduce growth rate or running performance, and development under hyperoxia did not significantly increase growth rate or running performance. The effects of developmental temperature and oxygen on tracheal morphology and metabolic rate were also not consistent with OCLTT predictions, suggesting that oxygen delivery capacity is not the primary driver shaping thermal tolerance in this species. Collectively, these findings suggest that the OCLTT hypothesis does not explain moderate to long-term thermal performance in N.cinerea, which raises further questions about the generality of the hypothesis.
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Affiliation(s)
- Emily J Lombardi
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Candice L Bywater
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Craig R White
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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23
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Thonis A, Ceballos RM, Tuen AA, Lovegrove BG, Levesque DL. Small Tropical Mammals Can Take the Heat: High Upper Limits of Thermoneutrality in a Bornean Treeshrew. Physiol Biochem Zool 2020; 93:199-209. [PMID: 32196407 DOI: 10.1086/708467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Tropical ectotherms are generally believed to be more vulnerable to global heating than temperate species. Currently, however, we have insufficient knowledge of the thermoregulatory physiology of equatorial tropical mammals, particularly of small diurnal mammals, to enable similar predictions. In this study, we measured the resting metabolic rates (via oxygen consumption) of wild-caught lesser treeshrews (Tupaia minor, order Scandentia) over a range of ambient temperatures. We predicted that, similar to other treeshrews, T. minor would exhibit more flexibility in body temperature regulation and a wider thermoneutral zone compared with other small mammals because these thermoregulatory traits provide both energy and water savings at high ambient temperatures. Basal metabolic rate was on average 1.03±0.10 mL O2 h-1 g-1, which is within the range predicted for a 65-g mammal. We calculated the lower critical temperature of the thermoneutral zone at 31.0°C (95% confidence interval: 29.3°-32.7°C), but using metabolic rates alone, we could not determine the upper critical temperature at ambient temperatures as high as 36°C. The thermoregulatory characteristics of lesser treeshrews provide a means of saving energy and water at temperatures well in excess of their current environmental temperatures. Our research highlights the knowledge gaps in our understanding of the energetics of mammals living in high-temperature environments, specifically in the equatorial tropics, and questions the purported lack of variance in the upper critical temperatures of the thermoneutral zone in mammals, emphasizing the importance of further research in the tropics.
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24
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Turner JM. Facultative hyperthermia during a heatwave delays injurious dehydration of an arboreal marsupial. J Exp Biol 2020; 223:jeb219378. [PMID: 32054679 DOI: 10.1242/jeb.219378] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/05/2020] [Indexed: 01/08/2023]
Abstract
Heatwaves negatively impact wildlife populations and their effects are predicted to worsen with ongoing global warming. Animal mass mortality at extremely high ambient temperature (Ta) is evidence for physiological dysfunction and, to aid conservation efforts, improving our understanding of animal responses to environmental heat is crucial. To address this, I measured the water loss, body temperature and metabolism of an Australian marsupial during a simulated heatwave. The body temperature of the common ringtail possum Pseudocheirus peregrinus increased passively by ∼3°C over a Ta of 29-39°C, conveying water savings of 9.6 ml h-1 When Ta crossed a threshold of 35-36°C, possums began actively cooling by increasing evaporative water loss and thermal conductance. It is clear that facultative hyperthermia is effective up to a point, but once this point is surpassed - the frequency and duration of which are increasing with climate change - body water would rapidly deplete, placing possums in danger of injury or death from dehydration.
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Affiliation(s)
- James M Turner
- Institute for Land, Water and Society, Charles Sturt University, Albury, NSW 2640, Australia
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25
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Cooper CE, Hurley LL, Griffith SC. Effect of acute exposure to high ambient temperature on the thermal, metabolic and hygric physiology of a small desert bird. Comp Biochem Physiol A Mol Integr Physiol 2020; 244:110684. [PMID: 32114093 DOI: 10.1016/j.cbpa.2020.110684] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 02/19/2020] [Accepted: 02/25/2020] [Indexed: 11/19/2022]
Abstract
The intensity and frequency of extreme weather events, such as heat waves, are increasing as a consequence of global warming. Acute periods of extreme heat can be more problematic for wildlife than a chronic increase in mean temperature, to which animals can potentially acclimatise. Predicting effects of heat exposure requires a clear understanding of the capacity of individuals to respond to heat waves, so we examined the physiological response of a small desert bird, the zebra finch (Taeniopygia guttata), after acute previous exposure to high ambient temperature, simulating heatwave-like conditions. The standard physiology of the zebra finches was unaffected by prior exposure to heatwave-type conditions, suggesting that periodic exposure to heatwaves is unlikely to impact their longer-term day-to-day energy and water requirements. When finches were thermally challenged, prior experience of heatwave-like conditions did not impact overall body temperature and evaporative water loss, but birds previously experiencing high temperatures did reduce their metabolic heat production, and the variance in water loss and metabolism between individuals was significantly lower. This suggests that some individuals are more likely to become dehydrated if they have not had prior experience of high temperatures, and do not prioritise water conservation over thermoregulation. However, our observations overall suggest that acute periods of heat exposure do little to modify the general physiology of small birds, supporting the hypothesis that periodic extreme heat events may be more problematic for them than chronic warming.
