Spatiotemporal patterning of acoustic gaze in echolocating bats navigating gaps in clutter

Amaro Tuninetti,Chen Ming,Kelsey N Hom,James A Simmons,Andrea Megela Simmons

doi:10.1016/j.isci.2021.102353

Abstract

SummaryWe challenged four big brown bats to maneuver through abrupt turns in narrow corridors surrounded by dense acoustic clutter. We quantified bats' performance, sonar beam focus, and sensory acquisition rate. Performance was excellent in straight corridors, with sonar beam aim deviating less than 5° from the corridor midline. Bats anticipated an upcoming abrupt turn to the right or left by slowing flight speed and shifting beam aim to “look” proactively into one side of the corridor to identify the new flightpath. All bats mastered the right turn, but two bats consistently failed the left turn. Bats increased their sensory acquisition rate when confronting abrupt turns in both successful and failed flights. Limitations on biosonar performance reflected failures to switch beam aim and to modify a learned spatial map, rather than failures to update acquisition rate.

Highlights

Echolocating bats intercept flying prey and navigate through their environments using information provided by reflected echoes
Four big brown bats were challenged to fly through a 40-cm-wide corridor surrounded by an array of 217 hanging plastic chains that produced intense, extended echoes
All bats flew through the Straight corridor with few errors [mean (M) percent correct = 94.2%, N = 420 flights]

Summary

Introduction

Echolocating bats intercept flying prey and navigate through their environments using information provided by reflected echoes. Many bat species forage and navigate in noisy, highly echoic (cluttered) environments, such as vegetation, forests, and caves (Schnitzler and Kalko, 2001), that challenge their biosonar system to decipher multiple, dynamic streams of echoes from numerous objects located at different distances In these noisy environments, bats maintain flightpaths, detect specific (prey) objects in surrounding (nonprey) background clutter, identify particular echoes in multiple overlapping streams of echoes, and selectively attend to relevant echoes amid a stream of irrelevant ones that constitute the clutter (Amichai and Yovel, 2017; Beetz et al, 2019; Fujioka et al, 2014; Hiryu et al, 2010; Knowles et al, 2015; Melcon et al, 2011; Petrites et al, 2009; Sandig et al, 2014; Surlykke et al, 2009; Wheeler et al, 2016). Multiple objects in this environment are located nearer than the upcoming opening in the scene, so the bat has to peer through a screen of echoes to discern the place where a turn will be necessary to maintain the flightpath

Methods

Results

Discussion

Conclusion