Different or alike? Female rainbow kribs choose males of similar consistency and dissimilar level of boldness

Article (Accepted Version)

http://sro.sussex.ac.uk

Scherer, Ulrike, Kuhnhardt, Mira and Schuett, Wiebke (2017) Different or alike? Female rainbow kribs choose males of similar consistency and dissimilar level of boldness. Animal Behaviour, 128. pp. 117-124. ISSN 0003-3472

This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/78355/

This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version.

Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University.

Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.

Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way.

http://sro.sussex.ac.uk/

1

Differentoralike?Femalerainbowkribschoosemalesofsimilarconsistency1

anddis‐similarlevelofboldness23

U.Scherer1,M.Kuhnhardt1andW.Schuett14561ZoologicalInstitute,BiocentreGrindel,UniversityofHamburg,Martin‐Luther‐KingPlatz3,720146Hamburg,Germany8910Correspondence:11UlrikeScherer,ZoologicalInstitute,BiocentreGrindel,UniversityofHamburg,Martin‐12Luther‐KingPlatz3,20146Hamburg,Germany.13E‐Mail:u.k.scherer@gmail.com14Phone:+494042838–789415 16

2

17Althoughtheexistenceofconsistentbetween‐individualdifferencesinbehaviour18("personalitydifferences")hasbeenwelldocumentedduringthelastdecade,theadaptive19valueofsuchbehaviourallimitationsstillremainsanopenfieldforresearchersofanimal20behaviour.Personalitiesclearlyrestrictindividualsintheirabilitytoadjusttheirbehaviour21todifferentconditions.However,sheercostsofflexibilitycannotexplainthepolymorphism22createdbypersonalityvariation.Inacorrelativeapproach,weheretestedwhethermate23choicemightactasamajordrivingforcemaintainingpersonalityvariationinthe24monogamous,biparentalrainbowkrib,Pelvicachromispulcher.Wepersonality‐typedall25malesandfemalesfortheirboldness(activityundersimulatedpredationrisk)andallowed26femalestochoosebetweentwomalesthatdifferedintheirboldness(behaviouralleveland27consistency).Priortothechoice,femaleswereallowedtoobservebothmales,expressing28theirnaturalboldnesstowardsavideoanimatednaturalpredator.Bothsexesshowed29personalitydifferencesinboldnessovertheshort‐andlong‐term.Furthermore,when30removingside‐biasedfemales,wefoundadis‐assortativematingpreferenceforthe31behaviourallevelandanassortativepreferenceforbehaviouralconsistencyinboldness.32Suchpreferencepatternsmightfacilitateeffectiveparentalroleallocationduringoffspring33careand/orprovidegeneticbenefits.Ourresultssuggestthatsexualselectionplaysan34importantroleintheevolutionofpersonalitydifferences.3536Keywords:anti‐predatorbehaviour,assortative,behaviouralcompatibility,cichlid,mate37choice,Pelvicachromispulcher,personality,risk‐taking,sexualselection,sidebias38 39

3

Individualshavetocopewithawidearrayofenvironmentalchallenges.Therefore,40flexibilityintheexpressionofbehaviouralresponsestowardsdifferentandchanging41conditionsshouldbefavouredbyselection(Sihetal.,2004).Yet,individualsoftenshow42considerableconsistentbetween‐individualdifferencesinbehaviourovertimeand/or43contexts(Boissy,1995).Suchpersonalitydifferencesarecommonthroughouttheanimal44kingdom(reviewedinGosling,2001;Kralj‐Fišeretal.,2014)andhavebeenshownfor45variousbehaviouraltraits,suchasactivitypattern,aggressiveness,exploratorytendencies,46boldnessandfearfulness(reviewedinDalletal.,2004;Gosling,2001;Sihetal.,2004).47Personalitytraitsaremoderatelyheritable(Ariyomo,Carter,etal.,2013;Patricketal.,482013;Reifetal.,2003;vanOersetal.,2005)andhavefitnessconsequences(e.g.Ariyomoet49al.,2012;Dingemanseetal.,2005;Smithetal.,2008),suggestingtheyarenotmerelynon‐50adaptivenoisethatsurroundsanadaptiveoptimum(Wilson,1998).Nevertheless,51underlyingmechanismsthatgenerateandmaintainbehaviouralpolymorphismarelargely52unclearandmanyaspectsofthegrowingbodyoftheoreticalframeworksstillremaintobe53empiricallytested(reviewedine.g.Schuettetal.,2010;Wolfetal.,2010).5455Recently,Schuettetal.(2010)pointedoutthatsexualselectionmaybeimportantin56generatingandmaintainingpersonalityvariationthoughthispossibilityhasrarelybeen57tested(butseee.g.Montiglioetal.,2016;Schuettetal.,2011).Accordingtotheproposed58framework(Schuettetal.,2010),personalitiesareexpectedtoplayanimportantrolein59matechoicewhenapotentialmate'sbehaviouralphenotypeiseitherassociatedwith60good/compatiblegenesthatincreaseoffspringfitness(Dingemanseetal.,2004;Ihleetal.,612015;Maysetal.,2004)orprovidesnon‐geneticbenefitsincreasingthereproductive62

4

successthroughparentalabilityand/orbehaviouralcompatibilitybetweenmates.While63matechoiceforgeneticqualityandparentalabilityshouldfavourinter‐individual64agreementinthepreferenceforabehaviouraltrait,matechoiceforgeneticorbehavioural65compatibilityshoulddependonaninteractionbetweenmaleandfemale(geno‐or)66phenotype(Schuettetal.,2010).Thus,matechoiceforcompatibilitywouldleadtointer‐67individualdifferencesinmatingpreferences,creatingeitheranassortativeordis‐68assortativematingpattern(Schuettetal.,2010).6970Notmanystudiestodatehaveinvestigatedtheeffectofpersonalitytraitsonmatechoice71(reviewedinSchuettetal.,2010)andsomehaveonlyassessedthebehaviourofthechosen72butnotthechoosingsex(Godinetal.,1996;Ophiretal.,2003).Thefewstudiesconsidering73apotentialinterplaybetweenmaleandfemalepersonalityduringmatechoicehaveoften74foundassortativematechoiceforvariousbehaviouraltraits,incorrelative(Gonzagaetal.,752010;Kralj‐Fišeretal.,2013;Mascie‐Tayloretal.,1988;Montiglioetal.,2016)or76experimentalsettings(Schuettetal.,2011)andanincreasedreproductivesuccessof77assortativepairs(e.g.Ariyomo&Watt,2013;Schuettetal.,2011).However,instudiesthat78foundincreasedsuccessofassortativepairs,personalitydataareoftenobtainedpost79pairing(Bothetal.,2005;Harrisetal.,2014;Laubuetal.,2016)notallowingtoteaseapart80whethermatechoicewasaffectedbyindividualpersonalitiesorwhetherbehavioural81similaritywasachievedpost‐pairinginhighlysuccessfulpairs(Laubuetal.,2016).Indirect82evidencethatdis‐assortmentforpersonalitycansometimesbebeneficialisprovidedby83vanOersetal.(2008),whofoundassortativepairsofgreattits,Parusmajor,toshowhigher84ratesofextra‐pairpaternity.Generally,positiveassortmentforgenotypicorphenotypic85

