Daily energy expenditure of the grey mouse lemur (Microcebus murinus): a small primate that uses torpor

J Schmid, J R Speakman

Research output: Contribution to journalArticle

79 Citations (Scopus)

Abstract

We aimed to investigate the pattern of utilisation of torpor and its impact on energy budgets in free-living grey mouse femurs (Microcebus murinus), a small nocturnal primate endemic to Madagascar. We measured daily energy expenditure (DEE) and water turnover using doubly labelled water, and we used temperature-sensitive radio collars to measure skin temperature (T-sk) and home range. Our results showed that male and female mouse lemurs in the wild enter torpor spontaneously over a wide range of ambient temperatures (T-a) during the dry season, but not during the rainy season. Mouse lemurs remained torpid between 1.7-8.9 h with a daily mean of 3.4 h. and their T-sk s fell to a minimum of 18.8 degreesC. Mean home ranges of mouse lemurs which remained normothermic were similar in the rainy and dry season. During the dry season? the mean home range of mouse lemurs showing daily torpor was significantly smaller than that of animals remaining normothermic. The DEE of M. murinus remaining normothermic in the rainy season (122 +/- 65.4 kJ day(-1)) was about the same of that of normothermic mouse lemurs in the dry season (115.5 +/- 27.3 kJ day(-1)). During the dry season, the mean DEE of M. murinus that utilised daily torpor was 103.4 +/- 32.7 kJ day(-1) which is not significantly different from the mean DEE of animals remaining normothermic. We found that the DEE of mouse lemurs using daily torpor was significantly correlated with the mean temperature difference between T-sk and T-a (r(2) = 0.37) and with torpor bout length (r(2) = 0.46), while none of these factors explained significant amounts of variation in the DEE of the mouse lemurs remaining normothermic. The mean water flux rate of mouse lemurs using daily torpor (13.0 +/- 4.1 ml day(-1)) was significantly lower than that of mouse lemurs remaining normothermic (19.4 +/- 3.8 ml day(-1)), suggesting the lemurs conserve water by entering torpor. Thus, this first study on the energy budget of free-ranging M. murinus demonstrates that torpor may not only reflect its impact on the daily energy demands, but involve wider adaptive implications such as water requirements.

Original languageEnglish
Pages (from-to)633-641
Number of pages9
JournalJournal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Volume170
Publication statusPublished - 2000

Keywords

  • daily energy expenditure
  • doubly labelled water
  • grey mouse lemur
  • Microcebus murinus
  • torpor
  • EVAPORATIVE WATER-LOSS
  • BASAL METABOLIC-RATE
  • MAMMALS
  • PATTERNS
  • BIRDS
  • TEMPERATURE
  • MADAGASCAR
  • SEX
  • THERMOREGULATION
  • HIBERNATION

Cite this

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title = "Daily energy expenditure of the grey mouse lemur (Microcebus murinus): a small primate that uses torpor",
abstract = "We aimed to investigate the pattern of utilisation of torpor and its impact on energy budgets in free-living grey mouse femurs (Microcebus murinus), a small nocturnal primate endemic to Madagascar. We measured daily energy expenditure (DEE) and water turnover using doubly labelled water, and we used temperature-sensitive radio collars to measure skin temperature (T-sk) and home range. Our results showed that male and female mouse lemurs in the wild enter torpor spontaneously over a wide range of ambient temperatures (T-a) during the dry season, but not during the rainy season. Mouse lemurs remained torpid between 1.7-8.9 h with a daily mean of 3.4 h. and their T-sk s fell to a minimum of 18.8 degreesC. Mean home ranges of mouse lemurs which remained normothermic were similar in the rainy and dry season. During the dry season? the mean home range of mouse lemurs showing daily torpor was significantly smaller than that of animals remaining normothermic. The DEE of M. murinus remaining normothermic in the rainy season (122 +/- 65.4 kJ day(-1)) was about the same of that of normothermic mouse lemurs in the dry season (115.5 +/- 27.3 kJ day(-1)). During the dry season, the mean DEE of M. murinus that utilised daily torpor was 103.4 +/- 32.7 kJ day(-1) which is not significantly different from the mean DEE of animals remaining normothermic. We found that the DEE of mouse lemurs using daily torpor was significantly correlated with the mean temperature difference between T-sk and T-a (r(2) = 0.37) and with torpor bout length (r(2) = 0.46), while none of these factors explained significant amounts of variation in the DEE of the mouse lemurs remaining normothermic. The mean water flux rate of mouse lemurs using daily torpor (13.0 +/- 4.1 ml day(-1)) was significantly lower than that of mouse lemurs remaining normothermic (19.4 +/- 3.8 ml day(-1)), suggesting the lemurs conserve water by entering torpor. Thus, this first study on the energy budget of free-ranging M. murinus demonstrates that torpor may not only reflect its impact on the daily energy demands, but involve wider adaptive implications such as water requirements.",
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TY - JOUR

