Environmental acoustic cues guide the biosonar attention

RESEARCH ARTICLE

Environmental acoustic cues guide the biosonar attention of ahighly specialised echolocatorElla Z Lattenkamp Samuel Kaiser Rozle Kaucic Martina Groszligmann Klemen KoseljDaggersectpara

and Holger R Goerlitzsectpara

ABSTRACTSensory systems experience a trade-off between maximizing thedetail and amount of sampled information This trade-off is particularlypronounced in sensory systems that are highly specialised for a singletask and thus experience limitations in other tasks We hypothesisedthat combining sensory input from multiple streams of informationmay resolve this trade-off and improve detection and sensingreliability Specifically we predicted that perceptive limitationsexperienced by animals reliant on specialised active echolocationcan be compensated for by the phylogenetically older and lessspecialised process of passive hearing We tested this hypothesis ingreater horseshoe bats which possess morphological and neuralspecialisations allowing them to identify fluttering prey in densevegetation using echolocation only At the same time theirecholocation system is both spatially and temporally severelylimited Here we show that greater horseshoe bats employ passivehearing to initially detect and localise prey-generated and otherenvironmental sounds and then raise vocalisation level andconcentrate the scanning movements of their sonar beam on thesound source for further investigation with echolocation Thesespecialised echolocators thus supplement echo-acoustic informationwith environmental acoustic cues enlarging perceived space beyondtheir biosonar range Contrary to our predictions we did not findconsistent preferences for prey-related acoustic stimuli indicating theuse of passive acoustic cues also for detection of non-prey objectsOur findings suggest that even specialised echolocators exploit awide range of environmental information and that phylogeneticallyolder sensory systems can support the evolution of sensoryspecialisations by compensating for their limitations

KEY WORDS Attentional switches Passive acoustic cues Preydetection Sensory integration Sensory specialisation Trade-off

INTRODUCTIONSpecialised sensory systems that provide a high level of detail such asfoveal vision typically suffer from a limited spatial extent and slowtemporal update rate (Land 2006) In contrast sensory systemscapable of sampling a large area at a high sampling rate are at the sametime limited in the acuity and resolution of the acquired information

To solve this trade-off the brain combines information from differentsensory systems using attentional sampling routines (Schroeder et al2010) Such sensory integration and attentional switches acrossdifferent sensory modalities have been studied in depth (Yorzinskiet al 2017) In contrast less is known about how animals coordinatemultiple streams of information within a single modality Here wedemonstrate how a sensory specialist the echolocating horseshoe batcompensates for the limitations of its specialised active echolocationsystem by relying on the phylogenetically older and less specializedmechanism of passive hearing

Echolocation as used by bats toothed whales and some birds isan active sensory system based on emitting sound energy into theenvironment and analysing the returning echoes (Nelson andMacIver 2006 Schroeder et al 2010) While permitting activecontrol over sensory input echolocation is at the same time severelylimited the stroboscopic and highly directional emission of callsand the strong atmospheric attenuation of ultrasonic frequencieslimits the space that can be probed both temporally and spatially(Jakobsen et al 2013 Nelson and MacIver 2006) Theselimitations are especially pronounced in bats with a highlyspecialised echolocation system that is based on calls with longconstant-frequency components (CF-FM bats) horseshoe batshipposiderid bats and Pteronotus parnellii (Fenton et al 2012Jones 1999 Schnitzler and Kalko 2001) While theirmorphological and neural specialisations enable them to identifyand evaluate prey with high precision (Denzinger and Schnitzler2013 Koselj et al 2011 Ostwald 1984 Schnitzler and Kalko2001 Vater et al 1985 von der Emde and Menne 1989) theirspecialised biosonar is even more directional and short range thanthat of other echolocators (Grinnell and Schnitzler 1977 Jakobsenet al 2013 Schnitzler and Grinnell 1977 Schuchmann andSiemers 2010) In consequence relying solely on echolocation iscostly The small perception volume of echolocation results inlonger and delayed average detection times for prey and predatorsboth of which can have substantial negative fitness consequences

Given these limitations of high-frequency CF-FM biosonar wehypothesised that bats compensate for these limitations of their activeecho-acoustic perception with passive listening for environmentalinformation More specifically we hypothesised that the bat auditorysystem employs wide-angle perception of peripheral passive acousticinformation in combination with the focused perception of theactively probed environment This process is paralleled in the visualsystem of many vertebrates and cephalopods where blurry and broadperipheral vision is combined with well-resolved and directionalfoveal vision Saccadic eye movements sequentially sample a visualscene in fast temporal succession by steering the gaze to points ofinterest and can be used to infer the underlying attentional process(Hayhoe and Ballard 2005 Henderson 2003 Yarbus 1967)Correspondingly we here evaluated the scanning movements of thebiosonar beam of horseshoe bats to infer the batsrsquo sonar attentionReceived 29 June 2017 Accepted 8 March 2018

Acoustic and Functional Ecology Group Max Planck Institute for OrnithologySeewiesen 83219 GermanyPresent address Neurogenetics of Vocal Communication Group Max PlanckInstitute for Psycholinguistics Nijmegen 6525 XD The Netherlands DaggerPresentaddress SubBioLab Department of Biology Biotechnical Faculty University ofLjubljana Ljubljana sectThese authors contributed equally to this work

paraAuthors for correspondence (koseljornmpgde hgoerlitzornmpgde)

HRG 0000-0002-9677-8073

1

copy 2018 Published by The Company of Biologists Ltd | Journal of Experimental Biology (2018) 221 jeb165696 doi101242jeb165696

Journal

ofEx

perim

entalB

iology

(Fujioka et al 2016 Ghose and Moss 2003 Seibert et al 2013Surlykke and Moss 2000) towards passive acoustic environmentalcuesWe presented greater horseshoe bats either consecutively

(Experiment I) or simultaneously (Experiment II) with recordingsof moths rustling on vegetation and spectral and temporal controlversions of these recordings We had two main predictions First ifbats use passive hearing to improve the acquisition of environmentalinformation we predicted that they would concentrate the scanningmovements of their echolocation beam around a sound source forfurther biosonar-based investigation Second if bats use passiveacoustic information for prey detection we predicted that theywould show a preference for insect rustling over control sounds Totest these predictions we compared call levels recorded at differentmicrophones and how often the sonar beam was directed at theplayback position between silence and playback conditions andbetween different acoustic stimuli

MATERIALS AND METHODSExperimental setupExperiments were conducted in a large sound- and echo-attenuatedflight room (6times35times3 m3) at theMax Planck Institute for OrnithologySeewiesen Germany A small wooden plate (5times7 cm2 widthtimesheight)215 cm above the ground served as a perch for the bats It was faced bya spherical arrangement of eight condenser ultrasound microphones(CM16CMPA Avisoft Bioacoustics Glienicke Germany) and threeloudspeakers (NeoCD10 Fountek Electronics Co JiaXing China)which were mounted on a wooden board (285times205 msup2widthtimesheight) covered by echo-attenuating foam (Fig 1) Themicrophones were arranged in three symmetrical star-shaped sub-arrays each with a central microphone surrounded by three peripheralmicrophones which were equidistant (87plusmnmax 1 cm) andequiangular (25 deg) to the central one (Fig 1AndashD) The membraneof each microphone was 2 m (plusmnmax 09 cm) away from and orientedtowards the head of the perched bat The speakers were mounted

0 deg330

5040

3020

10

50

659 deg475 deg

429 deg

25 deg

4030

2010

429

deg

300

270

240

210180

Rustling

96

0 1 s

kHz

Amplitude inversion Phase-scramble

150

120

90

60

30

A B

C D

E

F

G

0 deg330

300

270

0

ndash20

ndash40

ndash60dB

240

210180

150

120

90

60

30

25 de

g

Fig 1 Experimental setup polar plot ofthe microphone-speaker-array andplayback stimuli (AB) Photograph (A)and sketch (B) of the echo-attenuatedexperimental room with the eight-microphonendashthree-loudspeaker array andthe perch for the bat B also shows theboard (which is covered in A by thecurtain) behind which the experimenterhid during the recordings (CD) Polar plotof the microphone (circles numbered 1ndash8)and loudspeaker (squares marked L MR) positions as seen from the batrsquos perchThe three star-shaped microphonesubarrays around each of the centralmicrophones 3 5 and 6 are highlighted bydifferent colours (purple red orange)The active loudspeaker is marked in green(C central D left) Green dotted circlesdepict constant off-axis angles relative tothe axis from the batrsquos head to the activeloudspeaker Note that the number ofmicrophones surrounding the activeloudspeaker at a given angle variesbetween the middle and the leftrightactive loudspeaker (EndashG) Waveforms(top) and spectrograms (bottom) of threestimulus examples For each the rustlingrecording spectral control (amplitudeinversion) and temporal control (phasescramble) are shown Note that only thefirst second of the full stimulus duration(3 s) is shown

2

RESEARCH ARTICLE Journal of Experimental Biology (2018) 221 jeb165696 doi101242jeb165696

Journal

ofEx

perim

entalB

iology

5ndash8 cm from each of the three central microphones The acousticimpulse response of each microphone (and thus its sensitivity andfrequency response) was calculated based on recordings ofwhite noisepresented from a loudspeaker placed at the batrsquos position Microphonesignals were pre-amplified (Octopre LE Focusrite High WycombeUK) and recorded at 192 kHz sampling rate and 16 bit resolution(Fireface 800 RME Haimhausen Germany) Sound playbacks wereplayed via the same soundcard (Fireface 800) amplified (AVR 445HarmanKardon Stamford CT USA) and presented to the bats viathe loudspeakers Sound presentation and recording was controlled bycustom-written code for MATLAB (R2007b MathWorks IncNatick MA USA) using SoundMexPro (version 15816 HoumlrtechOldenburg Germany)