5

traitsisbyfarmoreprominentintheanimalkingdomthanevidencefordis‐assortment86(reviewedinJiangetal.,2013).8788Personalitytraitsconsistoftwomeasures:thebehaviourallevelandthedegreeof89behaviouralconsistency.Althoughthereisconsiderablevariationinwithin‐individual90behaviouralconsistency(Dingemanseetal.,2009)theeffectofsuchindividualdifferences91inconsistencyonmatechoicehasrarelybeenconsidered(butseeSchuettetal.,2011).92Behaviouralconsistencymightbesexuallyselectedforifitreflectsindividualquality(i.e.93consistencyiscostlyunderchangingconditions)orifchoosingapredictable(i.e.consistent)94mateprovidesreliableinformationaboutfutureparentalcarebehaviourpriortomating95(Dalletal.,2004;Royleetal.,2010;Schuettetal.,2010).Forexample,afemalemightbe96abletopredictamale'sabilitytoprotectprospectiveoffspringfromtheconsistencyin97boldnessexpressedpriortomatechoice.9899Inthepresentstudy,weinvestigatedtheinfluenceofmaleandfemaleboldness(propensity100toengageinriskybehaviour;Wilsonetal.,1994)onfemalematepreferenceinasocially101monogamous,biparentalcichlidfromWestAfrica,therainbowkrib,Pelvicachromispulcher.102Inthisspecies,pairsarehighlyterritorial:theydefendterritoriesandoffspringaggressively103againstcon‐andheterospecifics.Therefore,weassumedindividualboldnesstobeatrait104thatislikelyconsideredduringmatechoice.Furthermore,boldnesshasbeenshownto105affectforagingsuccess(Dyeretal.,2008),eggfertilizationrates(Ariyomoetal.,2012),106dominance(Dahlbometal.,2011),survivorship(Smithetal.,2010),andparentalcareeffort107(Budaevetal.,1999)inotherfishspecies.Wemeasuredmaleandfemaleboldness(activity108

6

undersimulatedpredationrisk)repeatedlytotestforpersonalitydifferences.Duringmate109choiceexperiments,femaleswerefirstallowedtoobserveabolderandashyermale110expressingtheirnaturalboldnesstowardsapredatoranimation.Subsequentfemalemating111preferenceforthetwomaleswasassessedinastandardmatechoicescenario.We112consideredbothaspectsofmaleandfemalepersonality:thebehaviouralleveland113behaviouralconsistencyofeachindividual. 114115Weexpectedfemalepreferencestodependonboth,thebehaviourallevelandbehavioural116consistency,withourpredictionsbeingguidedbySchuettetal.(2010).Forthebehavioural117level,weexpected,thatifmatechoiceisbasedonmale(parentalorgenetic)quality,118femalesshouldshowageneralpreferenceforeitherboldorshymales(e.g.Godinetal.,1191996;Kortetetal.,2012).Alternatively,ifmatecompatibilityismoreimportantduring120matechoice,femalesshouldnotshowanoverallagreementbutalsoconsidertheirown121personalityduringtheirchoice.Becausebothrainbowkribparentsprovideoffspringcare122weconsideredthesecondpossibility,i.e.matecompatibility,tobemoreimportantformate123choicebasedonboldness.Inspecieswithbiparentalcare,anassortativematingpreference124forcertainbehaviouraltraitscouldreducesexualconflictoverparentalinvestment(Royle125etal.,2010)andfacilitateoffspringcarecoordinationthroughabettersynchronisationof126parentalactivities(Schuettetal.,2011).Dependingontheenvironmentalconditionsorthe127biologyofthespecies,alsodis‐assortativematingmightsometimeshaveadvantages128(Schuettetal.,2010).Forinstance,speciesthatperformseveralparentalactivitiesmight129alsobenefitfromexpressingadis‐assortativematingpreference,facilitatingroleallocation130andspecialisationduringoffspringcare.Often,asexualdimorphisminrolespecialisation131

7

canbeobservedwiththefemaleprovidingmoredirectoffspringcareandthemale132defendingtheterritory(e.g.Guerraetal.,1995;Itzkowitz,1984;Neil,1984;Richteretal.,1332010;Solomon,1993).Nevertheless,inmanyspeciesbothpartnerscanordoperformthe134samebehaviours(seeRoyleetal.,2014forareviewontheflexibilityofparentalcare135behaviour),andatleastpartlycompensatefortheirmates’tasksifneeded(Itzkowitz,1984;136Laveryetal.,2010;Sasvari,1986;Storeyetal.,1994)indicatingthatsexrolesmightbeless137fixed.Forthebehaviouralconsistency,wefolloweduptwopossiblematechoicescenarios:138ageneralpreferenceforconsistentoverinconsistentmales,whichmightindicate139predictabilityoflaterparentalperformance,and/orindividualquality(Royleetal.,2010;140Schuettetal.,2010)ormatechoiceforcompatibilityleadingtoapositiveassortative141preference(Schuettetal.,2011;Schuettetal.,2010).142143144METHODS145146EthicalNote147Inconsiderationofanimalwelfare,wefollowedthe"3R"framework(Russelletal.,1959).148Todecreasethenumberofstudyanimalsneededweusedpredatoranimationsinsteadof149livepredatorsandtestmalesformatechoicetrialswereusedtwice.Duringexperiments,150noanimalswereharmedorexposedtoactualpredationrisk.Preyfishandpredatorswere151keptseparatelyanddidnothavevisualcontactduringfishmaintenance.Thestudywas152permittedbytheGerman"BehördefürGesundheitundVerbraucherschutzHamburg".153154

8

StudyAnimalsandHoldingConditions155StudyindividualswereobtainedfromacaptivebreedingstockattheUniversityof156Hamburgandlocalsuppliers.Malesandfemalesusedinthisstudywere1‐2yearsoldand157sexuallyinexperienced.Individualsweremaintainedinsame‐sexsiblinggroupsunder158standardisedholdingconditions(100x50x25cmand200x50x25cmtanks,26±1°C159watertemperature,aeratedandfilteredwater,weeklywaterchanges,12:12hours160light:dark)andwerefedonceadayon5daysaweekwithArtemiaspec.On161experimentationdays,fishwerefedafterobservations.Onedaybeforethefirstpersonality162test,individualsweremeasuredfortheirstandardlength(males:3.8‐6.2cm,females:3.5‐1635.1cm)usingImageJ(Schneideretal.,2012)andtransferredintoindividualtanks(25cmx16425cmx50cm)forthedurationofexperimentaltrials(5daysperindividual).Tankswere165endowedwithsand,halfaclaypotasshelterandaninternalfilter.Foridentification,all166individualsweremarkedwithVIEs(visibleimplantelastomers;VIE‐NorthwestMarine167Technology,ShawIsland,Washington,USA).Suchartificialcolourmarkshavenoinfluence168onmatechoiceinourpopulation(Schuettetal.,2017).169170ExperimentalOutline171Duringpersonalitytestingandmatechoicetrialsboldnesswasmeasuredasactivityunder172simulatedpredationriskusingcomputeranimationsofanaturallysympatricoccurring173predator,theAfricanobscuresnakehead,Parachannaobscura.Allmales(N=48)and174females(N=45)usedduringmatechoiceexperimentsweretestedfortheirboldnessthree175times(day0,day4,day33)inordertoassessthebehaviourallevelandconsistencyforall176individuals,andshort‐andlong‐termrepeatabilityinthepopulation.Thefirstandsecond177

