AreagroupofbaskingRed‐bellyturtlesactuallysocial?EvelynRamirezandCharlesW.GunnelsIV

DepartmentofBiologicalSciences,FloridaGulfCoastUniversity10501FGCUBlvd.South,Ft.Myers,FL33965

ResultsAbstractSocialinterac,ons,althoughcostly,areexhibitedbycountlessorganisms.Theseinterac,onsrangeinstructurefromverysimpletoextremelycomplex.Ironically,ithasbeenextremelycomplexsocialgroups,suchashoneybeesandnakedmolerats,thathavebeenstudiedthemostextensively.Baskingfreshwaterturtlesmaybeaperfectmodelorganismtostudytheforma,onofthemostsimplesocialgroups.Turtlescangroupwhilebasking,butthisbehaviorhasbeenoverlookedassocialbecauseofthelimitedamountofsocialityobservedamongmostspeciesofrep,les.Turtles,likeotherrep,les,basktothermoregulatetheirbodytemperature,andhavebeenassumedtodosoingroupsasaresultofhabitatrestric,ons.Throughthisstudy,weexaminedwhetherred‐bellyturtles,Pseudemysnelsoni,onthecampusofFloridaGulfCoastUniversitybasktogetherbecausetheyaresocialorasaresultoflimitedsuitablebaskingloca,ons.SocialityimpliesthatRed‐bellyturtlesaggregatebecausetheysearcheachotheroutwithintheenvironmenttobasktogether.Bycomparison,groupingresultsfromtherandomdistribu,onofindividualswithinalimitedenvironment.Todetermineifturtleschoosetobasksocially,weprovidedanimalswithachoiceoftwoiden,calplaFormsspaced10mapart.Theresultsofthispairedtestwerecomparedtoanullmodelofhowindividualsshoulddistributerandomlybetweentwodiscretesites.Thisstudyrevealedthatred‐bellyturtlesdisplayaverysimpleformofsociality.

FGCUmapdisplayingsitesofbaskingplaQorms.

PlaQormDesign

MethodsSamplingMethod

Eightypreliminaryobserva,onsweremadewithoutplaFormstoassesshowturtlesnaturallybaskinanurbanenvironment,suchasFGCU.Scansamplingwasusedtosurveynaturallyoccurringpopula,onsofred‐bellyturtles.Datawerecollectedtwiceaday,at10:00amandat3:00pmover10daysdistributedhaphazardlybetweenDecember12th‐January29thtodeterminethenumberofturtlesobservedbaskingonnaturalbaskingsites,i.e.arockorlog.PairsofplaFormswerethenplacedintofourlakestodeterminewhetherbaskingturtlesaresocial.TwoplaFormsspaced10metersapartwereposi,onedineachlakeawayfromshorelines,rocks,fountains,bridges,oranyotherpoten,alpointsofdisturbance.Scansampleobserva,onswerecollectedofturtlesbaskingontheplaForms.

CreaSonofnullmodelAnullmodelofturtleswasconstructedbasedonabinomialdistribu,on.ArandomnumberwasgeneratedinRbasedonabinomialprobabilitymassfunc,on(5).Thisbinomialdistribu,onprovidedamathema,calrepresenta,onofhowturtlescouldrandomlybaskoneitheroftwoplaForms.Separatenullmodelswerecreatedforeachobservedpopula,onofturtles,rangingfrom2‐15individualstodescribehoweachpopula,onsizewouldrandomlydistributebetweentwoplaForms.Eachnullmodelwasrun10,000,mes.Foreachitera,onofthemodel,thelargerofthetwovalueswasusedtocreatetherandomdistribu,on.Theserandomdistribu,onswerethencomparedwithobserveddistribu,onsofbaskingturtlesinaseriesoft‐test.

DiscussionSocialityofred‐bellyturtles?

Red‐bellyturtlesappeartobasksocially;groupsofturtlesbaskingtogetherarenotmereaggrega,ons.Freshwaterred‐bellyturtlesappeartosearchforeachotherwithintheenvironmentforpopula,onsizesoftwoandthreeanimals.Turtlesappeartobesocialforlargerpopula,onsizesbasedonthepropor,onofanimalsbaskingonthemorepopulatedplaForm.

