Auditory opportunity and visual constraint enabled the evolution of echolocation in bats


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Auditory opportunity and visual constraint enabled the evolution of echolocation in bats

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Auditory opportunity and visual constraint enabled the evolution of echolocation in bats
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Nature Communications
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Thiagavel, Jeneni
Cechetto, Clément
Santana, Sharlene E.
Jakobsen, Lasse
Warrant, Eric J.
Ratcliffe
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English

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Laryngeal Echolocation ( local )
Bats ( local )
Biomechanical Transition ( local )
Phytophagous Pteropodidae ( local )
Predatory Bats ( local )
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serial ( sobekcm )

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Substantial evidence now supports the hypothesis that the common ancestor of bats was nocturnal and capable of both powered flight and laryngeal echolocation. This scenario entails a parallel sensory and biomechanical transition from a nonvolant, vision-reliant mammal to one capable of sonar and flight. Here we consider anatomical constraints and opportunities that led to a sonar rather than vision-based solution. We show that bats’ common ancestor had eyes too small to allow for successful aerial hawking of flying insects at night, but an auditory brain design sufficient to afford echolocation. Further, we find that among extant predatory bats (all of which use laryngeal echolocation), those with putatively less sophis- ticated biosonar have relatively larger eyes than do more sophisticated echolocators. We contend that signs of ancient trade-offs between vision and echolocation persist today, and that non-echolocating, phytophagous pteropodid bats may retain some of the necessary foundations for biosonar.
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Nature Communications, Vol. 9, no. 98 (2018-01-08).

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ARTICLEAuditoryopportunityandvisualconstraintenabled theevolutionofecholocationinbatsJeneniThiagavel1,ClémentCechetto 2,SharleneE.Santana3,LasseJakobsen2EricJ.Warrant 4&JohnM.Ratcliffe 1,2,5,6Substantialevidencenowsupportsthehypothesisthatthecommonancestorofbatswas nocturnalandcapableofbothpowered ightandlaryngealecholocation.Thisscenarioentails aparallelsensoryandbiomechanicaltransitionfromanonvolant,vision-reliantmammalto onecapableofsonarand ight.Hereweconsideranatomicalconstraintsandopportunities thatledtoasonarratherthanvision-basedsolution.Weshowthatbats ’ commonancestor hadeyestoosmalltoallowforsuccessfulaerialhawkingof yinginsectsatnight,butan auditorybraindesignsuf cienttoaffordecholocation.Further,we ndthatamongextant predatorybats(allofwhichuselaryngealecholocation),thosewithputativelylesssophisticatedbiosonarhaverelativelylargereyesthandomoresophisticatedecholocators.We contendthatsignsofancienttrade-offsbetweenvisionandecholocationpersisttoday,and thatnon-echolocating,phytophagouspteropodidbatsmayretainsomeofthenecessary foundationsforbiosonar. DOI:10.1038/s41467-017-02532-x OPEN 1DepartmentofEcologyandEvolutionaryBiology,UniversityofToronto,25WillcocksStreet,Toronto,ONM5S3B2,Canada.2DepartmentofBiology, UniversityofSouthernDenmark,Campusvej55,5230,OdenseC,Denmark.3DepartmentofBiologyandBurkeMuseumofNaturalHistoryandCulture, UniversityofWashington,Seattle,WA98195,USA.4DepartmentofBiology,LundUniversity,Sölvegatan35,22362Lund,Sweden.5DepartmentofBiology, UniversityofTorontoMississauga,3359MississaugaRoad,Mississauga,ONL5L1C6,Canada.6DepartmentofNaturalHistory,RoyalOntarioMuseum,100 QueensPark,Toronto,ONM5S2C6,Canada.Correspondenceandrequestsformaterialsshouldbeaddressedto J.M.R.(email: j.ratcliffe@utoronto.ca )NATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications1 1234567890():,;

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Bats(Chiroptera)arethesecondlargestorderofmammals, comprising > 1300speciesandcharacterizedbypowered ight1.Thevastmajorityofbatsarestrictlynocturnal2, withafewspeciesalsoactivearounddawnanddusk3 , 4.Long beforethediscoveryofecholocation,batswereoncedividedinto “ megabats ” (membersofthefamilyPteropodidae)and “ microbats ” (theremaining~20chiropteranfamilies)1 , 5 – 7.Todaythese areanachronisticterms,andthepteropodids[(~200visiondependentspecies,noneusinglaryngealecholocation(LE)]are placedinYinpterochiroptera(a.k.a.Pteropodiformes),which togetherwithYangochiroptera(a.k.a.Vespertilioniformes)comprisethetwochiropteransuborders.Bothsubordersareotherwise comprisedsolelyoflaryngealecholocators6 , 7.Fromastrictparsimonyperspective,LE,ifconsideredasasingletrait,could thereforehaveevolvedonceinbats,andsubsequentlybeenlostin thepteropodids.Alternatively,LEcouldhaveevolvedatleast twiceindependently,onceormoreinYangochiroptera,andonce ormoreinYinpterochiroptera,afterthepteropodidsdiverged6 , 8(Fig. 1 ).Thesumofevidence,however,indicates(i)thatthebats ’ commonancestorwasapredatorylaryngealecholocatorand(ii) thatthephytophagouspteropodidshavelostmost,butperhaps notall,hallmarksofthiscomplexactivesensorysystem8 – 12. SinceDonaldGrif n ’ sdiscoveryofecholocation5 , 13,theprevailingviewhasbeenthatthe rstbatsweresmall,nocturnal, insectivorousecholocators6 , 14 – 16.Speci cally,batsarethoughtto haveoriginated 64mya17 , 18toexploitthethenunrealized foragingnicheofsmall,nightyinginsects,aresourcemostbats relyontoday5 , 12 , 15 , 19.Indarknessanddimlight,nascentecholocationwouldhaveallowedthesebatstopursuethesethen vulnerableinsects5 , 15.Grif n5toodividedbatsintothosethatuse laryngealecholocation(hereafter,LEbats)andthosethatdonot (i.e.,thepteropodids).WithinLEbats,heidenti edthreegroups: (i)batsproducingmulti-harmonic(MH)calls,withlittlefrequencymodulation,(ii)batsproducingdownward-sweeping, frequency-modulatedcalls,withmostenergyinthefundamental harmonic,and(iii)batsproducinglong,constantfrequencycalls, withenergytypicallyconcentratedinthesecondharmonic5. Thesefoursensorydivisions — non-laryngealecholocators (hereafter,pteropodidsorNLEbats),multi-harmonicecholocators(MHbats),frequencymodulating,dominantharmonic echolocators(DHbats),andconstantfrequencyecholocators(CF bats) — remainrobustfunctionaldescriptorsofbiosonardiversity inbats6 , 20.Grif n5andotherssince6 , 12 , 14 , 21 – 24havesuggested thatMHcallsmostcloselyre ectbats ’ ancestralcondition.Ifso, pteropodids,DH,andCFbatswouldrepresentthreederived sensorystates6 , 10 , 12.Whilenopteropdodidisthoughttobe predatoryortobecapableofLE,membersofthegenus Rousettus usebiosonarbasedontongueclickingfororientation25 , 26.This formofecholocation,whileeffective,fallsshortofthemaximum detectiondistancesandupdateratesobservedinLEbats19 , 25 , 26. AmongLEbats,ithasbeenpreviouslyarguedthatCFandDH batspossessmoreadvancedabilitiesfordetectingandtracking yingpreythandoMHbats5 , 27 – 30.Similarly,differentvisual abilitiesexistwithintoday ’ sbats,withpteropodidspossessingthe mostadvancedvisualsystems,insomespeciesincludinganoptic chiasm31,andtheLEvespertilionidsandrhinolophidsperhaps theleast32.Interestingly,allrhinolophidsuseCFcalls,whilemost vespertilionidsuseDHcalls12 , 20 , 29.ItisamongtheMHspecies thatwe ndtheLEbatscapableofthegreatestquanti edvisual resolution32 , 33andevenultravioletlightsensitivity34. Here,weusephylogeneticcomparativemethodstofurthertest thehypothesisthattheancestralbatwasasmall,predatory echolocator,whichproducedMHbiosonarsignals5 , 12 , 14.Additionally,wetestthreehypothesesabouttherelationshipsbetween visualabilitiesandecholocationbehaviorinbatsacrosstheirfour sensorydivisions,andwithrespecttodietandroostingbehavior, relativetoancestralstates(ASs).Thesethreehypothesesre ect mechanisticexplanationsfortheoriginationandevolutionofLE inbatsforpursuing yinginsects,andpredictauditoryopportunityandvisualconstraint5 , 35.Speci cally,wetestpredictions thattheancestralbathad(i)anauditorybraindesigncapableof supportingearlyLE,but(ii)eyesofinsuf cientabsolutesizeto allowinsecttrackingatnight.Wealsotestthepredictionsthat todaynotonlywouldpteropodidspossessrelativelylargereyes thanLEbatsbutthatamongpredatorybats(allofwhichuseLE), (i)MHbatswouldhaverelativelylargereyesthanDHandCF batsand(ii)short-wavelength-sensitive(SWS)opsingeneswould remainfunctionalinMHandDHbats,buthavelostfunctionality inCFspecies36. Usingmodernphylogeneticcomparativemethodsandarecent batmolecularphylogeny,we ndsupportforeachofthesefour hypotheses.Speci cally,ouranalysesunambiguouslysupportthe ideathatthecommonancestorofmodernbatswasasmall, ying nocturnalpredatorcapableofLEandthatthiscomplexsensory traithasregressedinthepteropodids.Further,ourresultssuggest thatthisvocal – auditorysolutionwasfavoredovervisiondueto Pteropodidae Rhinolophoidea Emballonuroidea Noctilionoidea Vespertilionoidea+ + + – Fig.1 Twoequallyparsimonioushypothesesfortheoriginationoflaryngeal echolocationinbats.Theunshadedsidedepictsthetwooriginshypothesis andpredictsthatlaryngealecholocationoriginatedinthecommonancestor totheEmballonuroidea,Noctilionoidea,andVespertilionoideaandagainin theRhinolophoidea.Theshadedsidedepictsthesingleoriginhypothesis, whichpredictslaryngealecholocationwaspresentinthecommonancestor ofallbatsandlostinthePteropodidae.Middlecolumndisplays(topto bottom) ve30 – 35gspeciesfromeachofthesemajorgroups: Cynopterus brachyotis (non-echolocating,phytophagous), Rhinolophushildebrandti (echolocating,predatory), Taphozousmelanopogon (echolocating, predatory), Tonatiaevotis (echolocating,predatory), Nyctalusnoctula (echolocating,predatory).Pleasenotethatbatswithconstantfrequency (CF),multi-harmonicfrequency-modulatedcalls(MH)andfundamental harmonicfrequencymodulatedcalls(DH)(i.e.,mostenergyinfundamental harmonic)arefoundinbothsubordersofbats.PhotographsbyBrock FentonandSigneBrinkløv ARTICLENATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-x2NATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications

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pre-existingsensoryopportunitiesandconstraintsandthatthese sensorytrade-offspersisttodifferentextentsinbatstoday. Results Estimatedstatesandtraitsoftheancestralbat .Weestimated Bayesianposteriorprobabilitiesforbothforagingstrategyandcall typeunderanequalrates(EQ)modelofevolution,asthismodel producedthelowestAICcscoresforbothcategories(foraging category:EQAICc = 45.43,symmetrictransition(SYM)AICc = 48.51,all-rates-different(ARD)AICc = 53.35;calldesigncategories:EQ(AICc) = 41.2,SYM = 44.17,ARD = 49.44).Wefound anadditionalsupportforthehypothesisthattheancestralbatwas apredatory,echolocatingbat(Bayesianposteriorprobabilities: animal-eatinglaryngealecholocator > 0.999,phytophagouslaryngealecholocator < 0.001,phytophagousNLE < 0.001;Fig. 2 a). ThesesameresultssupporttheideathatphytophagyhasoriginatedatleasttwiceintheChiroptera,onceinthePteropodidae andatleastonceinthePhyllostomidae(Fig. 2 a).Withrespectto biosonarsignaldesign,wefoundsupportforthehypothesisthat theancestralbatproducedmultiharmoniccalls(Bayesianposteriorprobabilities:MH > 0.999,constantfrequency < 0.001, fundamentalharmonicfrequencymodulated < 0.001;nonlaryngealecholocating: < 0.001;Fig. 2 b). WereconstructedASsofbodyandbrainmass.These reconstructionssuggestthattheancestralbatwas~20g,roughly themeansizeoftoday ’ slaryngealecholocatingbats,andsmaller thanmostextantpteropodidbats(Fig. 3 ;SupplementaryFig. 1 ), witharelativebrainmass > 20%smallerthanthatofextant pteropodidspecies(bodymass: N = 183,rootAS = 18.55g,95% con denceinterval(CI) = 7.18(lowerlimit),47.91(upperlimit); brainmass: N = 183;AS = 428.33mg,CI = 229.59,799.08), con rmingapreviousreport37.ForcomparisonwithAS reconstructionsofauditorybrainregions(seebelow)andfor comparisonwithmoderndaybats,wealsoreconstructedtheASs ofseveralnon-auditorybrainregionmassesassociatedwith sensoryinformationprocessing(neocortex: N = 149;AS = 94.15 mg,CI = 61.25,144.71;hippocampus: N = 149;AS = 26.53mg,CI = 18.24,38.58;olfactorybulb: N = 149;AS = 9.02mg,CI = 5.8, 14.05;superiorcolliculus: N = 84;AS = 6.66mg,CI = 4.69,9.45; Fig. 3 ;SupplementaryFig. 1 ). Phylogeneticsignal .Toestimatethedegreetowhichphylogeny predictsthepatternofcovarianceamongspecies,weusedarecent molecularphylogenetictree38andPagel ’ slambda39.Wefound signi cantphylogeneticsignalforalllog-transformedvariables (bodymass: = 0.9787;log L = 210.37, p < 0.001;brainmass: = 0.82;log L = 143.59, p < 0.001;eyemass: = 0.95;log L = 351.73, p < 0.001;log L = 55.85, p < 0.001;neocortex: = 0.95;log L = 135.26, p < 0.001;hippocampus: = 0.92;log L = 187.85, p < 0.001;superiorcolliculus: = 1.0;log L = 72.65, p < 0.001;olfactorybulb: = 0.97;log L = 146.76, p < 0.001;inferiorcolliculus: = 0.87;log L = 72.79, p < 0.002;auditorynucleus: = 0.84;log L = 68.21, p< 0.001). Mass-residuals .Weshow(usingphylogeneticgeneralizedleastsquaresbyrestrictedmaximumlikelihood)thatbrainandeye masswerepositivelycorrelatedwithbodymass(brain: b = 0.654 ± 0.010; t = 64.917; p < 0.001; R2= 0.877;eye: b = 0.745 ± 0.056; t = 13.197; p < 0.001; R2= 0.705),aswerebrainregions(inferior colliculus: b = 0.566 ± 0.030; t = 18.673 p < 0.001, R2= 0.295; auditorynucleus: b = 0.578 ± 0.000; t = 745,121.1, p < 0.001, R2= 0.246;superiorcolliculus: b = 0.590 ± 0.021; t = 28.344, p < 0.001, R2= 0.930;olfactorybulb: b = 0.726 ± 0.035; t = 20.895, p < 0.001, R2= 0.800;hippocampus: b = 0.603 ± 0.022; t = 26.896, p < 0.001, R2= 0.740;neocortex: b = 0.710 ± 0.000; t = 9,202,949, p < 0.001, R2= 0.879).Thus,wegeneratedphylogeneticresidualsforlogtransformedbrainmass,eyesize,andbrainregionmasseson bodymass,andtestedfordifferencesintheseresidualsacrossour threeforagingstrategiesandfourbiosonarsignaldesigns. Ancestralbrainregionsversusmodernforagingcategories . Phylogeneticanalysesofvariance(ANOVAs)indicatethatpteropodidbatsaresigni cantlylargerthananimal-eatingbats( F = 40.353, p = 0.03;SupplementaryTable 1 ).Wealsofoundthat absolutebrain,neocortex,hippocampus,andolfactorybulbsizes aresigni cantlylargerinpteropodidsthaninanimal-eatingbats (brain: F = 70.763, p = 0.009;neocortex: F = 55.618, p = 0.006; hippocampus: F = 82.641, p = 0.001;olfactorybulb: F = 85.068, p = 0.001;SupplementaryTable 1 ).ASreconstructionssuggestthat thesestructureshavebecomelargerinpteropodids,whilethe neocortexandolfactorybulbmayhavebecomesmallerin animal-eatingspecies(Fig. 3 ;SupplementaryFig. 1 ).Wefound thatabsolutesuperiorcolliculiarelargerinpteropodidbatsthan inanimal-eatingbats( F = 26.937, p = 0.014;Supplementary Table 1 )andlargerinpteropodidscomparedtoancestral reconstructions,suggestinggreaterinvestmentinvisualtracking (Fig. 3 ;SupplementaryFig. 1 ).Foreachofthesetraits,thephytophagousphyllostomidsfellsomewherebetweenthepteropodids andanimal-eatingbats,anddidnotdifferfromeitherofthese groupssigni cantly(SupplementaryTable 1 ). We,likepreviousauthors40 – 42,foundthatphytophagous speciesingeneralhaverelatively(i.e.,phylogeneticallyinformed mass-residuals)largerbrains( F = 113.747, p = 0.001)than predatorybats.Also,likepreviousstudies,wefoundthat phytophagousspecieshaverelativelylargerneocortices( F = 80.525, p = 0.002),hippocampi F = 126.534, p = 0.001),olfactory bulbs F = 129.473, p = 0.001)thandopredatoryspecies41 , 43. Additionally,wefoundthatthephytophagousbatsalsohad relativelylargersuperiorcolliculi( F = 35.649, p = 0.006)than animal-eaters(SupplementaryTable 2 ). Ancestralbrainregionsversusmodernecholocationcategories . Withrespecttoecholocationsignaldesign,wefoundthatbats thatdonotproduceecholocationsignalsusingtheirlarynges(i.e., thepteropodids)hadlargerabsolutebrains,neocortices,hippocampiandolfactorybulbsthandidCFandDHbats(brain: F = 49.96, p = 0.016,neocortex: F = 41.58, p = 0.016,hippocampus: F = 43.16, p = 0.017,olfactorybulb: F = 35.09, p = 0.025)andlarger absolutesuperiorcolliculithanDHbats(brain: F = 21.36, p = 0.011)(seeSupplementaryTable 3 ). Inrelativeterms,wefoundthatthepteropodidshadlarger relativebrains,neocortices,olfactorybulbsthanbothCFandDH bats(brain: F = 84.54, p = 0.002,neocortex: F = 90.16, p = 0.001, olfactorybulb: F = 25.45, p = 0.016),largerrelativehippocampi thanDHbats( F = 35.82, p = 0.023),andlargerrelativesuperior colliculithanalllaryngealecholocatingbats,regardlessofcall type( F = 44, p = 0.001).Otherthanwithrespecttorelative superiorcolliculussize,MHbatsfellbetweenthepteropodids,on theonehand,andtheCFandDHbats,ontheother,forallother measuresofrelativebrainandbrainregionsize(seeSupplementaryTable 4 ). Ancientauditorybrainversusmodernforagingcategories . Withrespecttorelativeauditorybrainregionsize,wefoundthe oppositetrendstothoseabovefortheinferiorcolliculiand auditorynuclei.Speci cally,pteropodidauditorybrainregionswererelativelysmallerthanthoseoflaryngealecholocatingbats41(inferiorcolliculus: F = 73.291, p = 0.001;auditorynucleus: F = 58.585, p = 0.001;SupplementaryTable 2 ). NATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-xARTICLENATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications3