9

testseriesofmaleboldnesstestswereintegratedintomatechoicetrials(N=45),allowing178femalestoobservetwomalesexpressingtheirnaturalboldness.Aftertheobservation,179femaleswereallowedtochoosebetweenthetwomalestheyhadjustobservedina180standardmatechoicetest(seeMateChoiceTrials).Fortheremainingboldnesstrials(third181seriesofmaleboldnesstestsandallfemaleboldnesstests)thetestprocedurewasidentical182tothoseintegratedintomatechoicetrialstoensureequaltestconditionsthroughout.183184BoldnessTest185Boldnesstestswereconductedinatesttank(waterlevel10cm,watertemperature26±1861°C;Figure1),whichwasdividedintothreecompartments:twoparalleltestcompartments187inwhichtwoindividualscouldbetestedfortheirboldnessatthesametimeandanadjacent188observercompartment.Aone‐waymirrorbetweentheobserverandthetestcompartments189allowedtheobservertoseethetestindividualsbutinhibitedtestindividualstoseethe190observer.Ontheothershortside,testcompartmentsfacedacomputermonitor(Dell,191UltraSharpU2412M61cm,24”)forthepresentationofpredatoranimations.Removable192opaquedividersbetweenthetestandtheobservercompartmentsaswellasbetweenthe193testcompartmentsandthemonitorallowedvisualseparationduringacclimationbefore194trials.195196Priortoaboldnesstest,weintroducedtwosame‐sexindividuals(fordetailsseealsoMate197ChoiceTrials)intoaclearcylinder(diameter=11cm)each,onepertestcompartment(test198compartmentswerepermanentlyvisuallyseparatedfromeachother).Anobserverofthe199oppositesexwasintroducedintotheobservercompartmentbeingallowedtofreelyswim200

10

around.Anobserverwasalwaysintroduced(eveninmaleandfemalepersonalityteststhat201werenotintegratedintomatechoicetrials)becauseitmaybepossiblethatchemicalcues202weretransmittedfromtheobservertothetestcompartmentsdespitephysicalseparation.203Aftera15minacclimation,theopaquedividerswereremovedallowingfreeviewofthe204animation(testindividualsandobserver)andtestindividuals(observer).Afteranother1205minthecylinderswereremovedandthetestperiodof11minstarted.Trialswerevideo‐206recordedfromabovewithnohumanbeingpresentduringtrialsandthetesttankwas207surroundedwithwhitePlexiglastoavoiddisturbances.Individualswerealwaysboldness‐208typedatthesametimeofday±30mintoaccountforpotentialeffectsoftimeofdayand209hungerlevelonindividualactivitypattern(Ariyomoetal.,2015;MacPhailetal.,2009).In210eachboldnesstest,individualswereexposedtoarandomlychosenanimationshowinga211predatorspecimentheyhadnotseenbefore.212213Predatoranimations(N=4,eachusinganotherspecimen)werepreparedusing214PowerPoint©followingFischeretal.(2014).Animationsdisplayedastillphotographofthe215predatorswimmingbackandforthinfrontofawhitebackground.Wehavevalidatedthis216method:P.pulcherdecreasedtheiractivityinresponsetopredatoranimationscomparedto217acontrolwhilenodifferenceinresponsetowardsalivepredatorandtheanimationwas218found(Schereretal.,2017).219220Boldnesswasmeasuredasindividualactivity(totaldistancemoved;cm)fromthevideo221recordingsusingthetrackingsoftwareEthovisionXT11(Noldus,Wageningen,The222Netherlands).Theactivitywasassessedforatestperiodof10min,beginning1minafter223

11

thestartofthevideo.Forallindividualsthebehaviourallevelwasdefinedasthemean224activityofthefirstandsecondtestseries.Behaviouralconsistencywascalculatedfollowing225Ioannouetal.(2016)astheabsolutevalueofthedifferenceinactivitybetweenthefirstand226secondboldnesstest.WefurtherdividedthemeasureofIoannouetal.(2016)bythetotal227variationinthepopulation(rangeofactivitywithinfirstandsecondboldnesstest).As228suggestedbyDingemanseetal.(2009),suchanindexwouldprovideameasurethatis229standardisedinrelationtothepopulation.Wecalculatedbehaviouralconsistencyformales230andfemalesseparately.Valuesforconsistencycanrangefrom0(highconsistency)to1231(lowconsistency).232233MateChoiceTrials234Matechoicetrialsconsistedoftwoparts:theabovedescribedobservationanda235subsequentchoice.Duringobservation,thefemalecouldobservetwomalesshowingtheir236naturalboldness(seeBoldnessTest).Subsequentmatechoicewasconductedimmediately237aftertheobservationinastandarddichotomouschoicetest,suitabletopredictmate238preferencefromtheamountoftimespentwithamaleincichlids(Dechaume‐Moncharmont239etal.,2011;Thünkenetal.,2007).Thechoicechamber(35x100x25cm,waterlevel=10240cm)wasseparatedintothreecompartmentswiththefemalecompartmentbeinginthe241middle(60x35x25cm)andamalecompartmentateachside(20x35x25cm).242243Tobeginthechoicetest,wetransferredthefemaleandthetwomalesshehadjustobserved244fromtheboldnesstesttanktothechoicechamber.Maleswererandomlyassignedtothe245twomalecompartments.Allindividualswereallowedtoacclimatefor10minwhilebeing246

12

visuallyseparatedfromeachother.Then,opaquedividerswereremovedandthefirsttest247periodof12minbegan.Thereafter,theprocedurewasrepeatedwiththemalesswitching248sidestotakeaccountforapotentialsidebias(again10minacclimationfollowing12min249testperiod).Toavoiddisturbancesthechoicechamberwassurroundedwithwhite250Plexiglasandnohumanwaspresentduringtrials.Trialswerevideo‐recordedfromabove.251252Eachfemalewasusedonceduringmatechoicetrials.Thetwomalesusedinamatechoice253trialwerematchedforsize(standardlengthdifference≤5%,i.e.≤3mm)andfamilybut254otherwiserandomlychosen.Thefemaleobserveroriginatedfromadifferentfamilythan255themales.256257Theassociationtimeforthetwomaleswasdeterminedfrombothtestperiods(i.e.20min)258usingEthovisionXT11.Testperiodswereanalysedfor10min,starting2minafterthestart259ofthevideo.Theassociationtimewasdefinedasthetimethefemalespentwithin5cm260distancetoeachmalecompartment(whichcorrespondstoca.onefishlength;hereafter261“preferencezone”).Femalestrengthofpreferencewasthenquantifiedastherelative262amountoftimeshespentinthepreferencezoneoftheboldmale(associationtimeforthe263boldmalewasdividedbytheassociationtimeforbothmales;e.g.Dugatkin,1996;264Makowiczetal.,2010).Foreachmatechoicetest,theboldmalewasdefinedasthemale265beingmoreactiveduringtheboldnesstestandtheshymalewasdefinedasbeingtheless266activemale(mean±SEforabsolutesimilaritybetweenshyandboldmales:behavioural267level=975.95±147.81;behaviouralconsistency=0.11±0.02;pleaseseeStatistical268Analysesforcalculationofsimilarityindices).Also,wecalculatedthesidebiasforall269

