Energy allocation by yellow-bellied marmots [Affectation de l'énergie par les marmottes à ventre jaune].

Résumé

Energy intake, daily energy expenditure (DEE), and energy availbale for production were determined for yellow-bellied marmots (Marmota flaviventris) at three study sites in the Elk Mountains of southwestern Colorado. Energy intake, estimated from tritiated-water turnover rates and the water and energy contents of food plants, ranged from 3,283 Kjd-1 for two lactatin females in July to 666 Kj d-1 for a yearling female in September. Maintenance, activity, and thermoregulatory components of DDE were estimated from time-budget data, estimated or measured activity costs, and beat-transfer theory. Not including energy allocated to productionn, DDE ranged from 1,017 kj d-1 for a lactating female in July to 539 Kj d-1 for a female yearling in June. Time spent in the burrow accounted for 41%-60% of DDE, foraging, for 11%-51%, s!itting on rocks by the burrow, for 1%-28%, and thermoregualting, for 1%-6%. Assimilated energy exceeded DDE for all but one animal studied, mass gains calculated assuming that assimlilated energy in excess of DEE was available for production closely matched average measured mass gains of field animals.