Ecology of Australian Chats (Epthianura Gould): Reproduction in Aridity.

1979 ◽  
Vol 27 (2) ◽  
pp. 213 ◽  
Author(s):  
CK Williams
Keyword(s):  
Arid Regions ◽  
Vapour Pressure Deficit ◽  
Physiological Adaptation ◽  
Water Requirements ◽  
Territorial Defence ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Hormonal Mechanism ◽  
Gloger’S Rule ◽  
Breeding Seasons

The four species of Australian chats differentially occupy arid regions and are considered to have problems of water balance during reproduction. They breed mainly during the winter semester, when ambient temperatures and vapour pressure deficit are lower and evaporative losses of body water are reduced. During a drought breeding is depressed; but chats breed opportunistically after abundant rainfall and exploit, by nomadism, the unpredictable rainfall in semiarid and arid Australia. The breeding season of the most mesic species, Epthianura albifrons, is reduced in the more xeric regions. In arid sympatric breeding areas the more xeric species have the more extended breeding seasons. Chats are territorial only during reproduction. The male protects the receptive female and the eggs and offspring, but not environmental resources. Territorial defence involves plumage pigmentation consistent with Gloger's rule, plumage patterns, postures and ritualized fighting displays. Territoriality and territorial behaviour are reduced in the more mesic species. This is consistent with relative rates of evaporative water loss, synchrony and apparent density of nesting, water requirements and physiological adaptation to aridity. A hypothesis is presented which suggests an adaptive hormonal mechanism relating to physiological adaptation to aridity and determining the different plumages.

scholarly journals The ship of the desert. The dromedary camel (Camelus dromedarius), a domesticated animal species well adapted to extreme conditions of aridness and heat

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 231 ◽  
Author(s):  
S. Bornstein
Keyword(s):  
Animal Species ◽  
Physiological Adaptation ◽  
Dromedary Camel ◽  
Large Animal ◽  
Water Losses ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Adaptive Mechanisms ◽  
Adaptation To Heat ◽  
Arabian Camel

The dromedary camel (Camel dromedarius) is extremely well adapted to life in hot and arid lands. In terms of physiological adaptation to heat and water deprivation it surpasses by far every other large animal of which data have been collected. None of the adaptive mechanisms to cope with the environmental stresses are unique to the Arabian camel, but the efficiency of its adaptation is superior. At high ambient temperatures the camels adapt to the scarcity of water by reducing their faecal, urinary and evaporative water losses. During dehydration, the kidneys reduce water losses both by decreasing the glomerual filtration rate and by increasing the tubular reabsorption of water. Also their ability of regulating their body temperature from 34.5-40.7 °C conserves a lot of water, when most needed.

Ecology of Australian chats (Epthianura Gould) season movements, metabolism and ecaporative water loss

1976 ◽  
Vol 24 (3) ◽  
pp. 397 ◽  
Author(s):  
CK Williams ◽  
AR Main
Keyword(s):  
Water Loss ◽  
Arid Regions ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Seasonal Movements ◽  
Ambient Temperatures ◽  
Thermoneutral Zone ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
Body Heat

The four species of Australian chats differ in their utilization of arid regions. Comparisons were made between the rates of metabolism and evaporative water loss of three species at moderate and high ambient temperatures, after trapping in the field during winter and after acclimation in the laboratory to 22�C and 14�C. When acclimated to winter temperatures the three species had similar rates of metabolism at moderate and high ambient temperatures. The rates of evaporative water loss at moderate temperatures were similar, but at temperatures above the thermoneutral zone the rates were lower in the more xeric than the more mesic species. When acclimated to summer temperatures the more xeric species had lower rates of metabolism and evaporative water loss than the more mesic species at temperatures within and above the thermoneutral zone. Variation in the rates of metabolism and evaporative water loss in field populations was greatest in the most mesic species and least in the most xeric species. Rates of metabolism and evaporative water loss were lower in all species after acclimation to 22�C than after acclimation to 14�C. The rates of metabolism and evaporative water loss tended to be lower than the rates predicted on the basis of body weight. In thermoregulation at high ambient temperatures the more xeric species evaporated relatively less body water in dissipating body heat than the more mesic species, apparently without a greater increase in body temperature. The ability of Australian chats to utilize semiarid and arid regions is explained by distributions and seasonal movements which complement the physiology of evaporative water loss and thermoregulation in a manner that enhances survival at high ambient temperatures.

Studies on the water economy of some Australian frogs.