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microphyllumCardioderma corMegaderma spasmaPteropus vampyrusPteropus poliocephalusPteropus hypomelanusPteropus tonganusPteropus samoensisParanyctimene raptorMacroglossus minimusSyconycteris australisEpomophorus gambianusMicropteropus pusillusEpomophorus wahlbergiEpomops franquetiHypsignathus monstrosusMyonycteris torquataRousettus aegyptiacusRousettus leschenaultiiScotonycteris zenkeriMegaerops ecaudatusMegaerops niphanaeCynopterus brachyotisCynopterus sphinxChalinolobus morioChalinolobus gouldiiTylonycteris robustulaTylonycteris pachypusVespertilio murinusPipistrellus kuhliiNyctalus noctulaPipistrellus javanicusEptesicus serotinus Eptesicus brasiliensisEptesicus fuscus Plecotus auritusBarbastella barbastellusPipistrellus subflavusRhogeessa tumidaRhogeessa parvulaLasiurus borealisScotophilus dinganiiScotophilus nigritaScotophilus heathiiScotophilus kuhliiMyotis annectansMyotis adversusMyotis horsfieldiiMyotis dasycnemeMyotis muricolaMyotis nattereriMyotis myotisMyotis bechsteiniiMyotis daubentoniiMyotis bocagiiMyotis tricolorMyotis albescensMyotis nigricansMyotis ripariusMyotis lucifugusMyotis mystacinusMiniopterus inflatusMiniopterus pusillusMiniopterus tristisMiniopterus magnaterMiniopterus schreibersiiEumops glaucinusEumops perotisEumops auripendulusMolossus molossusMops condylurusChaerephon pumilusChaerephon jobensisTadarida aegyptiacaOtomops martiensseni Molossus aterCheiromeles torquatusNatalus tumidirostrisArtibeus lituratusArtibeus concolorArtibeus jamaicensisArtibeus glaucusArtibeus toltecusArtibeus phaeotisSphaeronycteris toxophyllum Ardops nichollsiArtibeus hartii Platyrrhinus infuscusPlatyrrhinus vittatusPlatyrrhinus brachycephalusPlatyrrhinus helleriVampyrodes caraccioliPlatyrrhinus lineatus Chiroderma villosumChiroderma trinitatumChiroderma salviniMesophylla macconnelliUroderma bilobatum Sturnira tildaeSturnira ludoviciSturnira lilium Rhinophylla pumilioCarollia perspicillataCarollia castaneaLionycteris spurrelliLonchophylla mordaxLonchophylla thomasiPhyllostomus hastatus Phyllostomus elongatusMimon crenulatumPhylloderma stenopsLophostoma schulziLophostoma silvicolumTonatia bidensPhyllostomus diacolorTrachops cirrhosusMacrophyllum macrophyllumVampyrum spectrumGlossophaga longirostrisGlossophaga soricinaMonophyllus plethodonBrachyphylla cavernarumAnoura geoffroyi Anoura caudiferMicronycteris megalotisMicronycteris minutaMicronycteris brachyotisPteronotus personatusPteronotus devyiPteronotus gymnonotusPteronotus parnelliiMormoops megalophyllaThyroptera tricolor Noctilio leporinusNoctilio albiventrisFuripterus horrensPeropteryx macrotisPeropteryx trinitatisCormura brevirostrisSaccopteryx canescensSaccopteryx bilineataSaccopteryx leptura Rhynchonycteris nasoEmballonura monticolaEmballonura semicaudata Coleura afraTaphozous mauritianusTaphozous melanopogonTaphozous hildegardeaeTaphozous longimanusSaccolaimus saccolaimus Nycteris javanicaNycteris argeNycteris grandisNycteris macrotisNycteris thebaica Nycteris hispidaRhinolophus hildebrandtiRhinolophus eloquensRhinolophus clivosusRhinolophus ferrumequinumRhinolophus capensisPredatory laryngeal echolocators (>0.999) Phytophagous laryngeal echolocators (<0.001) Phytophagous non-laryngeal echolocators (<0.001) MH bats (–99.9%) NLE bats (<0.0004%) DH bats (<0.004%) CF bats (<0.005%) a b ARTICLENATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-x4NATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications

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However,wefoundnodifferencesbetweenforagingcategories withrespecttotheabsolutemassesoftheauditorybrainregions: absoluteinferiorcolliculussize( F = 0.323, p = 0.946)andabsolute auditorynucleussize( F = 0.043, p = 0.992),whichremainsimilar acrossthesethreecategories(SupplementaryTable 1 ).Neither didweobserveanydifferencesinthesizesofauditorybrain regionsinmodernbatsrelativetothecommonancestor(inferior colliculus: N = 84;AS = 12.93mg,CI = 9.09,18.4;auditory nucleus: N = 84;AS = 5.7mg,CI = 4.08,7.97)(Fig. 3 ;SupplementaryFig. 1 ;SupplementaryTable 1 ). Ancientauditorybrainversusmodernecholocationcategories . Withrespecttobiosonarsignaldesigncategories,wefoundthat therewerenosigni cantdifferencesintheabsoluteauditory regionsofthenon-laryngealecholocatingpteropodidsandanyof thelaryngealecholocatingbats,regardlessofsignaldesign (inferiorcolliculus: F = 1.558, p = 0.826,auditorynucleus: F = 1.558, p = 0.817;SupplementaryTable 3 ).Inrelativeterms,we foundthatthepteropodidshadsmallerauditoryregionsthan laryngealecholocatingbats,regardlessofcalltype(inferiorcolliculus: F = 42.598, p = 0.001,auditorynucleus: F = 47.309, p = 0.001)(seeSupplementaryTable 4 ). Eyesizeintheancestralbatversusinmodernbats .Wefound thatthePlasticinemodelsbestpredictedeyediametersreported intheliterature,andthususedtheseasproxiesforeyediameter inouranalyses(Plasticinemodel: R2= 0.9, p < 0.001;eyelid length: R2= 0.78, p < 0.001;ZB – IOD: R2= 0.3, p < 0.002).Using theseestimates,wereconstructedtheASofabsoluteeyesize( N = 183;AS = 7.67mg,CI = 20.23,110.09;Fig. 3 ).Thistranslates intoanancestraleyediameterof3.13mm.Thisissmallerthan thesmallestpteropodideyefoundtoday( Syconycterisaustralis withadiameterof5.03mm)andsimilarinsizetothatofthe largestextantphytophagousandpredatorylaryngealecholocating bats(seeSupplementaryData 1 ). Wealsocon rmedthatpteropodidshaveabsolutelylargereyes thandolaryngealecholocators( F = 149.248, p = 0.001;SupplementaryTable 1 ),andcomparedtotheASestimateattheroot node,thissuggestsatrendofincreasingeyesizeinpteropodids andpossiblereductionineyesizeinmostextantlaryngeal echolocatingbats(Fig. 3 ;SupplementaryFig. 1 ).Wealsofound thatinrelativeterms,thenon-laryngealecholocatingpteropodids hadlargereyesthanlaryngealecholocatingbats,regardlessofdiet ( F = 88.362, p < 0.001)(SupplementaryTable 2 )orcalltype (absolute: F = 136.18, p = 0.001;relative: F = 146.86, p = 0.001)(see SupplementaryTables 3 and 4 ). Toconsidertherelationshipbetweenvisualinvestmentand echolocationsophistication,withouttheconfoundingeffectsof diet,wethenconsideredtherelationshipsbetweenalltraitsand echolocationcalldesigninonlypredatoryspecies(i.e.,after removingallpteropodidsandallphytophagousphyllostomids). Thatis,betweenpredatorybatsproducingMHcalls(AS),andCF andDHcalls(bothderived).Wefoundnodifferencesbetween MH,DH,andCFpredatorybatswithrespecttoabsolutebody, brain,brainregion,noreyemass(i.e.,alltraitsconsidered; SupplementaryTable 5 ).However,wefounddifferencesamong thesebatswithrespecttorelativeeyemass( F = 31.450, p = 0.048), neocortexmass( F = 41.499, p = 0.004),andsuperiorcolliculus mass( F= 14.256 p = 0.048)(Fig. 4 ;SupplementaryTable 6 ). Speci cally,wefoundthatrelativeeyesizewassigni cantly largerinMHbatsthaninDHbats( p = 0.05),andnearlysoin MHversusCFbats( p = 0.08).Wefoundnodifferenceinrelative eyesizebetweenDHandCFbats( p = 0.957).Similarly,wefound thatrelativeneocortexwaslargerinMHthaninDHbats( p = 0.003),andnearlysowithrespecttorelativesuperiorcolliculus mass( p = 0.063)(Fig. 4 ;SupplementaryTable 6 ).Last,as predicted36,wefoundthattheancestralbatlikelypossessed functionalSWSopsingenes(Bayesianposteriorprobabilities: functionalSWSopsingene:0.971;non-functionalSWSopsin gene:0.029),andthatamongpredatorybats,thesegenesarenow non-functionalinCFbatsbutremainfunctionalinMHandDH bats( p = 0.002)(SupplementaryFig. 3 ). Becausetheaboveresultsurprisedus,wewantedtoconsider thepotentialin uenceofroostingpreference(i.e.,whetherlight environmentmightimpactrelativeeyesize).However,after categorizingpredatoryspeciesasroostingeitherexclusivelyin caves/cavitiesorasalsousingexposedroosts(Supplementary Data 1 ),wefoundnodifferencesinabsolute( F = 0.676, p = 0.427) orrelative( F = 0.412, p = 0.545)eyemassbetweenthe3calltype groups.Wealsofoundnosigni cantrelationshipbetweenthese tworoostcategoriesandancestral(MH)versusderived(CF+ DH)calltypes( p = 0.950).Wedidhowever ndthattheancestral batwaslikelytohaveroostedusingexposedsurfaces,ratherthan cavesorcavities(Bayesianposteriorprobabilities:exposedroosts: 0.998,caves/cavities:0.002). Figure 5 illustratesthephylogeneticallyinformedlinear regressionsbetweeneyeandbodymassinthe vemostspeciose familiesofbats,andsuggeststhestrictlypredatoryemballonurids (allMHbats)havethelargesteyesamongLEbats. Discussion Ourcomparativeanalyseslendstrongsupporttothealreadywellsupportedhypothesisthatthecommonancestorofbatswasa small(~20g),predatory,laryngealecholocator5 , 12 , 37.Speci cally, abatthattook yinginsectsonthewingatnight5androosted externally,ratherthandeepincaves.Ourresults,thus,also supporttheconclusionthatLEhasbeenlost,ratherthannever gained,inthefamilyPteropodidae8(Figs. 1 – 3 ).Theyalsoindicate thataswitchtoaphytophagousdietoccurredatleasttwicein batssincetheirorigin,onceinthepteropodids(Yinpterochiroptera)andonceormorewithinthelaryngealecholocating familyPhyllostomidae(Yangochiroptera)44(Fig. 2 a). Wealsocon rmrelativebrainsizeisgreaterinphytophagous bats(i.e.,thepteropodidsandthelaryngealecholocatingphytophagousphyllostomids)thantoday ’ spredatorybats40 – 42 , 45(SupplementaryTable 2 ;SupplementaryFig. 2 ),andcomparedto Fig.2 Theancestralstateestimatesofcalltypesandforagingcategories. a Theecholocationsignalsofbatspecies( N = 183)werecategorizedas(i) constantfrequency(CF),(ii)multi-harmoniccalls(MH),(iii)frequencymodulatedcallsdominatedbythefundamentalharmonic(DH),ornon-laryn geal (NLE,i.e.,pteropodids).ModelsofevolutionwerecomparedusingAICcscoresandthecharacterstatesforancestralcalltypeswereestimatedunder an equalratesmodelofevolution.Thesemarginalancestralstates(i.e.,theempiricalBayesianposteriorprobabilities)havebeenoverlainontheph ylogeny. We ndsupportforamulti-harmonicancestralcalltype(Bayesianposteriorprobabilities:CF: < 0.001;MH: > 0.999;DH: < 0.001;MLE: < 0.001). b Bats werealsocategorizedas(i)predatorylaryngealecholocators(ALE),(ii)phytophagouslaryngealecholocators(PLE)and(iii)phytophagousnon-l aryngeal echolocators(PNLE).ModelsofevolutionwerecomparedusingAICcscoresandthecharacterstatesforancestralcalltypeswereestimatedunderan equalratesmodelofevolution.Thesemarginalancestralstateshavebeenoverlainonthephylogeny.Ourresultssuggestthattheancestralbatwasa predatorylaryngealecholocator(Bayesianposteriorprobabilities:ALE: > 0.999;PLE: < 0.001;PNLE: < 0.001) NATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-xARTICLENATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications5

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thecommonancestor.Thistrendislargelyduetoenlargementof theolfactorybulb,hippocampus,andneocortexinphytophagous bats41 , 43(Fig. 3 ;SupplementaryFig. 1 ).Further,ouranalyses demonstratetheancestralbathadarelativelylargerbrainthan some,butnotall,extantpredatorybatlineages,perhapsreconcilingacurrentpointofcontention37 , 46(SupplementaryFig. 2 ). Ourresultsalsosupportthehypothesisthatthisbatusedmultiharmonic(MH)echolocationcalls,andthusthatconstantfrequency(CF)anddominant-harmonic(DH)calldesignsare derivedstates5 , 12 , 14 , 29(Fig. 2 b). Basedonthishypotheticalframework,wenowconsiderthree hypothesesabouttheevolutionofbatecholocation.Speci cally, weinvestigatewhatpotentialauditoryopportunitiesandvisual constraintsmayhavecharacterizedthiscommonancestor,and thepastandpresentrelationshipsbetweenthesesensesinbats.A dietofnightyinginsectsisthoughttohaveconstrainedthe ancestralbat(andindeedmostpredatorybatstoday)toasmall bodysize47.Basedonourresults,wecontendthatthisnocturnal ancestorhadanauditorysystemsuf cienttoaffordecholocation, buteyestoosmallinabsolutesize — duetotheconstraintsof smallskull — toallowsuccessfultrackingofnightyingprey35. Wealsoprovideevidencethatspecies-speci ctrade-offsbetween visionandsonarpersisttothisday. Tobetterunderstandvertebratebrainevolution,itisnow establishedthatweshouldconsidernotonlybrainandbrain regionsizeinrelativeterms,butintermsofabsolutesize.Thisis becauseabsolutesizebetterre ectsprocessingpower,neural investment,andinformationuse48.Strikingly,althoughweconrmedthatphytophagousspecieshaverelativelylargerbrains40 – 42andnon-auditorybrainregionsthantoday ’ spredatory bats41 , 43,andthantheancestralbat(SupplementaryTable 2 ; SupplementaryFig. 2 ),wefoundthattheancestralbat ’ sauditory brainregionswereofthesamerelativesizeasinextantpredatory batsandhadauditoryregionsroughlythesameabsolutesizeas thosefoundintoday ’ sLEbats(Fig. 3 ;SupplementaryTable 1 ; SupplementaryFig. 1 ). Thisoutcomesupportsourhypothesisthattheancestralbat hadsuf cientauditorypowersthatcouldplausiblyallowfora sonarsolutioninaidofdetectingnight yinginsects.However, thisbatwouldhavealmostcertainlypossessedasonarsystemless sophisticatedthanthoseoftoday ’ spredatorybats.First,because ~65millionyearsofevolutionaryre nementhavesince elapsed5 , 12 , 19 , 22.Second,sonarperformanceshouldalsohave improvedbecausethenight-activeinsectshavesincebecome betteratevadingpursuitandthusrepresent~65millionyearsof selectivepressuresonmostbats ’ sonarsystemstoeffectivelytrack prey15 , 19.Indeed,whilepaleontologicalevidencesuggeststhatthe oldestknownfossilbat,theinsect-eating Onychonycteris nneyi (~52.5mya),possessedthetympanalboneconnectionnecessary forsonartargetranging11,thecochleasuggestsfrequencydiscriminationandupperfrequencysensitivityinferiortothatof mostextantLEbats49. Ourresultssuggesttousthatpteropodidshaveapparently maintainedauditorybrainregionsofthesameabsolutesizeasthe 1600 1400 1200 1000 800 600 400 200 0Inferior colliculus (mg) Superior colliculus (mg) Auditory nucleus (mg)30 25 20 15 10 5 0 60 50 40 30 20 10 0Eye (mg) Neocortex (mg) Body (g)500 400 300 200 100 0 250 200 150 100 50 0 ALE PLE PNLE ASR ALE PLE PNLE ASR ALEPLEPNLEASR ALE PLEPNLEASR ALE PLE PNLE ASR ALEPLEPNLEASR 12.5 10 15 7.5 5 2.5 0abc def Fig.3 Theancestralstatesofbatsversusmodernforagingcategories.Theancestralstates(maximumlikelihoodestimateoftherootnode)ofsix continuoustraitsconsideredinthisstudyareshownwith95%con denceintervals.Thetreewasre-rootedateachinternalnodesandcontrastsstateat therootwascomputedeachtime.ASestimateattherootcomparedtoextantforagingcategoriesfor: a bodymass( N = 183), b eyemass( N = 183), c neocortexmass( N = 149), d superiorcolliculusmass( N = 84), e inferiorcolliculusmass( N = 84),and f auditorynucleusmass( N = 84).Theancestral staterangeofeyemassandnon-auditorybrainregions( b-d )suggestanincreaseinpteropodids,whilethoseoftheauditoryregions( e , f )suggestabasic auditorybraindesignhasbeenconservedinallbats.Wefoundthattheauditoryregions(i.e.,inferiorcolliculus,auditorynucleus)weretheonlyb rain regionsthatdidnotdifferbetweentheancestralbatandtoday ’ sspecies(seealsoSupplementaryFig.1),supportingthenotionthattheancestralbathad anauditorybrainsuf cientforecholocation ARTICLENATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-x6NATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications

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commonancestorandextantLEbats(Fig. 3 ;Supplementary Table 1 ;SupplementaryFig. 1 ).Thislendssupporttothe hypothesisthatLEwaslost,ratherthanneverpresent,inthis phytophagouslineage(Fig. 2 a),asdoseveralotherlinesofevidence.Duringprenatalcochleardevelopment,pteropodidsexhibitarapidincreaseincochleasize,similartolaryngeal echolocatorsandfasterthanothermammals8.Theyarealsomore sensitivetohighfrequencysoundsthanaresimilar-sizedterrestrialmammals9 , 26.Indeed,theecholocationcallsofmostbats havepeakfrequenciesbetween20 – 60kHz12 , 15 , 50,wellwithin mostpteropodids ’ auditorylimits9 , 51.Further,geneticvestiges suggestancientbiosonarabilitiesinthepteropodids10. WhileLEisunknowninextantpteropodids – asisthecasefor echolocationofanykindinalmostall~200pteropodidspecies – the biosonar-basedorientationabilitiesofthetongue-clickingpteropodid, Rousettusaegyptiacus ,haverecentlybeenrecognizedas beingmoresophisticatedthanpreviouslythought25.Furthermore, morerudimentaryecho-basedorientationhasnowbeenexperimentallysupportedinatleasttwootherpteropodidgenera,based onwingclickspotentiallyusedinnaturefor ndingsuitable roostingplacesindarkcaves52 , 53.Takentogether,alloftheabove suggeststhatnotonlywasLElost,ratherthanneverpresent,inthe Pteropodidae,butthatthefoundationsforchiropteranecholocationmaynothaveregressedentirelyandinsteadremainavailable tobebuiltuponinthislineage.Indeed,thishas,perhaps,happened severaltimesalready(seeFig. 3 inref.53). Ourresultsalsodemonstratethatecholocationmayhaveoriginated rstintheprogenitorsofbats,andonlyrarelyinany vertebrategroupthereafter26 , 54,notsimplybecausetheywere pre-adaptedforasonarsolution,butalsobecausetheywere constrainedbyasmallbody37 , 47(Fig. 3 ),andthusskullandorbit size35,frominsteadrealizingavision-basedsolution.Thatis, whileourASreconstructionindicatesthattheancestralbathad relativelyandabsolutelylargereyes(~3mmdiameter)thanmost extantLEbats(Fig. 3 ;SupplementaryFig. 2 ;Supplementary Data 1 ),thesesameresultsrevealthattheireyeswereboth relativelyandabsolutelysmallerthanthoseofallextantpteropodidspecies,includingthosepteropodidspeciessmaller inbodysizethantheancestralbat(i.e.,allextantpteropodid specieshaveeyes > 5mmdiameter,whilethesmallestspecies weigh~15g;Fig. 3 ;SupplementaryFigs. 1 , 2 ).Asweoutline below,vertebrateeyesofthesizeestimatedfortheancestralbat wouldbe,thenandnow,toosmalltoallowforthesuccessful aerialpursuitofevenundefended yinginsectsatnight. Fortwocloselyrelatedvertebratesofsimilarsize,onenocturnalandtheotherdiurnal,relativelylargereyesintheformeris thenormandindicativeofgreaterinvestmentinvisiontobeable toacquireenoughlighttoseeadequatelyatnight55 , 56.For example,crepuscularaerialinsectivorousbirdsnotonlyhave disproportionatelylargereyesbutalsohaverelativelylargerskulls thanotherwisesimilarlysizeddiurnalaerialinsectivorous birds55 , 57,andhaveaveragebodyweightsof~50gormore47. Thus,wesuggesttheancestralbats ’ skullmayhavebeentoosmall toaffordeyeslargeenoughtoallowsuf cientsensitivityand resolutiontoguideandcontrol ightatlowlightintensitiesand successfullytrackandcapture yinginsects.Underthisscenario, 4 3 2 1 0 –1Log eye mass (mg) Log neocortex mass (mg)6 5 4 3MH bats DH bats CF bats8910111289101112 Log body mass (mg)Log body mass (mg)b a Fig.4 Phylogeneticallyinformedlinearregressionsofeyemassandneocortexonbodymassbycalltype.Phylogeneticgeneralizedleastsquaremodels showingtheregressionsoflog-transformed a eyemass( N = 162)and b neocortex( N = 162)onbodymasswhileaccountingforthephylogeneticnonindependencebetweendatapoints.Thecallsoflaryngealecholocatingbatswerecategorizedas(i)constantfrequency(CF),(ii)multi-harmonicca lls (MH),(iii)frequencymodulatedcallsdominatedbythefundamentalharmonic(DH)andareshownseparatelyontheplots 6 4 2 0Log eye mass (mg)Log body mass (mg) 891011121344Pteropodidae Phyllostomidae Emballonuridae Rhinolophidae Vespertilionidae Fig.5 Phylogeneticallyinformedlinearregressionsofbrainandeyemass onbodymassbyfamily.Phylogeneticgeneralizedleastsquaremodels showingtheregressionsoflog-transformedeyemass( N = 183)onbody massaccountingforphylogeneticnon-independenceamongdatapoints. The5mostspeciosefamiliesofbatsareshownseparatelyontheplots.The pteropodidshavethelargestabsoluteeyesizewhilethepredatory emballonuridshavethelargesteyesamongthelaryngealecholocatingbats. Thesmallesteyesarefoundinthemoreadvancedecholocating rhinolophidsandvespertilionids,suggestingthattheremaybean echolocation-visiontrade-offevenamongpredatoryspecies. NATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-xARTICLENATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications7

