The ecological significance of thermoregulatory responses to heat stress shown by two populations of an Australian murid, Rattus fuscipes

How do measurement duration and timing interact to influence estimation of basal physiological variables of a nocturnal rodent?

“…We can assess here the potential impact of short measurement duration on measurement of BMR for the bush rat. Collins (1973) measured a minimal CO 2 of 1.00 ± 0.061 ml CO 2 g -1 h -1 for bush rats also from the Albany region. This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002).…”

“…This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002). Collins' (1973) experimental protocol measured MR between 1100 h and h, a maximal measurement duration of h, commencing close to the species' circadian minima.…”

How do measurement duration and timing interact to influence estimation of basal physiological variables of a nocturnal rodent?

“…We can assess here the potential impact of short measurement duration on measurement of BMR for the bush rat. Collins (1973) measured a minimal CO 2 of 1.00 ± 0.061 ml CO 2 g -1 h -1 for bush rats also from the Albany region. This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002).…”

“…This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002). Collins' (1973) experimental protocol measured MR between 1100 h and h, a maximal measurement duration of h, commencing close to the species' circadian minima.…”

Survivable hypothermia or torpor in a wild-living rat: rare insights broaden our understanding of endothermic physiology

“…However, it is possible that an increasing T a could have made active arousal easier by reducing the T b -T a differential, especially during the earlier phase of rewarming. We think it highly unlikely the animal was exposed to direct solar radiation, because bush rats normally use underground burrows or ground nests under dense grass trees (Collins 1973 ; Frazer and Petit 2007 ). Basking in the sun should also have led to faster rewarming rates than those recorded.…”

Odorants differentiate Australian Rattus with increased complexity in sympatry

“…Where they are sympatric, they co-occur at mid-elevations, with only R. fuscipes at the highest and only R. leucopus at the lowest elevations (Table S1, Rowe et al, 2020). These latitudinal and elevation differences are expected to underlie significant physiological differences between the species (Collins, 1973) that may affect their biochemical composition. In addition, ecological differences between species, including diet (Havlíček et al, 2019) and microbiotic community (Archie & Theis, 2011;Davis et al, 2013), can change species' biochemical composition.…”

How do measurement duration and timing interact to influence estimation of basal physiological variables of a nocturnal rodent?

“…We can assess here the potential impact of short measurement duration on measurement of BMR for the bush rat. Collins (1973) measured a minimal CO 2 of 1.00 ± 0.061 ml CO 2 g -1 h -1 for bush rats also from the Albany region. This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002).…”

“…This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002). Collins' (1973) experimental protocol measured MR between 1100 h and h, a maximal measurement duration of h, commencing close to the species' circadian minima.…”

Survivable hypothermia or torpor in a wild-living rat: rare insights broaden our understanding of endothermic physiology

“…However, it is possible that an increasing T a could have made active arousal easier by reducing the T b -T a differential, especially during the earlier phase of rewarming. We think it highly unlikely the animal was exposed to direct solar radiation, because bush rats normally use underground burrows or ground nests under dense grass trees (Collins 1973 ; Frazer and Petit 2007 ). Basking in the sun should also have led to faster rewarming rates than those recorded.…”

Odorants differentiate Australian Rattus with increased complexity in sympatry

“…Where they are sympatric, they co-occur at mid-elevations, with only R. fuscipes at the highest and only R. leucopus at the lowest elevations (Table S1, Rowe et al, 2020). These latitudinal and elevation differences are expected to underlie significant physiological differences between the species (Collins, 1973) that may affect their biochemical composition. In addition, ecological differences between species, including diet (Havlíček et al, 2019) and microbiotic community (Archie & Theis, 2011;Davis et al, 2013), can change species' biochemical composition.…”

How do measurement duration and timing interact to influence estimation of basal physiological variables of a nocturnal rodent?

“…We can assess here the potential impact of short measurement duration on measurement of BMR for the bush rat. Collins (1973) measured a minimal CO 2 of 1.00 ± 0.061 ml CO 2 g -1 h -1 for bush rats also from the Albany region. This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002).…”

“…This value was 116% of our minimal value of 0.863 ± 0.029 ml CO 2 g -1 h -1 and was significantly higher (one sample T-test; t = 4.72, P = 0.002). Collins' (1973) experimental protocol measured MR between 1100 h and h, a maximal measurement duration of h, commencing close to the species' circadian minima.…”

Survivable hypothermia or torpor in a wild-living rat: rare insights broaden our understanding of endothermic physiology

“…However, it is possible that an increasing T a could have made active arousal easier by reducing the T b -T a differential, especially during the earlier phase of rewarming. We think it highly unlikely the animal was exposed to direct solar radiation, because bush rats normally use underground burrows or ground nests under dense grass trees (Collins 1973 ; Frazer and Petit 2007 ). Basking in the sun should also have led to faster rewarming rates than those recorded.…”

Odorants differentiate Australian Rattus with increased complexity in sympatry

“…Where they are sympatric, they co-occur at mid-elevations, with only R. fuscipes at the highest and only R. leucopus at the lowest elevations (Table S1, Rowe et al, 2020). These latitudinal and elevation differences are expected to underlie significant physiological differences between the species (Collins, 1973) that may affect their biochemical composition. In addition, ecological differences between species, including diet (Havlíček et al, 2019) and microbiotic community (Archie & Theis, 2011;Davis et al, 2013), can change species' biochemical composition.…”