- Department of Ecology, Physiology and Ethology - CNRS and Strasbourg University - France 2 Department of Ecology and Biodiversity Management - CNRS and MNHN Brunoy - France
Background Global Changes
Environment with low food availability
loss
MASS
gain
Food deprivation
Limits?
Energie Ingested ingérée Energy
∆ Body Reserves Physiological Mechanisms of Energy Savings
Survival Reproduction
Fitness
Energy Expenditure
Madagascar: - Critical hotspot for biodiversity conservation - High endemism level - Highly contrasted climate
Background
Seasonal variability in trophic resources
Cold and dry season
80
Heterothermy Seasonal fattening
Minimal T °C
120
100
Microcebus murinus
35
140
30
120
25 20
60 15 40
10
% of variations
Rainfall (mmH2O) Resources
The Grey mouse lemur
Torpor
100
Resting metabolism
80 60
No Torpor
Body mass Sexual rest
Season of reproduction
Dry season
20
A S
O N D
J
F
M A M J
J
A S
Ecological constraints
Seasonal variations of several biological parameters in percentage of the annual average
Adaptive mechanisms of energy and water economy Perret 1998; Perret and Aujard 1999; Schmid 2000
Background
Global Climate Changes El Niño phenomenon Rainfall (mmH2O) Resources
Minimal T °C 35
120
100
Cold and dry season
80
30 25 20
60 15 40
10
Unpredictable events
?
20
A S
O N D
J
F
M A M J
J
A S
Reproductive season Fattening processes
Physiological plasticity
Question
In M. murinus facing a chronic food shortage: - Nature and limits of physiological plasticity? - Impacts of adaptive mechanisms on organism?
Experimental protocol - part 1
Male Mouse lemurs
Short-days SD Winter-like
Summer-like
10-day control period Stable energy balance Before
Long-days LD
40 and 80% 35-day food restriction Continuous telemetry recording
Changes in
After
• Body mass • Total energy expenditure and body composition (doubly-labeled water)
• Resting metabolic rate (respirometry) • Body temperature and torpor pattern (telemetry)