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Affiliation(s)
- C E Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia; Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.
| | - L L Hurley
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - S C Griffith
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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26
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Cooper CE, Withers PC, Turner JM. Physiological implications of climate change for a critically endangered Australian marsupial. AUST J ZOOL 2020. [DOI: 10.1071/zo20067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Extreme weather events (e.g. heatwaves and droughts) can expose animals to environmental conditions outside of their zones of physiological tolerance, and even resistance, and impact long-term viability of populations and species. We examined the thermal and hygric physiology of the critically endangered western ringtail possum (Pseudocheirus occidentalis), a member of a family of marsupial folivores (Pseudocheiridae) that appear particularly vulnerable to environmental extremes. Basal metabolic rate and other standard physiological variables measured at an ambient temperature of 30°C conformed to values for other marsupials. At lower temperatures, body temperature decreased slightly, and metabolic rate increased significantly at 5°C. At higher temperatures, possums experienced mild hyperthermia and increased evaporative heat loss by licking rather than panting. Their point of relative water economy (–8.7°C) was more favourable than other pseudocheirid possums and the koala (Phascolarctos cinereus). We predict that western ringtail possums should tolerate low ambient temperatures well and be more physiologically tolerant of hot and dry conditions than common (Pseudocheirus peregrinus) and particularly green (Pseudochirops archeri) ringtail possums, and koalas. Our physiological data can be incorporated into mechanistic species distribution models to test our hypothesis that western ringtail possums should physiologically tolerate the climate of habitat further inland than their current distribution, and withstand moderate impacts of climate change in the south-west of Western Australia.
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27
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Cox SM, Salzano MQ, Piazza SJ, Rubenson J. Eliminating high-intensity activity during growth reduces mechanical power capacity but not submaximal metabolic cost in a bipedal animal model. J Appl Physiol (1985) 2019; 128:50-58. [PMID: 31751181 DOI: 10.1152/japplphysiol.00679.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Decreases in activity levels in children worldwide are feared to have long-term health repercussions. Yet, because of the difficulty of performing controlled long-term studies in humans, we do not yet understand how decreases in childhood activity influence adult functional capacity. Here, in an avian bipedal model, we evaluated the elimination of all high-intensity activity during growth on adult performance. We evaluated three alternative hypotheses: Elimination of high-intensity activity 1) does not influence adult function, 2) results in task-specific deficits in adulthood, or 3) results in deficits that generalize across locomotor tasks. We found that animals restricted from jumping and sprinting during growth showed detriments as adults in maximal jump performance in comparison to controls, but did not require more metabolic energy during steady-state running or standing. From this, we conclude that functional deficits from elimination of high-intensity exercise are task specific and do not generalize across all locomotor functions.NEW & NOTEWORTHY Decreasing childhood activity levels are feared to have long-term health repercussions, but testing this hypothesis is hampered by restrictions of human experimentation. Here, in a bipedal animal model, we examine how the elimination of high-intensity activity during all of maturation influences adult locomotor capacity. We found restricted activity during growth reduced mechanical power capacity but not submaximal metabolic cost. This suggests that reduced childhood activity may result in task-specific, rather than generalized locomotor deficits.
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Affiliation(s)
- Suzanne Michelle Cox
- Biomechanics Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Matthew Q Salzano
- Biomechanics Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Integrative and Biomedical Physiology Program, The Pennsylvania State University, University Park, Pennsylvania
| | - Stephen J Piazza
- Biomechanics Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Jonas Rubenson
- Biomechanics Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Integrative and Biomedical Physiology Program, The Pennsylvania State University, University Park, Pennsylvania
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28
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Mokhatla M, Measey J, Smit B. The role of ambient temperature and body mass on body temperature, standard metabolic rate and evaporative water loss in southern African anurans of different habitat specialisation. PeerJ 2019; 7:e7885. [PMID: 31660269 PMCID: PMC6814148 DOI: 10.7717/peerj.7885] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 09/12/2019] [Indexed: 12/12/2022] Open
Abstract
Temperature and water availability are two of the most important variables affecting all aspects of an anuran’s key physiological processes such as body temperature (Tb), evaporative water loss (EWL) and standard metabolic rate (SMR). Since anurans display pronounced sexual dimorphism, evidence suggests that these processes are further influenced by other factors such as vapour pressure deficit (VPD), sex and body mass (Mb). However, a limited number of studies have tested the generality of these results across a wide range of ecologically relevant ambient temperatures (Ta), while taking habitat use into account. Thus, the aim of this study was to investigate the role of Ta on Tb, whole-animal EWL and whole-animal SMR in three wild caught African anuran species with different ecological specialisations: the principally aquatic African clawed frog (Xenopus laevis), stream-breeding common river frog (Amietia delalandii), and the largely terrestrial raucous toad (Sclerophrys capensis). Experiments were conducted at a range of test temperatures (5–35 °C, at 5 °C increments). We found that VPD better predicted rates of EWL than Ta in two of the three species considered. Moreover, we found that Tb, whole-animal EWL and whole-animal SMR increased with increasing Ta, while Tb increased with increasing Mb in A. delalandii and S. capensis but not in X. laevis. Whole-animal SMR increased with increasing Mb in S. capensis only. We did not find any significant effect of VPD, Mb or sex on whole-animal EWL within species. Lastly, Mb did not influence Tb, whole-animal SMR and EWL in the principally aquatic X. laevis. These results suggest that Mb may not have the same effect on key physiological variables, and that the influence of Mb may also depend on the species ecological specialisation. Thus, the generality of Mb as an important factor should be taken in the context of both physiology and species habitat specialisation.