13

femalesandconsideredafemalebeingside‐biasedwhenshespentmorethan80%ofthe270totaltimespentinpreferencezones(bothtestperiods)injustonezone,regardlesswhich271malewasthere(Poschadeletal.,2009;Schlüteretal.,1998).272273StatisticalAnalyses274AlldataanalyseswereconductedinR3.2.3(RCoreTeam,2015).Totestforpersonality275differencesrepeatabilityofourmeasureforboldness(activityundersimulatedpredation276risk)wasassessedwithlinearmixedeffectmodels(LMMs)usingtherptR‐package277(Schielzethetal.,2013).Weassessedshort‐termrepeatability(boldnesstest:day0,day4)278aswellaslong‐termrepeatability(boldnesstest:day4,day33)forsexesseparatelywith2791000bootstrappingrunsand1000permutations.Significancewasinferredwhenthe95%280CIdidnotincludezero.Activitywassquareroot‐transformedfornormalityandmodels281werefitforGaussianerrorstructure.282283Totestforageneralpreferenceforboldorshymales,weranaLMMwithfemalestrengthof284preferenceforboldmalesastheresponseandmaleIDasrandomeffect.Wedidnotinclude285anyfixedeffects.Tocheckforadeviationfromrandomchoice(i.e.strengthofpreference=28650%)weobtainedthe95%CIoftheestimatedmean.Apreferenceforeitherboldorshy287maleswouldbeindicatediftheCIdoesnotinclude0.50.Similarly,wetestedforageneral288preferenceforbehaviouralconsistencybyrunninganullmodelwithfemalestrengthof289preferenceforthemaleshowingthehigherconsistencyduringtheobservationasthe290responseandmaleIDasrandomeffect.Apreferenceforeitherconsistencyorinconsistency291wouldberevealedifthe95%CIofthemeandoesnotinclude0.50.292

14

293Totestfor(dis)‐assortativefemalematechoicewefittedaLMMwithfemalestrengthof294preferenceforboldmalesastheresponsevariableandmaleIDasrandomterm.Asfixed295effectsweincludedrelativesimilarityforthebehaviourallevelandrelativesimilarityfor296thebehaviouralconsistencybetweenthefemaleandthemalesshesawduringthe297observationphaseandmatechoicetest.Tocalculaterelativesimilarity(forleveland298consistency,respectively),wefirstcomputeddifference‐scorebasedsimilaritybetweenthe299femaleandeachofthetwomales(boldandshy)astheabsolutevalueofthedifferencein300therespectivebehaviour(e.g.Gaunt,2006;Luoetal.,2005;Montiglioetal.,2016)between301thefemaleandtheboldmale,andthefemaleandtheshymale.Thus,similarity(inleveland302consistency,respectively)ishighestatzeroanddis‐similarityincreaseswithincreasing303values.RelativesimilaritywasthencalculatedfollowingGasparinietal.(2015):the304similaritybetweenthefemaleandtheboldmalewassubtractedfromthesimilarity305betweenthefemaleandtheshymale.Positivevaluesforrelativesimilarity(inleveland306consistency,respectively)indicatehighersimilaritybetweenthefemaleandtheboldmale307whilenegativevaluesindicatetheshymaleismoresimilartothefemalethanthebold308male.Priortotheanalysis,wez‐transformedbothrelativesimilarityforthebehavioural309levelandforthebehaviouralconsistencyforstandardisation.310311Weusedthelme4‐package(Batesetal.,2015)forLMMs.Weusedstepwisebackward312modelsimplificationtofittheminimumadequatemodel.PartialR2withCL(confidence313level)werecalculatedforexplanatoryvariablesusingtheapproachsuggestedbyNakagawa314etal.(2013),implementedinther2glmm‐package(Jaeger,2016).Fornon‐significant315

15

explanatoryvariableswereportedregressionestimatesandpartialR2ofthemodelbefore316thetermwasdropped.Modelassumptionswerevisuallyensuredthroughmodeldiagnosis317plots.Forallanalyses,femalestrengthofpreferencewasarcsine‐squareroot‐transformed318fornormality.Wehadaprioridecidedtoexcludeside‐biasedfemales(N=6)from319preferenceanalyses(Dosenetal.,2004;Hoysaketal.,2007;Knieletal.,2015;Schluppetal.,3201999;Schlüteretal.,1998;Williamsetal.,2010).Bydefinition,aside‐biasedfemaleshows321contradictorypreferencesduringthetwotestperiodsofachoicetest.Theremovalofsuch322inconsistentbehaviourthatappearsrandominregardtothepresentedmalesiscrucialas323toremovefemalesthatwouldnotexpressamatingpreferenceforthepresentedmalesbut324ratherapreferencefor(oragainst)aspecificsideofthechoicechamber(e.g.becauseofa325lackofmotivation).Leavingsuchbiasedpreferencedatainthedatasetwouldartificially326increasethesamplesizeanddistorttheactualpreferencepattern.Ontheotherhand,327removingside‐biasedfemalesfromthedatasetcanlowerthebehaviouralrange328representedinthisstudy.Astherearedifferentapproachesbutnocommonagreementin329howtohandlesidebiasesinmatechoicetrials,weperformedallpreferenceanalysestwice,330oncewithandoncewithoutremovingside‐biasedfemales(N=45).Thoughwehere331considerbothapproaches,weadvocatetheremovalofclearlybiasedpreferencedatafrom332analysesandwillthereforemainlyfocusonthepresentationofpreferenceanalyses333performedwithoutobvioussidebiasesinthedata.334335RESULTS336337

16

Malesandfemalesweresignificantlyrepeatableintheirboldnessovertheshort‐term338(LMMmales:R=0.507,SE=0.110,CI=[0.246,0.686],N=48;LMMfemales:R=0.604,SE339=0.097,CI=[0.380,0.763],N=45)andlong‐term(LMMmales:R=0.463,SE=0.113,CI=340[0.233,0.657],N=48;LMMfemales:R=0.557,SE=0.111,CI=[0.311,0.732],N=42).341342Wefoundnogeneralpreferenceforeitherboldorshymales(meanpreferenceforbold343males:46.5%;95%CI=[40.8,52.1%]).Also,wedidnotdetectageneralpreferencefor344maleconsistency(meanpreferenceforconsistentmales:53.5%,95%CI=[47.8,58.9%]).345346Femalestrengthofpreferencefortheboldmalesignificantlydecreasedwithincreasing347relativesimilarityinthebehaviourallevel(LMM:χ21=10.572,N=39,P=0.001,coefficient348±SE(standardised)=‐0.091±0.026;R2=0.242,CL=[0.056,0.475];Figure2a).Further,349femalestrengthofpreferenceincreasedwithincreasingrelativesimilarityinbehavioural350consistency(LMM:χ21=4.528,N=39,P=0.033,coefficient±SE(standardised)=0.058±3510.026;R2=0.114,CL=[0.003,0.341];Figure2b).352353Whenperformingpreferenceanalysiswithouttheremovalofside‐biasedfemales,we354receivedsimilarresultswithregardtofemalestrengthofpreferenceforboldmales(mean355preference:46.5%;95%CI=[41.5,51.6%])andforconsistentmales(meanpreference:35653.9%;95%CI=[49.1,59.1%])notshowingadeviationfromrandomchoice.However,357differenttotheanalysiswithremovedsidebiases,relativesimilarityinthebehavioural358leveltendedtonegativelyinfluencefemalepreferenceforboldmales(LMM:χ21=2.885,N=35945,P=0.089,coefficient±SE(standardised)=‐0.043±0.034;R2=0.066,CL=[0.001,360

