Time Changes Everything: Analysing Temporal Patterns of Evaporative Water Loss

Abstract Higher air temperatures and drier conditions may create stronger water vapour pressure and increase rates of cutaneous water loss, while elevated body temperatures may in turn directly speed up metabolic rates that lead to higher respiratory water loss. Therefore, water budgets are an important organismal trait for understanding their responses to climate change. The most common method of water loss estimation combines respiratory and cutaneous pathways by measuring body weight loss over a defined period of time. Currently, obtained values are often summed or averaged for population or species comparisons. We warn about potential statistical problems using average or summed values of water loss due to emerging temporal patterns. In this study we used a model dataset of lizards and to investigate temporal patterns in water loss datasets. We found that temporal patterns strongly vary across datasets and often deviate from the summed/average profile. Also, the duration of the experiment needs to remain long enough to detect the temporal patterns and produce representative results, while averages at different end-points of the experiment will also vary with temporal patterns. We propose that a simple statistical approach including hour of the experiment as non-linear explanatory variable in GAMM is used to investigate and adequately account for temporal patterns, which will ensure comparability of studies using meta-analyses in the future. Found signal of temporal variation in water loss also suggests that it holds significant biological relevance, potentially mostly connected to behavioural but also physiological adjustments and needs research attention in the future.

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Evaporative water loss in domestic fowls and its partition in relation to ambient temperature

The Journal of Agricultural Science ◽

10.1017/s002185960003313x ◽

1976 ◽

Vol 87 (3) ◽

pp. 527-532 ◽

Cited By ~ 46

Author(s):

S. A. Richards

Keyword(s):

Ambient Temperature ◽

Water Loss ◽

Absolute Humidity ◽

Evaporative Water Loss ◽

Linear Functions ◽

Whole Body ◽

Water Vapour Pressure ◽

Evaporative Water ◽

Open Flow ◽

Low Levels

SummaryThe rate of evaporative water loss has been studied in domestic fowls in the ambient temperature range from 0 to 40°C.Results for whole-body evaporation were similar when obtained by the open-flow and direct-weighing methods. At low levels of absolute humidity the rate increased by 0·03 mg/(g.h.°C) from 0 to 22 °C and by 0·17 mg/(g.h.°C) from 23 to 40 °C. Wholebody evaporation decreased with rising ambient water vapour pressure by 0·7 mg/(g.h.kPa).Cutaneous water loss was greater than respiratory water loss below 21 °C; it accounted for 78% of whole-body evaporation at 0 °C, falling to 25% at 40 °C.The rates of respiratory and whole-body evaporation could both be expressed as linear functions of respiratory frequency.

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Spatial and temporal patterns of water loss in heterogeneous landscapes: using plaster models as amphibian analogues

Canadian Journal of Zoology ◽

10.1139/cjz-2012-0229 ◽

2013 ◽

Vol 91 (3) ◽

pp. 135-140 ◽

Cited By ~ 29

Author(s):

W.E. Peterman ◽

J.L. Locke ◽

R.D. Semlitsch

Keyword(s):

Water Loss ◽

Activity Patterns ◽

Physiological Mechanism ◽

Temporal Patterns ◽

Spatial And Temporal Patterns ◽

Evaporative Water ◽

Heterogeneous Landscape ◽

Field Deployment ◽

And Performance ◽

Plaster Models

Water balance is critical to survival, growth, and performance of many terrestrial organisms because it can influence foraging time, limit dispersal, and curtail courtship activities. Water loss can vary in time and space across the landscape, and can also be modulated by behavior. Amphibians are particularly sensitive to water loss because their skin provides little to no resistance to evaporative water loss. Our study sought to quantify rates of water loss across a heterogeneous landscape using plaster of Paris models as analogues for the Western Slimy Salamander (Plethodon albagula Grobman, 1944). Models were validated within a controlled laboratory setting prior to field deployment, and were shown to approximate rates and magnitudes of water loss observed in living salamanders. In the field, we tested both adult- and juvenile-sized models, and found that juvenile-sized models lost water at a greater rate under all contexts. The rates of water loss measured at night (1.5%/h–4.5%/h) was nearly half of those measured during the day (2%/h–10%/h). Rates of water loss were greatest on ridges with southwestern aspects during the day (5%/h–10%/h) and lowest in ravines with northeast aspects at night (1.50%/h–3.75%/h). The results of spatial and temporal patterns of water loss corroborate field observations of salamander activity patterns and distribution across the landscape, providing a physiological mechanism driving fine-scale habitat use and distribution. Although we tested plaster models as analogues for salamanders, this approach should be generalizable to other amphibian taxa, providing an efficient means of measuring rates of water loss in the field under biologically meaningful contexts.