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Affiliation(s)
- Mohlamatsane Mokhatla
- Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa.,Scientific Services, South African National Parks, Sedgefield, South Africa
| | - John Measey
- Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
| | - Ben Smit
- Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa.,Department Zoology, Nelson Mandela University, Port Elizabeth, South Africa
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Granatosky MC, Bryce CM, Hanna J, Fitzsimons A, Laird MF, Stilson K, Wall CE, Ross CF. Inter-stride variability triggers gait transitions in mammals and birds. Proc Biol Sci 2019; 285:20181766. [PMID: 30963900 DOI: 10.1098/rspb.2018.1766] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Speed-related gait transitions occur in many animals, but it remains unclear what factors trigger gait changes. While the most widely accepted function of gait transitions is that they reduce locomotor costs, there is no obvious metabolic trigger signalling animals when to switch gaits. An alternative approach suggests that gait transitions serve to reduce locomotor instability. While there is evidence supporting this in humans, similar research has not been conducted in other species. This study explores energetics and stride variability during the walk-run transition in mammals and birds. Across nine species, energy savings do not predict the occurrence of a gait transition. Instead, our findings suggest that animals trigger gait transitions to maintain high locomotor rhythmicity and reduce unstable states. Metabolic efficiency is an important benefit of gait transitions, but the reduction in dynamic instability may be the proximate trigger determining when those transitions occur.
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Affiliation(s)
- Michael C Granatosky
- 1 Department of Organismal Biology and Anatomy, University of Chicago , Chicago, IL , USA
| | - Caleb M Bryce
- 2 Botswana Predator Conservation Trust , Maun , Botswana
| | - Jandy Hanna
- 3 Biomedical Sciences, West Virginia School of Osteopathic Medicine , Lewisburg, WV , USA
| | - Aidan Fitzsimons
- 4 Department of Evolutionary Anthropology, Duke University , Durham, NC , USA
| | - Myra F Laird
- 1 Department of Organismal Biology and Anatomy, University of Chicago , Chicago, IL , USA
| | - Kelsey Stilson
- 1 Department of Organismal Biology and Anatomy, University of Chicago , Chicago, IL , USA
| | - Christine E Wall
- 4 Department of Evolutionary Anthropology, Duke University , Durham, NC , USA
| | - Callum F Ross
- 1 Department of Organismal Biology and Anatomy, University of Chicago , Chicago, IL , USA
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30
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Andersson MN, Nilsson J, Nilsson JÅ, Isaksson C. Diet and ambient temperature interact to shape plasma fatty acid composition, basal metabolic rate and oxidative stress in great tits. ACTA ACUST UNITED AC 2018; 221:jeb.186759. [PMID: 30361459 DOI: 10.1242/jeb.186759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 10/17/2018] [Indexed: 11/20/2022]
Abstract
Diet and ambient temperature affect animal physiology, survival and reproductive success. However, knowledge of how these environmental factors interact to shape physiological processes and life-history traits of birds and other animals is largely lacking. By exposing adult great tits (Parus major) to two contrasting diets (saturated or unsaturated fatty acids; SFAs and UFAs, respectively) and ambient temperatures (3°C versus 20°C) that the birds encounter in nature, we investigated the effects of these two factors on several physiological parameters. Our results show that diet and ambient temperature interact to affect the composition of plasma fatty acids, basal metabolic rate (BMR) and oxidative stress, which are thought to affect the life-history and survival of individuals. Specifically, birds provided the SFA-rich diet had higher mass-specific BMR and oxidative stress (levels of lipid peroxidation) after exposure to low compared with high ambient temperature, whereas the opposite pattern was evident for birds with a UFA-rich diet. Surprisingly, birds on the SFA diet had higher relative levels of monounsaturated fatty acids compared with the UFA-fed birds at low ambient temperature, whereas the opposite, and expected, pattern was found at the high temperature. Although the present study focuses on the physiological implications of the diet×temperature interaction, our results might also be important for the leading theories of ageing, which currently do not take interactions between environmental factors into account. In addition, the present results are important for wildlife management, especially with regards to anthropogenic feeding of wild animals across variable and changing climatic conditions.
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Affiliation(s)
| | - Johan Nilsson
- Department of Biology, Lund University, SE-223 62 Lund, Sweden
| | - Jan-Åke Nilsson
- Department of Biology, Lund University, SE-223 62 Lund, Sweden
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31
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Stubbs JL, Mitchell NJ. The Influence of Temperature on Embryonic Respiration, Growth, and Sex Determination in a Western Australian Population of Green Turtles (Chelonia mydas). Physiol Biochem Zool 2018; 91:1102-1114. [DOI: 10.1086/700433] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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32
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Cooper CE, Withers PC, Munns SL, Geiser F, Buttemer WA. Geographical variation in the standard physiology of brushtail possums ( Trichosurus): implications for conservation translocations. CONSERVATION PHYSIOLOGY 2018; 6:coy042. [PMID: 30135736 PMCID: PMC6097599 DOI: 10.1093/conphys/coy042] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/22/2018] [Accepted: 08/06/2018] [Indexed: 06/08/2023]
Abstract
Identifying spatial patterns in the variation of physiological traits that occur within and between species is a fundamental goal of comparative physiology. There has been a focus on identifying and explaining this variation at broad taxonomic scales, but more recently attention has shifted to examining patterns of intra-specific physiological variation. Here we examine geographic variation in the physiology of brushtail possums (Trichosurus), widely distributed Australian marsupials, and discuss how pertinent intra-specific variation may be to conservation physiology. We found significant geographical patterns in metabolism, body temperature, evaporative water loss and relative water economy. These patterns suggest that possums from warmer, drier habitats have more frugal energy and water use and increased capacity for heat loss at high ambient temperatures. Our results are consistent with environmental correlates for broad-scale macro-physiological studies, and most intra-generic and intra-specific studies of marsupials and other mammals. Most translocations of brushtail possums occur into Australia's arid zone, where the distribution and abundance of possums and other native mammals have declined since European settlement, leading to reintroduction programmes aiming to re-establish functional mammal communities. We suggest that the sub-species T. vulpecula hypoleucus from Western Australia would be the most physiologically appropriate for translocation to these arid habitats, having physiological traits most favourable for the extreme Ta, low and variable water availability and low productivity that characterize arid environments. Our findings demonstrate that geographically widespread populations can differ physiologically, and as a consequence some populations are more suitable for translocation to particular habitats than others. Consideration of these differences will likely improve the success and welfare outcomes of translocation, reintroduction and management programmes.