Acoustic stimuliWe recorded the rustling sounds of one individual each from threemoth species (Ochropleura plecta Noctuidae Pterostoma palpinaNotodontidae and Sphinx pinastri Sphingidae) while the moth wasfluttering its wings and walking on dry leaves Rustling sounds wererecorded in the flight room with an omnidirectional microphone(CO-100K Sanken Microphone Co Ltd Tokyo Japan) connectedto a preamplifier (Fireface 800 RME) and soundcard (USG 416HAvisoft Bioacoustics) using Avisoft Recorder software (samplingrate 250 kHz) Out of a total of 66 recordings we selected sevenrecordings for each of the three moth species that differed intemporal structure intensity pattern and frequency spectrum(Fig 1EndashG) resulting in 21 different rustling sounds used in theexperiments Recordings were subsequently trimmed to a length of3 s and high-pass filtered at 1 kHz (Hamming window 1024 tabszero-phase filter Avisoft SASLab Pro version 5209) Averagesound pressure level of the selected recordings was 42 dB SPL [re20 μPa root mean square (RMS) at 01 m] and ranged from 31 to52 dB SPL RMS Zero-to-peak sound pressure level varied between62 and 81 dB SPL (re 20 μPa) with an average of 73 dB SPLThree types of acoustic stimuli were used to investigate the batsrsquo

reactions to passively presented environmental acoustic cues namelythe recorded rustling sound and two control sounds (Fig 1EndashG) Ascontrol sounds we generated amplitude-inverted and phase-scrambled versions of each rustling recording in MATLABresulting in a total of 63 playbacks Amplitude inversion inverts thesign of the amplitude values of one randomly chosen half of thesamples resulting in a flat frequency spectrum while preserving the

temporal envelope of the sound For phase-scrambling the amplitudeand phase spectrum of each rustling recording was calculated thephase spectrum randomized and thewaveform recreated by an inversefast Fourier transform resulting in a disrupted noise-like temporalpattern without notable temporal fluctuation but with maintainedfrequency spectrum

Experimental protocolThree captive adult male individuals of the greater horseshoe bat[Rhinolophus ferrumequinum (Schreber 1774)] were perch-trainedfor 5 days a week in daily sessions of 45 min length with breaksfrom March to November 2015 (pre-experimental training) Duringthese training sessions the bats were motivated with food rewards(mealworms larvae of Tenebrio molitor) to land and stay on theperch Note that during the training the bats were not presented withnor trained to attend to any particular acoustic stimuli When the batshad learned to remain on the perch data collection for Experiment I(single playbacks) and Experiment II (paired playbacks) wasconducted with breaks from November 2015 until March 2016Animal husbandry (no 3115-568211-2014-023) and animalprotocols (no 552-1-54-2532-18-2015) were licenced by therelevant authorities (Landratsamt Starnberg and Regierung vonObernbayern respectively)

Each experimental trial during data collection consisted of threephases three initial seconds of silence (silence1) 3 s of stimuluspresentation (playback) and three terminal seconds of silence afterthe playback stopped (silence2) The batrsquos echolocation behaviourwas recorded simultaneously on all eight microphones during thewhole trial resulting in eight 9-s-long audio tracks (Fig 2) InExperiment I (single playbacks) we presented only a singleplayback to the bats and monitored their echolocation Each of the63 sound files was presented twice to every bat in two successiverepeats each repetition consisting of all 63 playbacks resulting in atotal of 126 trials per individual (presented over 18ndash20 days with amean of seven trials per daily session range 2ndash8 trials) Within eachrepetition of 63 playbacks stimulus type was block-wiserandomised for every three consecutive playbacks with eachsound file only used once and randomly chosen per stimulus typeThe active speaker was chosen pseudo-randomly with aGellermann-like sequence (Gellermann 1933) adapted for threealternatives [per 15 playbacks all three speakers were active anequal number of times each speaker was active at least twice during

Silence1PlaybackA

B

C

Central microphone (0 deg)

85

kHz

kHz

70Peripheral microphone (25 deg)

85

0 s 3 s 6 s 9 s

0

dB

ndash60

70

Rustling playback Silence2 Fig 2 Example trial with rustling playback andcall recordings on two microphones Batecholocation calls during a 9 s experimental trial(consisting of pre-playback silence1 rustlingplayback and post-playback silence2 A) wererecorded on multiple microphones (BC) whichwere either next to the playback loudspeaker (B0 deg) or at fixed angular distances (C 25 deg off-axis) Call rate and call level increased after onsetof the playback and decreased after its offset (BC) During rustling playback call level on thecentral microphone (B) was higher than on theperipheral microphone (C) showing that the batdirected its sonar beam towards the sound source

3


Journal

ofEx

perim

entalB

iology

the first eight and last eight playbacks the active speaker changednine times between playbacks (ie five times the speaker did notchange) and no speaker was active more than twice in a row]Playback level at 10 cm distance to the loudspeaker was set tonatural levels of 42 dB SPL RMS (range 37ndash50 dB SPL RMS)with an average zero-to-peak level of 74 dB SPL (range 63ndash82 dBSPL) Considering spherical (minus26 dB) and atmospheric (minus2 dB at30 kHz minus4 dB at 60 kHz maximally minus65 dB at 95 kHz for 20degCand 52 relative humidity calculated according to ISO 9613-1International Organization for Standardization 1993) attenuationon the way to the bat this results in frequency-dependent receivedlevels at the batrsquos position of approximately 10ndash14 dB SPL RMS(range 5ndash9 to 18ndash22 dB SPL RMS) with a zero-to-peak level ofapproximately 42ndash46 dB SPL (range 31ndash35 to 50ndash54 dB SPL)In Experiment II (paired playbacks) we paired a rustling sound

playback from one speaker with one of three different controlstimulus types played from another speaker For this only the leftand right speakers were used Control stimuli were the amplitude-inverted or phase-scrambled versions of the rustling sounds as inExperiment I and silence Pairing the rustling with silence basicallyresulted in an equivalent situation as in Experiment I Again wepresented the set of 63 playbacks twice resulting in 126 trials perindividual (presented over 13ndash14 days with a mean of eight trialsper daily session range 3ndash11) Per repetition of 63 playbacks eachof the 21 rustling sounds was paired once with all three controltypes using a Gellermann-like sequence (Gellermann 1933)adapted for three alternatives [per 21 playbacks all three controlswere presented an equal number of times each control waspresented at least three times during the first and last 11 playbacksthe control type changed 13 times (ie seven times the control typedid not change) and no control type was presented more than twicein a row] The specific sound file was chosen randomly and did notrepeat per 21 playbacks ensuring that a rustling sound was nevercombined with its own control sounds The rustling speaker waschosen pseudo-randomly according to Gellermann (1933) Toexclude any potential bias in the batsrsquo behaviour owing to leveldifferences of the presented stimuli the RMS of the rustling andcontrol playback (if not silence) was equalised Playback level at10 cm distance to the speaker was set to 47 dB SPL RMS with aroving level of up to plusmn3 dB with 1 dB step size applied randomly toboth stimuli resulting in frequency-dependent received levels at thebatrsquos position of 13ndash19plusmn3 dB SPL RMSDuring experimental sessions one experimenter was inside the

room hiding motionless behind a wooden board directly behindthe bat (Fig 1B) Another experimenter controlled stimuluspresentation and data acquisition from outside the room andviewed the bat via an infrared camera Trials started when the batwas perched and attentive which was signalled by the experimenteroutside to the experimenter inside the room by switching on an LEDhidden behind the board inside the room Bats were fed withmealworms in irregular intervals between trials by the experimenterinside the room

Data pre-processingAll trials during which the bats left the perch were excluded from theanalysis (see Table S1 for final sample sizes) Firstly all recordingswere convolved with each microphonersquos compensatory impulseresponse to ensure flat frequency response and equal sensitivitybetween all eight channels (custom-written code for MATLAB2016a) Secondly we used batch processing in SASLab Pro(Avisoft Bioacoustics) to automatically detect [call level gtminus60 dBfull scale (FS) ie 60 dB below the highest recordable sound level]

and separate (6 ms minimal inter-call interval) calls and to measuretheir start and end time and their RMS level Thirdly we conducteda temporal comparison across all eight recordings of each trialOwing to the rapid scanning movement of the batsrsquo sonar beam anygiven call was not necessarily recorded on all eight channelsespecially not with the same startend time Also the recorded callamplitude at a given microphone can strongly fluctuate and even fallbelow the detection level thus resulting in the detection of multipleparts of the same call at a single microphone We used a methodanalogous to contig assembly in the process of de novo genomemapping (Gregory 2005) to identify unique calls (MATLAB) Weassigned calls recorded on different microphones as belonging tothe same unique call if they overlapped in time or were separated bya hold time of up to 2 ms If a call was split into multiple parts on asingle channel these multiple parts were also assigned to the sameunique call by this process In this case the RMS level for thischannel was calculated as the weighted average of all parts of thiscall Start and end time of each unique call was set to the earliestlaststartend time of all contributing call parts from all channels Allfurther analyses were conducted with these unique calls (seeTable S1 for sample sizes)

Data analysisTo analyse whether the bats concentrated the scanning movement oftheir sonar beam around the different presented acoustic stimuli wefirst compared the recorded call levels across all microphones andfocused our analyses later on the microphones located next to the threeloudspeakers (ie on microphones 3 5 and 6 Fig 1CD) Recordedcall levels are reported as RMS average in dB FS Second weanalysed how often the sonar beam was directed towards the activeplayback speaker compared with the silent loudspeakers Call leveland number of beam directions towards playback were comparedbetween the three experimental phases (silence1 playback andsilence2) to which the calls were assigned based on their start time

In Experiment I recorded call levels were analysed as a functionof the off-axis angle relative to the active speaker in each trial bygrouping all microphones with the same off-axis angle Hence themicrophone next to the active speaker is always represented by 0 deg(termed central microphone) the directly surrounding microphonesby 25 deg (termed peripheral microphones) and the microphones inits wider periphery by 429 475 and 659 deg (Fig 1CD) Becausethe angles 475 and 659 deg only occurred for the left and rightspeakers but not for the central one they were excluded fromfurther analyses In Experiment II recorded call levels werecompared between the two microphones next to the left and rightloudspeakers which presented the paired acoustic stimuli

