ISSN:
1432-136X
Schlagwort(e):
Key words Body temperature
;
Metabolic rate
;
Torpor
;
Pygmy mouse lemur, Microcebus myoxinus
;
Environmental conditions
;
Madagascar
;
AbbreviationsANOVA analysis of variance
;
AMR metabolic rate during active arousal
;
MR metabolic rate
;
RMR resting metabolic rate
;
SD standard deviation
;
Ta ambient temperature
;
Tb body temperature
;
TMR torpid metabolic rate
;
VO2 rate of oxygen consumption
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Medizin
Notizen:
Abstract Thermoregulation, energetics and patterns of torpor in the pygmy mouse lemur, Microcebus myoxinus, were investigated under natural conditions of photoperiod and temperature in the Kirindy/CFPF Forest in western Madagascar. M. myoxinus entered torpor spontaneously during the cool dry season. Torpor only occurred on a daily basis and torpor bout duration was on average 9.6 h, and ranged from 4.6 h to 19.2 h. Metabolic rates during torpor were reduced to about 86% of the normothermic value. Minimum body temperature during daily torpor was 6.8 °C at an ambient temperature of 6.3 °C. Entry into torpor occurred randomly between 2000 and 0620 hours, whereas arousals from torpor were clustered around 1300 hours within a narrow time window of less than 4 h. Arousal from torpor was a two-step process with a first passive climb of body temperature to a mean of 27 °C, carried by the daily increase of ambient temperature when oxygen consumption remained more or less constant, followed by a second active increase of oxygen consumption to further raise the body temperature to normothermic values. In conclusion, daily body temperature rhythms in M. myoxinus further reduce the energetic costs of daily torpor seen in other species: they extend to unusually low body temperatures and consequently low metabolic rates in torpor, and they employ passive warming to reduce the energetic costs of arousal. Thus, these energy-conserving adaptations may represent an important energetic aid to the pygmy mouse lemur and help to promote their individual fitness.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s003600050008
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