17

0.258])andrelativesimilarityinbehaviouralconsistencydidnotaffectfemalepreference361(LMM:χ21=2.279,N=45,P=0.131,coefficient±SE(standardised)=0.040±0.025;R2=3620.052,CL=[0.000,0.235]).363364365DISCUSSION366367BothsexesofP.pulchershowedconsistentshort‐andlong‐termpersonalitydifferencesfor368boldness.Wedidnotdetectanoverallagreementinfemalematingpreferenceforeither369malelevelorconsistencyofboldness.However,wefounddis‐assortativefemalechoicefor370thelevelofboldness.Also,femalepreferenceincreasedwithsimilarityinbehavioural371consistency,suggestingassortativechoiceforconsistencyinboldness(whenside‐biased372femaleswereremoved).373374Thedis‐assortativepreferenceforthebehaviouralleveliscontradictorytotheresultsof375mostothermatechoicestudiestestingforbehavioural(dis‐)assortmentthatmainly376reportedassortativematingpreferences(e.g.Montiglioetal.,2016;Schuettetal.,2011).At377thispoint,wecanonlyspeculateaboutpossibleadaptivebenefitsofadis‐assortative378preference.Behaviouraldis‐similaritycouldpossiblyincreasewithin‐pairbehavioural379and/orgeneticcompatibility(Schuettetal.,2010).Behaviouralcompatibilityhasprimarily380beendiscussedforbiparentalspecieswhenbothparentsperformmoreorlessthesame381parentalactivity,forinstanceoffspringprovisioninginsomebirds(Royleetal.,2010).In382zebrafinches,Taeniopygiaguttata,forinstance,similarityinthebehaviourallevelhasbeen383

18

showntoincreasepaircompatibility(e.g.Schuettetal.,2011).However,whenspecies384performvariousparentalactivitiestheymightsometimesbenefitfromexpressingadis‐385assortativematingpreference,facilitatingroleallocationduringoffspringcare.InP.pulcher,386parentstypicallydividethelabourwithoneindividualstayingmorewiththeoffspringand387theotheronedefendingtheterritory.Thoughsexualdimorphisminrolespecialisationhas388beendescribedformanycichlids(McKayeetal.,2008;Neil,1984;Richteretal.,2010),sex389rolesmightnotbeentirelystrictinthespeciesandmayratherdependontheinterplay390betweenmaleandfemalepersonality.Itzkowitzetal.(2005)haveshownthatmaleand391femaleparentconvictcichlids,Archocentrusnigrofasciatum,changedtheirdefense392behaviourinresponsetothemate'sbodysize,regardlessofthesex.Thisresultindicates393thatparentalroleallocationmayinsomespeciesratherdependonthemate'sbehaviour394andphysiologythanonthesexitself.Behaviouraldis‐similarityinboldnessmayfacilitate395labourdivisionwiththebolderindividualdefendingtheterritoryandtheshyerindividual396stayingwiththeyoung,regardlessofthesex.Hence,dis‐assortativematingforpersonality397couldsometimesleadtoinvertedparentalcarerolesthoughthishasnotbeeninvestigated398yet.Also,anincreasedgeneticcompatibilitythroughdis‐similaritycouldbepossibleifdis‐399assortativematingleadstoheterozygoteoffspringthataremoreviable(Charlesworthetal.,4001987;Dingemanseetal.,2004).Forexample,Marshalletal.(2003)showedastrong401correlationbetweenindividualgeneticdiversityandabehaviouraltrait,songcomplexity,in402sedgewarblers,Acrocephalusschoenobaenus.Femaleschosetomatewithmalesthat403increasedoffspringgeneticdiversity(Marshalletal.,2003).Seddonetal.(2004)foundmale404heterozygositytobecorrelatedwithterritorysizeandsongstructureinmale(butnot405female)subdesertmesite,Moniasbenschi.406

19

407Further,wefoundassortativematechoicefortheconsistencyofboldness.Thefewstudies408thathaveassessedthelinkbetweenbehaviouralconsistencyandsexualselectionfounda409positiverelationshipbetweenconsistencyandreproductivesuccess(Boteroetal.,2009;410Byers,2006)andahigherreproductivesuccessofpairsmatchedforbehavioural411consistency(Schuettetal.,2011).Schuettetal.(2011)haveshownthatpairsmatchedfor412consistencyraisedfosterfledglingsofbetterbodycondition,indicatingthepossible413mechanismdrivingassortmentforbehaviouralconsistencymightbeahigherefficiencyin414theprovisionofparentalcare.415416Clearly,ourstudyislimitedbythecorrelativedesign,notallowingtospecificallyaddress417thecausalityunderlyingthepreferencepattern.Furtherexaminationsusingbehavioural418manipulationsarenowneededtodecoupleboldnessfrompotentiallycorrelatedtraitsthat419mightinfluencematechoice,toensurethepreferencepatternwefoundisunequivocally420relatedtoindividualbehaviour.Moreover,itshouldbementionedthatourmeasurefor421behaviouralconsistencyderivedfromonlytwomeasurements.Weareherefacingacritical422trade‐off.Whilemultiplemeasurementscanleadtoachangeinbehaviourcausedbythe423numberoftimestested,e.g.throughhabituationorsensitization(Belletal.,2009;Stampset424al.,2012),themeasurementerrorishigherwhenonlytestedtwice.Inthisparticularstudy,425wetestedindividualresponsestowardsunfamiliarpredatoranimations,presentedina426novelsituation.Ourmeasurementforboldnesswouldlikelybeaffectedbypriorexperience427andfamiliaritywithtestconditions,makingitdifficulttoreceivethesamenatureof428measureforboldnesswhentestedmultipletimes.However,thestrengthofourstudyis429

20

thatfemalescouldobservemaleboldnessdirectlybeforematechoicetrialswhiletheywere430hiddenbehindone‐wayglassandpartitions.Thisway,malescouldexpresstheirnatural431behaviourwithoutbeingaffectedbythefemale'spresence.Adecouplingofobservationand432choiceensuredfemalepreferencenotbeingconfoundedbythepresenceofapredator.433434Conclusions435Insummary,weprovidesuggestiveevidencethatsexualselectionmayrepresentakeyrole436intheevolutionofpersonalitydifferences.Femalesshowedadis‐assortativemating437preferenceforthelevelofboldnessandanassortativepreferenceforthedegreeof438behaviouralconsistency.Ourresultsindicatematechoiceforbehaviouraland/orgenetic439compatibilitythoughonlyassessedinacorrelativeapproach.Suchamatingpreference440mightimproveparentalcareefficiencythroughfacilitationofparentalroleallocation441and/ortoincreaseoffspringfitnessthroughgeneticbenefits.Noticeable,thehandlingof442sidebiasessignificantlyaffectedourresults.Whilewefoundaneffectofbehavioural443similarityinlevelandconsistencywhenremovingsidebiases,wecouldnotdetectsuch444effectswithoutremovingside‐biasedfemalesfromthedata.Thisdiscrepancyinresults445underlinestheimportanceoftakingtheapproachusedintoconsiderationwhencomparing446theresultsofdifferentmatechoicestudies.Thehandlingofsidebiasesinmatechoice447studiesisnottrivialandcanlargelyaffectexperimentaloutcomes.448449450ACKNOWLEDGEMENTS451452

