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  • 1
    Electronic Resource
    Electronic Resource
    Temperature regulation and metabolism of an Australian bat, Chalinolobus gouldii (Chiroptera: Vespertilionidae) when euthermic and torpid (1997)
    Springer
    Journal of comparative physiology 167 (1997), S. 71-80 
    Details
    ISSN: 1432-136X
    Keywords: Key words Body temperature  ;  Metabolic rate  ;   Evaporative water loss  ;  Torpor  ;  Euthermy  ;   Thermal conductance  ;  Bat ; Chalinolobus gouldii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The thermal and metabolic physiology of Chalinolobus gouldii, an Australian vespertilionid bat, was studied in the laboratory using flow-through respirometry. Chalinolobus gouldii exhibits a clear pattern of euthermic thermoregulation, typical of endotherms with respect to body temperature and rate of oxygen consumption. The basal metabolic rate of euthermic Chalinolobus gouldii is approximately 86% of that predicted for a 17.5-g mammal and falls into the range of mass-specific basal metabolic rates ascribed to vespertilionid bats. However, like most vespertilionid bats, Chalinolobus gouldii displays extreme thermolability. It is able to enter into torpor and spontaneously arouse at ambient temperatures as low as 5 °C. Torpid bats thermoconform at moderate ambient temperature, with body temperature ≈ ambient temperature, and have a low rate of oxygen consumption determined primarily by Q 10 effects. At low ambient temperature (〈 10 °C), torpid C. gouldii begin to regulate their body temperature by increased metabolic heat production; they tend to maintain a higher body temperature at low ambient temperature than do many northern hemisphere hibernating bats. Use of torpor leads to significant energy savings. The evaporative water loss of euthermic bats is relatively high, which seems unusual for a bat whose range includes extremely arid areas of Australia, and is reduced during torpor. The thermal conductance of euthermic C. gouldii is less than that predicted for a mammal of its size. The thermal conductance is considerably lower for torpid bats at intermediate body temperature and ambient temperature, but increases to euthermic values for torpid bats when thermoregulating at low ambient temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050049
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen consumption by ammocoetes of the lampreyGeotria australis in air (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 331-336 
    Details
    ISSN: 1432-136X
    Keywords: Respiration ; Air ; Skin ; Lamprey ; Geotria Agnatha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract When covered by moistened lint-free gauze, the larvae (ammocoetes) of the lampreyGeotria australis survived, without apparent discomfort, for 4 days in water-saturated air at 10, 15 and 20°C. In air, the mean standard rates of O2 consumption of medium to large ammocoetes ofG. australis (000000000;=0.52 g) at 10, 15 and 20°C were 14.5, 35.7 and 52.1 μl·g−1·h−1, respectively. At 15°C, the slope of the relationship between log O2 consumption (μlO2·h−1) and log body weight for ammocoetes over a wide range in body weight was 0.987. TheQ 10s for rate of O2 consumption between 10 and 15°C, 15 and 20°C and 10 and 20°C were 4.9, 2.9 and 3.6, respectively. Our results and observations of the ammocoetes suggest that, when out of water, larvalG. australis derives most of its O2 requirements from cutaneous respiration, particularly at lower temperatures. This would be facilitated by the small size and elongate shape (and thus a relatively high surface-to-volume ratio), low metabolic rate, thin dermis, extensive subdermal capillary network and high haemoglobin concentration of larvalG. australis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02439920
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of erythrocythemia on blood viscosity, maximal systemic oxygen transport capacity and maximal rates of oxygen consumption in an amphibian (1985)
    Springer