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Affiliation(s)
- Christine E Cooper
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
- School of Biological Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Philip C Withers
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
- School of Biological Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Suzanne L Munns
- Biomedical Sciences, College of Veterinary and Biomedical Sciences, James Cook University Townsville, Queensland, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales, Australia
| | - William A Buttemer
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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33
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Eto EC, Withers PC, Cooper CE. Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals. Proc Biol Sci 2018; 284:rspb.2017.1478. [PMID: 29142111 DOI: 10.1098/rspb.2017.1478] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 10/16/2017] [Indexed: 11/12/2022] Open
Abstract
Birds have many physiological characteristics that are convergent with mammals. In the light of recent evidence that mammals can maintain a constant insensible evaporative water loss (EWL) over a range of perturbing environmental conditions, we hypothesized that birds might also regulate insensible EWL, reflecting this convergence. We found that budgerigars (Melopsittacus undulatus) maintain EWL constant over a range of relative humidities at three ambient temperatures. EWL, expressed as a function of water vapour pressure deficit, differed from a physical model where the water vapour pressure deficit between the animal and the ambient air is the driver of evaporation, indicating physiological control of EWL. Regulating EWL avoids thermoregulatory impacts of varied evaporative heat loss; changes in relative humidity had no effect on body temperature, metabolic rate or thermal conductance. Our findings that a small bird can regulate EWL are evidence that this is a common feature of convergently endothermic birds and mammals, and may therefore be a fundamental characteristic of endothermy.
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Affiliation(s)
- E C Eto
- School of Biological Sciences M092, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - P C Withers
- School of Biological Sciences M092, University of Western Australia, Crawley, Western Australia 6009, Australia.,Department of Environment and Agriculture, Curtin University, PO Box U1987, Perth, Western Australia 6847, Australia
| | - C E Cooper
- School of Biological Sciences M092, University of Western Australia, Crawley, Western Australia 6009, Australia .,Department of Environment and Agriculture, Curtin University, PO Box U1987, Perth, Western Australia 6847, Australia
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34
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Seasonal variation in energy expenditure in a rodent inhabiting a winter-rainfall desert. J Comp Physiol B 2018; 188:877-888. [PMID: 29948157 DOI: 10.1007/s00360-018-1168-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/23/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022]
Abstract
Animals that spend more energy than they obtain risk entering allostatic overload, reducing survival and fitness. They are predicted to adjust their daily energy expenditure (DEE) during periods of food scarcity. Adjustments of DEE to changes in food availability have been well-studied in species in temperate zones during winter, but less so in species enduring seasonal droughts. Likely mechanisms regulating DEE involve adjustments of activity and maintenance metabolism. Species that experience seasonal droughts and changes in food availability, like the African striped mouse (Rhabdomys pumilio), are appropriate model organisms to study the regulation of seasonal changes of DEE. We quantified DEE using the 'doubly labelled water' method, measured resting metabolic rate (RMR), and concomitantly determined activity levels using all-day focal observations of 69 free-living striped mice in the cold moist season with high food availability and the hot dry season with low food availability. Striped mice decreased their DEE in the food scarce dry season using multiple mechanisms, especially reductions in RMR, and reduced overall physical activity. This was further facilitated passively by reduced thermoregulatory costs. Our study demonstrates that animals reduce DEE via active and passive mechanisms in food-restricted environments, and highlights that several environmental factors should be considered simultaneously when aiming to understand how animals cope with harsh environments.
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35
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Nielsen ME, Levin E, Davidowitz G, Papaj DR. Colour plasticity alters thermoregulatory behaviour in Battus philenor caterpillars by modifying the cue received. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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36
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Tomlinson S, Dalziell EL, Withers PC, Lewandrowski W, Dixon KW, Merritt DJ. Measuring metabolic rates of small terrestrial organisms by fluorescence-based closed-system respirometry. ACTA ACUST UNITED AC 2018; 221:jeb.172874. [PMID: 29444841 DOI: 10.1242/jeb.172874] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/01/2018] [Indexed: 11/20/2022]
Abstract
We explore a recent, innovative variation of closed-system respirometry for terrestrial organisms, whereby oxygen partial pressure (PO2 ) is repeatedly measured fluorometrically in a constant-volume chamber over multiple time points. We outline a protocol that aligns this technology with the broader literature on aerial respirometry, including the calculations required to accurately convert O2 depletion to metabolic rate (MR). We identify a series of assumptions, and sources of error associated with this technique, including thresholds where O2 depletion becomes limiting, that impart errors to the calculation and interpretation of MR. Using these adjusted calculations, we found that the resting MR of five species of angiosperm seeds ranged from 0.011 to 0.640 ml g-1 h-1, consistent with published seed MR values. This innovative methodology greatly expands the lower size limit of terrestrial organisms that can be measured, and offers the potential for measuring MR changes over time as a result of physiological processes of the organism.