1965 ◽  
Vol 13 (2) ◽  
pp. 317 ◽  
Author(s):  
MR Warburg
Keyword(s):  
High Temperatures ◽  
Water Uptake ◽  
Water Loss ◽  
Vapour Pressure ◽  
Arid Regions ◽  
Vapour Pressure Deficit ◽  
Evaporative Water ◽  
Dry Air ◽  
Reduced Water ◽  
Semi Arid

The rate of evaporative water loss of several species of frog found in Australia and their ability to survive at high temperatures were studied at various temperatures in both dry and in humid air, and at constant vapour pressure deficit. The species studied were: Bufonidae, Bufo marinus (L.); Leptodactylidae, Crinia signifera Girard, Pseudophryne bibroni Gunther, Limnodynastes tasmaniensis Gunther, L. dorsalis (Gray), L. ornatus (Gray), Neobatrachus pictus Peters, N. centralis (Parker); Hylidae, Hyla ewingi (Dumeril & Bibron) and H. rubella Gray. To a certain extent, the trend for increased adaptation to terrestrial conditions follows the trend for reduced water loss. The rate of water uptake after dehydration is greatest in the burrowing frogs inhabiting arid and semi-arid regions. Survival at high temperatures in dry air was found to be a good criterion for judging the degree of adaptation of these frogs to life in arid regions.

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

2017 ◽  
Vol 13 (11) ◽  
pp. 20170537 ◽  
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.

Inhibiting ventilatory evaporation produces an adaptive increase in cutaneous evaporation in mourning doves Zenaida macroura

1999 ◽  
Vol 202 (21) ◽  
pp. 3021-3028 ◽  
Author(s):  
T.C. Hoffman ◽  
G.E. Walsberg
Keyword(s):  
Skin Surface ◽  
The Body ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Zenaida Macroura ◽  
Ambient Temperatures ◽  
Rapid Adjustment ◽  
Mourning Doves ◽  
A Minor ◽  
Cutaneous Evaporation

We tested the hypothesis that birds can rapidly change the conductance of water vapor at the skin surface in response to a changing need for evaporative heat loss. Mourning doves (Zenaida macroura) were placed in a two-compartment chamber separating the head from the rest of the body. The rate of cutaneous evaporation was measured in response to dry ventilatory inflow at three ambient temperatures and in response to vapor-saturated ventilatory inflow at two ambient temperatures. At 35 degrees C, cutaneous evaporation increased by 72 % when evaporative water loss from the mouth was prevented, but no increase was observed at 45 degrees C. For both dry and vapor-saturated treatments, cutaneous evaporation increased significantly with increased ambient temperature. Changes in skin temperature made only a minor contribution to any observed increase in cutaneous evaporation. This indicates that Z. macroura can effect rapid adjustment of evaporative conductance at the skin in response to acute change in thermoregulatory demand.

scholarly journals Subtropical mouse-tailed bats use geothermally heated caves for winter hibernation

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142781 ◽  
Author(s):  
Eran Levin ◽  
Brit Plotnik ◽  
Eran Amichai ◽  
Luzie J. Braulke ◽  
Shmulik Landau ◽  
...  
Keyword(s):  
High Temperature ◽  
Skin Temperature ◽  
Metabolic Rates ◽  
Evaporative Water ◽  
Open Flow ◽  
Ambient Temperatures ◽  
Northern Edge ◽  
Average Skin ◽  
World Distribution ◽  
Winter Hibernation

We report that two species of mouse-tailed bats ( Rhinopoma microphyllum and R. cystops ) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure the bats’ skin temperature in the natural hibernacula and open flow respirometry to measure torpid metabolic rate at different ambient temperatures ( T a , 16–35°C) and evaporative water loss (EWL) in the laboratory. Bats average skin temperature at the natural hibernacula was 21.7 ± 0.8°C, and no arousals were recorded. Both species reached the lowest metabolic rates around natural hibernacula temperatures (20°C, average of 0.14 ± 0.01 and 0.16 ± 0.04 ml O 2 g −1 h −1 for R. microphyllum and R. cystops , respectively) and aroused from torpor when T a fell below 16°C. During torpor the bats performed long apnoeas (14 ± 1.6 and 16 ± 1.5 min, respectively) and had a very low EWL. We hypothesize that the particular diet of these bats is an adaptation to hibernation at high temperatures and that caves featuring high temperature and humidity during winter enable these species to survive this season on the northern edge of their world distribution.

Ecology of Australian Chats (Epthianura Gould): Aridity, Electrolytes and Water Economy.