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Physiological regulation of evaporative water loss in endotherms: is the little red kaluta ( Dasykaluta rosamondae ) an exception or the rule?

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.0149 ◽

2014 ◽

Vol 281 (1784) ◽

pp. 20140149 ◽

Cited By ~ 15

Author(s):

Philip C. Withers ◽

Christine E. Cooper

Keyword(s):

Water Loss ◽

Thermal Conductance ◽

Vapour Pressure Deficit ◽

Evaporative Water Loss ◽

Water Vapour Pressure ◽

Published Data ◽

Evaporative Heat Loss ◽

Evaporative Water ◽

Physiological Regulation ◽

Ambient Relative Humidity

It is a central paradigm of comparative physiology that the effect of humidity on evaporative water loss (EWL) is determined for most mammals and birds, in and below thermoneutrality, essentially by physics and is not under physiological regulation. Fick's law predicts that EWL should be inversely proportional to ambient relative humidity (RH) and linearly proportional to the water vapour pressure deficit (Δwvp) between animal and air. However, we show here for a small dasyurid marsupial, the little kaluta ( Dasykaluta rosamondae ), that EWL is essentially independent of RH (and Δwvp) at low RH (as are metabolic rate and thermal conductance). These results suggest regulation of a constant EWL independent of RH, a hitherto unappreciated capacity of endothermic vertebrates. Independence of EWL from RH conserves water and heat at low RH, and avoids physiological adjustments to changes in evaporative heat loss such as thermoregulation. Re-evaluation of previously published data for mammals and birds suggests that a lesser dependence of EWL on RH is observed more commonly than previously thought, suggesting that physiological independence of EWL of RH is not just an unusual capacity of a few species, such as the little kaluta, but a more general capability of many mammals and birds.

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Contribution of gular flutter to evaporative cooling in Japanese quail

Journal of Applied Physiology ◽

10.1152/jappl.1976.40.4.521 ◽

1976 ◽

Vol 40 (4) ◽

pp. 521-524 ◽

Cited By ~ 15

Author(s):

W. W. Weathers ◽

D. C. Schoenbaechler

Keyword(s):

Oxygen Consumption ◽

Heat Stress ◽

Body Temperature ◽

Japanese Quail ◽

Water Loss ◽

Evaporative Water ◽

Coturnix Coturnix ◽

Air Temperatures ◽

Acute Heat Stress ◽

Cooling Mechanism

Oxygen consumption, body temperature (Tb), and evaporative water loss (mwe) were determined in intact Japanese quail (Coturnix coturnix), and in quail in which the hyoid musculature responsible for gular flutter had been surgically transected several days prior to study. Abolishing gular flutter reduced total mwe by an average of 20% at air temperatures (Ta) above 40 degrees C. Treated birds developed a significantly greater degree of hyperthermia during acute heat stress than the controls and, unlike the controls, were unable to maintain Tb less than Ta above 40 degrees C. These data demonstrate that gular flutter represents a significant cooling mechanism in heat-stressed quail.

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Can birds do it too? Evidence for convergence in evaporative water loss regulation for birds and mammals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.1478 ◽

2017 ◽

Vol 284 (1867) ◽

pp. 20171478 ◽

Cited By ~ 5

Author(s):

E. C. Eto ◽

P. C. Withers ◽

C. E. Cooper

Keyword(s):

Water Vapour ◽

Water Loss ◽

Vapour Pressure ◽

Vapour Pressure Deficit ◽

Ambient Air ◽

Evaporative Water Loss ◽

Water Vapour Pressure ◽

Evaporative Heat Loss ◽

Evaporative Water ◽

Water Vapour Pressure Deficit

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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Respiratory and cutaneous evaporative water loss at high environmental temperatures in a small bird