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Affiliation(s)
- Sean Tomlinson
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley 6102, Western Australia, Australia .,Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park 6005, Western Australia, Australia
| | - Emma L Dalziell
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley 6102, Western Australia, Australia.,Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park 6005, Western Australia, Australia
| | - Philip C Withers
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Wolfgang Lewandrowski
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park 6005, Western Australia, Australia.,School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Kingsley W Dixon
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley 6102, Western Australia, Australia
| | - David J Merritt
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park 6005, Western Australia, Australia.,School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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37
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Levesque DL, Tuen AA, Lovegrove BG. Staying hot to fight the heat-high body temperatures accompany a diurnal endothermic lifestyle in the tropics. J Comp Physiol B 2018; 188:707-716. [PMID: 29623412 DOI: 10.1007/s00360-018-1160-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 03/20/2018] [Accepted: 04/01/2018] [Indexed: 11/25/2022]
Affiliation(s)
- Danielle L Levesque
- Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia.
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.
| | - Andrew Alek Tuen
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA
| | - Barry G Lovegrove
- School of Life Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, 3209, South Africa
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38
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Tickle PG, Hutchinson JR, Codd JR. Energy allocation and behaviour in the growing broiler chicken. Sci Rep 2018; 8:4562. [PMID: 29540782 PMCID: PMC5852157 DOI: 10.1038/s41598-018-22604-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 02/15/2018] [Indexed: 01/16/2023] Open
Abstract
Broiler chickens are increasingly at the forefront of global meat production but the consequences of fast growth and selection for an increase in body mass on bird health are an ongoing concern for industry and consumers. To better understand the implications of selection we evaluated energetics and behaviour over the 6-week hatch-to-slaughter developmental period in a commercial broiler. The effect of posture on resting metabolic rate becomes increasingly significant as broilers grow, as standing became more energetically expensive than sitting. The proportion of overall metabolic rate accounted for by locomotor behaviour decreased over development, corresponding to declining activity levels, mean and peak walking speeds. These data are consistent with the inference that broilers allocate energy to activity within a constrained metabolic budget and that there is a reducing metabolic scope for exercise throughout their development. Comparison with similarly sized galliforms reveals that locomotion is relatively energetically expensive in broilers.
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Affiliation(s)
- Peter G Tickle
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - John R Hutchinson
- Department of Comparative Biomedical Sciences, Structure and Motion Laboratory, Royal Veterinary College, London, UK
| | - Jonathan R Codd
- School of Biological Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK.
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39
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Cooper CE, Withers PC. Thermoregulatory role of insensible evaporative water loss constancy in a heterothermic marsupial. Biol Lett 2018; 13:rsbl.2017.0537. [PMID: 29142044 DOI: 10.1098/rsbl.2017.0537] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/24/2017] [Indexed: 11/12/2022] Open
Abstract
'Insensible' evaporative water loss of mammals has been traditionally viewed as a passive process, but recent studies suggest that insensible water loss is under regulatory control, although the physiological role of this control is unclear. We test the hypothesis that regulation of insensible water loss has a thermoregulatory function by quantifying for the first time evaporative water loss control, along with metabolic rate and body temperature, of a heterothermic mammal during normothermia and torpor. Evaporative water loss was independent of ambient relative humidity at ambient temperatures of 20 and 30°C, but not at 25°C or during torpor at 20°C. Evaporative water loss per water vapour pressure deficit had a positive linear relationship with relative humidity at ambient temperatures of 20 and 30°C, but not at 25°C or during torpor at 20 or 25°C. These findings suggest that insensible water loss deviates from a physical model only during thermoregulation, providing support for the hypothesis that regulation of insensible evaporative water loss has a thermoregulatory role.
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Affiliation(s)
- Christine Elizabeth Cooper
- Department of Environment and Agriculture, Curtin University, Perth, Western Australia, Australia .,School of Biological Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Philip Carew Withers
- Department of Environment and Agriculture, Curtin University, Perth, Western Australia, Australia.,School of Biological Sciences, University of Western Australia, Perth, Western Australia, Australia
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40
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Neville KE, Bosse TL, Klekos M, Mills JF, Weicksel SE, Waters JS, Tipping M. A novel ex vivo method for measuring whole brain metabolism in model systems. J Neurosci Methods 2017; 296:32-43. [PMID: 29287743 DOI: 10.1016/j.jneumeth.2017.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/21/2017] [Accepted: 12/24/2017] [Indexed: 01/31/2023]
Abstract
BACKGROUND Many neuronal and glial diseases have been associated with changes in metabolism. Therefore, metabolic reprogramming has become an important area of research to better understand disease at the cellular level, as well as to identify targets for treatment. Model systems are ideal for interrogating metabolic questions in a tissue dependent context. However, while new tools have been developed to study metabolism in cultured cells there has been less progress towards studies in vivo and ex vivo. NEW METHOD We have developed a method using newly designed tissue restraints to adapt the Agilent XFe96 metabolic analyzer for whole brain analysis. These restraints create a chamber for Drosophila brains and other small model system tissues to reside undisrupted, while still remaining in the zone for measurements by sensor probes. RESULTS This method generates reproducible oxygen consumption and extracellular acidification rate data for Drosophila larval and adult brains. Single brains are effectively treated with inhibitors and expected metabolic readings are observed. Measuring metabolic changes, such as glycolytic rate, in transgenic larval brains demonstrates the potential for studying how genotype affects metabolism. COMPARISON WITH EXISTING METHODS AND CONCLUSIONS Current methodology either utilizes whole animal chambers to measure respiration, not allowing for targeted tissue analysis, or uses technically challenging MRI technology for in vivo analysis that is not suitable for smaller model systems. This new method allows for novel metabolic investigation of intact brains and other tissues ex vivo in a quick, and simplistic way with the potential for large-scale studies.
