Modeling perspectives on echolocation strategies inspired by bats flying in groups

Abstract

Bats navigating with echolocation - which is a type of active sensing achieved by interpreting echoes resulting from self-generated ultrasonic pulses - exhibit unique behaviors during group flight. While bats may benefit from eavesdropping on their peers׳ echolocation, they also potentially suffer from confusion between their own and peers׳ pulses, caused by an effect called frequency jamming. This hardship of group flight is supported by experimental observations of bats simplifying their sound-scape by shifting their pulse frequencies or suppressing echolocation altogether. Here, we investigate eavesdropping and varying pulse emission rate from a modeling perspective to understand these behaviors׳ potential benefits and detriments. We define an agent-based model of echolocating bats avoiding collisions in a three-dimensional tunnel. Through simulation, we show that bats with reasonably accurate eavesdropping can reduce collisions compared to those neglecting information from peers. In large populations, bats minimize frequency jamming by decreasing pulse emission rate, while collision risk increases; conversely, increasing pulse emission rate minimizes collisions by allowing more sensing information generated per bat. These strategies offer benefits for both biological and engineered systems, since frequency jamming is a concern in systems using active sensing.

Extracting Interactions between Flying Bat Pairs Using Model-Free Methods

“…Nevertheless, this work only begins to open a wide field of research questions that can be asked about such systems and methods that can be used to answer them. The model-free methods used to capture directed coupling between individuals can further be tested using self-propelled particle models [ 40 ], where the coupling direction can be set a priori. The trajectories generated with this modeling approach can be used as a test bed for verifying the ability of these methods to correctly identify the directed coupling.…”

Suppression of emission rates improves sonar performance by flying bats

“…This distinction could be accounted for by the different test conditions and experimental design, or may be further evidence of species-specific differences in how bats respond to acoustic interference. There is evidence that some bats may cease calling and eavesdrop to exploit signals of their conspecifics 20 24 . We did not test for eavesdropping explicitly; we flew pairs of bats towards each other, in converging flight, which is an orientation that Chiu et al .…”

“…An alternative to modulating pulse acoustics is modulating the timing of their call emissions to minimize temporal overlap with another bat’s echolocation pulses 23 24 . Temporal strategies have been described in other animal communication systems where animals compete to transmit signals, including insects, fish, frogs, birds and mammals 25 26 27 28 29 30 31 32 33 34 , several of which offer clues to how bats might coordinate their pulses in time.…”

Bats dynamically change echolocation parameters in response to acoustic playback

“…Some bats reduce their call rate (Adams et al, 2017) and temporally even cease to emit calls (Jarvis et al, 2013). This adaptation may be beneficial if the bats eavesdrop on echolocation signals from conspecifics and use the signals for orientation (Barclay, 1982;Chiu et al, 2008;Leonard and Fenton, 1984;Lin and Abaid, 2015). Although, C. perspicillata emitted fewer calls during test compared to control trials, the pendulum paradigm was not designed to test for eavesdropping on the playback stimulus.…”