    Journal of comparative physiology 155 (1985), S. 577-581 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Graded erythrocythemia was induced by isovolemic loading of packed red blood cells in the toad,Bufo marinus. Blood viscosity, hematocrit, hemoglobin concentration, maximal aortic blood flow rate and maximal rates of oxygen consumption were determined after each load. 2. Blood viscosity was related to hematocrit in the expected exponential manner; ln η=0.43+0.035 Hct (Fig. 2). 3. Maximal blood flow rates in the dorsal aorta were inversely proportional to blood viscosity and fit predictions of the Poiseuille-Hagen flow formula (Fig. 3). The effect of increased blood viscosity was to reduce aortic pulse volume, but not maximal heart rate (Figs. 4, 5). 4. Maximal systemic oxygen transport capacity (aortic blood flow rate x hemoglobin concentration x O2 binding capacity of hemoglobin) was linearly correlated with the maximal rate of oxygen consumption (Fig. 6). 5. These data indicate that optimal hematocrit theory is applicable for maximal blood flow rates in vivo, and that systemic oxygen transport is the primary limitation to aerial $$\dot V_{O_2 } $$ max in amphibians.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694447
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  • 4
    Electronic Resource
    Electronic Resource
    The hemodynamic consequences of hemorrhage and hypernatremia in two amphibians (1988)
    Springer
    Journal of comparative physiology 157 (1988), S. 807-812 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Graded hypovolemia was induced by hemorrhagic blood loss and graded hypernatremia by salt load in the toad,Bufo marinus, and the bullfrog,Rana catesbeiana. Maximal blood flow rates in the systemic arches and arterial and venous pressures were measured during activity after each stress. 2. Maximal blood flow rates in theB. marinus did not decline until blood loss exceeded 5% of initial body mass. InR. catesbeiana, losses of 2% initial body mass caused a decline (Fig. 1). 3. Maximal heart rates did not change with hemorrhage (Fig. 2). The decline in blood flow rates with hemorrhage was due to declining pulse volumes in both species (Fig. 3). 4. Arteriovenous pressure difference declined with hemorrhage in both species (Fig. 4). Peripheral resistance increased with hemorrhage in parallel with compromised blood flow rates (Fig. 5). 5. Plasma sodium concentration slightly increased with hemorrhage, while plasma protein concentration and hematocrit declined. Lymphatic compensation for hemorrhagic loss is indicated in both species (Fig. 6). 6. Induced hypernatremia compromised blood flow rates in both species at plasma sodium concentrations above 175 mM. The decline in flow rates was principally a result of a decrease in pulse volume, though maximal heart rates also declined (Figs. 2, 3, 7). 7. Induced hypernatremia had no effect on the arteriovenous pressure difference inB. marinus but caused it to decline inR. catesbeiana. Peripheral resistance increased in onlyB. marinus but notR. catesbeiana (Figs. 4, 5). Hematocrit did not change with salt load, indicative of a constant vascular volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691012
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  • 5
    Electronic Resource
    Electronic Resource
    The effects of hypoxia on pulmonary function and maximal rates of oxygen consumption in two anuran amphibians (1983)
    Springer
    Journal of comparative physiology 152 (1983), S. 125-129 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The effects of ambient $$P_{O_2 } $$ on the maximal rate of oxygen consumption, alveolar $$P_{O_2 } $$ and alveolar ventilation rate were measured for two species of anuran amphibians during forced activity. The maximal rates of oxygen consumption were independent of ambient $$P_{O_2 } $$ values as low as 80 Torr for bothBufo cognatus (1.5 ml O2 g−1 h−1) andRana pipiens (0.64 ml g−1 h−1), and were linearly proportional to ambient $$P_{O_2 } $$ at less than 80 Torr. 2. The alveolar $$P_{O_2 } $$ ofB. cognatus andR. pipiens during forced activity at a normal ambient $$P_{O_2 } $$ was 125–135 Torr. Alveolar $$P_{O_2 } $$ declined linearly for both species under hypoxic conditions. 3. The alveolar ventilation rate was calculated from maximal oxygen consumption rate and alveolar $$P_{O_2 } $$ at various ambient $$P_{O_2 } $$ values. The alveolar ventilation rate at 153 Torr was 32 ml min−1 atpd forB. cognatus and 19 forR. pipiens during forced activity. Theatpd alveolar ventilation increased substantially at lowered ambient $$P_{O_2 } $$ , although thestpd alveolar ventilation declined markedly. The interspecific differences in maximal rates of oxygen consumption were correlated with the interspecific differences in alveolar ventilation rates. 4. The relationship between maximal rate of oxygen consumption and ambient $$P_{O_2 } $$ forB. cognatus andR. pipiens indicates that ambient $$P_{O_2 } $$ and pulmonary ventilation rates do not normally limit the maximal rates of respiratory gas exchange in anuran amphibians. The critical $$P_{O_2 } $$ (80 Torr), below which the maximal rate of oxygen consumption declines, corresponds to an altitude of about 4500 m, and is less than the ambient $$P_{O_2 } $$ encountered by terrestrial anuran amphibians in their natural environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689736
