scholarly journals 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 ◽  
Vol 7 ◽  
pp. e7885 ◽  
Author(s):  
Mohlamatsane Mokhatla ◽  
John Measey ◽  
Ben Smit
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Body Mass ◽  
Water Loss ◽  
Standard Metabolic Rate ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Habitat Specialisation ◽  
Wide Range

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.

Inhibitors of nitric oxide synthesis block cold-induced thermogenesis in rats

2003 ◽  
Vol 81 (8) ◽  
pp. 834-838 ◽  
Author(s):  
Peter R Kamerman ◽  
Helen P Laburn ◽  
Duncan Mitchell
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Body Temperature ◽  
Nitric Oxide Synthase ◽  
Metabolic Rate ◽  
Water Loss ◽  
T Test ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Oxide Synthase

N-nitro-L-arginine methyl ester (L-NAME), an unspecific nitric oxide synthase inhibitor, was administered to individually caged Sprague–Dawley rats exposed to cold (18°C) and thermoneutral (30°C) environmental temperatures during the active phase of the animals' circadian cycle. Unrestrained rats were administered intraperitoneal injections of 100 mg·kg–1 L-NAME or 1 mL·kg–1 saline. Telemetry was used to measure abdominal temperature. On a separate occasion, metabolic rate and evaporative water loss were measured using indirect calorimetery, before and after the injection of 100 mg·kg–1 L-NAME, in rats exposed to the two environments. Injection of L-NAME had no significant effect on body temperature, metabolic rate, or evaporative water loss in rats exposed to the 30°C environment. In the 18°C environment, L-NAME injection caused a prolonged fall in body temperature (F(1,12) = 17.43, P = 0.001) and a significant decrease in metabolic rate (Student's t test, P = 0.001) and evaporative water loss (one-sample t test, P = 0.04). Therefore, the effects that systemic injection of L-NAME has on body temperature are dependent on environmental temperature, with nitric oxide synthase inhibition seemingly preventing the metabolic component of cold defence.Key words: N-nitro-L-arginine methyl ester, thermoregulation, telemetry, oxygen consumption.

Regulation of body temperature in the Budherygah, Melopsittacus undulatus

1976 ◽  
Vol 24 (1) ◽  
pp. 39 ◽  
Author(s):  
WW Weathers ◽  
DC Schoenbaechler
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Water Loss ◽  
Standard Metabolic Rate ◽  
Evaporative Water Loss ◽  
Metabolic Heat Production ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Metabolic Water

The standard metabolic rate of budgerygahs, determined during October and November, was 30% lower at night (1.96 ml O2 g-1 h-1) than during the day (2.55 ml O2 g-1h-1 ). The zone of thermal neutrality extended from 29 to 41�C. At ambient temperatures (Ta) below 29�C, oxygen consumption [V(02)] increased with decreasing Ta according to the relation V(02) (ml O2 g-1 h-1) = 5.65 - 0.127Ta. At Ta's between 0 and 16�C, body temperature (Tb) averaged 37.7�C (which is low by avian standards) and was independent of Ta. Above 20�C, Tb increased with increasing Ta, and within the zone of thermal neutrality Tb increased by approximately 4�C. The relation between V(O2) and Tb within the zone of thermal neutrality is described by the equation V(O2 = 6.29 - 0.105 Tb. This ability to decrease metabolic heat production while Tb rises could contribute to the water economy of budgerygahs. At moderate Ta's the rate of evaporative water loss of budgerygahs is only 60% that predicted for a 31 g bird. At Ta's below 14�C budgerygahs can balance evaporative water loss with metabolic water production. At 45�C Tb was between 1.0 and 5.0�C below Ta, and evaporative cooling accounted for up to 156% of metabolic heat production. At high Ta's budgerygahs appear to augment evaporation by lingual flutter.

Metabolism, Water-Balance and Temperature Regulation in the Golden Bandicoot (Isoodon-Auratus)

1992 ◽  
Vol 40 (5) ◽  
pp. 523 ◽  
Author(s):  
PC Withers
Keyword(s):  
Body Temperature ◽  
Water Balance ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Temperature Regulation ◽  
Water Loss ◽  
Thermal Conductance ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Low Rate

The Barrow I. golden bandicoot (Isoodon auratus) is a small arid-adapted marsupial. It has a low and labile body temperature, a low basal metabolic rate, a low thermal conductance, and a low rate of evaporative water loss. Its metabolic, thermal and hygric physiology resembles that of another arid-adapted bandicoot, the bilby, and differs from temperate and tropical bandicoots.

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