We first investigated whether the call level recorded at theplayback loudspeaker was higher during the playback phase thanbefore and after Further analyses explored whether this increaseresulted from a general increase in echolocation call level during theplayback phase or whether the bats concentrated their sound beamsmore around the playback source The small number and coarsespatial arrangement of the microphones in our array prevented usfrom directly reconstructing the sonar beam direction and beamwidth of all calls However we used three different approaches toinvestigate whether the bats concentrated the scanning movementsof their sonar beams around passive acoustic cues First wecompared call levels recorded at the microphone next to theplayback loudspeaker (0 deg) with call levels at equidistantsurrounding microphones Second we compared call levelsrecorded at the three microphones next to the three loudspeakersto test whether the bats were scanning the active loudspeaker Third

4


Journal

ofEx

perim

entalB

iology

we determined how often the sonar beam was directed at the activeplayback loudspeaker versus the other silent loudspeakers Note thatwe can only identify the beam direction if a beam is directed ontothe central microphones of the array and not on the array edge oroutside the array and that owing to the ongoing scanningmovements any given call can be dynamically directed at severallocations within a single call To obtain the total number of beamdirections we determined for each unique call the maximum peak-to-peak level (PP level) recorded at each of the three loudspeakerstogether with the time point when this maximum PP level wasrecorded We then compared each maximum PP level with the PPlevel recorded at all other seven microphones at the same point intime If the PP level was highest on the loudspeaker microphone andlower on all other microphones the beam of this call was directed atthat particular loudspeaker at that point in time We ran analyses onthe number of these events across the different experimental phasesand additionally on the RMS level of these calls as recorded with themicrophone at which the call was directed To estimate the generalincrease in vocalisation level in response to a playback wecompared the levels of calls directed at the two microphones nextto the non-active loudspeakers among experimental phases Weexcluded calls directed at the microphone next to the playbackloudspeaker in this analysis to avoid the influence of the changedconcentration of scanning movements on the recorded RMS levelsNote that the half-amplitude beamwidth of greater horseshoe bats

is approximately between 13 deg (vertically Matsuta et al 2013)and 25 deg (horizontally Matsuta et al 2013 Schnitzler andGrinnell 1977) and that horseshoe bats continuously scan theirenvironment (Yamada et al 2016) Therefore we expected to findrather small statistically estimated differences in recorded levelsamong experimental phases and a large recorded level variationamong individual calls owing to the ongoing scanning movementsIf bats directed their sonar beams perfectly onto the playbacks forthe full playback duration of 3 s call levels at the centralmicrophone (0 deg) would be approximately 6 dB higher than atthe three peripheral 25 deg microphones and the proportion of on-playback beam directions would rise to 100 In contrast underrealistic conditions with ongoing scanning movement thedifference in call level should be smaller than 6 dB and theproportion of directed calls should increase but not to 100

StatisticsStatistical analysis was conducted in R version 321 (httpswwwr-projectorg) Data were analysed separately for each individual batWe used linear mixed effects models (LMMs) run with the packagenlme (httpscranr-projectorgwebpackagesnlmeindexhtml) tomodel call levels recorded on different microphones as a function ofthe following factors (1) Experiment I phase stimulus (rustlingamplitude inversion or phase-scramble) angle (of the microphoneeither 0 25 or 429 deg) and loudspeaker (left middle or right) andtheir interactions (2) Experiment II phase condition (rustling orcontrol) and control type (silence amplitude inversion or phase-scramble) and their interactions We fitted generalized linear mixedeffects models (GLMMs) with the package lme4 (version 11-12httpscranr-projectorgwebpackageslme4indexhtml) to thenumber of beam directions at the active loudspeaker relative tothe number of identified beam directions at the silent loudspeakersIn both LMMs and GLMMs we nested phase within the trial ID as arandom intercept to model the longitudinal data structure Herebywe were only interested in the changes of the dependent variableswithin the trials and not among them Additionally when wecompared call levels across the different microphones we nested

angle within call ID which in turn was nested within phase Wethereby concentrated on call levels of the same calls betweendifferent microphone angles In the call level analysis of callsdirected at the non-active loudspeakers we did not include call ID inthe random effect structure because here there was only onerecording per call

Fixed effects or their interactions were excluded from the models ifthis did not significantly decrease the likelihood This was computedwith the log likelihood ratio tests (LLRwith a letter subscript denotingindividual bat) Likelihood was computed assuming normal variationof residuals for call levels in dB FS and binomial variation with logitlink function was used for proportion of beam directions Thesedistributions were found to be well suited during the exploratory dataanalysis with Q-Q plots Only in the call level analysis of callsdirected at the non-active loudspeakers was the distribution slightlynegatively skewed Note that the mammalian auditory systemanalyses sound level on a logarithmic scale therefore we canexpect that call levels expressed in dB originate from a normaldistribution All maximum likelihood estimates [MLEs or restrictedmaximum likelihood estimates (REMLEs) for LMMs] are reportedfrom the final models from which all higher-level non-significantterms were removed Model selection was confirmed by the Akaikeinformation criterion (AIC) which in all but a few cases supported thesame models as the log likelihood ratio tests

RESULTSWe collected more than 38000 calls during 707 experimental trials(Table S1) with each 9-s-long trial consisting of three phases (3 s ofsilence 3 s of sound playback and 3 s of silence Fig 2)We comparedthe recorded call levels and the proportion of sonar beam directionsthat were oriented towards the playback between experimental phasesand acoustic stimuli to test whether bats reacted to environmentalacoustic cues by concentrating the scanningmovements of their sonarbeam around passive acoustic cues (Experiment I) and whether theypreferred certain acoustic cues over others (Experiment II)

Experiment ICall levels recorded next to the active loudspeaker increased duringthe playbacksIn Experiment I call levels recorded on the central microphone (iethe microphone next to the active loudspeaker 0 deg) generallyincreased during the playbacks For individuals A and B the call levelincreased between 21 and 96 dB and decreased again to pre-playback levels during the silence2 phase (Fig 3 Fig S1 Table S2)Call levels increased differently for the different stimuli (Table S2)Therefore we found a significant interaction between stimulus typeand experimental phase (Table S3) To investigate stimulus effect weanalysed the datasets of each stimulus type separately Individuals Aand B reacted to all stimulus types (rustling sounds and both controls)with an increase in call level during the playback phase (ie significantphase effect Table S4) Although the stimulusndashphase interactionwas not significant in the full dataset for individual C we foundthat call levels differed significantly between different phases forthe amplitude-inverted stimuli (Table S4) being 13 and 18 dBhigher during and after the playback respectively than before theplayback

Increasing vocalisation level and concentrating sonar scanningaround the sound sourceThere are two potential explanations for the increase in call level atthe active loudspeaker during the playbacks Either the bats merelyincreased the emission level of their calls without changing the

5


Journal

ofEx

perim

entalB

iology

direction of emission or they (additionally) concentrated thescanning movement of their sonar beam around the playbacksource We were mainly interested in the latter mechanism andfound three lines of evidence for it (1) significantly higher calllevels on the central than the surrounding microphones duringplaybacks (2) significantly higher call levels at the active playbackloudspeaker than at the two silent loudspeakers and (3) asignificantly larger proportion of beam directions orientedtowards the active loudspeaker We present this evidence in thefollowing three sections However we also found evidence for ageneral increase in vocalisation level during the playbackAnalysing the recorded call levels of calls directed at non-playback loudspeakers we found a significant interaction betweenstimulus type and experimental phase in individuals A and B(log-likelihood ratio tests df=4 LLRA=1212 P=00165LLRB=2112 P=00003 LLRC=551 P=02387) Specificallythe recorded call levels increased in individual A by up to 86 dBwith the playback (of phase-scrambled stimuli) and in individual Bby up to 49 dB (amplitude-inverted stimuli Table S5) No

significant change with either stimulus or phase was found inindividual C (log-likelihood ratio test df=2 experimental phaseLLRC=144 P=04857 stimulus type LLRC=367 P=01599) Theangle to the playback loudspeaker (either 25 or 429 deg) did nothave a significant effect for individuals A and B (log-likelihoodratio tests df=1 LLRA=033 P=05678 LLRB=038 P=05376LLRC=4513 Plt00001) indicating that concentrated scanningmovements around the playback source did not influence the calllevels recorded at the non-active loudspeakers The general increasein vocalisation level (Table S5) was lower than the observedincrease in call level at the playback loudspeaker (Table S2) Thisindicates that individuals A and B not only increased theirvocalisation level in response to playbacks but also concentratedthe scanning of their sonar beam around the playback source Notehowever that the contribution of the scanning cannot be simplycomputed by subtracting the vocalisation level increase (Table S5)from the total level increase (Table S2) because both values are notadditive Instead we confirm the scanning effect statistically in thefollowing three sections

ndash30ndash24ndash18ndash12

ndash606

12182430

698 731 681

0 de

g

25 d

eg

429

deg

Individual A

Rustling

745 769 691

Amplitude inversion

738 841 692

Phase-scramble


ndash606

12182430

617 641 634

0 de

g

25 d

eg

429

deg

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

670 743 637 613 618 584

Silence1 Playback Silence2-30-24-18-12

-606

12182430

745 772 777

0 de

g

25 d

eg

429

deg

Individual C

Silence1 Playback Silence2813 828 790


Fig 3 Relative recorded call levels in Experiment I (single playbacks) for three individual bats and for three different playback types (left to right mothrustling amplitude-inverted control and phase-scrambled control) Call levels are expressed relative to the mean level of all calls recorded at the samemicrophone during the silence1 phase Each panel displays the median (plusmnquartiles) of all calls (dots) recorded on the microphone beside the active playbackspeaker (0 deg) and the microphones at 25 and 429 deg angle around this speaker separately for the three 3-s-long phases of an experimental trial (silence1playback and silence2) Values at the bottom report the total number of unique echolocation calls recorded during the respective phase The horizontal dotted lineat 0 dB indicates no chance in call level relative to the silence1 phase Experimental phase microphone angle and stimulus type andor their interactionssignificantly influenced the recorded call level (see Results and Tables S2ndashS8 for detailed statistics) Note that the considerable variation in call level is caused bythe batsrsquo continuous sonar beam scanning on top of sonar beam focusing which was controlled for by a longitudinal random factors structure

