Squeezing through the energetic bottleneck
STRI/DICYT The tiny transmitters Dina Dechmann places on bats cannot surpass five percent of their body mass. Unfortunately for Teague O'Mara, a Marie Curie Fellow based at the Max Plank Institute for Ornithology, STRI and the University of Konstanz no such restrictions exist for bat-tracking biologists. His gear includes a large, hand-held antenna, bulky headphones, a radio receiver hanging around his neck since his hands are full, and a sound recorder—all connected by a couple meters of cable. A GPS receiver, headlamp, compass and water complete the kit.
Add a proton pack and O'Mara would look ready to spend the night ghostbusting in a Panamanian forest. Dechmann and O'Mara are actually on the trail of something that, until recently, was equally elusive: they use heart rate information sent by the transmitter to calculate second-by-second activity and energy expenditure of the diminutive Peter's Tent-Making Bat.
Sharing information is central to Uroderma bilobatum's survival. It depends almost entirely upon the sugary juice of figs, and fig trees, that, though abundant in Central Panama's forests, don't fruit on a particular schedule. Dechmann and O'Mara's work shows the bats likely exhaust their energy stores in less than two days. "They are living on the energetic edge of life," said O'Mara.
"This is the first time we've been able to follow such a small bat in the wild, just because before, the technology wasn't available," said Dechmann, now a research associate at STRI based at the Max Planck Institute for Ornithology. Dechmann has studied evolution of social behavior since 2000 as a visiting researcher in Panama. Her primary focus is on how bats exchange information about food sources.