Revista Chilena de Historia Natural 78 (2): 207-214, 2005
RESEARCH ARTICLE
Intraspecific differences in metabolic rate of Chroeomys olivaceus (Rodentia:
Muridae): the effect of thermal acclimation in arid and mesic habitats
Studies of metabolic capacities in rodents have been largely studied at an inter-specific
levels, but physiological capacities of populations belonging to the same species have received lesser attention. Here we studied the
maximum and basal metabolic rates of two populations of the rodent Chroeomys olivaceus dwelling in habitats with
contrasting temperature and rainfall regimes, and to test if differences in metabolic capacities are due to local adaptation or
acclimatization effect. After four weeks of acclimation to 25 and 10 ºC, the BMR and MMR were determined in individuals from the
northern population of Caleta Loa, and the southern population of La Picada. Individuals from ‘La Picada’ population were heavier than
those from Caleta Loa. MMR and BMR exhibited higher values in cold acclimated animals compared with warm-acclimated animals.
Besides, BMR, but not MMR, was lower in Caleta Loa individuals, in spite of the acclimation treatment. Hence, the differences in the
metabolic capacities and the response to acclimation of C. olivaceus populations appear to be an evolutionary response to
the environmental cues.
Key words:
basal metabolic
rate, Chroeomys olivaceus, maximum metabolic rate, population, phenotypic
plasticity