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  • 6
    Electronic Resource
    Electronic Resource
    Oxygen consumption by ammocoetes of the lamprey Geotria australis in air (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 331-336 
    Details
    ISSN: 1432-136X
    Keywords: Key words Respiration ; Air ; Skin ; Lamprey ; Geotria Agnatha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  When covered by moistened lint-free gauze, the larvae (ammocoetes) of the lamprey Geotria australis survived, without apparent discomfort, for 4 days in water-saturated air at 10, 15 and 20 °C. In air, the mean standard rates of O2 consumption of medium to large ammocoetes of G. australis (x¯=0.52 g) at 10, 15 and 20 °C were 14.5, 35.7 and 52.1 μl⋅g-1⋅h-1, respectively. At 15 °C, the slope of the relationship between log O2 consumption (μl O2⋅h-1) and log body weight for ammocoetes over a wide range in body weight was 0.987. The Q 10s for rate of O2 consumption between 10 and 15 °C, 15 and 20 °C and 10 and 20 °C were 4.9, 2.9 and 3.6, respectively. Our results and observations of the ammocoetes suggest that, when out of water, larval G. australis derives most of its O2 requirements from cutaneous respiration, particularly at lower temperatures. This would be facilitated by the small size and elongate shape (and thus a relatively high surface-to-volume ratio), low metabolic rate, thin dermis, extensive subdermal capillary network and high haemoglobin concentration of larval G. australis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050016
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  • 7
    Electronic Resource
    Electronic Resource
    Effectors of metabolic depression in an estivating pulmonate snail (Helix aspersa): whole animal and in vitro tissue studies (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 375-381 
    Details
    ISSN: 1432-136X
    Keywords: Oxygen consumption ; Estivation ; Metabolic depression ; Acidosis ; Snail,Helix aspersa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have examined metabolic depression in the land snail (Helix aspersa) during estivation, and have developed a tissue model of metabolic depression using an in vitro mantle preparation. The metabolic rate ofH. aspersa is depressed by 84% in vivo within 4 weeks of onset of estivation, and this metabolic depression is accompanied by a decrease in haemolymphPO2 and pH, and an increase in haemolymphPCO2. The in vitro mantle preparation has a stable O2 consumption and energy charge, and an energy charge similar to that of mantle in vivo. The in vitro mantle is an O2-conforming tissue, withVO2 varying curvilinearly withPO2. Consequently, we have developed a mathematical method of calculating tissueVO2 at anyPO2. These calculations show that under appropriate incubation conditions of pH andPO2, the mantle from estivating animals shows a stable in vitro metabolic depression of 48% compared to mantle from control snails. The extrinsic effects ofPO2 and pH account for 70% of the total in vitro metabolic depression of mantle tissue; intrinsic effectors contribute a further 30%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02336920
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  • 8
    Electronic Resource
    Electronic Resource
    Effectors of metabolic depression in an estivating pulmonate snail (Helix aspersa): whole animal and in vitro tissue studies (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 375-381 
    Details
    ISSN: 1432-136X