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Affiliation(s)
- Kathryn E Neville
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
| | - Timothy L Bosse
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
| | - Mia Klekos
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
| | - John F Mills
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
| | - Steven E Weicksel
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
| | - James S Waters
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
| | - Marla Tipping
- Department of Biology, Providence College, 1 Cunningham Square, Providence, RI 02918, United States.
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41
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Gienger C, Urdiales EM. Influences on Standard Metabolism in Eastern Box Turtles (Terrapene carolina). CHELONIAN CONSERVATION AND BIOLOGY 2017. [DOI: 10.2744/ccb-1252.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- C.M. Gienger
- Department of Biology and Center of Excellence for Field Biology, Austin Peay State University, Clarksville, Tennessee 37044 USA []
| | - Eva M. Urdiales
- Department of Biology and Center of Excellence for Field Biology, Austin Peay State University, Clarksville, Tennessee 37044 USA []
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42
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Rising R, Foerster T, Arad AD, Albu J, Pi-Sunyer X. Validation of whole room indirect calorimeters: refinement of current methodologies. Physiol Rep 2017; 5:5/22/e13521. [PMID: 29180485 PMCID: PMC5704087 DOI: 10.14814/phy2.13521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/15/2017] [Accepted: 10/29/2017] [Indexed: 11/24/2022] Open
Abstract
Whole room indirect calorimeter (WRIC) validation techniques consist of propane combustion (PC) or infusion of mixed carbon dioxide (CO2) and nitrogen (N2) by a precision blender (PB). To determine the best method, PC of 6, 10, 22‐h and PB infusions of 6, 10, and 14‐h, were conducted. The 14‐h infusion consisted of two metabolic settings. Energy expenditure (EE; kJ), ventilation (V; liters/min) of oxygen (VO2), VCO2, and respiratory quotient (VCO2/VO2) obtained from the WRIC were extrapolated to the respective test durations and compared to similarly calculated values. Moreover, accurate equations (AE) were derived to correct infusions for additional N2. As a final evaluation of a PC validated WRIC, weight maintenance (WM), energy balance (EB), respiratory quotient (RQ), and food quotients (FQ) were determined in 22 subjects who had repeat 24‐h EE measurements. Statistical analyses (P < 0.05) were conducted (SPSS, version 23). Significant differences in RQ existed between PC and stoichiometry after 6‐h. Errors for the rest of the PC tests ranged from −1.5 ± 2.4 (VCO2) to 2.8 ± 4.6% (EE). When compared with the WRIC, all uncorrected metabolic parameters for six and 10‐h PB infusions were significantly different with errors from −12.8 ± 1.6 (VO2) to 6.0 ± 2.8% (RQ). The AE reduced the magnitude of errors to −12.4 ± 1.5 (RQ) to 2.2 ± 3.0% (RQ). The PB infusion with two settings showed similar performance. No differences in WM, EB, RQ, or FQ existed in the subjects. In conclusion, 10‐h PC tests are sufficient for validating WRICs.
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Affiliation(s)
- Russell Rising
- New York Obesity/Nutrition Research Center, Department of Medicine, Columbia University, New York, New York
| | | | - Avigdor D Arad
- Department of Endocrinology, Diabetes, and Metabolism, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jeanine Albu
- Department of Endocrinology, Diabetes, and Metabolism, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Xavier Pi-Sunyer
- New York Obesity/Nutrition Research Center, Department of Medicine, Columbia University, New York, New York
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43
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Kühsel S, Brückner A, Schmelzle S, Heethoff M, Blüthgen N. Surface area-volume ratios in insects. INSECT SCIENCE 2017; 24:829-841. [PMID: 27234132 DOI: 10.1111/1744-7917.12362] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/04/2016] [Indexed: 05/15/2023]
Abstract
Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have not been measured explicitly in this context. We quantified surface area-volume (SA/V) ratios for the first time using 3D surface models based on a structured light scanning method for 126 species of pollinating insects from 4 orders (Diptera, Hymenoptera, Lepidoptera, and Coleoptera). Water loss of 67 species was measured gravimetrically at very dry conditions for 2 h at 15 and 30 °C to demonstrate the applicability of the new 3D surface measurements and relevance for predicting the performance of insects. Quantified SA/V ratios significantly explained the variation in water loss across species, both directly or after accounting for isometric scaling (residuals of the SA/V ∼ mass2/3 relationship). Small insects with a proportionally larger surface area had the highest water loss rates. Surface scans of insects to quantify allometric SA/V ratios thus provide a promising method to predict physiological responses, improving the potential of body mass isometry alone that assume geometric similarity.