1977 ◽  
Vol 25 (4) ◽  
pp. 673 ◽  
Author(s):  
CK Williams ◽  
AR Main
Keyword(s):  
Drinking Water ◽  
Arid Regions ◽  
Body Water ◽  
Seasonal Movements ◽  
Ambient Temperatures ◽  
Complex Interactions ◽  
Low Concentrations ◽  
Access To Water ◽  
High Concentrations ◽  
High Degree

The four species of Australian chats differentially occupy semiarid and arid regions where surface water commonly contains high concentrations of electrolytes, especially during the summer. The effects of variations in ambient temperature and salinity of drinking water on nutrition, water and electrolyte balances were compared between three species of chats in a split-plot, factorial design. The homeostatic responses revealed very complex interactions between thermoregulation, nutrition, and balances of electrolytes and water. All species have very low tolerance of electrolytes in the drinking water. Ingested electrolytes are not stored but are rapidly excreted in low concentrations at the expense of body water. Survival of chats in arid regions depends on a high degree of selectivity in avoiding water sources with even moderate concentrations of electrolytes. This avoidance is achieved by nomadism and seasonal movements to areas of recent rainfall, thereby increasing the access to water with low concentrations of electrolytes. The ability of the more xeric species to occupy regions of greater aridity cannot be explained by enhanced abilities to excrete electrolytes in high concentrations. The three species studied excrete electrolytes in similar, low concentrations. The more xeric species possess an advantage in water and electrolyte balances through lower evaporative losses of body water, especially at high ambient temperatures.

scholarly journals Climate change increases the likelihood of catastrophic avian mortality events during extreme heat waves

2009 ◽  
Vol 6 (2) ◽  
pp. 253-256 ◽  
Author(s):  
Andrew E. McKechnie ◽  
Blair O. Wolf
Keyword(s):  
Climate Change ◽  
Heat Waves ◽  
Extreme Heat ◽  
Survival Times ◽  
Water Requirements ◽  
Evaporative Water ◽  
Change Models ◽  
Air Temperatures ◽  
Hot Weather

Severe heat waves have occasionally led to catastrophic avian mortality in hot desert environments. Climate change models predict increases in the intensity, frequency and duration of heat waves. A model of avian evaporative water requirements and survival times during the hottest part of day reveals that the predicted increases in maximum air temperatures will result in large fractional increases in water requirements (in small birds, equivalent to 150–200 % of current values), which will severely reduce survival times during extremely hot weather. By the 2080s, desert birds will experience reduced survival times much more frequently during mid-summer, increasing the frequency of catastrophic mortality events.

Studies of the environmental physiology of tropical merinos

1978 ◽  
Vol 29 (1) ◽  
pp. 161 ◽  
Author(s):  
PS Hopkins ◽  
GI Knights ◽  
AS Le Feuvre
Keyword(s):  
Low Temperature ◽  
Rectal Temperature ◽  
Water Loss ◽  
Heat Dissipation ◽  
Evaporative Water Loss ◽  
Compensatory Mechanisms ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Diurnal Patterns ◽  
Made In

Rectal temperature measurements of tropical Merino sheep taken in the sun during summer indicated that there were high and low temperature groups. Animals of low temperature status (e.g. 39.4°C) also exhibited a low respiration rate (e.g. 110/min) in comparison with their less adapted counterparts (40.0° and 190/min). These differences were greatest when ambient temperatures were high. The repeatability of temperature status was 0.46 (P < 0.01). Animals of folds (+) phenotype had significantly higher rectal temperatures than folds (–) animals (P < 0.05). Shearing caused a marked but transient increase in rectal temperature. Compensatory mechanisms apparently involved an increase in cutaneous heat dissipation and/or a decrease in exogenous heat load. Evaporative water loss (80–115 ml/kg/day) greatly exceeded the non-evaporative water loss (40–65 ml/kg/day) of sheep in metabolism cages. Respiratory water loss could account for only 8–10% of the total daily evaporative water loss. Non-respiratory evaporative water loss (as measured by difference) was c. 75–100 ml/kg/day. There were no striking differences between high and low temperature status sheep in this regard. Measurements of respiratory (2 ml/kg/hr) and non-respiratory (5.5 ml/kg/hr) evaporative water loss made in hygrometric tents suggested that the greater non-respiratory water loss was partly due to a higher rate of loss and partly to a longer period of loss per day. This suggestion was supported by the diurnal patterns of rectal temperatures and respiration rates reported here, though no firm conclusions could be made as to the thermotaxic effect of non-respiratory water loss and thermoregulation of tropical Merinos with varying amounts of wool cover.

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