1
|
Weaver SJ, McIntyre T, van Rossum T, Telemeco RS, Taylor EN. Hydration and evaporative water loss of lizards change in response to temperature and humidity acclimation. J Exp Biol 2023; 226:jeb246459. [PMID: 37767755 DOI: 10.1242/jeb.246459] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023]
Abstract
Testing acclimation plasticity informs our understanding of organismal physiology and applies to conservation management amidst our rapidly changing climate. Although there is a wealth of research on the plasticity of thermal and hydric physiology in response to temperature acclimation, there is a comparative gap for research on acclimation to different hydric regimes, as well as the interaction between water and temperature. We sought to fill this gap by acclimating western fence lizards (Sceloporus occidentalis) to experimental climate conditions (crossed design of hot or cool, dry or humid) for 8 days, and measuring cutaneous evaporative water loss (CEWL), plasma osmolality, hematocrit and body mass before and after acclimation. CEWL changed plastically in response to the different climates, with lizards acclimated to hot humid conditions experiencing the greatest increase in CEWL. Change in CEWL among individuals was negatively related to treatment vapor pressure deficit and positively related to treatment water vapor pressure. Plasma osmolality, hematocrit and body mass all showed greater changes in response to temperature than to humidity or vapor pressure deficit. CEWL and plasma osmolality were positively related across treatment groups before acclimation and within treatment groups after acclimation, but the two variables showed different responses to acclimation, suggesting that they are interrelated but governed by different mechanisms. This study is among few that assess more than one metric of hydric physiology and that test the interactive effects of temperature and humidity. Such measurements will be essential for predictive models of activity and survival for animals under climate change.
Collapse
Affiliation(s)
- Savannah J Weaver
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| | - Tess McIntyre
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| | - Taylor van Rossum
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| | - Rory S Telemeco
- Department of Conservation Science, Fresno Chaffee Zoo, Fresno, CA 93728, USA
- Department of Biology, College of Science and Mathematics, California State University, Fresno, CA 93740, USA
| | - Emily N Taylor
- Biological Sciences Department, Bailey College of Science and Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA
| |
Collapse
|
2
|
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]
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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: 0.6] [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.
Collapse
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
| |
Collapse
|
5
|
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: 1.6] [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.
Collapse
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
| |
Collapse
|
6
|
Seymour RS, Ito K, Umekawa Y. Respiration of thermogenic inflorescences of skunk cabbage Symplocarpus renifolius in heliox. PLANT, CELL & ENVIRONMENT 2018; 41:367-373. [PMID: 29121698 DOI: 10.1111/pce.13097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 11/03/2017] [Accepted: 11/03/2017] [Indexed: 06/07/2023]
Abstract
The respiration rate of the thermogenic inflorescences of Japanese skunk cabbage Symplocarpus renifolius can reach 300 nmol s-1 g-1 , which is sufficient to raise spadix temperature (Ts ) up to 15 °C above ambient air temperature (Ta ). Respiration rate is inversely related to Ta , such that the Ts achieves a degree of independence from Ta , an effect known as temperature regulation. Here, we measure oxygen consumption rate (Ṁo2 ) in air (21% O2 in mainly N2 ) and in heliox (21% O2 in He) to investigate the diffusive conductance of the network of gas-filled spaces and the thermoregulatory response. When Ts was clamped at 15 °C, the temperature that produces maximal Ṁo2 in this species, exposure to high diffusivity heliox increased mean Ṁo2 significantly from 137 ± 17 to 202 ± 43 nmol s-1 g-1 FW, indicating that respiration in air is normally limited by diffusion in the gas phase and some mitochondria are unsaturated. When Ta was clamped at 15 °C and Ts was allowed to vary, exposure to heliox reduced Ts 1 °C and increased Ṁo2 significantly from 116 ± 10 to 137 ± 19 nmol s-1 g-1 , indicating that enhanced heat loss by conduction and convection can elicit the thermoregulatory response.
Collapse
Affiliation(s)
- Roger S Seymour
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Kikukatsu Ito
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Yui Umekawa
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
| |
Collapse
|
7
|
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: 0.7] [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.
Collapse
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
| |
Collapse
|
8
|
Baldo MB, Luna F, Antenucci CD. Does acclimation to contrasting atmospheric humidities affect evaporative water loss in the South American subterranean rodentCtenomys talarum? J Mammal 2016. [DOI: 10.1093/jmammal/gyw104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|