The potential function of individual signal frequency for masking avoidance in the greater bulldog bat Noctilio leporinus
Feit, BenjaminÜbernickel, KirstinTschapka, MarcoK.V. Kalko, Elisabeth
Bats using echolocation for orientation in space and for foraging rely on the information provided by the echoes of their emitted signals. In the presence of conspecifics, signals of individuals may overlap in time and frequency and may impede the bats ability to process their own echo information. Adjustment of echolocation signal parameters as a mechanism to minimize the effects of signal overlap has been proposed for bats. We conducted a field study in Panama, confronting free-flying Greater bulldog bats Noctilio leporinus (Noctilionidae) with playbacks of conspecific search signals that matched the constant-frequency (QCF) signal component of the bats expected echo. Additionally, we recorded echolocation signals of bats flying in pairs to compare the results of our playback experiments with bats encountering conspecifics under natural conditions. Noctilio leporinus did not shift the frequency of its QCF components, neither when confronted with our playbacks nor in the presence of conspecifics. We discuss modifications of signal parameters and foraging behavior as strategies to avoid masking situations in N. leporinus.(AU)