T1 - Daily energy expenditure of the grey mouse lemur (Microcebus murinus): a small primate that uses torpor

AU - Schmid, J

AU - Speakman, J R

PY - 2000

Y1 - 2000

N2 - We aimed to investigate the pattern of utilisation of torpor and its impact on energy budgets in free-living grey mouse femurs (Microcebus murinus), a small nocturnal primate endemic to Madagascar. We measured daily energy expenditure (DEE) and water turnover using doubly labelled water, and we used temperature-sensitive radio collars to measure skin temperature (T-sk) and home range. Our results showed that male and female mouse lemurs in the wild enter torpor spontaneously over a wide range of ambient temperatures (T-a) during the dry season, but not during the rainy season. Mouse lemurs remained torpid between 1.7-8.9 h with a daily mean of 3.4 h. and their T-sk s fell to a minimum of 18.8 degreesC. Mean home ranges of mouse lemurs which remained normothermic were similar in the rainy and dry season. During the dry season? the mean home range of mouse lemurs showing daily torpor was significantly smaller than that of animals remaining normothermic. The DEE of M. murinus remaining normothermic in the rainy season (122 +/- 65.4 kJ day(-1)) was about the same of that of normothermic mouse lemurs in the dry season (115.5 +/- 27.3 kJ day(-1)). During the dry season, the mean DEE of M. murinus that utilised daily torpor was 103.4 +/- 32.7 kJ day(-1) which is not significantly different from the mean DEE of animals remaining normothermic. We found that the DEE of mouse lemurs using daily torpor was significantly correlated with the mean temperature difference between T-sk and T-a (r(2) = 0.37) and with torpor bout length (r(2) = 0.46), while none of these factors explained significant amounts of variation in the DEE of the mouse lemurs remaining normothermic. The mean water flux rate of mouse lemurs using daily torpor (13.0 +/- 4.1 ml day(-1)) was significantly lower than that of mouse lemurs remaining normothermic (19.4 +/- 3.8 ml day(-1)), suggesting the lemurs conserve water by entering torpor. Thus, this first study on the energy budget of free-ranging M. murinus demonstrates that torpor may not only reflect its impact on the daily energy demands, but involve wider adaptive implications such as water requirements.

AB - We aimed to investigate the pattern of utilisation of torpor and its impact on energy budgets in free-living grey mouse femurs (Microcebus murinus), a small nocturnal primate endemic to Madagascar. We measured daily energy expenditure (DEE) and water turnover using doubly labelled water, and we used temperature-sensitive radio collars to measure skin temperature (T-sk) and home range. Our results showed that male and female mouse lemurs in the wild enter torpor spontaneously over a wide range of ambient temperatures (T-a) during the dry season, but not during the rainy season. Mouse lemurs remained torpid between 1.7-8.9 h with a daily mean of 3.4 h. and their T-sk s fell to a minimum of 18.8 degreesC. Mean home ranges of mouse lemurs which remained normothermic were similar in the rainy and dry season. During the dry season? the mean home range of mouse lemurs showing daily torpor was significantly smaller than that of animals remaining normothermic. The DEE of M. murinus remaining normothermic in the rainy season (122 +/- 65.4 kJ day(-1)) was about the same of that of normothermic mouse lemurs in the dry season (115.5 +/- 27.3 kJ day(-1)). During the dry season, the mean DEE of M. murinus that utilised daily torpor was 103.4 +/- 32.7 kJ day(-1) which is not significantly different from the mean DEE of animals remaining normothermic. We found that the DEE of mouse lemurs using daily torpor was significantly correlated with the mean temperature difference between T-sk and T-a (r(2) = 0.37) and with torpor bout length (r(2) = 0.46), while none of these factors explained significant amounts of variation in the DEE of the mouse lemurs remaining normothermic. The mean water flux rate of mouse lemurs using daily torpor (13.0 +/- 4.1 ml day(-1)) was significantly lower than that of mouse lemurs remaining normothermic (19.4 +/- 3.8 ml day(-1)), suggesting the lemurs conserve water by entering torpor. Thus, this first study on the energy budget of free-ranging M. murinus demonstrates that torpor may not only reflect its impact on the daily energy demands, but involve wider adaptive implications such as water requirements.

KW - daily energy expenditure

KW - doubly labelled water

KW - grey mouse lemur

KW - Microcebus murinus

KW - torpor

KW - EVAPORATIVE WATER-LOSS

KW - BASAL METABOLIC-RATE

KW - MAMMALS

KW - PATTERNS

KW - BIRDS

KW - TEMPERATURE

KW - MADAGASCAR

KW - SEX

KW - THERMOREGULATION

KW - HIBERNATION

M3 - Article

VL - 170

SP - 633

EP - 641

JO - Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology

JF - Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology

SN - 0174-1578

ER -