Meeting Abstract
The balance between energy intake, distribution and expenditure drives many aspects of animal ecology and evolution. However, the relationship between the energetic cost of life and how it is maintained within an ecological context is not well understood for most animals. We take a multi-pronged approach including instantaneous energetic expenditure (heart rate), metabolic incorporation rates (carbon dioxide isotopes of breath), and energy mobilization (cortisol) to investigate how tent-making bats (Uroderma bilobatum) maintain a high-energy lifestyle fueled primarily by fig juice. Uroderma undergo cyclical depressions in heart rate at rest to less than 200 beats per minute (bpm) that counters heart rates of over 900 bpm during flight. They use some of the fastest metabolic incorporation rates measured in vertebrates to support this explosive metabolic shift between rest and flight and elevate circulating cortisol values to 10-15 times basal values when stressed, which indicates rapid mobilization of glucose reserves as bats transition from rest to active states. These data suggest that Uroderma suppress energetic expenditure at multiple physiological levels when at rest, but rapidly mobilize resources to fuel activity and their specialization on a widely distributed, but temporally unpredictable fruit resource.