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thereductioninrelativeeyesizeinextantLEbatsascomparedto ancestralbatwouldre ectagreaterrelianceonmoresophisticatedecholocationoverevolutionarytimeandareducedreliance onvision(Fig. 3 ,SupplementaryFig. 1 ).Thelossofafunctional SWSopsingeneinCFbats(SupplementaryTable 7 ;SupplementaryFig. 3 ),likelyresultinginmonochromaticratherthan dichromaticvisioninthesesophisticatedecholocators36,supports theplausibilityofthisviewpoint. Conversely,thesensorydivergenceofthepteropodidsaway fromearlyLEandtowardsaprimarilyvision-basedsolution re ectsatransitionfromaninsecttoplant-baseddiet.Thisshift torelativelylarger,energy-rich,stationaryfoodtimeswouldhave allowedforlargerbodies,skulls,andeyes,andselectedforlarger brainregionsassociatedwithvision,olfaction,andspatial memory45.LElikelyregressedduetophysiologicalcostandlack ofstabilizingselection,giventhereducedbene tofsonarfor locatingstationaryripefruitand owersrelativetodetectingand trackingsmallmovinginsects.Notably,almostnophytophagous batisknowntousederived(i.e.,CForDH)echolocationcalls. Thepteropodid Rousettusaegyptiacus isatongue-clickingecholocator,whileallphytophagousphyllostomids,butone58,useMH calldesigns(SupplementaryData 1 ). Amongpredatorybats,allofwhichlaryngeallyecholocate,we foundthatthosethatproducestrictlyMHcallshadrelatively largereyesthandidDHandCFbats(Fig. 4 ,Supplementary Table 6 ).Ourresultsandtheconclusionsofresearchersbefore us5 , 12 , 14 , 21indicatethatMHcallsmostcloselyresemblethoseof theancestralbat(Fig. 2 b)andareclosestinstructuretothoseof non-echolocatingterrestrialmammals12 , 14.Ourresultstherefore suggestthatalthoughabsoluteandrelativeeyesizehasdecreased inallextantlineagesofpredatorybatsascomparedtothe commonancestor(Fig. 3 ,SupplementaryFig. 1 ,Supplementary Fig. 2 ),relativeeyesizehasdecreasedleastinMHbatsandmost inDHandCFbats.Ouranalysessuggestthatthisdifferenceis notaccountedforbyroostpreference,andsuggestthatthe exclusivelypredatoryemballonuridshaveeyesatleastaslargeas thoseofphyllostomids(Fig. 5 ). WhilerelativelyandabsolutelylargereyesinMHbatssuggest betternightvision,DHandCFcalldesignsarenotonlyderived butmaybesuperiorfordetectingandtracking yingprey.DH bats(andtoalesserextent,CFbats)canadjusttheirsonarbeam shapetosuithabitatandtask(reviewedinref.19),whileMHbats apparentlycannot28 , 30.Additionally,onlyCFbats,andperhaps someDHbats,useacousticglintsresultingfromechoesfrom insects ’ appingwingtodetecttargetsinclutteredhabitat (reviewedinref.29).Withrespecttoproduction,DHandCFcall designsrequirelaryngealspecializationsforharmonicsuppression,steepdownwardfrequencysweepsand,inthecaseofCF bats,constantfrequencycomponents59.Further,thecochleaof DHandCFbatsaremorespecializedrelativetonon-echolocating mammalsthanarethoseofMHbats60 – 62.Interestingly,theonly predatorybatknownto “ shutoff ” echolocationwhilehunting underbrightmoonlightistheMHbat, Macrotuscalifornicus63. Thus,atrade-offbetweenecholocationandvisioninbats apparentlyendurestothisday,andisnotaccountedforonlyby diet,butextendstobatsthatcontinuetohunt yinginsectson thewingunderthecoverofnight. MethodsSpeciescategorizationandbraindata .Batspecieswereclassi edaccordingto twosystems.First,as(i)apteropodidspecies,(ii)aphytophagouslaryngeal echolocating(LE)species(roughlytwo-thirdsofextantphyllostomidspecies),or (iii)asanimal-eatingLEbats(allremainingspecies,representingallfamiliesexcept thePteropodidae).Dietandforagingstrategieswereassignedbasedonbehavioral observationsfromtheliterature43 , 44 , 64 – 66.Thatis,wedidnotfurthersubdivide predatorybatsintogleanersandtrawlersbecauseallpredatorybatsareapparently abletotakepreyonthewing15 , 19 , 44 , 67,butthosespeciesthathavebeenreportedto alsogleanandtrawlpreymayre ectobservationandreportingbiases44. Wealsocategorizedeachbatspeciestooneofthefoursensorycategoriesput forthbyGrif n5:(i)batsthatdonotuseLE(i.e.,pteropodids),(ii)LEbatsthatonly producemulti-harmoniccalls(MHbats),(iii)LEbatsthatcanproducesteeply downwardsweepingcallswithmostenergyinthefundamentalharmonic(DHbats), and(iv)LEbatswhichproduceconstantfrequencycalldesigns(CFbats)5 , 6 , 12 , 21.We alsocategorizedbatsasroostinginternallyorunderexposedconditions.Forthelist ofspeciesandcategories,seeSupplementaryData 1 .Last,forthosebatspeciesinthe phylogeny38forwhichreliablegeneticvisualpigmentdataexist,wecategorized speciesashavingeitherfunctionalornon-functionalshort-wavelengthsensitive (SWS)opsingenes36 , 68 – 71(seeSupplementaryTable 7 ). Theabsoluteandrelativesizesofthebrainandbrainregionsre ectcognitive andspatialmemoryperformanceandre ectthedegreetowhichdifferentsensory modalitiesarereliedupontoacquireenvironmentalinformation.Wecompared totalbrainmassandsixbrainregionsamongbatswithdifferentecholocating abilities,foragingstrategies,anddiets:theneocortex,hippocampus,olfactorybulb, superiorcolliculus,inferiorcolliculus,andauditorynucleus.Thesuperiorcolliculus andolfactorybulbareprimarilyinvolvedintrackingvisualandprocessingodor stimuli,respectively72.Theinferiorcolliculusandauditorynucleusareprimarily devotedtoprocessingauditoryinformation37 , 72.Thehippocampusplaysan importantroleinmemoryandspatialinformationprocessingandtheneocortexin higherordercognitionandcomplexstimuliperception72.Mass,brainandbrain regionmassesweretakenfromref.72. Phylogeneticsignal .Closelyrelatedspeciestendtobemoresimilartooneanother thantothosemoredistantlyrelated,thusspeciesdataarenotstatisticallyindependent73.Weusedphylogeneticcomparativemethodstocontrolforthisnonindependence.Weestimatedthedegreetowhichphylogenypredictsthepatternof covarianceamongspecieswithPagel ’ slambda39andtheShiandRabosky38tree. Allsubsequentanalyseswerephylogeneticallyinformed. ContinuousandcategoricalASreconstruction .Weused phytools (v.0.5 – 38)to reconstructASs74foralllog-transformedcontinuousvariables,whichwethenantilogged.Thecon denceintervalsoftheancestralestimatesforeachvariablewere thencomparedtospecies-levelmoderncategories(Fig. 1 ).WealsousedAICc scorestodeterminethemostappropriatemodelofrateevolutionandwith phytools (v.0.5 – 38),estimatedthescaledlikelihoodsofeachAS74attherootnodeforour threeforagingcategories,fourcalltypecategories,tworoostcategoriesandforthe functionalityoftheSWSopsingene.Theprobabilitiesoftheseancestralcharacter estimateshavebeenoverlainonthephylogeniesinFig. 2 andSupplementaryFig. 3 . Eyesizeestimation .Toestimateeyesizewithoutsacri cingbats,eyeswere modeledforthosespeciesthat(i)werefoundinref.72,(ii)occurredintherecent comprehensivemolecularphylogenyofShiandRabosky38,and(iii)forwhichthe RoyalOntarioMuseum(ROM,Toronto,Canada)ortheNaturalHistoryMuseum ofDenmark(Copenhagen)hadatleastoneintactadultskull.Thisresultedin 183species(name-matchedusingthetaxonomyandspeciesbinomialsfoundin WilsonandReeder75representing18of21chiropteranfamilies).Plasticineballs weremadebyhandtocomfortably tintotheorbitofeachskull,neartheoptic nerveforamen(usingatleastonemaleandonefemalewheneverpossible),as describedandvalidatedbyBrookeandcolleagues55.Balldiameterwasmeasured usingdigitalcalipersandusedasaproxyofspecies-speci ceyediametertoestimateeyemass55.Wefurthercon rmedthevalidityofthisnon-lethalmeansofeye sizeestimationusingtwoothermethods(seebelow),andcomparedallestimates withfresheyediametersfromtheliterature. First,usingthesameskulls,wetookphotographs(usingaNikonD40xdigital SLRcamera)oftheirdorsalsurface.Themaximumzygomaticbreadth(ZB)and theleastinterorbitalbreadth(IOD)weremeasuredandthedifferencebetween thesemeasureswasusedasanalternativeproxyofeyesize.Second,we photographedtheeyesofintactalcohol-preservedspecimensattheROM(150of 183species).Wheneverpossible,atleastonemaleandonefemalewereused.The horizontalpalpebralaperturewasusedasaproxyforeyelength,measuredasthe distancebetweenthemedialandlateralcanthi.WeexportedallphotostoImageJ v.1.49(NationalInstitutesofHealth,USA)andtookmeasurementsthreetimesfor eachspecimentoobtainameanvalueforeachspecies,fromwhichweestimated diameter.Last,wetooktheaxiallengthsoffresheyesfor33speciesfromthe literature32andcomparedtothethreepotentialproxiesforeyesize(i.e.,Plasticine models,thedifferencebetweentheZBandIOD,andeyelidlengthsfromwet specimens).Foreyeandskullmeasurements,specimennumbers,andmuseum collections,seeSupplementaryTable 8 . Phylogeneticallyinformedcomparisonsamonggroups .Totestfordifferences inlog-transformedbody,brain,andeyemassesacrossdiets,foragingstrategies, andecholocationability,wecarriedoutphylogeneticANOVAs74(1000iterations), usingaprunedversionofthemostcomprehensivemolecularphylogenycurrently availableforbats38.Totestfordifferencesamonggroups,weconductedposthoc comparisonsofmeans.The p -valuesforthesecomparisonswereobtainedvia phylogeneticsimulationandadjustedusingtheHolm – Bonferronicorrectionto ARTICLENATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-x8NATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications

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accountformultipletesting76.Therelationshipsbetweentotalbrainmass,eyesize, andmassweremodeledusingphylogeneticgeneralizedleast-squaresbyRestricted MaximumLikelihood77withR-package ape78. Brainandeyemasswerepositivelycorrelatedwithbodymass.Thus,we generatedphylogeneticresidualsforlog-transformedbrainmass,eyemass,and brainregionmassesonbodymass,andtestedfordifferencesintheseresiduals acrossourfourcalltypecategoriesandourthreeforagingcategories.Summaries fortheresultsareprovidedin-textandinSupplementaryTables 1 – 6 .Wealsoused Pagel ’ sbinarycharactercorrelationtesttoexploredwhetherthereweresigni cant correlationsbetweenwherebatsroost(i.e.,internally,externally)and(i)absolute andrelativeeyesizeor(ii)echolocationcalltypes74.Further,usingthesametest, wetestedthepredictionthatamongpredatorybats,therewouldbeasigni cant correlationbetweenCFecholocationandthelossoffunctionalityinSWSopsin genes.Last,weplottedregressionsoflogtransformedeyemassonbodymassinthe vemostspeciesrichbatfamilies,whileaccountingforthephylogeneticnonindependenceamongspecies. Dataavailability .Alldatageneratedoranalyzedduringthisstudyareincludedin thispublishedarticle(anditssupplementaryinformation les).Received:28February2017Accepted:7December2017 References1.Fenton,M.B.&Simmons,N.B. Bats:AWorldofScienceandMystery . (UniversityofChicagoPress,Chicago,2015). 2.Maor,R.,Dayan,T.,Ferguson-Gow,H.&Jones,K.E.Temporalniche expansioninmammalsfromanocturnalancestorafterdinosaurextinction. Nat.Ecol.Evol. 1 ,1889 – 1895(2017). 3.Moore,N.W.Thediurnal ightoftheAzoreanbat( Nyctalusazoreum )andthe avifaunaoftheAzores. J.Zool. 177 ,483 – 486(1975). 4.Russo,D.,Cistrone,L.,Garonna,A.P.&Jones,G.Theearlybatcatchesthe y: daylightforaginginsopranopipistrelles. Mamm.Biol. 76 ,87 – 89(2009). 5.Grif n,D.R. ListeningintheDark (YaleUniversityPress,NewHaven,1958). 6.Jones,G.&Teeling,E.C.Theevolutionofecholocationinbats. TrendsEcol. Evol. 21 ,149 – 156(2006). 7.Fenton,M.B.&Ratcliffe,J.M.Bats. Curr.Biol. 20 ,R1060 – R1062(2010). 8.Wang,Z.etal.Prenataldevelopmentsupportsasingleoriginoflaryngeal echolocationinbats. Nat.Ecol.Evol. 1 ,0021(2017). 9.Calford,M.B.&McNally,K.I.Hearingin yingfoxes(Chiroptera: Pteropodidae). Aust.Mammal. 10 ,97 – 100(1987). 10.Teeling,E.C.Hear,hear:theconvergentevolutionofecholocationinbats? TrendsEcol.Evol. 24 ,351 – 354(2009). 11.Veselka,N.etal.Abonyconnectionsignalslaryngealecholocationinbats. Nature 463 ,939 – 942(2010). 12.Collen,A. Theevolutionofecholocationinbats:acomparativeapproach . (UniversityCollegeLondon,462Doctoraldissertation,2012). 13.Grif n,D.R.Echolocationbyblindmen,batsandradar. Science 100 ,589 – 590 (1944). 14.Simmons,J.A.&Stein,R.A.Acousticimaginginbatsonar:echolocation signalsandtheevolutionofecholocation. J.Comp.Physiol. 135 ,61 – 84(1980). 15.terHofstede,H.M.&Ratcliffe,J.M.Evolutionaryescalation:thebat-moth armsrace. J.Exp.Biol. 219 ,1589 –1602(2016). 16.Fenton,M.B.&Ratcliffe,J.M.Batsunitedbycochleardevelopment. Nat.Ecol. Evol. 1 ,0046(2017). 17.Teeling,E.C.etal.Amolecularphylogenyforbatsilluminatesbiogeography andthefossilrecord. Science 307 ,580 – 584(2005). 18.Bininda-Emonds,O.R.P.etal.Thedelayedriseofpresent-daymammals. Nature 446 ,507 – 512(2007). 19.Ratcliffe,J.M.,Elemans,C.P.H.,Jakobsen,L.&Surlykke,A.Howthebatgot itsbuzz. Biol.Lett. 9 ,20121031(2013). 20.Schnitzler,H.-U.&Kalko,E.K.V.Echolocationbyinsect-eatingbats. Bioscience 51 ,557 – 569(2001). 21.Neuweiler,G.2003.Evolutionaryaspectsofbatecholocation. J.Comp.Physiol. A 189 ,245 – 256(2003). 22.Schnitzler,H.-U.,Kalko,E.K.V.&Denzinger,A.in EcholocationinBatsand Dolphins (edsThomas,J.A.,Moss,C.F.,&Vater,M.)331 – 338(Universityof ChicagoPress,Chicago,2004). 23.Ratcliffe,J.M.,Raghuram,H.,Marimuthu,G.,Fullard,J.H.&Fenton,M.B. Huntinginunfamiliarspace:echolocationintheIndianfalsevampirebat, Megadermalyra ,whengleaningprey. Behav.Ecol.Sociobiol. 58 ,157 – 164 (2005). 24.Ratcliffe,J.M.,Jakobsen,L.,Kalko,E.K.V.&Surlykke,A.Frequency alternationandanoffbeatrhythmindicateforagingbehaviorinthe echolocatingbat. Saccopteryxbilineata.J.Comp.Physiol.A. 197 ,413 – 423 (2011). 25.Yovel,Y.,Geva-Sagiv,M.&Ulanovsky,N.Click-basedecholocationinbats:not soprimitiveafterall. J.Comp.Physiol.A 197 ,515 – 530(2011). 26.Brinkløv,S.,Fenton,M.B.&Ratcliffe,J.M.EcholocationinOilbirdsand swiftlets. Front.Physiol. 4 ,123(2013). 27.Jakobsen,L.&Surlykke,A.Vespertilionidbatscontrolthewidthoftheir biosonarsoundbeamdynamicallyduringpreypursuit. Proc.Natl.Acad.Sci. 107 ,13930 – 13935(2010). 28.Brinkløv,S.,Jakobsen,L.,Ratcliffe,J.M.,Kalko,E.K.V.&Surlykke,A. Echolocationcallintensityanddirectionalityin yingshort-tailedfruit bats, Carolliaperspicillata (Phyllostomidae). J.Acoust.Soc.Am. 129 ,427 – 435 (2011). 29.Fenton,M.B.,Faure,P.A.&Ratcliffe,J.M.Evolutionofhighdutycycle echolocationinbats. J.Exp.Biol. 215 ,2935 – 2944(2012).30.Jakobsen,L.,Olsen,M.N.&Surlykke,A.Dynamicsoftheecholocationbeam duringpreypursuitinaerialhawkingbats. Proc.Natl.Acad.Sci. 112 , 8118 – 8123(2015). 31.Pettigrew,J.D.Flyingprimates?Megabatshavetheadvancedpathwayfromeye tomidbrain. Science 231 ,1304 – 1306(1986). 32.EklöfJ. Visioninecholocatingbats. (GöteborgUniversity,Doctoraldissertation, 2003). 33.Bell,G.P.&Fenton,M.B.Visualacuity,sensitivityandbinocularityina gleaninginsectivorousbat, Macrotuscalifornicus (Chiroptera:Phyllostomidae). Anim.Behav. 34 ,409 – 414(1986). 34.Winter,Y.,López,J.&VonHelversen,O.Ultravioletvisioninabat. Nature 425 ,612 – 614(2003). 35.Speakman,J.A rstforbats. Nature 451 ,774 – 775(2008). 36.Zhao,H.etal.Theevolutionofcolorvisioninnocturnalmammals. Proc.Natl. Acad.Sci.USA 106 ,8980 – 8985(2009). 37.Sa ,K.,Seid,M.A.&Dechmann,D.K.N.Biggerisnotalwaysbetter:when brainsgetsmaller. Biol.Lett. 1 ,283 – 286(2005). 38.Shi,J.J.&Rabosky,D.L.Speciationdynamicsduringtheglobalradiationof extantbats. Evolution 69 ,1528 – 1545(2015). 39.Pagel,M.Inferringthehistoricalpatternsofbiologicalevolution. Nature 401 , 877 – 884(1999). 40.Eisenberg,J.F.&Wilson,D.E.Relativebrainsizeandfeedingstrategiesinthe Chiroptera. Evolution 32 ,740 – 751(1978). 41.Hutcheon,J.M.,Kirsch,J.W.&Garland,T.Jr.Acomparativeanalysisofbrain sizeinrelationtoforagingecologyandphylogenyintheChiroptera. Brain Behav.Evol. 60 ,165 – 180(2002). 42.Jones,K.E.&MacLarnon,A.M.Affordinglargerbrains:testinghypothesesof mammalianbrainevolutiononbats. Am.Nat. 164 ,E20 – E31(2004). 43.Sa ,K.&Dechmann,D.K.N.Adaptationofbrainregionstohabitat complexity:acomparativeanalysisinbats(Chiroptera). Proc.Roy.Soc.Lond.B 272 ,179– 186(2005). 44.Dechmann,D.K.N.&Sa ,K.Comparativestudiesofbrainevolution:acritical insightfromtheChiroptera. Biol.Rev. 84 ,161 – 172(2009). 45.Ratcliffe,J.M.Neuroecologyanddietselectioninphyllostomidbats. Behav. Proc. 80 ,247 – 251(2009). 46.Yao,L.etal.Evolutionarychangeinthebrainsizeofbats. BrainBehav.Evol. 80 ,15 – 25(2012). 47.Barclay,R.M.&Brigham,R.M.Preydetection,dietarynichebreadth,and bodysizeinbats:whyareaerialinsectivorousbatssosmall? Am.Nat. 137 , 693 – 703(1991). 48.Deaner,R.O.,Isler,K.,Burkart,J.&vanSchaik,C.P.Overallbrainsize,and notencephalizationquotient,bestpredictscognitiveabilityacrossnon-human primates. BrainBehav.Evol. 70 ,115 – 124(2007). 49.Simmons,N.B.,Seymour,K.L.,Habersetzer,J.&Gunnell,G.F.Primitiveearly EocenebatfromWyomingandtheevolutionof ightandecholocation. Nature 451 ,818 – 821(2008). 50.Fullard,J.H.in ComparativeHearing:Insects (edsHoy,R.R.,Popper,A.N.& Fay,R.R.)279 – 326(Springer,NewYork,NY,1998). 51.Heffner,R.S.,Koay,G.&Heffner,H.E.Hearinginlarge( Eidolonhelvum )and small( Cynopterusbrachyotis )non-echolocatingfruitbats. Hear.Res. 221 , 17 – 25(2006). 52.Gould,E.G.Wing-clappingsoundsof Eonycterisspelaea (Pteropodidae)in Malaysia. J.Mammal. 69 ,378 – 379(1988). 53.Boonman,A.,Bumrungsri,A.&Yovel,Y.Nonecholocatingfruitbatsproduce biosonarclickswiththeirwings. Curr.Biol. 24 ,2962 – 2967(2014). 54.Thomas,J.A.,Moss,C.F.,&Vater,M. EcholocationinBatsandDolphins (UniversityofChicagoPress,Chicago,2004). 55.Brooke,M.,de,L.,Hanley,S.&Laughlin,S.B.Thescalingofeyesizewithbody massinbirds. Proc.R.Soc.Lond.B 266 ,405 – 412(1999). 56.Cronin,T.,Johnsen,S.,Marshall,N.J.&Warrant,E.J. VisualEcology (PrincetonUniversityPress,NewHaven,2014). 57.Hall,M.I.&Ross,C.F.Eyeshapeandactivitypatterninbirds. J.Zool. 271 , 437 –444(2007). NATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-xARTICLENATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications9