6


Journal

ofEx

perim

entalB

iology

Call levels recorded at the central microphonewere higher than thoserecorded at the surrounding microphonesIf the bats directed their sonar beams towards the playbacks then thecall levels recorded at the central microphone next to the activeloudspeaker (0 deg) should be higher than those recorded at thethree peripheral microphones at 25 deg off-axis from the batndashloudspeaker axis (Fig 1) Indeed during the playback the averagecall levels recorded on the central microphone exceeded thoserecorded on the peripheral 25 deg microphones by approximately15 dB (range 09ndash28 Fig 3 Fig S1 Table S6) However thisdifference was much smaller or negative during the pre-playbacksilence for individuals A and B Because this angle effect should notbe present during the silence1 phase but should be present duringthe playback phase and potentially also during the subsequentsilence2 phase we expected to find a significant anglendashphaseinteraction Additionally if the bats reacted differently to the threestimulus types we also expected to find a significant anglendashphasendashstimulus interaction The results from bats A and B agree with thesepredictions whereas individual C only showed a significant anglendashstimulus interaction (Table S7) When analysing each phaseseparately we found that stimulus did not play a role in themodels during silence1 (Table S8) In contrast we found asignificant interaction between microphone angle and stimulusduring the playback phase for individuals A and B This shows thatfor particular stimuli (eg rustling for individuals A and B phase-scrambled for individual A and amplitude-inverted for individualB Fig 3) recorded call levels were higher at the playback sourcethan in the surroundings This result was not found for individual Cwhich showed no significant difference in its response to thedifferent stimuli (Table S8) Note that these models which werecalculated separately for each experimental phase also includedloudspeaker as an effect Significant anglendashloudspeaker interactionspossibly resulted from preferred scanning directions of the bats

causing additional variation in recorded call level acrossmicrophones (see Fig S2)

Call levels recorded at the active loudspeaker were higher than thoserecorded at the silent loudspeakersTo further exclude the possibility that the bats scanned all threeloudspeakers equally during the playback and to show that theyinstead scanned more around the active playback loudspeaker weanalysed a subset of our data including only recordings from themicrophones next to the three loudspeakers (microphones 3 5 and 6)For bats A and B we again found a significant interaction of anglephase and stimuli (Table S9) This was the case because call levelsrecorded at the active loudspeaker were higher than those recorded atthe silent loudspeakers (Fig S1 Table S10) During playbacks ofphase-scrambled stimuli call levels of individual A recorded at theactive loudspeaker were 24 and 70 dB higher than those recorded atthe loudspeaker 25 and 429 deg off-axis (Table S10) Similarlyduring playbacks of amplitude-inverted stimuli call levels ofindividual B recorded at the active loudspeaker were 19 and53 dB higher than those recorded at the loudspeaker 25 and 429 degoff-axis (Table S10) This pattern was not found during the silence1phase indicating that increased call levels at the active loudspeakerwere indeed a response to the playbacks Indeed stimulus effect andits interactions were only supported in the models for the playbackphase but not the silence1 phase (Table S11) confirming that batsscanned more around the active than the silent loudspeakers We didnot find evidence for increased scanning of individual C around theactive loudspeakers during playbacks

More identified sonar beam directions were aimed at the active thanthe silent loudspeakersWe counted how often the sonar beam direction could be assignedto one of the three microphones next to a speaker (see Materials

0

025

05

53 112 49

13

Individual ARustling

53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49

Silence1 Playback Silence20

025

05

62 89 108

13

Individual C



Fig 4 Sonar beam direction inExperiment I (single playbacks) forthree individual bats and for threedifferent playback types (left to rightmoth rustling amplitude-invertedcontrol and phase-scrambledcontrol) Each panel shows theproportion of all identified sonar beamdirections that were aimed at theplayback separately for each of thethree 3-s-long phases of anexperimental trial (silence1 playbackand silence2) The horizontal dotted lineindicates the expected proportion (13) ifall speakers were scanned equally bythe bats Small numbers at the bottomindicate the number of identified beamdirections that were aimed at theplayback during the respective phaseExperimental phase significantlyinfluenced the proportion of identifiedbeam directions in individuals A and B(see Results and Tables S12 and S13for detailed statistics)

7


Journal

ofEx

perim

entalB

iology

and methods) For individuals A and B but not for individual Cthe proportion of sonar beam directions aiming at the activeloudspeaker changed significantly with experimental phase(Table S12) Specifically the modelled proportions increasedfrom the silence1 phase to the playback phase from 028ndash039 to033ndash053 (Fig 4 Table S13) and were not influenced by stimulustype (Table S12) Likewise we also found a clear increase in theproportion of on-playback sonar beam directions when calculated inrelation to the total number of calls with up to 20 (individual B)and 25 (individual A) of all calls directed at the playback (Fig S3)

Experiment IISimultaneous playbacks confirmed the guidance of biosonar byenvironmental cuesTo explore the batsrsquo natural interest and preference for prey-generated rustling sounds we conducted a second experiment inwhich we paired rustling sounds with simultaneous playbacks ofsilence amplitude-inverted or phase-scrambled control stimuli In

addition to microphone-specific variation (Fig S4) call levelsincreased during the playback phase but to different extentsdependent on the presented stimulus combination (Fig 5) exceptfor individual C Thus the interaction between the condition(rustling versus control sound) control type (silence amplitudeinverted and phase-scrambled) and experimental phase had asignificant effect (log-likelihood ratio tests df=4 LLRA=7631Plt00001 LLRB=6638 Plt00001 LLRC=586 P=02099) Toinvestigate the effects of control type we analysed the dataset fromeach control type separately The increase in recorded call leveldiffered between the rustling and the control loudspeaker for allcontrol types in individuals A and B (significant effects of thephasendashcondition interaction or of phase and condition Table S14)Individual C did not react to the playbacks (no significant effectsof the phasendashcondition interaction or phase Table S14) Forindividuals A and B call levels recorded at the rustling loudspeakerduring the playback were 27 and 28 dB higher compared with thesilent control speaker but fainter than at the control speaker when

ndash30ndash24ndash18ndash12ndash6

06

12182430

680 712 639

R CIndividual ASilence

677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578

Silence1 Playback Silence2ndash30ndash24ndash18ndash12ndash6

06

12182430

684 694 671

R CIndividual C



Fig 5 Relative recorded call levels in Experiment II (paired playbacks) for three individual bats and for three paired playback types The sound of amothrustling on leaves was paired with silence (left) or with the amplitude-inverted (middle) or phase-scrambled (right) control version of a different rustling sound Calllevels are expressed relative to the mean level of all calls recorded at the same microphone during the silence1 phase Each panel displays the median(plusmnquartiles) of all calls (dots) recorded on the microphone beside the rustling playback speaker (R) and the microphone beside the control playback speaker (C)separately for the three 3-s-long phases of an experimental trial (silence1 playback and silence2) Values at the bottom report the total number of uniqueecholocation calls recorded during the respective phase The horizontal dotted line at 0 dB indicates no chance in call level relative to the silence1 phaseExperimental phase condition (rustling versus control sound) control type andor their interactions significantly influenced the recorded call level (see Resultsand Tables S14 and S15 for detailed statistics) Note that the considerable variation in call level is caused by the batsrsquo continuous sonar beam scanning on top ofsonar beam focusing which was controlled for by a longitudinal random factors structure

8


Journal

ofEx

perim

entalB

iology

paired with the amplitude-inverted (A minus05 dB B minus24 dB) orphase-scrambled controls (A minus27 dB B minus05 dB Table S15)To test whether the observed call level differences were the result

of the bats directing their sonar beam towards the respectiveloudspeaker and not caused by a general increase in emission levelwe again compared the proportion of sonar beam directions aimed atthe rustling loudspeaker across all three experimental phases(Fig 6) For individuals A and B we found a significant phasendashcontrol interaction In other words the type of control stimulusinfluenced how the proportion of on-playback beam directionschanged with experimental phase (df=4 LLRA=2043 P=00004LLRB=2447 Plt00001 LLRC=145 P=08363) When the rustlingsoundwas pairedwith silence individuals A andB directed their callssignificantly towards the rustling loudspeaker (df=2 LLRA=1412P=00009 LLRB=691 P=00315) increasing the proportion of on-playback beam directions from 048 and 044 before the playback to066 and 073 during the playback (Table S16) When the rustlingplayback was paired with either of the other control stimuli we foundno significant difference of the proportion of sonar beam directionsbetween the playback speakers except for a slight decrease from 037to 032 in individual B when presented with the amplitude-inverted

control (df=2 LLRB=691 P=00315 Table S16) In individual Cexperimental phase again did not explain the variation in theproportion of beam directions (df=2 LLRC=091 P=06318) As inExperiment I the clear increase in the on-playback sonar beamdirections was also present when calculated in relation to the totalnumber of calls with approximately 25 of all calls directed at one ofthe playbacks (Fig S5)

Results summaryThese results clearly show that the bats reacted to passive acousticcues by concentrating their sonar beam movements around thesound source and increasing the level of vocalisations Theindividuals varied in the strength of their reactions towardsdifferent stimuli Individuals A and B concentrated their sonarbeam movements around the playback source This reaction wasstrongest when phase-scrambled and amplitude-inverted stimuliwere played back to individuals A and B respectively They bothalso reacted to rustling sounds as shown by the higher call level atthe central microphone than at the peripheral ones and those at thesilent loudspeakers and by the higher proportion of beamdirections aimed at the rustling than the silent loudspeakers