    Keywords: Key words Oxygen consumption ; Estivation ; Metabolic depression ; Acidosis ; Snail ; Helix aspersa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We have examined metabolic depression in the land snail (Helix aspersa) during estivation, and have developed a tissue model of metabolic depression using an in vitro mantle preparation. The metabolic rate of H. aspersa is depressed by 84% in vivo within 4 weeks of onset of estivation, and this metabolic depression is accompanied by a decrease in haemolymph PO2 and pH, and an increase in haemolymph PCO2. The in vitro mantle preparation has a stable O2 consumption and energy charge, and an energy charge similar to that of mantle in vivo. The in vitro mantle is an O2-conforming tissue, with VO2 varying curvilinearly with PO2. Consequently, we have developed a mathematical method of calculating tissue VO2 at any PO2. These calculations show that under appropriate incubation conditions of pH and PO2, the mantle from estivating animals shows a stable in vitro metabolic depression of 48% compared to mantle from control snails. The extrinsic effects of PO2 and pH account for 70% of the total in vitro metabolic depression of mantle tissue; intrinsic effectors contribute a further 30%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050022
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  • 9
    Electronic Resource
    Electronic Resource
    Metabolic depression and Na+/K+ gradients in the aestivating Australian goldfields frog, Neobatrachus wilsmorei (1993)
    Springer
    Journal of comparative physiology 163 (1993), S. 587-593 
    Details
    ISSN: 1432-136X
    Keywords: Aestivation ; Ion gradients ; Metabolic depression ; Inulin ; Frog, Neobatrachus wilsmorei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract During aestivation the metabolic rate of the Australian goldfields frog Neobatrachus wilsmorei was reduced by 80% from its standard metabolic rate. The in vitro rate of oxygen consumption of isolated muscle and skin from aestivating frogs was up to 50% lower than that of the non-aestivating frogs. This in vitro rate of oxygen consumption was maintained for 6–12 h, indicating an intrinsic metabolic depression of tissues during aestivation. Frogs became dehydrated during aestivation. Muscle, skin and liver also became dehydrated during aestivation, but brain and kidney did not. Na+ and K+ contents and extracellular space measurement for muscle indicated that ion gradients were maintained across the muscle cell membrane during aestivation. Increases in plasma concentrations of Na+ and K+ were matched with similar increases in muscle intracellular ion concentrations. Extracellular space measurements were unsuccessful in the other tissues, but K+ content in all tissues (per dry weight) was maintained during aestivation, and the concentration of plasma K+ did not increase above that which can be accounted for by dehydration, indicating that K+ gradients were maintained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302118
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  • 10
    Electronic Resource
    Electronic Resource
    Some costs of reproduction for male bushcrickets, Requena verticalis (Orthoptera : Tettigoniidae) allocating resources to mate attraction and nuptial feeding (1992)
    Springer
    Behavioral ecology and sociobiology 31 (1992), S. 57-62 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cost of reproductive effort is known to result in a trade-off between current and future reproduction. Similarly, trade-offs in energy allocation may occur between components of reproductive effort, mating and parental effort, within a single reproductive episode. We investigated the energy allocated to mating effort (calling to attract females) and parental effort (donation of spermatophore nutrients at mating) by male bushcrickets, Requena verticalis, under two dietary regimes. Males provided with a low quality diet reduced the daily energy allocated to calling activity while maintaining their investment in spermatophores. Males provided with a high quality diet did not allocate more resources per day to their spermatophores but stored excess energy for future reproduction. Thus, on a per day basis, males appear to hold constant their investment in the spermatophore at the cost of reduced mating effort when resources are limited. Males on both diets, however, increased the size of their spermatophore donations when the interval between female encounters was increased. One explanation for this pattern could be a frequency-dependent optimization of spermatophore size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167816
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