Flexible use of visual and acoustic cues during roost finding in Spix’s disc-winged bat Thyroptera tricolor

The ability of an animal to detect environmental cues is crucial for its survival and fitness. In bats, sound certainly plays a significant role in the search for food, spatial navigation, and social communication. Yet, the efficiency of a bat’s echolocation could be limited by atmospheric attenuation and background clutter. In this context, sound can be complemented by other sensory modalities, like smell or vision. Spix’s disc-winged bat (Thyroptera tricolor) uses acoustic cues from other group members to locate the roost (tubular unfurled leaves of plants in the order Zingiberales). Our research focused on how individuals find a roost that has not been yet occupied, considering the urge to find a suitable leaf approximately every day, during nighttime or in daylight. We observed the process of roost finding in T. tricolor in a flight cage, manipulating the audio/visual sensory input available for each trial. A broadband noise was broadcast in order to mask echolocation, while experim..., We captured individuals of Thyroptera tricolor in a secondary forest in southwestern Costa Rica. We conducted experiments in a flight cage (2.5 x 3.5 x 5.5 m) containing a roosting resource available for the bat (a furled leaf of Heliconia sp. or Calathea luthea). In daylight experiments, the flight cage was made of saran shade cloth while in night experiments it was made of a double-walled cloth to reduce the amount of light. Two Ultrasonic Omnidirectional Dynamic Speakers were positioned on both sides of the leaf, at 1 m distance. We tested the time needed to enter the roost under different treatments, that we named after the sensory cue available for the bats: \"Vision\" (a playback broadcasted a broadband noise masking the frequencies of Thyroptera's echolocation, with daylight), \"Sound and Vision\" (no playbacks, with daylight), \"Lessen input\" (broadband noise, during nighttime), \"Sound\" (no playbacks, during nighttime). \"Noise Control\" was an additional treatment in which we broadcas..., Microsoft Excel or Libre Office Calc; Google Chrome or any other browser