0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A

Silence1 Playback Silence2144 152 133158 133 139


RC

Fig 6 Sonar beam direction in Experiment II (paired playbacks) for three individual bats and for three paired playback types The sound of a mothrustling on leaves was pairedwith silence (left) or with the amplitude-inverted (middle) or phase-scrambled (right) control version of a different rustling sound Eachpanel shows the proportion of all identified sonar beam directions that were aimed at the rustling (coloured R) and control playback (black C) separately for eachof the three 3-s-long phases of an experimental trial (silence1 playback and silence2) The horizontal dotted line indicates the expected proportion (05) if bothplaybacks were scanned equally by the bats (only two loudspeakers the left and right were included in this analysis) Small numbers at the bottom indicate thenumber of unique identified beam directions that were aimed at the respective playback during the respective phase Experimental phase control type andor theirinteractions significantly influenced the proportion of focused calls in individuals A and B (see Results and Table S16 for detailed statistics)

9


Journal

ofEx

perim

entalB

iology

Individual C did not show a clear reaction towards a specificstimulus

DISCUSSIONScanning the environment with a narrowly focused echolocation beamfor object detection is a time-consuming task prone to overlookingobjects Here we show for the first time that bats with a highlyspecialised echolocation system for prey detection and evaluationsupport this biosonar by attending to prey-generated sounds Using aspherically arranged eight-microphonendashthree-loudspeaker array forsimultaneous acoustic playback and recording we demonstrate thatpassive hearing guides the active biosonar-based sampling of spaceTwo important corollaries follow from our results First exploitingsounds that originate from the environment provides excellent guidancefor directing biosonar attention towards potential objects of interestsaving biosonar search time Second in addition to saving search timelistening for environmental sounds also increases the spatial volume inwhich a bat is able to instantly detect prey and predators Linkinginformation from environmental cues with biosonar-based perceptionenables an obligate echolocator to overcome the spatio-temporallimitations of its biosonar Thus phylogenetically older sensorysystems such as passive hearing could facilitate the evolution of sensoryspecialisations by compensating for their shortcomingsRelying on prey-generated sounds to find food is common in

gleaning bats (Fuzessery et al 1993 Russo et al 2007) ie speciesthat pick their prey from surfaces where detection by echolocationis hindered by background masking (Schnitzler and Kalko 2001)Several gleaning bats possess morphological (eg large ears Coleset al 1989 Obrist et al 1993) and neural specialisations thatenable them to detect and process prey-generated sounds (Razaket al 1999 2007) In contrast to gleaning bats however it is notclear to what extent species that use echolocation for hunting mightalso rely on prey-generated sounds Horseshoe bats echolocatecontinuously even when at rest (Schnitzler 1968 Speakman et al2004) and are highly specialised for the auditory analysis of echoesfrom wing-beating insects Our results however show that theseobligate echolocators still perceive localise and react to the soundsproduced by prey We therefore predict that the use of prey-generated sounds for foraging will be common in bats with stronglylimited echolocation systems for example bats with very high callfrequencies low call amplitude high directionality or low dutycycle which would most strongly benefit from combining bothstreams of auditory information Functionally this might beimplemented by neurons that respond to information frommultiple sensory streams In passive-listening specialists singlecortical neurons indeed process both call echoes and insect-generated transients (Razak et al 1999) while peripherally eachtype of information is still processed in its own separate pathway(Razak et al 2007) Likewise information from differentmodalities can lead to common neural representations (Green andAngelaki 2010 Hoffmann et al 2016 Lakatos et al 2009) Arecent study by Hoffman et al (2016) showed a spatially congruentrepresentation of visual and acoustic space in the superior colliculusof the bat Phyllostomus discolor with neighbouring neuronal layersreceiving input from the visual and the echolocation system Thisclose spatial proximity and congruent spatial maps might be theneuronal basis for cross-modal integration of visual and acousticspace In contrast Goerlitz et al (2008) suggested an independentprocessing of passive and active auditory information showing thatthe evaluation of spectral echo features was not influenced bysimultaneously presented passive acoustic information in theecholocating bat Phyllostomus discolor However the localization

performance in Antrozous pallidus decreased when bats were forcedto simultaneously process passive and active auditory information(Barber et al 2003) indicating that passive and active systems sharesome processing resources

A similar perceptual combination of passive and active sensoryinformation was also found in weakly electric fish Gnathonemuspetersii possesses two electrosensory foveae one of which relies onscanning movements to probe the environment (Pusch et al 2008)This species increases the rate of electric organ discharges inresponse to acoustic visual passive electrical and activeelectrolocation stimuli (Post and Von Der Emde 1999) LikewiseBrevimyrus niger integrates sensory information from its passiveand active electrosense and the mechanosensory lateral line system(Pluta and Kawasaki 2008) Our study did not directly addressmultisensory integration which is classically shown asmultiplicative combination of neuronal activity (Kayser et al2007 Meredith and Stein 1986) and improved detection orlocalisation performance (Gomes et al 2016) However ourfinding that passive acoustic information steers biosonar attentiontowards the passive acoustic sound source forms the basis for apotential integration of both auditory streams for a joint internalrepresentation of the batrsquos prey It will be a fascinating task toelucidate how both sensory streams conveying passive and activeacoustic information are combined and how this is influenced bytop-down task-dependent attentional mechanisms

In contrast to our expectations bats directed their sonar beam notonly towards the rustling sounds but also towards the controlversions (Experiment I) and reacted in fact more to the control thanto the rustling sounds (Experiment II) This suggests that horseshoebats exploit environmental sounds not only during foraging (whichwe aimed to investigate here) but also for other fitness-relevantbehaviours such as predator detection Considering this it is notsurprising that the unfamiliar control sounds elicited a strongerreaction as unfamiliar sounds might signal danger and thereforeelicit an exploratory response This is reminiscent of novel objectrecognition tasks in behavioural studies which generate a strongexploratory response to introduced novel stimuli (Antunes andBiala 2012 Bevins and Besheer 2006) The reaction to the controlsounds cannot be simply explained by the controls being moreaudible and more salient than the rustling sounds The playbacklevels of a rustling and its controls were equal although theperceived loudness likely differed The amplitude-inverted controlshad a flat frequency spectrum thus containing more energy in thehigher frequencies potentially making them more audible for thebats (Long and Schnitzler 1975) In contrast the phase-scrambledcontrols had the same frequency spectrum as the rustling sounds andwere additionally missing any transient high-amplitude peaks thusmaking them much less salient than the rustling soundsFurthermore the repeatable individual preferences in ExperimentsI and II contradict the notion that the playbacks simply startled thebats but speak for a consistent reaction to different environmentalcues This is additionally supported by the individual change invocalisation level in reaction to different stimuli types that matchedthe strength of reaction in beam scanning movements Therefore itis likely that the increase in vocalisation level results from an activeprocess that reflects the batsrsquo interest in the environmental cue Thisis further supported by the lacking reaction of individual C whoneither focused the scanning movements nor increased its generalvocalisation level in response to playbacks

Aside from the experiments presented here we conducted apreliminary pilot study similar in design to Experiment I In thatstudy we also found that bats reacted to all three playback stimuli

10


Journal

ofEx

perim

entalB

iology

Interestingly individuals A and B reacted most strongly to the samestimulus type as in the present study Furthermore in the pilot studywe also found significant reactions of individual C most strongly inresponse to amplitude-inverted sounds We conclude that the smalleffect sizes for individual C observed in the present study are due tohabituation which we also observed for the other two individualsbut to amuch lesser extent The overall observed habituation ratewasvery low and the bats continued to volitionally direct their sonarbeams towards repeating environmental acoustic cues Despite neverbeing rewarded for scanning their surroundings or directing theirsonar beam to environmental sounds all bats exhibited ongoingscanning behaviour and continued reactions to hundreds ofplaybacks presented in the course of 15 weeks although nomatching echo-acoustic information was ever presented togetherwith the playback This continued reaction has two importantconsequences first it indicates a highly adaptive value of reacting toand tracking environmental sounds by biosonar gaze and second itsuggests a low cost of this process and a much higher cost of failingto detect nearby predators or prey The adaptive value likely consistsof an increase in sampled volume of space for detecting prey andpredators and in a reduced detection time compared with relyingsolely on non-guided biosonar scanning Both the increased volumeof sampled space and the reduced search time likely bear importantadaptive consequences for foraging success and survival

ConclusionsWe demonstrated that greater horseshoe bats react to environmentalsounds by concentrating the scanning movements of their sonar beamtowards the sound source in addition to generally increasing the levelof their vocalisations Passive auditory information thus guides thebiosonar sampling of space enabling bats to extent their perceptiverange beyond the reach of their biosonar and to react faster to novelsounds in their surroundings This has important implications for theneuronal processing of multiple auditory streams including thepotential sensory integration of passive and active auditoryinformation and the evolution of sensory specialisations Ourresults suggest that phylogenetically older sensory systems mayfacilitate the evolution of novel sensory mechanisms bycompensating for potential limitations in the novel system

AcknowledgementsWe thank Daniela Schmieder for sharing her anecdotal observations of horseshoebat prey pursuit behaviour with us Uwe Firzlaff Wouter Halfwerk SusanneHoffmann Lutz Wiegrebe Brock Fenton and an anonymous reviewer for helpfulcomments on a previous version of this article Jacob Engelmann for discussionabout electrolocation Erich Koch for help with building the experimental setup andthe Max Planck Institute for Ornithology for providing facilities

Competing interestsThe authors declare no competing or financial interests

Author contributionsConceptualization HRG Methodology EZL RK KK HRG SoftwareHRG Validation EZL KK HRG Formal analysis EZL KK HRGInvestigation EZL SK RK MG Resources KK HRG Data curationEZL SK KK HRG Writing - original draft EZL KK HRG Writing -review amp editing EZL KK HRG Visualization EZL HRG SupervisionKK HRG Project administration KK HRG Funding acquisition HRG

FundingThis research was funded through the Deutsche Forschungsgemeinschaft EmmyNoether Program (grant number GO 20912-1) to HRG