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Affiliation(s)
- Sara Kühsel
- Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany
| | - Adrian Brückner
- Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany
| | - Sebastian Schmelzle
- Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany
| | - Michael Heethoff
- Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany
| | - Nico Blüthgen
- Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany
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44
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Welman S, Tuen AA, Lovegrove BG. Searching for the Haplorrhine Heterotherm: Field and Laboratory Data of Free-Ranging Tarsiers. Front Physiol 2017; 8:745. [PMID: 29018365 PMCID: PMC5623056 DOI: 10.3389/fphys.2017.00745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 09/12/2017] [Indexed: 01/26/2023] Open
Abstract
The observation of heterothermy in a single suborder (Strepsirrhini) only within the primates is puzzling. Given that the placental-mammal ancestor was likely a heterotherm, we explored the potential for heterothermy in a primate closely related to the Strepsirrhini. Based upon phylogeny, body size and habitat stability since the Late Eocene, we selected western tarsiers (Cephalopachus bancanus) from the island of Borneo. Being the sister clade to Strepsirrhini and basal in Haplorrhini (monkeys and apes), we hypothesized that C. bancanus might have retained the heterothermic capacity observed in several small strepsirrhines. We measured resting metabolic rate, subcutaneous temperature, evaporative water loss and the percentage of heat dissipated through evaporation, at ambient temperatures between 22 and 35°C in fresh-caught wild animals (126.1 ± 2.4 g). We also measured core body temperatures in free-ranging animals. The thermoneutral zone was 25-30°C and the basal metabolic rate was 3.52 ± 0.06 W.kg-1 (0.65 ± 0.01 ml O2.g-1.h-1). There was no evidence of adaptive heterothermy in either the laboratory data or the free-ranging data. Instead, animals appeared to be cold sensitive (Tb ~ 31°C) at the lowest temperatures. We discuss possible reasons for the apparent lack of heterothermy in tarsiers, and identify putative heterotherms within Platyrrhini. We also document our concern for the vulnerability of C. bancanus to future temperature increases associated with global warming.
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Affiliation(s)
- Shaun Welman
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Andrew A. Tuen
- Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
| | - Barry G. Lovegrove
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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45
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Thompson LJ, Downs CT. Altitudinal variation in metabolic parameters of a small Afrotropical bird. Comp Biochem Physiol A Mol Integr Physiol 2017; 212:88-96. [PMID: 28774754 DOI: 10.1016/j.cbpa.2017.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 11/16/2022]
Abstract
Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10-12g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (Ta). Cape White-eyes were 0.8g heavier at the higher altitude site and 0.5g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing Ta, as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. WHAT IS ALREADY KNOWN Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. WHAT THE STUDY ADDS There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate.
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Affiliation(s)
- Lindy J Thompson
- School of Life Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.
| | - Colleen T Downs
- School of Life Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.
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46
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Douglas TK, Cooper CE, Withers PC. Avian torpor or alternative thermoregulatory strategies for overwintering? J Exp Biol 2017; 220:1341-1349. [PMID: 28356368 DOI: 10.1242/jeb.154633] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 01/16/2017] [Indexed: 11/20/2022]
Abstract
ABSTRACT
It is unclear whether torpor really is uncommon amongst passerine birds. We therefore examined body temperature and thermoregulatory strategies of an Austral passerine, the white-browed babbler (Pomatostomus superciliosus), which has characteristics related to a high probability of torpor use; it is a sedentary, insectivorous, cooperative breeding species, which we studied during winter in a temperate habitat. Wild, free-living babblers maintained normothermy overnight, even at sub-zero ambient temperatures, with a mean minimum body temperature of 38.5±0.04°C that was independent of minimum black bulb temperature. Physiological variables measured in the laboratory revealed that babblers had a low basal metabolic rate and evaporative water loss, but their body temperature and thermal conductance were typical of those of other birds and they had a typical endothermic response to low ambient temperature. Huddling yielded significant energy savings at low temperatures and a roost nest created a microclimate that buffered against low temperatures. Low basal energy requirements, communal roosting and the insulation of a roost nest confer sufficient energetic benefits, allowing babblers to meet energy requirements without resorting to heterothermia, even in their depauperate, low-productivity landscape, suggesting that passerine birds use alternatives to torpor to balance their energy budgets when possible.
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Affiliation(s)
- Tegan K. Douglas
- Department of Environment and Agriculture, Curtin University, Bentley, WA 6845, Australia
| | - Christine E. Cooper
- Department of Environment and Agriculture, Curtin University, Bentley, WA 6845, Australia
- School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia
| | - Philip C. Withers
- Department of Environment and Agriculture, Curtin University, Bentley, WA 6845, Australia
- School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia
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47
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Cooper CE, Withers PC, Hardie A, Geiser F. Marsupials don't adjust their thermal energetics for life in an alpine environment. Temperature (Austin) 2017; 3:484-498. [PMID: 28349088 PMCID: PMC5079228 DOI: 10.1080/23328940.2016.1171280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/20/2016] [Accepted: 03/23/2016] [Indexed: 11/03/2022] Open
Abstract
Marsupials have relatively low body temperatures and metabolic rates, and are therefore considered to be maladapted for life in cold habitats such as alpine environments. We compared body temperature, energetics and water loss as a function of ambient temperature for 4 Antechinus species, 2 from alpine habitats and 2 from low altitude habitats. Our results show that body temperature, metabolic rate, evaporative water loss, thermal conductance and relative water economy are markedly influenced by ambient temperature for each species, as expected for endothermic mammals. However, despite some species and individual differences, habitat (alpine vs non-alpine) does not affect any of these physiological variables, which are consistent with those for other marsupials. Our study suggests that at least under the environmental conditions experienced on the Australian continent, life in an alpine habitat does not require major physiological adjustments by small marsupials and that they are physiologically equipped to deal with sub-zero temperatures and winter snow cover.
