scholarly journals Heat and water loss versus shelter: a dilemma in thermoregulatory decision making for a retreat-dwelling nocturnal gecko

2020 ◽  
Vol 223 (20) ◽  
pp. jeb231241
Author(s):  
Christian O. Chukwuka ◽  
Joanne M. Monks ◽  
Alison Cree
Keyword(s):  
Water Loss ◽  
The Body ◽  
Thermal Limit ◽  
Evaporative Water ◽  
Thermal Histories ◽  
Hot Weather ◽  
Will Force ◽  
Duration Of Heating ◽  
Laboratory Protocol ◽  
Cool Climate

ABSTRACTUnderstanding the interaction between upper voluntary thermal limit (VTmax) and water loss may aid in predicting responses of ectotherms to increasing temperatures within microhabitats. However, the temperature at which climate heating will force cool-climate nocturnal lizards to abandon daytime retreats remains poorly understood. Here, we developed a new laboratory protocol for determining VTmax in the retreat-dwelling, viviparous Woodworthia ‘Otago/Southland’ gecko, based on escape behaviour (abandonment of heated retreat). We compared the body temperature (Tb) at VTmax, and duration of heating, between two source groups with different thermal histories, and among three reproductive groups. We also examined continuous changes in Tb (via an attached biologger) and total evaporative water loss (EWL) during heating. In the field, we measured Tb and microhabitat thermal profiles to establish whether geckos reach VTmax in nature. We found that VTmax and duration of heating varied between source groups (and thus potentially with prior thermal experience), but not among reproductive groups. Moreover, geckos reached a peak temperature slightly higher than VTmax before abandoning the retreat. Total EWL increased with increasing VTmax and with the duration of heating. In the field, pregnant geckos with attached biologgers reached VTmax temperature, and temperatures of some separately monitored microhabitats exceeded VTmax in hot weather implying that some retreats must be abandoned to avoid overheating. Our results suggest that cool-climate nocturnal lizards that inhabit daytime retreats may abandon retreats more frequently if climate warming persists, implying a trade-off between retention of originally occupied shelter and ongoing water loss due to overheating.

Water Balance of the Camel

1956 ◽  
Vol 185 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Bodil Schmidt-Nielsen ◽  
Knut Schmidt-Nielsen ◽  
T. R. Houpt ◽  
S. A. Jarnum
Keyword(s):  
Body Weight ◽  
Water Loss ◽  
Plasma Concentrations ◽  
The Body ◽  
Evaporative Water Loss ◽  
Weight Changes ◽  
Evaporative Water ◽  
Hot Environment ◽  
Dry Food ◽  
High Degree

Camels ( Camelus dromedarius) were exposed to prolonged periods of water deprivation during winter, spring and summer in the Sahara desert. Determinations were made of: weight changes, water and food intake, urine flow and concentrations, plasma concentrations, etc. It was found that the camel can tolerate a loss of water corresponding to 30% of its body weight even when exposed to the severe desert heat. Other mammals dehydrated in a hot environment may die from circulatory failure already when the water loss involves 12% of the body weight. Unlike many other mammals the camel does not lose its appetite when deprived of water but continues to eat normally until the desiccation becomes very severe. It has a low urine output (0.5–1 l/day when kept on a diet of dates and hay), a low water content in the feces, and, when dehydrated in the summer, a very low evaporative water loss. When offered water the camel drinks in 10 minutes enough water for complete rehydration. The longest period that we kept a camel on dry food without drinking water in the hot summer was 17 days. This camel was not working and it had its protective fur which decreased the heat gain from the environment. It is concluded that the ability of the camel to withstand prolonged dehydration is due to: a) tolerance to an extremely high degree of desiccation of the body and b) low overall water expenditure. Particularly effective as a water conserving mechanism is the low evaporative water loss during dehydration in the summer.

Effects of Warm Temperatures on Metabolic Rate and Evaporative Water Loss in Tuatara, a Cool-Climate Rhynchocephalian Survivor

2018 ◽  
Vol 91 (4) ◽  
pp. 950-966
Author(s):  
Scott Jarvie ◽  
Tim Jowett ◽  
Michael B. Thompson ◽  
Philip J. Seddon ◽  
Alison Cree
Keyword(s):  
Metabolic Rate ◽  
Water Loss ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Cool Climate

Energetics of the Little Penguin, Eudyptula Minor: Temperature Regulation, the Calorigenic Effect of Food, and Moulting.

1986 ◽  
Vol 34 (1) ◽  
pp. 35 ◽  
Author(s):  
RV Baudinette ◽  
P Gill ◽  
M O'driscoll
Keyword(s):  
Heat Production ◽  
Water Loss ◽  
Thermal Conductance ◽  
Fold Increase ◽  
The Body ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Effect Of Food ◽  
Little Penguin

Rates of oxygen consumption and means of augmenting the resultant heat production were studied in the little penguin, Eudyptula minor. Metabolic rates were lower than those predicted for a 1-kg bird, but shivering and an energy response to feeding were both present. The latter effect was independent of ambient temperatures between 2 deg and 22 deg C. The birds have limited ability to dissipate heat by evaporative water loss. About 40% of the total heat production was the maximum amount lost by this route. Cooling of expired respiratory gas provided an effective saving of heat and water. Moulting resulted in a 1.5-fold increase in metabolic rate but rates of evaporative water loss were reduced. The increase in heat production is correlated with increased thermal conductance across the body surface, as new feathers are synthesized, but body temperature is the same as in non-moulting penguins. The results suggest that increased heat loss when the birds are in water might be replaced by calorigenesis associated with the response to feeding, and by shivering, as well as by activity.

Water collection by the body in a viperid snake, Bothrops moojeni

2000 ◽  
Vol 21 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Augusto Abe ◽  
Denis Andrade
Keyword(s):  
Body Surface ◽  
Water Loss ◽  
Functional Significance ◽  
Close Contact ◽  
Volume Ratio ◽  
The Body ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Water Collection ◽  
Bothrops Moojeni

AbstractWe describe a previously unreported behavior for water collection in juveniles of a neotropical viperid snake, Bothrops moojeni. When sprayed over, this snake displays a stereotyped coiling, bringing its body loops in close contact with each other, so that water is retained between the loops and over the body surface. This water is continuously ingested during and after its collection. The functional significance of the water collecting behavior is suggested to be related with the acquisition of water from short rainfalls, and with the special climatic and geologic conditions of B. moojeni habitat. Rates of evaporative water loss did not differ between juvenile and adult snakes, but since juveniles have a greater surface-to-volume ratio, they were significantly more sensitive to desiccation than the adults.

Shell Resistance and Evaporative Water Loss from Bird Eggs: Effects of Wind Speed and Egg Size

1981 ◽  
Vol 54 (2) ◽  
pp. 195-202 ◽  
Author(s):  
James R. Spotila ◽  
Christina J. Weinheimer ◽  
Charles V. Paganelli
Keyword(s):  
Wind Speed ◽  
Water Loss ◽  
Egg Size ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Bird Eggs

Scaling of Evaporative Water Loss in Marsupials

1986 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
David S. Hinds ◽  
Richard E. MacMillen
Keyword(s):  
Water Loss ◽  
Evaporative Water Loss ◽  
Evaporative Water

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.

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