Data availabilityData are archived in EDMOND (httpdxdoiorg101761731b) MATLAB and Rcode can be obtained on request from the corresponding authors

Supplementary informationSupplementary information available online athttpjebbiologistsorglookupdoi101242jeb165696supplemental

ReferencesAntunes M and Biala G (2012) The novel object recognition memory

neurobiology test procedure and its modifications Cogn Process 13 93-110Barber J R Razak K A and Fuzessery Z M (2003) Can two streams of

auditory information be processed simultaneously Evidence from the gleaningbat Antrozous pallidus J Comp Physiol A 189 843-855

Bevins R A and Besheer J (2006) Object recognition in rats and mice a one-trial non-matching-to-sample learning task to study lsquorecognition memoryrsquo NatProtoc 1 1306-1311

Coles R B Guppy A Anderson M E and Schlegel P (1989) Frequencysensitivity and directional hearing in the gleaning bat Plecotus auritus (Linnaeus1758) J Comp Physiol A 165 269-280

Denzinger A and Schnitzler H-U (2013) Bat guilds a concept to classify thehighly diverse foraging and echolocation behaviors of microchiropteran batsFront Physiol 4 1-15

Fenton M B Faure P A and Ratcliffe J M (2012) Evolution of high duty cycleecholocation in bats J Exp Biol 215 2935-2944

Fujioka E Aihara I Sumiya M Aihara K and Hiryu S (2016) Echolocatingbats use future-target information for optimal foraging Proc Natl Acad Sci USA113 4848-4852

Fuzessery Z M Buttenhoff P Andrews B and Kennedy J M (1993)Passive sound localization of prey by the pallid bat (Antrozous p pallidus)J Comp Physiol A 171 767-777

Gellermann L W (1933) Chance orders of alternating stimuli in visualdiscrimination experiments Pedagog Semin J Genet Psychol 42 206-208

Ghose K andMoss C F (2003) The sonar beam pattern of a flying bat as it trackstethered insects J Acoust Soc Am 114 1120-1131

Goerlitz H R Hubner M and Wiegrebe L (2008) Comparing passive andactive hearing spectral analysis of transient sounds in bats J Exp Biol 2111850-1858

Gomes D G E Page R A Geipel I Taylor R C Ryan M J and HalfwerkW (2016) Bats perceptually weight prey cues across sensory systems whenhunting in noise Science 353 1277-1280

Green A M and Angelaki D E (2010) Multisensory integration resolvingsensory ambiguities to build novel representation Curr Opin Neurobiol 20353-360

Gregory S G (2005) Contig assembly Encycl Life Sci 1-4Grinnell A D and Schnitzler H-U (1977) Directional sensitivity of echolocation

in the horseshoe bat Rhinolophus ferrumequinum II Behavioral directionality ofhearing J Comp Physiol A 116 63-76

Hayhoe M and Ballard D (2005) Eye movements in natural behavior TrendsCogn Sci 9 188-194

Henderson J (2003) Human gaze control during real-world scene perceptionTrends Cogn Sci 7 498-504

Hoffmann S Vega-Zuniga T Greiter W Krabichler Q Bley A Matthes MZimmer C Firzlaff U and Luksch H (2016) Congruent representation ofvisual and acoustic space in the superior colliculus of the echolocating batPhyllostomus discolor Eur J Neurosci 44 2685-2697

International Organization for Standardization (1993) ISO 9613-1 Acoustics -Attenuation of sound during propagation outdoors 1-26

Jakobsen L Brinkloslashv S and Surlykke A (2013) Intensity and directionality ofbat echolocation signals Front Physiol 4 1-9

Jones G (1999) Scaling of echolocation call parameters in bats J Exp Biol 2023359-3367

Kayser C Petkov C I Augath M and Logothetis N K (2007) Functionalimaging reveals visual modulation of specific fields in auditory cortex J Neurosci27 1824-1835

Koselj K Schnitzler H-U and Siemers B M (2011) Horseshoe bats makeadaptive prey-selection decisions informed by echo cues Proc R Soc B 2783034-3041

Lakatos P OrsquoConnell M N Barczak A Mills A Javitt D C and SchroederC E (2009) The leading sense supramodal control of neurophysiologicalcontext by attention Neuron 64 419-430

Land M F (2006) Eye movements and the control of actions in everyday life ProgRetin Eye Res 25 296-324

Long G R and Schnitzler H-U (1975) Behavioural audiograms from the batRhinolophus ferrumequinum J Comp Physiol 100 211-219

Matsuta N Hiryu S Fujioka E Yamada Y Riquimaroux H and WatanabeY (2013) Adaptive beam-width control of echolocation sounds by CF-FM batsRhinolophus ferrumequinum nippon during prey-capture flight J Exp Biol 2161210-1218

Meredith M A and Stein B E (1986) Visual auditory and somatosensoryconvergence on cells in superior colliculus results in multisensory integrationJ Neurophysiol 56 640-662

11


Journal

ofEx

perim

entalB

iology

Nelson M E and MacIver M A (2006) Sensory acquisition in active sensingsystems J Comp Physiol A 192 573-586

Obrist M K Fenton M B Eger J L and Schlegel P A (1993) What ears dofor bats a comparative study of pinna sound pressure transformation in chiropteraJ Exp Biol 180 119-152

Ostwald J (1984) Tonotopical organization and pure tone responsecharacteristics of single units in the auditory cortex of the greater horseshoebat J Comp Physiol A 155 821-834

Pluta S R and Kawasaki M (2008) Multisensory enhancement of electromotorresponses to a single moving object J Exp Biol 211 2919-2930

Post N and Von Der Emde G (1999) The ldquonovelty responserdquo in an electric fishresponse properties and habituation Physiol Behav 68 115-128

Pusch R von der Emde G Hollmann M Bacelo J Nobel S Grant K andEngelmann J (2008) Active sensing in a mormyrid fish electric images andperipheral modifications of the signal carrier give evidence of dual foveationJ Exp Biol 211 921-934

R Core Team (2015) R a language and environment for statistical computingRazak K A Fuzessery Z M and Lohuis T D (1999) Single cortical neuronsserve both echolocation and passive sound localization J Neurophysiol 811438-1442

Razak K A Shen W Zumsteg T and Fuzessery Z M (2007) Parallelthalamocortical pathways for echolocation and passive sound localization in agleaning bat Antrozous pallidus J Comp Neurol 500 322-338

Russo D Jones G and Arlettaz R (2007) Echolocation and passive listeningby foraging mouse-eared bats Myotis myotis and M blythii J Exp Biol 210166-176

Schnitzler H-U (1968) Die Uhraschall-Ortungslaute der Hufeisen-Fledermause(Chiroptera-Rhinolophidae) in verschiedenen Orientierungssituationen Z VglPhysiol 57 376-408

Schnitzler H-U and Grinnell A D (1977) Directional sensitivity of echolocationin the horseshoe bat Rhinolophus ferrumequinum I Directionality of soundemission J Comp Physiol A 116 51-61

Schnitzler H-U and Kalko E K V (2001) Echolocation by insect-eating batsBioscience 51 557-569

Schroeder C E Wilson D A Radman T Scharfman H and Lakatos P(2010) Dynamics of active sensing and perceptual selection Curr OpinNeurobiol 20 172-176

Schuchmann M and Siemers B M (2010) Variability in echolocation callintensity in a community of horseshoe bats a role for resource partitioning orcommunication PLoS ONE 5 1-9

Seibert A-M Koblitz J C Denzinger A and Schnitzler H-U (2013)Scanning behavior in echolocating common pipistrelle bats (Pipistrelluspipistrellus) PLoS ONE 8 e60752

Speakman J R Lancaster W C Ward S Jones G and Cole K C (2004)Energy costs of echolocation in stationary insectivorous bats In Echolocation inBats and Dolphins (ed J Thomas C Moss and M Vater) pp 361-365 ChicagoChicago Press

Surlykke A and Moss C F (2000) Echolocation behavior of big brown batsEptesicus fuscus in the field and the laboratory J Acoust Soc Am 1082419-2429

Vater M Feng A S and Betz M (1985) An HRP-study of the frequency-placemap of the horseshoe bat cochlea morphological correlates of the sharp tuning toa narrow frequency band J Comp Physiol A 157 671-686

von der Emde G and Menne D (1989) Discrimination of insect wingbeat-frequencies by the bat Rhinolophus ferrumequinum J Comp Physiol A 164663-671

Yamada Y Hiryu S and Watanabe Y (2016) Species-specific control ofacoustic gaze by echolocating bats Rhinolophus ferrumequinum nippon andPipistrellus abramus during flight J Comp Physiol A 202 791-801

Yarbus A L (1967) Saccadic eye movements In Eye Movements and Vision (edL A Riggs) pp 129-146 Boston MA Springer US

Yorzinski J L Patricelli G L Bykau S and Platt M L (2017) Selectiveattention in peacocks during assessment of rival males J Exp Biol 2201146-1153

12


Journal

ofEx

perim

entalB

iology

~ SUPPLEMENTARY TABLES ~

Table S1 Sample sizes Number of successful trials (out of 42 presented trials) and number of all

unique calls recorded per stimulus and individual The column lsquostimulus typersquo lists the presented

sound (Exp I) or control stimulus (Exp II)

individual

Experiment stimulus type A B C

I

successful trials

rustling 42 39 40

amplitude inversion 42 36 41

phase scramble 42 41 42

unique calls recorded

rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065



Table S2 Modelled difference in call level (in dB REMLE) recorded at the central microphone

