Daily Torpor In A Pregnant Common Blossom-Bat (Syconycteris Australis: Megachiroptera)

Geiser, Fritz; Körtner, Gerhard; Law, BS

doi:10.1071/am01053

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…The decrease in metabolic rate of pregnant females during the resting phase may enable them to spend more time in other activities such as foraging (Korine et al 1994), or potentially to allocate more energy to fat storage or milk production. It was also reported that female common blossom-bats, Syconycteris australis (small Megachiropteran bats), use daily torpor during pregnancy (Geiser et al 2001). However Voigt (2003) did not find any evidence that captive female glossophagine bats use torpor or hypothermia during pregnancy or lactation.…”

Section: Gestationmentioning

confidence: 96%

Reproductive Energetics of Captive and Free-Ranging Egyptian Fruit Bats (Rousettus Aegyptiacus)

Korine

Speakman

Arad

2004

Ecology

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This study explored how a flying frugivorous mammal, the Egyptian fruit bat (Rousettus aegyptiacus), meets the increased energy requirements of reproduction. This bat feeds on low‐protein fruit, and females have bimodal polyestrous cycles that are relatively long for a small mammal. We measured the energy and water balance of captive nonreproductive, pregnant, and lactating females, and of free‐ranging lactating females. Our results indicate that females use more than one strategy to cope with the high energy demands of reproduction. These strategies may change according to the availability of food and reproductive status. The primary strategy near the end of pregnancy and at peak lactation was increased food consumption. In the laboratory, mean metabolizable energy intake (MEI) of pregnant and lactating females (271 and 360 kJ/d, respectively) increased by 35% and 80%, respectively, compared to that of nonreproductive females (200 kJ/d). At peak lactation, energy intake measured by doubly labeled water averaged 350 kJ/d. During late pregnancy, water turnover rate (WTO) increased by 15–23% compared to that of nonreproductive females. In the field, WTO at peak lactation was 44% higher than in captive lactating females, and milk production was estimated to be 22 mL/d. Absolute resting metabolic rate (RMR) in late pregnancy was significantly lower than the RMR of nonreproductive females, suggesting that a metabolic depression was used as a compensatory mechanism. Fat deposition was evident during the second pregnancy, when food availability was high, presumably in preparation for a second lactation period. Fetal tissue represented ∼1.3% of the total energy assimilated during pregnancy, and the gross efficiency of lactation averaged 24%. Both values are lower than the values reported for other eutherian mammals, but similar to estimates for other bat species, and probably reflect the high energy costs associated with flight. A long lactation period may be constrained by flight and the low‐protein diet of fruits. We conclude that the energy costs of Egyptian fruit bats during reproduction are distributed over a relatively long time, similar to those observed in large mammals.

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Section: Gestationmentioning

confidence: 96%

Reproductive Energetics of Captive and Free-Ranging Egyptian Fruit Bats (Rousettus Aegyptiacus)

Korine

Speakman

Arad

2004

Ecology

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“…In some species, physiological constraints appear to prevent bats from expressing extensive torpor during the reproductive period. For example, in S. australis measured in the laboratory, depth of torpor in pregnant females was similar to that of non‐reproductive females in the same study, but the duration of torpor was shorter in the former (Geiser, Körtner & Law, ), suggesting that there was a physiological change. On the contrary, other bat species appear to use roost selection to promote or avoid torpor use during reproductive periods rather than or in addition to physiological differences.…”

Section: Torpor In Relation To the Natural History Of Batsmentioning

confidence: 99%

The importance of temporal heterothermy in bats

2014

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Animals must balance their energy budgets even when confronted with periodic food shortages and/or adverse environmental conditions. Especially, small endothermic animals require large amounts of energy to maintain high and stable body temperatures (Tb) via endogenous heat production. To deal with energetic challenges, many small endotherms are heterothermic, abandon regulation of high Tb and enter a state of torpor resulting in large energy savings. Torpor is used by many bat species because they are small, have high rates of heat loss and rely on fluctuating food resources (e.g. insects, fruit, nectar). Many bats use torpor all year, but the expression of temporal heterothermy can be strongly seasonal especially for temperate and subtropical species, which may hibernate for long periods. Recent advances in our understanding of torpor expression in bats have been made using temperature telemetry for remote data collection of Tb in free-ranging wild individuals from all climate zones. This new knowledge on free-ranging bats has revealed the importance of torpor expression not only for energy conservation but also for other benefits, such as reduction of extrinsic mortality (e.g. predation). On the contrary, dense clustering during hibernation, important for minimizing energy and water loss, may also expose bats to infectious disease. An emerging, cold-tolerant fungal pathogen of bats causes a new disease called white-nose syndrome (WNS), which is devastating populations of multiple species in eastern North America. Given the importance of temporal heterothermy to their biology, and links between torpor expression and mortality from WNS, it is becoming increasingly important to understand the ecology and physiology of torpor in this largely understudied and cryptic mammalian group. Here, we review past and current literature to summarize the importance and evolution of heterothermy in bats.

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“…There is growing evidence that torpor is a plesiomorphic trait widespread in basal lineages (Geiser 2008), especially among species with smaller body sizes. Laboratory studies have established that several small (16-18 g) pteropodids express daily torpor with T b falling as low as 17.2 °C, especially when food is restricted (Bartels et al 1998;Geiser et al 2001;McNab and Bonnacorso 2001; reviewed by Stawski et al 2014). In contrast, most medium sized tropical and semi-tropical pteropodids (50-200 g) appear not to use torpor (Bartholomew et al 1970;McNab and Bonnacorso 2001;Riek et al 2010;Downs et al 2012;but see McNab 1989), suggesting that the energetic demands of medium-sized bats in the tropics may not be stringent enough to warrant the use of torpor.…”

mentioning

confidence: 99%

Thermoregulation by captive and free-ranging Egyptian rousette bats (Rousettus aegyptiacus) in South Africa

Barclay

Jacobs

Harding

et al. 2017

Journal of Mammalogy

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Daily Torpor In A Pregnant Common Blossom-Bat (Syconycteris Australis: Megachiroptera)

Cited by 7 publications

References 12 publications

Reproductive Energetics of Captive and Free-Ranging Egyptian Fruit Bats (Rousettus Aegyptiacus)

Reproductive Energetics of Captive and Free-Ranging Egyptian Fruit Bats (Rousettus Aegyptiacus)

The importance of temporal heterothermy in bats

Thermoregulation by captive and free-ranging Egyptian rousette bats (Rousettus aegyptiacus) in South Africa

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