Auditory-feedback control of temporal call patterns in echolocating horseshoe bats

Area of Science:

• Bioacoustics
• Neuroethology
• Animal Communication

Background:

• Horseshoe bats adjust vocalization duration and repetition rate during flight based on auditory feedback.
• Echolocation behavior in bats involves both graded adjustments and abrupt transitions in temporal calling patterns as they approach targets.

Purpose of the Study:

• To investigate the roles of echo frequency and delay in controlling vocalization duration and interpulse interval (IPI) in horseshoe bats.
• To differentiate the neural mechanisms underlying graded and transitional changes in bat echolocation calls.

Main Methods:

• Bats were exposed to artificial echoes with manipulated frequencies and delays.
• Constant-frequency (CF) and frequency-modulated (FM) stimuli were used to mimic specific echo components.
• Changes in bat call duration and IPI were measured in response to acoustic stimuli.

Main Results:

• Echoes with frequencies above the emitted call induced a switch from single calls to doublets.
• Increasing echo delay progressively increased IPI but did not alter call duration.
• CF stimuli triggered doublet calls, while FM sweep timing strongly affected IPI, indicating separate processing pathways.

Conclusions:

• Echo frequency and delay differentially control temporal aspects of horseshoe bat echolocation.
• Distinct neural feedback pathways, likely involving separate processing of CF and FM components, regulate bat vocalization patterns.
• This study elucidates the complex auditory-motor control of echolocation in bats.