(0deg) during playback compared to silence1 in Experiment I These results originate from the

models that were selected by the tests in Table S3

individual stimulus

rustling amplitude inversion phase scramble

A 36 31 96

B 21 61 27

C

Journal of Experimental Biology 221 doi101242jeb165696 Supplementary information

Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S3 Statistical results for the effect of stimulus type experimental phase and their

interactions on the call level recorded at the central microphone (0deg) in Experiment I

individual effect LLR df p

A stimulus phase 3558 4 lt 00001

B stimulus phase 1841 4 00010

C stimulus phase 864 4 00707

stimulus 257 2 02763

phase 278 2 02489

Table S4 Statistical results for the effect of experimental phase on the call level recorded at the

central microphone (0deg) in Experiment I Note that these models were computed separately for each

stimulus type as opposed to the models in Tab S3 which were computed for the full data set

stimulus individual effect LLR df p

rustling A phase 1702 2 00002

B phase 669 2 00352

C phase 205 2 03588

amplitude inversion A phase 2409 2 lt 00001

B phase 4829 2 lt 00001

C phase 831 2 00156

phase scramble A phase 6241 2 lt 00001

B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S5 Modelled general increase in call level (in dB REMLE) during playback compared to

silence1 in Experiment I These models were computed for calls whose sonar beam was directed at

the non-active loudspeakers angles (25deg and 429deg) using their call RMS level recorded at the non-

active loudspeakers The values in the table should not be subtracted from the values in Table S2

because they are not additive being means Note however that the values are lower than in Table

S2 because besides the general increase in call level bats also concentrated their scanning beam

movements towards the playback source

individual stimulus


A 15 31 86

B -19 49 13

C

Table S6 Modelled difference between the call levels (in dB REMLE) recorded at the central

microphone (0deg) and the peripheral microphones (25deg) separately for silence1 and playback

phase in Experiment I Note that the difference was higher during the playback phase in individuals

A and B showing that the beam movements were more often aimed at the playback loudspeaker

during the playback than during pre-playback silence These results originate from the models that

were selected by the tests in Table S6

phase individual stimulus


silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S7 Statistical results for the microphone angle experimental phase presented stimulus

type and their interactions in Experiment I Recordings from the central microphones (0deg) and the

surrounding peripheral microphones (25deg) were included in the modelled dataset


A angle phase stimulus 1700 4 00019

B angle phase stimulus 456 4 03353

angle stimulus 691 2 00315

angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001

C angle phase stimulus 216 4 07064


angle phase 048 2 07829

phase stimulus 972 4 00454


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S8 Statistical results for the microphone angle presented stimulus type loudspeaker

position and their interactions computed separately for the silence1 and playback phase of

Experiment 1 Note that stimulus effect and its interactions did not play a role in the model during

the silence1 phase but only during the playback phase Significant angleloudspeaker interactions are

a result of different call levels recorded at each microphones probably due to preferred scanning

directions of the bats (see Fig S2) These interactions were present irrespective of experimental phase

or individual tested The threefold interactions anglestimulusloudspeaker did not have a significant

effect and are therefore not shown in the table

experimental phase individual effect LLR df p

silence1 A angle stimulus 137 2 05046

stimulus loudspeaker 719 4 01260


angle loudspeaker 19523 2 lt 00001

B angle stimulus 145 2 04833




C angle stimulus 117 2 05568




playback A angle stimulus 1639 2 00003









This interaction term had a high p-value and was not supported by the AIC


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion


type and their interactions in Experiment I These results were calculated for a subset of the data

including only recordings of the three microphones located next to the loudspeakers (ie microphones

3 5 and 6) For each playback the microphone next to the active playback loudspeaker had an angle

of 0deg while the other two microphones were either located at 25deg and 429deg (if stimuli were played

from the left or right loudspeaker) or were both located at 25deg (if stimuli were played from the middle

loudspeaker)


A angle phase stimulus 8875 8 lt 00001

B angle phase stimulus 3579 8 lt 00001





Table S10 Modelled difference in call level (in dB REMLE) between the playback microphone

(0deg) and the other two microphones at the silent loudspeakers (at 25deg or 429deg) in Experiment I

Note that this difference is higher during the playback phase than the silence1 phase for those

playbacks where individuals A and B directed their calls towards the playback

phase difference

re angle individual

stimulus


silence1 25deg A 07 08 01

B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02

playback 25deg A 08 14 24

B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S11 Statistical results for microphone angle presented stimulus type and their

interaction computed separately for the silence1 and playback phase of Experiment 1 These

results were calculated using a subset of the data (ie only recordings of the three microphones

located next to the loudspeakers were included)




angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415

playback A angle stimulus 9169 4 lt 00001

B angle stimulus 8070 4 lt 00001



angle 2846 2 lt 00001

These interactions had a high p-value and were not supported by the AIC


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S12 Statistical results for the effects of stimulus type experimental phase and their

interaction on the proportion of identified sonar beam directions aimed at the playback

loudspeaker in Experiment I In individuals A and B we found no significant effect of stimulus (not

shown) Only a significant effect of phase or its interaction shows that there was a response to the

playback


A stimulus phase 809 4 00885

phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431


Both phase and stimulus had three levels resulting in df=4 ( (3-1) times (3-1) ) for interactions and df=2

(3-1) for isolated effects

Table S13 Modelled proportion of identified sonar beam directions aimed at the playback

loudspeaker (MLE) in Experiment I Note that 033 indicates that the sonar beam was aimed

equally often at the three loudspeakers whereas higher values show the preference for the playback

loudspeaker (cf Fig 4) Preferences for the playback loudspeaker were found for individuals A and

B during the playback phase

phase individual Stimulus


silence1 A 039 037 028

B 033 029 035

C 021 034 034

playback A 046 037 052

B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S14 Statistical results for the effect of experimental phase condition (rustling vs control

sound) and their interaction on the call level recorded at the playback microphones in

Experiment II If no interaction was found the effect of experimental phase and condition were

analysed separately

Stimuli individual effect LLR df p

rustling vs silence A phase condition 4053 2 lt 00001

B phase condition 4739 2 lt 00001

C phase condition 342 2 01809

phase 229 2 03183

condition 543 1 00198

rustling vs amplitude

inversion

A phase condition 899 2 00112

B phase condition 1776 2 00001


phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble

A phase condition 3094 2 lt 00001


phase 2677 2 lt 00001



phase 036 2 08367


Table S15 Modelled difference in call level (in dB REMLE) at the rustling-loudspeaker

compared to the control-loudspeaker during the playback phase of Experiment II

Individual control stimulus

silence amplitude inversion phase scramble

A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Table S16 Modelled proportion of identified sonar beam directions aimed at the rustling-

loudspeaker (MLE) in Experiment II Only identified sonar beam directions aimed at either of the

two playback loudspeakers were used for estimating the proportions Therefore 05 indicates that bats

scanned the playback and control loudspeaker equally whereas higher values indicate that the sonar

beam was more often aimed at the rustling loudspeaker (cf Fig 6) This was found for individuals A

and B during the playbacks of rustling with silence showing a clear reaction to insect-generated

sound

Phase individual control stimulus


silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

~ SUPPLEMENTARY FIGURES ~

Fig S1 Relative call levels in Experiment I (Single Playbacks) recorded only on the three central

microphones (ie 3 5 and 6) Displayed is the data for three individual bats (A-C) and for three

different playback types (left to right moth rustling amplitude-inverted control phase-scrambled

control) Call levels are expressed relative to the mean level of all calls recorded at the same

microphone during the silence1 phase Each panel displays the median (plusmn quartiles) of all calls (dots)

recorded on the microphone beside the active playback speaker (0deg) and the microphones at 25deg and

429deg angle around this speaker separately for the three 3-s long phases of an experimental trial

(silence1 playback silence2) Small numbers at the bottom report the total number of unique

echolocation calls recorded during the respective phase The horizontal dotted line at 0 dB indicates

no chance in call level relative to the silence1-phase Experimental phase microphone angle and

stimulus type andor their interactions significantly influenced the recorded call level (see results and

Tables S8-S10 for detailed statistics) Note that the considerable variation in call level is caused by

the batsrsquo continuous sonar beam scanning on top of sonar beam focusing which was controlled for by

a longitudinal random factors structure


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Fig S2 Recorded call levels in Experiment I (Single Playbacks) at each microphone (1-8) for

three individual bats (A-C) and for three different playback types (left to right moth rustling

amplitude-inverted control phase-scrambled control) Each panel displays the median (plusmn quartiles) of

all calls (dots) recorded on each microphone separately for the three 3-s long phases of an

experimental trial (silence1 playback silence2) Small numbers at the bottom report the total number

of unique echolocation calls recorded on each microphone during the respective phase Note that

despite the calibration there is still considerable variation in recorded call level between the

microphones as well as between the bats potentially caused by preferred scanning directions of the

bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Fig S3 Sonar beam direction in Experiment I (Single Playbacks) for three individual bats (A-C)

and for three different playback types (left to right moth rustling amplitude-inverted control phase-

scrambled control) Each panel shows the proportion of identified sonar beam directions aimed at the

playback relative to the total number of all identified sonar beam directions separately for each of the

three 3-s long phases of an experimental trial (silence1 playback silence2) Small numbers at the

bottom indicate the number of identified beam directions that were aimed at the playback during the

respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Fig S4 Recorded call levels in Experiment II (Paired Playbacks) at each microphone (1-8) for








bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Fig S5 Sonar beam direction in Experiment II (Paired Playbacks) For the three bats (individuals

A-C) the proportion of identified sonar beam directions are shown with each column displaying the

results for one of the three paired playback types The sound of a moth rustling on leaves was either

paired with silence (left) or with the amplitude-inverted (middle) or phase-scrambled (right) control

version of a different rustling sound Each panel shows the proportion of identified beam directions

that were aimed at the rustling (coloured R) and control playback (black C) relative to the total

number of identified beam directions separately for each of the three 3-s long phases of an

experimental trial (silence1 playback silence2) Only two loudspeakers the left and right one were

included in this analysis Small numbers at the bottom indicate the number of unique directed calls

that were focused on the two playbacks during the respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

(Fujioka et al 2016 Ghose and Moss 2003 Seibert et al 2013Surlykke and Moss 2000) towards passive acoustic environmentalcuesWe presented greater horseshoe bats either consecutively