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Affiliation(s)
- Christine E Cooper
- Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia; Animal Biology M092, University of Western Australia, Crawley, Western Australia, Australia
| | - Philip C Withers
- Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia; Animal Biology M092, University of Western Australia, Crawley, Western Australia, Australia
| | - Andrew Hardie
- Department of Environment and Agriculture, Curtin University , Bentley, Western Australia, Australia
| | - Fritz Geiser
- Zoology, University of New England , Armidale, New South Wales, Australia
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48
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Klüg-Baerwald BJ, Brigham RM. Hung out to dry? Intraspecific variation in water loss in a hibernating bat. Oecologia 2017; 183:977-985. [PMID: 28213638 DOI: 10.1007/s00442-017-3837-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 02/07/2017] [Indexed: 02/05/2023]
Abstract
Hibernation is a period of water deficit for some small mammals, and humidity strongly influences hibernation patterns. Dry conditions reduce length of torpor bouts, stimulate arousals, and decrease overwinter survival. To mitigate these effects, many small mammals hibernate in near saturated (100% RH) conditions. However, big brown bats (Eptesicus fuscus) hibernate in a wider variety of conditions and tolerate lower humidity than most other bats. To assess arid tolerance in this species, we compared torpid metabolic rates (TMR) and rates of total evaporative water loss (TEWL) between two populations of E. fuscus with differing winter ecologies: one that hibernates in humid karst caves and one that hibernates in relatively dry rock crevices. We used flow-through respirometry to measure TMR and TEWL of bats in humid and dry conditions. Torpid metabolic rates did not differ between populations or with humidity treatments. Rates of TEWL were similar between populations in humid conditions, but higher for cave-hibernating bats than crevice-hibernating bats in dry conditions. Our results suggest that E. fuscus hibernating in arid environments have mechanisms to decrease evaporative water loss that are not evident at more humid sites. Drought tolerance may facilitate the sedentary nature of the species, allowing them to tolerate more variable microclimates during hibernation and thus increasing the availability of overwintering habitat. The ability to survive arid conditions may also lessen the susceptibility of E. fuscus to diseases that affect water balance.
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Affiliation(s)
| | - R Mark Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK, Canada
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49
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Gienger CM, Brien ML, Tracy CR, Manolis SC, Webb GJW, Seymour RS, Christian KA. Ontogenetic comparisons of standard metabolism in three species of crocodilians. PLoS One 2017; 12:e0171082. [PMID: 28182696 PMCID: PMC5300253 DOI: 10.1371/journal.pone.0171082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/16/2017] [Indexed: 01/02/2023] Open
Abstract
Due in part to their large size, aggressive temperament, and difficulty in handling, there are few physiological studies of adult crocodilians in the literature. As a result, studies comparing individuals across an ontogenetic series and comparisons among species are also lacking. We addressed this gap in knowledge by measuring standard metabolic rates (SMR) of three species of crocodilians (Crocodylus porosus, C. johnsoni, and Alligator mississippiensis), and included individuals that ranged from 0.22 to 114 kg. Allometric scaling of SMR with body mass was similar among the species, but C. porosus had significantly higher SMR than did C. johnsoni or A. mississippiensis. Differences in SMR among species are potentially related to behavioural differences in levels of aggression; C. porosus are the most aggressive of the crocodilians measured, and have rates of standard metabolism that are approximately 36% higher at the grand mean body size than those measured for C. johnsoni or A. mississippiensis, which are among the least aggressive crocodilians.
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Affiliation(s)
- C. M. Gienger
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
- * E-mail:
| | - Matthew L. Brien
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
- Wildlife Management International and Crocodylus Park, Berrimah, Northern Territory, Australia
| | - Christopher R. Tracy
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
| | - S. Charlie Manolis
- Wildlife Management International and Crocodylus Park, Berrimah, Northern Territory, Australia
| | - Grahame J. W. Webb
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
- Wildlife Management International and Crocodylus Park, Berrimah, Northern Territory, Australia
| | - Roger S. Seymour
- School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Keith A. Christian
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
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50
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Tomlinson S, Dixon KW, Didham RK, Bradshaw SD. Landscape context alters cost of living in honeybee metabolism and feeding. Proc Biol Sci 2017; 284:rspb.2016.2676. [PMID: 28179522 DOI: 10.1098/rspb.2016.2676] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 01/10/2017] [Indexed: 11/12/2022] Open
Abstract
Field metabolic rate (FMR) links the energy budget of an animal with the constraints of its ecosystem, but is particularly difficult to measure for small organisms. Landscape degradation exacerbates environmental adversity and reduces resource availability, imposing higher costs of living for many organisms. Here, we report a significant effect of landscape degradation on the FMR of free-flying Apis mellifera, estimated using 86Rb radio-isotopic turnover. We validated the relationship between 86Rb kb and metabolic rate for worker bees in the laboratory using flow-through respirometry. We then released radioisotopically enriched individuals into a natural woodland and a heavily degraded and deforested plantation. FMRs of worker bees in natural woodland vegetation were significantly higher than in a deforested landscape. Nectar consumption, estimated using 22Na radio-isotopic turnover, also differed significantly between natural and degraded landscapes. In the deforested landscape, we infer that the costs of foraging exceeded energetic availability, and honeybees instead foraged less and depended more on stored resources in the hive. If this is generally the case with increasing landscape degradation, this will have important implications for the provision of pollination services and the effectiveness and resilience of ecological restoration practice.
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Affiliation(s)
- Sean Tomlinson
- School of Animal Biology, The University of Western Australia, Perth, WA 6009, Australia .,Kings Park and Botanic Gardens, Perth, WA 6005, Australia
| | - Kingsley W Dixon
- Kings Park and Botanic Gardens, Perth, WA 6005, Australia.,Department of Environment and Agriculture, Curtin University, Bentley, WA 6102, Australia
| | - Raphael K Didham
- School of Animal Biology, The University of Western Australia, Perth, WA 6009, Australia.,CSIRO Land and Water, Centre for Environment and Life Sciences, Floreat, WA 6014, Australia
| | - S Donald Bradshaw
- School of Animal Biology, The University of Western Australia, Perth, WA 6009, Australia
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