21

ThisresearchwasfoundedbyDeutscheForschungsgemeinschaft(SCHU‐2927/2‐1,grantto453W.S.).WethankF.X.Dechaume‐Moncharmontandtwoanonymousreviewersfortheir454constructivecomments.455456457REFERENCES458459Ariyomo,T.O.,Carter,M.,&Watt,P.J.(2013).Heritabilityofboldnessandaggressivenessin460

thezebrafish.BehaviorGenetics,43,161‐167.461 462Ariyomo,T.O.,&Watt,P.J.(2012).Theeffectofvariationinboldnessandaggressivenesson463

the reproductive success of zebrafish. Animal Behaviour, 83(1), 41‐46.464doi:10.1016/j.anbehav.2011.10.004465

466Ariyomo, T. O., & Watt, P. J. (2013). Disassortative mating for boldness decreases467

reproductive success in the guppy. Behavioral Ecology, 24(6), 1320‐1326.468doi:10.1093/beheco/art070469

470Ariyomo,T.O.,&Watt,P.J.(2015).Effectofhungerlevelandtimeofdayonboldnessand471

aggression in the zebrafishDanio rerio. Journal of FishBiology, 86(6), 1852‐1859.472doi:10.1111/jfb.12674473

474

22

Bates,D.,Mächler,M.,Bolker,B.,&Walker,S. (2015).FittingLinearMixed‐EffectsModels475Usinglme4.JournalofStatisticalSoftware,67(1),1‐48.doi:10.18637/jss.v067.i01476

477Bell,A.M.,Hankison,S. J.,&Laskowski,L.(2009).Therepeatabilityofbehaviour:ameta‐478

analysis.AnimalBehaviour,77,771‐783.479 480Boissy,A. (1995).Fearand fearfulness inanimals.TheQuarterlyReviewofBiology,70(2),481

165‐191.482 483Botero, C. A., Rossman, R. J., Caro, L. M., Stenzler, L. M., Lovette, I. J., de Kort, S. R., &484

Vehrencamp,S.L.(2009).Syllabletypeconsistencyisrelatedtoage,socialstatusand485reproductive success in the tropical mockingbird. Animal Behaviour, 77, 701‐706.486doi:10.1016/j.anbehav.20487

488Both, C., Dingemanse,N. J., Drent, P. J., & Tinbergen, J.M. (2005). Pairs of extreme avian489

personalities have highest reproductive success. Journal of Animal Ecology, 74(4),490667‐674.doi:10.1111/j.1365‐2656.2005.00962.x491

492Budaev,S.V.,Zworykin,D.D.,&Mochek,A.D.(1999).Individualdifferencesinparentalcare493

andbehaviourprofileintheconvictcichlid:acorrelationstudy.AnimalBehaviour,58,494195‐202.495

496

23

Byers, B. E. (2006). Extrapair paternity in chestnut‐sided warblers is correlated with497consistent vocal performance. Behavioral Ecology, 18(1), 130‐136.498doi:10.1093/beheco/arl058499

500Charlesworth, D., & Charlesworth, B. (1987). Inbreeding depression and its evolutionary501

consequences.AnnualReviewofEcologyandSystematics,18,237‐268.502 503Dahlbom, S. J., Lagman, D., Lundstedt‐Enkel, K., Sundstrom, L. F., & Winberg, S. (2011).504

Boldness predicts social status in zebrafish (Danio rerio).PLoSOne,6(8), e23565.505doi:10.1371/journal.pone.0023565506

507Dall,S.R.X.,Houston,A.I.,&McNamara,J.M.(2004).Thebehaviouralecologyofpersonality:508

consistentindividualdifferencesfromanadaptiveperspective.EcologyLetters,7(8),509734‐739.doi:10.1111/j.1461‐0248.2004.00618.x510

511Dechaume‐Moncharmont,F.X.,Cornuau, J.H.,Keddar, I., Ihle,M.,Motreuil,S.,&Cezilly,F.512

(2011). Rapid assessment of female preference formale size predicts subsequent513choiceof spawningpartner ina sociallymonogamouscichlid fish.ComptesRendus514Biologies,334(12),906‐910.doi:10.1016/j.crvi.2011.08.004515

516Dingemanse,N. J.,Both,C.,Drent,P. J.,&Tinbergen, J.M. (2004).Fitnessconsequencesof517

avianpersonalitiesinafluctuatingenvironment.ProceedingsofTheRoyalSocietyB,518271(1541),847‐852.doi:10.1098/rspb.2004.2680519

24

520Dingemanse,N. J.,Kazem,A. J.,Réale,D.,&Wright, J. (2009).Behaviouralreactionnorms:521

animalpersonalitymeetsindividualplasticity.TrendsinEcologyandEvolution,25(2),52281‐89.doi:10.1016/j.tree.2009.07.013523

524Dingemanse,N.J.,&Réale,D.(2005).Naturalselectionandanimalpersonality.Behaviour,525

142,1165‐1190.526 527Dosen, L. D., &Montomerie, R. (2004). Female size influencesmate preferences ofmale528

guppies.Ethology,110,245‐255.529 530Dugatkin, L. A. (1996). Interface between culturally based preferences and genetic531

preferences: Femalemate choice inPoecilia reticulata.Proceedingsof theNational532AcademyofSciencesUSA,93,2770‐2773.533

534Dyer, J.R.G.,Croft,D.P.,Morrell,L. J.,&Krause, J. (2008). Shoal compositiondetermines535

foraging success in the guppy. Behavioral Ecology, 20(1), 165‐171.536doi:10.1093/beheco/arn129537

538Fischer,S.,Hess,S.,Oberhummer,E.,Burlaud,R.,Fernandez,A.A.,Frommen,J.G.,&Taborsky,539

B.(2014).Animatedimagesasatooltostudyvisualcommunication:acasestudyina540cooperatively breeding cichlid. Behaviour, 151(12‐13), 1921‐1942.541doi:10.1163/1568539x‐00003223542

25

543Gasparini,C.,Congiu,L.,&Pilastro,A. (2015).Majorhistocompatibilitycomplexsimilarity544

andsexual selection:differentdoesnotalwaysmeanattractive.MolecularEcology,54524(16),4286‐4295.doi:10.1111/mec.13222546

547Gaunt, R. (2006). Couple similarity andmarital satisfaction: are similar spouses happier?548

JournalofPersonality,74(5),1401‐1420.doi:10.1111/j.1467‐6494.2006.00414.x549 550Godin,J.‐G.J.,&Dugatkin,L.A.(1996).Femalematingpreferenceforboldmalesintheguppy,551

Poeciliareticulata.ProceedingsoftheNationalAcademyofSciencesUSA,93,10262‐55210267.553

554Gonzaga,G.C.,Carter,S.,&Buckwalter, J.G. (2010).Assortativemating,convergence,and555

satisfaction in married couples. Personal Relationships, 17(4), 634‐644.556doi:10.1111/j.1475‐6811.2010.01309.x557

558Gosling,S.D.(2001).Frommicetomen:Whatcanwelearnaboutpersonalityfromanimal559

research?PsychologicalBulletin,127,45‐86.560 561Guerra,M.,&Drummond,H. (1995).Reversedsexualsizedimorphismandparental care:562

minimaldivisionoflabourintheblue‐footedbooby.Behaviour,132,479‐496.563 564

26

Harris,M.R.,&Siefferman,L.(2014).Interspecificcompetitioninfluencesfitnessbenefitsof565assortativematingforterritorialaggressionineasternbluebirds(Sialiasialis).PLoS566One,9(2),e88668.doi:10.1371/journal.pone.0088668567