(Experiment I) or simultaneously (Experiment II) with recordingsof moths rustling on vegetation and spectral and temporal controlversions of these recordings We had two main predictions First ifbats use passive hearing to improve the acquisition of environmentalinformation we predicted that they would concentrate the scanningmovements of their echolocation beam around a sound source forfurther biosonar-based investigation Second if bats use passiveacoustic information for prey detection we predicted that theywould show a preference for insect rustling over control sounds Totest these predictions we compared call levels recorded at differentmicrophones and how often the sonar beam was directed at theplayback position between silence and playback conditions andbetween different acoustic stimuli

MATERIALS AND METHODSExperimental setupExperiments were conducted in a large sound- and echo-attenuatedflight room (6times35times3 m3) at theMax Planck Institute for OrnithologySeewiesen Germany A small wooden plate (5times7 cm2 widthtimesheight)215 cm above the ground served as a perch for the bats It was faced bya spherical arrangement of eight condenser ultrasound microphones(CM16CMPA Avisoft Bioacoustics Glienicke Germany) and threeloudspeakers (NeoCD10 Fountek Electronics Co JiaXing China)which were mounted on a wooden board (285times205 msup2widthtimesheight) covered by echo-attenuating foam (Fig 1) Themicrophones were arranged in three symmetrical star-shaped sub-arrays each with a central microphone surrounded by three peripheralmicrophones which were equidistant (87plusmnmax 1 cm) andequiangular (25 deg) to the central one (Fig 1AndashD) The membraneof each microphone was 2 m (plusmnmax 09 cm) away from and orientedtowards the head of the perched bat The speakers were mounted

0 deg330

5040

3020

10

50

659 deg475 deg

429 deg

25 deg

4030

2010

429

deg

300

270

240

210180

Rustling

96

0 1 s

kHz

Amplitude inversion Phase-scramble

150

120

90

60

30

A B

C D

E

F

G

0 deg330

300

270

0

ndash20

ndash40

ndash60dB

240

210180

150

120

90

60

30

25 de

g

Fig 1 Experimental setup polar plot ofthe microphone-speaker-array andplayback stimuli (AB) Photograph (A)and sketch (B) of the echo-attenuatedexperimental room with the eight-microphonendashthree-loudspeaker array andthe perch for the bat B also shows theboard (which is covered in A by thecurtain) behind which the experimenterhid during the recordings (CD) Polar plotof the microphone (circles numbered 1ndash8)and loudspeaker (squares marked L MR) positions as seen from the batrsquos perchThe three star-shaped microphonesubarrays around each of the centralmicrophones 3 5 and 6 are highlighted bydifferent colours (purple red orange)The active loudspeaker is marked in green(C central D left) Green dotted circlesdepict constant off-axis angles relative tothe axis from the batrsquos head to the activeloudspeaker Note that the number ofmicrophones surrounding the activeloudspeaker at a given angle variesbetween the middle and the leftrightactive loudspeaker (EndashG) Waveforms(top) and spectrograms (bottom) of threestimulus examples For each the rustlingrecording spectral control (amplitudeinversion) and temporal control (phasescramble) are shown Note that only thefirst second of the full stimulus duration(3 s) is shown

2


Journal

ofEx

perim

entalB

iology







Silence1PlaybackA

B

C


85

kHz

kHz


85

0 s 3 s 6 s 9 s

0

dB

ndash60

70


3


Journal

ofEx

perim

entalB

iology









4


Journal

ofEx

perim

entalB

iology









5


Journal

ofEx

perim

entalB

iology




ndash606

12182430

698 731 681

0 de

g

25 d

eg

429

deg

Individual A

Rustling

745 769 691

Amplitude inversion

738 841 692

Phase-scramble


ndash606

12182430

617 641 634

0 de

g

25 d

eg

429

deg

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

670 743 637 613 618 584


-606

12182430

745 772 777

0 de

g

25 d

eg

429

deg

Individual C




6


Journal

ofEx

perim

entalB

iology





0

025

05

53 112 49

13


53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49


025

05

62 89 108

13

Individual C




7


Journal

ofEx

perim

entalB

iology





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







Silence1PlaybackA

B

C


85

kHz

kHz


85

0 s 3 s 6 s 9 s

0

dB

ndash60

70


3


Journal

ofEx

perim

entalB

iology









4


Journal

ofEx

perim

entalB

iology









5


Journal

ofEx

perim

entalB

iology




ndash606

12182430

698 731 681

0 de

g

25 d

eg

429

deg

Individual A

Rustling

745 769 691

Amplitude inversion

738 841 692

Phase-scramble


ndash606

12182430

617 641 634

0 de

g

25 d

eg

429

deg

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

670 743 637 613 618 584


-606

12182430

745 772 777

0 de

g

25 d

eg

429

deg

Individual C




6


Journal

ofEx

perim

entalB

iology





0

025

05

53 112 49

13


53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49


025

05

62 89 108

13

Individual C




7


Journal

ofEx

perim

entalB

iology





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









4


Journal

ofEx

perim

entalB

iology









5


Journal

ofEx

perim

entalB

iology




ndash606

12182430

698 731 681

0 de

g

25 d

eg

429

deg

Individual A

Rustling

745 769 691

Amplitude inversion

738 841 692

Phase-scramble


ndash606

12182430

617 641 634

0 de

g

25 d

eg

429

deg

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

670 743 637 613 618 584


-606

12182430

745 772 777

0 de

g

25 d

eg

429

deg

Individual C




6


Journal

ofEx

perim

entalB

iology





0

025

05

53 112 49

13


53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49


025

05

62 89 108

13

Individual C




7


Journal

ofEx

perim

entalB

iology





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









5


Journal

ofEx

perim

entalB

iology




ndash606

12182430

698 731 681

0 de

g

25 d

eg

429

deg

Individual A

Rustling

745 769 691

Amplitude inversion

738 841 692

Phase-scramble


ndash606

12182430

617 641 634

0 de

g

25 d

eg

429

deg

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

670 743 637 613 618 584


-606

12182430

745 772 777

0 de

g

25 d

eg

429

deg

Individual C




6


Journal

ofEx

perim

entalB

iology





0

025

05

53 112 49

13


53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49


025

05

62 89 108

13

Individual C




7


Journal

ofEx

perim

entalB

iology





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




ndash606

12182430

698 731 681

0 de

g

25 d

eg

429

deg

Individual A

Rustling

745 769 691

Amplitude inversion

738 841 692

Phase-scramble


ndash606

12182430

617 641 634

0 de

g

25 d

eg

429

deg

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

670 743 637 613 618 584


-606

12182430

745 772 777

0 de

g

25 d

eg

429

deg

Individual C




6


Journal

ofEx

perim

entalB

iology





0

025

05

53 112 49

13


53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49


025

05

62 89 108

13

Individual C




7


Journal

ofEx

perim

entalB

iology





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





0

025

05

53 112 49

13


53 209 79

Amplitude inversion

70 120 51

Phase-scramble

0

025

05

43 87 63

13

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual B

55 80 68 46 149 49


025

05

62 89 108

13

Individual C




7


Journal

ofEx

perim

entalB

iology





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





06

12182430

680 712 639


677 699 622

Amplitude inversion

737 847 689

Phase-scramble


06

12182430

739 777 685

R C

Rel

ativ

e re

cord

ed c

all l

evel

(dB

) Individual B

591 711 576 642 744 578


06

12182430

684 694 671

R CIndividual C




8


Journal

ofEx

perim

entalB

iology





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





0

025

075

100 174 94106 95 96

05

Individual ASilence

90 104 9378 114 74

Amplitude inversion

89 136 84100 189 117

R

C

Phase-scramble

0

025

075

90 187 91110 68 76

05

Pro

porti

on o

f ide

ntifi

ed b

eam

dire

ctio

ns a

imed

at p

layb

ack

Individual A

55 87 8794 190 97 70 129 7583 154 81

RC


025

075

142 158 135159 173 162

05

Individual A



RC


9


Journal

ofEx

perim

entalB

iology








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








10


Journal

ofEx

perim

entalB

iology






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion






































11


Journal

ofEx

perim

entalB

iology























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion























12


Journal

ofEx

perim

entalB

iology





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





individual


I

successful trials

rustling 42 39 40




rustling 2163 1932 2393



II

successful trials

silence 41 36 39




silence 2309 2004 2065






individual stimulus


A 36 31 96

B 21 61 27

C


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








phase 278 2 02489






B phase 669 2 00352

C phase 205 2 03588


B phase 4829 2 lt 00001

C phase 831 2 00156


B phase 2325 2 lt 00001

C phase 321 2 02005


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








individual stimulus


A 15 31 86

B -19 49 13

C









silence1 A 11 08 04

B -02 03 03

C 06 13 13

playback A 17 17 28

B 09 14 14

C 06 13 13


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle phase

phase stimulus

3348

2310

2

4

lt 00001

00001






Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

































Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







loudspeaker)












phase difference

re angle individual

stimulus



B -09 01 02

C -04 -04 -04

429deg A 16 08 05

B -05 05 -02

C -02 -02 -02


B 02 19 08

C 02 02 02

429deg A 25 32 70

B 15 53 10

C -07 -07 -07


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion








angle 3054 2 lt 00001



angle 147 2 04788



angle 636 2 00415





angle 2846 2 lt 00001



Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion





playback



phase 2434 2 lt 00001


phase 1415 2 00008


phase 034 2 08431











silence1 A 039 037 028

B 033 029 035

C 021 034 034


B 033 060 035

C 021 034 034


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion




analysed separately





phase 229 2 03183



inversion




phase

condition

068

491

2

1

07103

00267

rustling vs

phase scramble



phase 2677 2 lt 00001



phase 036 2 08367






A 27 -05 -27

B 28 -24 -04

C -05 -04


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







sound



silence1 A 048 052 042

B 044 037 046

C 047 048 048


B 073 032 046

C 047 048 048


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

















Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion







respective phase


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion









bats


Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion












Jour

nal o

f Exp

erim

enta

l Bio

logy

bull S

uppl

emen

tary

info

rmat

ion

Documents

Environmental acoustic cues guide the biosonar attention