Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany; Smithsonian Tropical Research Institute, Panama City, Panama; Zukunftskolleg, University of Konstanz, Konstanz, Germany
Martin Wikelski
Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany
Christian C Voigt
Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
Andries Ter Maat
Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Starnberg, Germany
Henry S Pollock
Program in Ecology, Evolution and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, United States
Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany; Smithsonian Tropical Research Institute, Panama City, Panama
Active flight requires the ability to efficiently fuel bursts of costly locomotion while maximizing energy conservation during non-flying times. We took a multi-faceted approach to estimate how fruit-eating bats (Uroderma bilobatum) manage a high-energy lifestyle fueled primarily by fig juice. Miniaturized heart rate telemetry shows that they use a novel, cyclic, bradycardic state that reduces daily energetic expenditure by 10% and counteracts heart rates as high as 900 bpm during flight. Uroderma bilobatum support flight with some of the fastest metabolic incorporation rates and dynamic circulating cortisol in vertebrates. These bats will exchange fat reserves within 24 hr, meaning that they must survive on the food of the day and are at daily risk of starvation. Energetic flexibly in U. bilobatum highlights the fundamental role of ecological pressures on integrative energetic networks and the still poorly understood energetic strategies of animals in the tropics.