568Hoysak,D.J.,&Godin,J.‐G.J.(2007).Repeatabilityofmalematechoiceinthemosquitofish,569

Gambusia holbrooki. Ethology, 113(10), 1007‐1018. doi:10.1111/j.1439‐5700310.2007.01413.x571

572Ihle, M., Kempenaers, B., & Forstmeier, W. (2015). Fitness benefits of mate choice for573

compatibility in a socially monogamous species. PLoS biology, 13(9), e1002248.574doi:10.1371/journal.pbio.1002248575

576Ioannou,C.C.,&Dall,S.R.(2016).Individualsthatareconsistentinrisk‐takingbenefitduring577

collectiveforaging.ScientificReports,6,33991.doi:10.1038/srep33991578 579Itzkowitz,M.(1984).Parentaldivisionof laborinamonogomousfish.Behaviour,89,251‐580

260.581 582Itzkowitz, M., Santangelo, N., Cleveland, A., Bockelman, A., & Richter, M. (2005). Is the583

selectionofsex‐typicalparentalrolesbasedonanassessmentprocess?Atestinthe584monogamous convict cichlid fish. Animal Behaviour, 69(1), 95‐105.585doi:10.1016/j.anbehav.2003.12.027586

587

27

Jaeger,B. (2016). r2glmm:ComputesRsquared formixed(multilevel)models.Rpackage588version0.1.1.Retrievedfromhttps://CRAN.R‐project.org/package=r2glmm589

590Jiang,Y.,Bolnick,D.I.,&Kirkpatrick,M.(2013).Assortativematinginanimals.TheAmerican591

Naturalist,181(6),125‐138.doi:10.1086/670160592 593Kniel,N.,Durler,C.,Hecht,I.,Heinbach,V.,Zimmermann,L.,&Witte,K.(2015).Novelmate594

preference throughmate‐choice copying in zebra finches: sexes differ. Behavioral595Ecology,26(2),647‐655.doi:10.1093/beheco/aru241596

597Kortet,R.,Niemelä,P. T., Vainikka,A.,&Laakso, J. (2012). Femalespreferboldmales; an598

analysisofboldness,matechoice,andbacterialresistanceinthefieldcricketGryllus599integer.EcologicalParasitologyandImmunology,1,1‐6.doi:10.4303/epi/235580600

601Kralj‐Fišer, S., Sanguino Mostajo, G. A., Preik, O., Pekár, S., & Schneider, J. M. (2013).602

Assortativematingbyaggressivenesstypeinorbweavingspiders.BehavioralEcology,60324(4),824‐831.doi:10.1093/beheco/art030604

605Kralj‐Fišer, S., & Schuett,W. (2014). Studyingpersonality variation in invertebrates:why606

bother?AnimalBehaviour,91,41‐52.doi:10.1016/j.anbehav.2014.02.016607 608

28

Laubu,C.,Dechaume‐Moncharmont,F.X.,Motreuil,S.,&Schweitzer,C.(2016).Mismatched609partners that achievepostpairingbehavioral similarity improve their reproductive610success.ScienceAdvances,2(3),e1501013.doi:10.1126/sciadv.1501013611

612Lavery,R.J.,&Reebs,S.G.(2010).Effectofmateremovaloncurrentandsubsequentparental613

care in the convict cichlid (Pisces: Cichlidae). Ethology, 97(4), 265‐277.614doi:10.1111/j.1439‐0310.1994.tb01046.x615

616Luo, S., & Klohnen, E. C. (2005). Assortativemating andmarital quality in new‐lywed: A617

couple‐centeredapproach.JournalofPersonalityandSocialPsychology,88,304–326.618 619MacPhail, R. C., Brooks, J., Hunter, D. L., Padnos, B., Irons, T. D., & Padilla, S. (2009).620

Locomotion in larval zebrafish: Influence of time of day, lighting and ethanol.621Neurotoxicology,30(1),52‐58.doi:10.1016/j.neuro.2008.09.011622

623Makowicz,A.,Plath,M.,&Schlupp,I.(2010).Maleguppies(Poeciliareticulata)adjusttheir624

mate choice behaviour to the presence of an audience.Behaviour, 147(13), 1657‐6251674.doi:10.1163/000579510x528206626

627Marshall,R.C.,Buchanan,K.L.,&Catchpole,C.K. (2003). Sexual selectionand individual628

genetic diversity in a songbird. Proceedings of TheRoyal Society B, 270, 248‐250.629doi:10.1098/rsbl.2003.0081630

631

29

Mascie‐Taylor,C.G.N.,&Vandenberg,S.G.(1988).AssortativematingforIQandpersonality632duetopropinquityandpersonalpreference.BehaviorGenetics,18,339‐345.633

634Mays,H.L.,Jr.,&Hill,G.E.(2004).Choosingmates:goodgenesversusgenesthatareagood635

fit.TrendsinEcologyandEvolution,19(10),554‐559.doi:10.1016/j.tree.2004.07.018636 637McKaye,K.R.,&Murry,B.A.(2008).SexroledifferentiationinbrooddefensebyNicaraguan638

cichlidfish,Amphilophusxiloanensis.CaribbeanJournalofScience,44,13‐20.639 640Montiglio,P.O.,Wey,T.W.,Chang,A.T.,Fogarty,S.,&Sih,A.(2016).Multiplematingreveals641

complexpatternsofassortativematingbypersonalityandbodysize.JournalofAnimal642Ecology,85(1),125‐135.doi:10.1111/1365‐2656.12436643

644Nakagawa,S.,&Schielzeth,H.(2013).AgeneralandsimplemethodforobtainingR2from645

generalizedlinearmixed‐effectsmodels.MethodsinEcologyandEvolution,4(2),133‐646142.doi:10.1111/j.2041‐210x.2012.00261.x647

648Neil,S.J.(1984).FieldstudiesofthebehavioralecologyandagonisticbehaviorofCichlasoma649

meeki(Pisces:Cichlidae).EnvironmentalBiologyofFishes,10,59‐68.650 651Ophir,A.G.,&Galef,B.G.(2003).FemaleJapanesequailthat‘eavesdrop’onfightingmales652

prefer losers to winners. Animal Behaviour, 66(2), 399‐407.653doi:10.1006/anbe.2003.2230654

30

655Patrick, S. C., Charmantier, A., & Weimerskirch, H. (2013). Differences in boldness are656

repeatableandheritableinalong‐livedmarinepredator.EcologyandEvolution,3(13),6574291‐4299.doi:10.1002/ece3.748658

659Poschadel,J.R.,Plath,M.,&Schlupp,I.(2009).Divergentfemalematingpreferenceinaclonal660

fish.actaethologica,12(1),55‐60.doi:10.1007/s10211‐009‐0055‐8661 662R Core Team. (2015). R: A language and environment for statistical computing. Vienna,663

Austria: R Foundation for Statistical Computing. Retrieved from http://www.R‐664project.org/665

666Reif,A.,&Lesch,K.‐P.(2003).Towardamoleculararchitectureofpersonality.Behavioural667

BrainResearch,139,1‐20.doi:10.1016/S0166‐4328(02)00267‐X668 669Richter,M.,Santangelo,N.,&Itzkowitz,M.(2010).Biparentaldivisionofrolesintheconvict670

cichlidfish:influenceofintrudernumbersandlocations.EthologyEcology&Evolution,67117,1‐15.doi:10.1080/08927014.2005.9522611672