Journal of Experimental Biology ◽

10.1242/jeb.199.2.451 ◽

1996 ◽

Vol 199 (2) ◽

pp. 451-457 ◽

Cited By ~ 18

Author(s):

B Wolf ◽

G Walsberg

Keyword(s):

Metabolic Rate ◽

Air Temperature ◽

Water Loss ◽

Heat Dissipation ◽

Evaporative Water Loss ◽

Co2 Production ◽

Evaporative Heat Loss ◽

Evaporative Water ◽

Metabolic Chamber ◽

Air Temperatures

We measured rates of respiratory and cutaneous evaporative water loss as a function of air temperature in a small desert bird, the verdin Auriparus flaviceps. Birds were placed in a two-compartment metabolic chamber that separately collected water evaporated from the bird's head and body. Cutaneous and respiratory evaporative water loss, as well as CO2 production, were measured in resting birds at 2 °C intervals between 30 and 50 °C. Metabolic rate was lowest at 38 °C (19 mW g-1) and increased to 28 mW g-1 at 50 °C. At the lowest air temperature, 30 °C, resting metabolic rate was 34 mW g-1. As air temperature increased from 30 to 50 °C, cutaneous water loss increased from 3.3 to 10.3 mg g-1 h-1 and respiratory water loss increased from 2.1-64.1 mg g-1 h-1. At moderate air temperatures (30-36 °C), water loss was divided almost evenly between respiratory and cutaneous components. As air temperature increased, however, verdins became heavily dependent on respiratory evaporation for heat dissipation. Evaporative water loss data for other species at high air temperatures suggest that partitioning of water loss may follow two different patterns. Evaporative heat dissipation may depend primarily on either cutaneous or respiratory modes of evaporative heat transfer. The physiological mechanisms and functional significance of these contrasting patterns of evaporative heat loss remain unknown.

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Thermoregulatory role of insensible evaporative water loss constancy in a heterothermic marsupial

Biology Letters ◽

10.1098/rsbl.2017.0537 ◽

2017 ◽

Vol 13 (11) ◽

pp. 20170537 ◽

Cited By ~ 1

Author(s):

Christine Elizabeth Cooper ◽

Philip Carew Withers

Keyword(s):

Relative Humidity ◽

Water Loss ◽

Physiological Role ◽

Vapour Pressure Deficit ◽

Evaporative Water Loss ◽

Regulatory Control ◽

Water Vapour Pressure ◽

Evaporative Water ◽

Ambient Temperatures

‘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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A Meta-Analysis of Interviews and Cognitive Ability

Journal of Personnel Psychology ◽

10.1027/1866-5888/a000091 ◽

2013 ◽

Vol 12 (4) ◽

pp. 157-169 ◽

Cited By ~ 7

Author(s):

Philip L. Roth ◽

Allen I. Huffcutt

Keyword(s):

Cognitive Ability ◽

Meta Analysis ◽

Incremental Validity ◽

Employment Interviews ◽

Moderator Analysis ◽

The Future ◽

Research Questions ◽

Meta Analyses ◽

The Relationship

The topic of what interviews measure has received a great deal of attention over the years. One line of research has investigated the relationship between interviews and the construct of cognitive ability. A previous meta-analysis reported an overall corrected correlation of .40 ( Huffcutt, Roth, & McDaniel, 1996 ). A more recent meta-analysis reported a noticeably lower corrected correlation of .27 ( Berry, Sackett, & Landers, 2007 ). After reviewing both meta-analyses, it appears that the two studies posed different research questions. Further, there were a number of coding judgments in Berry et al. that merit review, and there was no moderator analysis for educational versus employment interviews. As a result, we reanalyzed the work by Berry et al. and found a corrected correlation of .42 for employment interviews (.15 higher than Berry et al., a 56% increase). Further, educational interviews were associated with a corrected correlation of .21, supporting their influence as a moderator. We suggest a better estimate of the correlation between employment interviews and cognitive ability is .42, and this takes us “back to the future” in that the better overall estimate of the employment interviews – cognitive ability relationship is roughly .40. This difference has implications for what is being measured by interviews and their incremental validity.

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