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58.Mora,E.C.&Macías,S.EcholocationcallsofPoey ’ s owerbat( Phyllonycteris poeyi )unlikethoseofotherphyllostomids. Naturwissenschaften 94 ,380 – 383 (2007). 59.Metzner,W.&Schuller,G.in HandbookofMammalianVocalization:An IntegrativeNeuroscienceApproach (ed.Brudzynski,S.M.)403 – 415(Academic Press,Amsterdam,2010). 60.Pye,A.Thestructureofthecochleainchiroptera.I.Microchiroptera: EmballonuroideaandRhinolophoidea. J.Morphol. 118 ,495 – 510(1966). 61.Pye,A.ThestructureofthecochleainChiroptera.II.TheMegachiropteraand VespertilionoideaoftheMicrochiroptera. J.Morphol. 119 ,101 – 119(1966). 62.Pye,A.ThestructureofthecochleainchiropteraIII.Microchiroptera: Phyllostomatoidea. J.Morphol. 121 ,241 – 254(1967). 63.Bell,G.P.ThesensorybasisforpreyselectionbytheCalifornianleaf-nosedbat, Macrotuscalifornicus . Behav.Ecol.Sociobiol. 16 ,343 – 347(1985). 64.Norberg,U.M.&Rayner,J.M.V.Ecologicalmorphologyand ightinbats (Mammalia;Chiroptera):wingadaptations, ightperformance,foraging strategyandecholocation. Philos.Trans.RSoc.Lond.BBiol.Sci. 316 ,335 – 427 (1987). 65.Findley,J. Bats:ACommunityPerspective (CambridgeUniversityPress, Cambridge,1993). 66.Nowak,R. Walker ’ sBatsoftheWorld (JohnsHopkinsUniversityPress, Baltimore,1994). 67.Ratcliffe,J.M.,Fenton,M.B.&Shettleworth,S.J.Behavioral exibility positivelycorrelatedwithrelativebrainvolumeinpredatorybats. BrainBehav. Evol. 67 ,165 – 176(2006). 68.Müller,B.,Goodman,S.M.&Peichl,L.Conephotoreceptordiversityinthe retinasoffruitbats(Megachiroptera). BrainBehav.Evol. 70 ,90 – 104(2007). 69.Mu ller,B.etal.Bateyeshaveultraviolet-sensitiveconephotoreceptors. PLoS ONE 4 ,e6390(2009). 70.Zhao,H.,Xu,D.,Zhou,Y.,Flanders,J.&Zhang,S.Evolutionofopsingenes revealsafunctionalroleofvisionintheecholocatinglittlebrownbat( Myotis lucifugus). Biochem.Syst.Ecol. 37 ,154 – 161(2009). 71.Melin,A.D.,Danosi,C.F.,McCracken,G.F.&Dominy,N.J.Dichromatic visioninafruitbatwithdiurnalproclivities:theSamoan yingfox( Pteropus samoensis ). J.Comp.Physiol.A 200 ,1015 – 1022(2014). 72.Baron,G.,Stephan,H.&Frahm,H.D. ComparativeNeurobiologyin Chiroptera .(Birkhäuser,Basel,1996). 73.Felsenstein,J.Phylogeniesandthecomparativemethod. Am.Nat. 125 ,1 – 15 (1985). 74.Revell,L.J.Phytools:anRpackageforphylogeneticcomparativebiology(and otherthings). MethodsEcol.Evol. 3 ,217 – 223(2012). 75.Wilson,D.E.&Reeder,D.M. MammalSpeciesoftheWorld:ATaxonomicand GeographicReference 3rdedition(JohnsHopkinsUniversityPress,Baltimore, 2005). 76.Holm,S.Asimplesequentiallyrejectivemultipletestprocedure. Scand.J.Stat. 6 ,65 – 70(1979). 77.Martins,E.P.&Hansen,T.F.Phylogeniesandthecomparativemethod:a generalapproachtoincorporatingphylogeneticinformationintotheanalysisof interspeci cdata. Am.Nat. 149 ,646 – 667(1997). 78.Paradis,E.,Claude,J.&Strimmer,K.APE:analysesofphylogeneticsand evolutioninRlanguage. Bioinformatics 20 ,289 – 290(2004).AcknowledgementsWethankB.LimandD.JohanssonoftheROMandMNHD,respectively,foraccessto thebatcollections.ThisresearchwasfundedbygrantsfromtheNaturalSciencesand EngineeringResearchCouncilofCanada(toJ.M.R.)andtheDanishCouncilforIndependentResearch(toL.J.).AuthorcontributionsJ.M.R.oversawtheproject.E.J.W.,C.C.,J.T.,J.M.R.andS.E.S.devisednon-invasive meansofestimatingeyesizeinbats.J.T.andC.C.collectedeyeandskullmeasurement data.J.T.,J.M.R.,L.J.andS.E.S.assignedbatspeciestocategoriesbasedontheavailable literature.J.T.,J.M.R.,andS.E.S.conductedphylogeneticstatisticalanalyses.J.T.andJ.M. R.wrotethemanuscriptwithinputfromallauthors.AdditionalinformationSupplementaryInformation accompaniesthispaperat https://doi.org/10.1038/s41467017-02532-x . Competinginterests: Theauthorsdeclarenocompeting nancialinterests. Reprintsandpermission informationisavailableonlineat http://npg.nature.com/ reprintsandpermissions/ Publisher'snote: SpringerNatureremainsneutralwithregardtojurisdictionalclaimsin publishedmapsandinstitutionalaf liations. OpenAccess ThisarticleislicensedunderaCreativeCommons Attribution4.0InternationalLicense,whichpermitsuse,sharing, adaptation,distributionandreproductioninanymediumorformat,aslongasyougive appropriatecredittotheoriginalauthor(s)andthesource,providealinktotheCreative Commonslicense,andindicateifchangesweremade.Theimagesorotherthirdparty materialinthisarticleareincludedinthearticle ’ sCreativeCommonslicense,unless indicatedotherwiseinacreditlinetothematerial.Ifmaterialisnotincludedinthe article ’ sCreativeCommonslicenseandyourintendeduseisnotpermittedbystatutory regulationorexceedsthepermitteduse,youwillneedtoobtainpermissiondirectlyfrom thecopyrightholder.Toviewacopyofthislicense,visit http://creativecommons.org/ licenses/by/4.0/ . ©TheAuthor(s)2017 ARTICLENATURECOMMUNICATIONS|DOI:10.1038/s41467-017-02532-x10NATURECOMMUNICATIONS| (2018) 9:98 |DOI:10.1038/s41467-017-02532-x|www.nature.com/naturecommunications


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