Frequency shifting reduces but does not eliminate acoustic interference between echolocating bats: A theoretical...

Area of Science:

• Bioacoustics
• Animal Communication
• Echolocation

Background:

• Bats use echolocation for navigation and foraging.
• Acoustic interference from other bats can disrupt echolocation.
• Jamming avoidance responses (JARs), like frequency shifts, are hypothesized to mitigate interference.

Purpose of the Study:

• To theoretically evaluate the efficacy of frequency shifting in bats' jamming avoidance responses.
• To analyze the impact of acoustic interference from conspecifics and congeneric heterospecifics on target acquisition.
• To compare the jamming avoidance strategies of Myotis californicus and Myotis yumanensis.

Main Methods:

• Utilized the wideband ambiguity function to model acoustic interference.
• Simulated unilateral and bilateral frequency shifts in echolocation calls.
• Assessed the effect of these shifts on target acquisition ability in simulated bat interactions.

Main Results:

• In conspecific interactions, Myotis yumanensis demonstrated more complete recovery of target acquisition with smaller frequency shifts than Myotis californicus.
• Optimal strategy for reducing heterospecific interference involved Myotis californicus downshifting its call and Myotis yumanensis upshifting.
• These shifts exaggerate existing frequency differences between the two species, potentially facilitating niche partitioning.

Conclusions:

• Frequency shifting can theoretically improve target acquisition under acoustic interference for both species.
• Species-specific optimal strategies exist for both conspecific and heterospecific interference.
• Further empirical research is needed to confirm active frequency shifting and its role in niche partitioning.