673Royle,N.J.,Russell,A.F.,&Wilson,A.J.(2014).Theevolutionofflexibleparenting.Science,674

346(6198),776‐781.675 676

31

Royle,N.J.,Schuett,W.,&Dall,S.R.X.(2010).Behavioralconsistencyandtheresolutionof677sexual conflict over parental investment. Behavioral Ecology, 21(6), 1125‐1130.678doi:10.1093/beheco/arq156679

680Russell,W.M. S., &Burch, R. L. (1959).Theprinciplesofhumane experimental technique.681

LondonW.C.I.:MethuenandCo.,Ltd.682 683Sasvari,L.(1986).Reproductiveeffortofwidowedbirds.JournalofAnimalEcology,55,553‐684

564.685 686Scherer,U.,Godin, J.G. J.,&Schuett,W. (2017).Validationof2D‐animatedpictures as an687

investigativetoolinthebehaviouralsciences–acasestudywithaWestAfricancichlid688fish,Pelvicachromispulcher.submittedmanuscript.689

690Schielzeth,H.,&Nakagawa, S. (2013). rptR: Repeatability forGaussian andnon‐Gaussian691

data.https://R‐Forge.R‐project.org/projects/rptr/. 692693Schlupp, I., Waschulewski, M., & Ryan, M. J. (1999). Female preferences for naturally‐694

occurringnovelmaletraits.Behaviour,136,519‐527.695 696Schlüter,A.,Parzefall,J.,&Schlupp,I.(1998).Femalepreferenceforsymmetricalverticalbars697

inmalesailfinmollies.AnimalBehaviour,56,147‐153.698 699

32

Schneider,C.A.,Rasband,W.S.,&Eliceiri,K.W.(2012).NIHImagetoImageJ:25yearsof700imageanalysis.Naturemethods,9(7),671‐675.doi:PMID22930834701

702Schuett, W., Dall, S. R. X., & Royle, N. J. (2011). Pairs of zebra finches with similar703

‘personalities’ make better parents. Animal Behaviour, 81(3), 609‐618.704doi:10.1016/j.anbehav.2010.12.006705

706Schuett,W.,Godin,J.G.J.,&Dall,S.R.X.(2011).Dofemalezebrafinches,Taeniopygiaguttata,707

choose their mates based on their ‘personality’? Ethology, 117(10), 908‐917.708doi:10.1111/j.1439‐0310.2011.01945.x709

710Schuett,W,Nava,TF,Rahmlow,T&UScherer(2017).ArtificialVisibleImplantElastomer711

(VIE) tags of different colour and symmetry do not influence mate choice in a712cichlid.Behaviour,inpress.713

714Schuett, W., Tregenza, T., & Dall, S. R. (2010). Sexual selection and animal personality.715

BiologicalReviews,85(2),217‐246.doi:10.1111/j.1469‐185X.2009.00101.x716717Seddon, N., Amos,W.,Mulder, R. A., & Tobias, J. A. (2004). Male heterozygosity predicts718

territorysize, songstructureandreproductivesuccess inacooperativelybreeding719bird. Proceedings of The Royal Society B, 271(1550), 1823‐1829.720doi:10.1098/rspb.2004.2805721

722

33

Sih,A.,Bell,A.,&Johnson,J.C.(2004).Behavioralsyndromes:anecologicalandevolutionary723overview. Trends in Ecology and Evolution, 19(7), 372‐378.724doi:10.1016/j.tree.2004.04.009725

726Sih,A.,Bell,A.M.,Johnson,J.C.,&Ziemba,R.E.(2004).Behavioralsyndromes:anintegrative727

overview.TheQuarterlyReviewofBiology,79(3),241‐277.728 729Smith,B.R.,&Blumstein,D.T.(2008).Fitnessconsequencesofpersonality:ameta‐analysis.730

BehavioralEcology,19(2),448‐455.doi:10.1093/beheco/arm144731 732Smith, B. R., & Blumstein, D. T. (2010). Behavioral types as predictors of survival in733

Trinidadian guppies (Poecilia reticulata). Behavioral Ecology, 21(5), 919‐926.734doi:10.1093/beheco/arq084735

736Solomon,N.G. (1993).Comparisonofparentalbehavior inmaleand femaleprairievoles737

(Microtus ochrogaster). Canadian Journal of Zoology, 71(2), 434‐437.738doi:10.1139/z93‐061739

740Stamps,J.A.,Briffa,M.,&Biro,P.A.(2012).Unpredictableanimals:individualdifferencesin741

intraindividual variability (IIV). Animal Behaviour, 83(6), 1325‐1334.742doi:10.1016/j.anbehav.2012.02.017743

744

34

Storey,A.E.,Bradbury,C.G.,&Joyce,T.L.(1994).Nestattendanceinmalemeadowvoles:the745roleofthefemaleinregulatingmaleinteractionswithpups.1994,47,1037‐1046.746

747Thünken,T.,Bakker,T.C.M.,Baldauf,S.A.,&Kullmann,H.(2007).Active inbreeding ina748

cichlidfishanditsadaptivesignificance.CurrentBiology,17,225‐229.749 750van Oers, K., de Jong, G., van Noordwijk, A. J., Kempenaers, B., & Drent, P. J. (2005).751

Contributionofgeneticstothestudyofanimalpersonalities:areviewofcasestudies.752Behaviour,142,1185‐1206.753

754vanOers,K.,Drent,P.J.,Dingemanse,N.J.,&Kempenaers,B.(2008).Personalityisassociated755

withextrapairpaternityingreattits,Parusmajor.AnimalBehaviour,76(3),555‐563.756doi:10.1016/j.anbehav.2008.03.011757

758Williams,T.H.,&Mendelson,T.C.(2010).Behavioralisolationbasedonvisualsignalsina759

sympatricpairofdarterspecies.Ethology,116(11),1038‐1049.doi:10.1111/j.1439‐7600310.2010.01816.x761

762Wilson,D.S.(1998).Adaptiveindividualdifferencewithinsinglepopulations.Philosophical763

TransactionsoftheRoyalSocietyB,353,199‐205.764 765Wilson, D. S., Clark, A. B., Coleman, K., & Dearstyne, T. (1994). Shyness and boldness in766

humansandotheranimals.TrendsinEcology&Evolution,9,442‐446.767

35

768Wolf, M., & Weissing, F. J. (2010). An explanatory framework for adaptive personality769

differences.PhilosophicalTransactionsoftheRoyalSocietyB,365(1560),3959‐3968.770doi:10.1098/rstb.2010.0215771

772 773

36

FIGURES774

Figure1:Experimentalset‐upfortheboldnesstest.Twosame‐sexfocalindividuals(visuallyseparated)wereexposedtoavideoanimationofapredator.Testindividualswereobservedbyafishoftheothersexbutcouldthemselvesnotseetheobserver:theobservercompartmentwasendowedwithaone‐waymirroralignedwithanangleof45°towardsthetestcompartmentsprovidingavisualcoverfortheobserver.Fishnottoscale.775

37

Figure2:Femalestrengthofpreferencefortheboldmaleindependenceofrelativesimilarityin(a)theleveland(b)theconsistencyofboldness.Positivesimilarityvaluesindicatetheboldmalewasmoresimilartothefemalethantheshymale,negativevaluesindicatehighersimilaritybetweenthefemaleandtheshymale.Datavisualisationonoriginaldata,strengthofpreferencewasarcsine‐squareroot‐transformedforanalyses.776