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VIII

CHAPITRE I-----------------------------------------------------------23

La flexibilite intra-saisonntere de la performance mćtabolique revćle un decouplage entre le metabolisme basal et la capacite thermogćnique chez les

oi$eaux    23

1.1    Rćsumć.....................................................................................................................26

1.2    Abstract....................................................................................................................27

1.3    Introduction..............................................................................................................28

1.4    Materiał and methods................................................................................................31

1.4.1    Capture and handling.......................................................................................31

1.4.2    Respirometry...................................................................................................32

1.4.3    Sexing individuals............................................................................................33

1.4.4    Statistical analysis............................................................................................33

1.5    Results......................................................................................................................34

1.5.1    Temperaturę....................................................................................................34

1.5.2    Inter-seasonal variation in body mass and metabolic performance.......................35

1.5.3    Intra-seasonal variation of body mass and metabolic performance.......................38

1.5.4    Relationship between BMR and Msum.............................................................41

1.6    Discussion................................................................................................................41

1.6.1    Inter-seasonal variation in metabolic performance..............................................41

1.6.2    Intra-seasonal variation in metabolic performance and the uncoupling of BMR and

Msum..............................................................................................................42

1.6.3    Intra-individual variation in winter metabolic performance.................................45

1.6.4    Is metabolic expansibility a meaningful variable?..............................................46

CHAPITRE II----------------------------------------------------------47

Normes de rćaction en conditions naturelles : comment les petits endothermes ajustent-ils leur performance mćtabolique aux variations mćtćorologiques ?    47

2.1    Rćsumć.....................................................................................................................50

2.2    Abstract....................................................................................................................51

2.3    Introduction..............................................................................................................52

2.4    Materials and methods..............................................................................................55