ConservaSonIns,lla,onofbaskingplaFormsinurbanappearstoenhancetheenvironmentforfreshwaterturtles.Red‐bellyturtleswereobservedbaskinginhighernumbersonlyaWerplaFormswereinstalled.Red‐bellyturtlesonthecampusofFGCUexperiencelossofhabitatandhumandisturbancesduetourbaniza,on.MaintenanceofwildlifeinurbanseYngscanbeimprovedbyaddressingtheneedsofanimals,includingphysiological,reproduc,ve,andbehavioral.Asmorehabitatsbecomeurbanized,itisessen,altostartunderstandinghowturtlesrespondtourbanwaterwaysandhowtheyinteractwitheachother(6).Ins,lla,onofbaskingplaFormsinurbanwaterwayscanprovideturtleswithabaskingloca,onthatisfreeofdisturbance.Knowledgethattheseturtlesaresocialisessen,altoconsiderthespecies’needs.Theseresultssuggestthatprovidingoneortwosuitablebaskingsiteperurbanlakeshouldsupporthealthypopula,onsofred‐bellyturtles.

FutureStudiesAtthispoint,weknowthatred‐bellyturtlesbasksocially.However,wedonotknowthelevelofinterac,onsthatturtlesshowwhilebasking.Determininghowturtlesinteractwhilebaskingwillhelpusdeterminethelevelofsocialitythatred‐bellyturtlesdisplay.Aspartofthiseffort,wewilltagtheanimalstodeterminehowindividualsinteractwitheachother.Thisinforma,onwillhelptodeterminethesocialstructureofthespecies.Inaddi,on,wehopetodeterminewhyred‐bellyturtlesbasksocially.Forexample,turtlesmaybasksociallythisenhancesthermoregula,onorminimizespreda,onrisk.

AcknowledgmentTheAnimalBehaviorResearchGroupofFloridaGulfCoastUniversityforgivingmeguidanceandsugges,ontoimprovethisstudy.HannahDisswhohelpedini,atethisstudyin2009.Dr.MarilynCruz‐Alvarezforalltheinputshehasprovided.Everyonewhoassistedineitherbuilding,removing,orinstallingtheplaForms,includingJuanJ.Ramirez,ChingLee,DavidCavanaugh,VirginiaCrosbie,ElliotKneba,andDr.WinEverham.

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IntroducSonSociality

Socialityrequiresthatindividualssearcheachotherouttohuddlewithintheenvironment.Forexample,s,ngrayswillformsocialgroupsinresponsetopredators(1).

AggregaSonsNotallgroupsaresocial.Agroupofbirdsthatcollectseedsfromthesamebackyardfeedermaynotbesocial.Thesebirdsmayaggregatebecausethefeederprovidesalimitedresource,i.e.food,inapatchyenvironment.Inthiscase,thebirdsarenotsocial;theyaresimplyconstrainedbythislimitedpatchyresource.

RepSlesAsaclade,rep,lesaremostlysolitary(2).However,thereareexcep,ons.SeveralspeciesofAustralianskinks(EgemiaandTiliquiaspp.)displaycomplexsocialbehaviors,includingreproduc,vealtruism,long‐termfamilygroups,monogamy,andparentalcare(3).Addi,onally,severalspeciesfromgeckostomarineiguanaswillformsocialgroupstoenhancethermoregula,on(4).

AreBaskingfreshwaterturtlessocial?Groupsoffreshwaterturtlesarefrequentlyfoundbaskingonthesamerockorlog.Theseturtlesmayshowaformofsimplesocialgroupsinrep,les.Ifthisisthecase,freshwaterturtlesareac,velysearchingeachotherouttobask.However,aggrega,onsoffreshwaterturtlesmayresultasaresponsetoalimitedpatchyresource,inthiscasetherockorlog.Ifbaskingsitesarelimited,thenaggrega,onsofbaskingturtlesrepresentadefaultresponsetoalimitedresource.

ResearchObjecSveTodeterminewhetherfreshwaterturtlesbasksocially,weneedtodeterminewhethergroupingresultsfromaresponsetotheenvironmentorachoicetoseekoutotherindividuals.

Figure1:Red‐bellyturtlesbaskmorewhenplaFormsarepresent(Mann‐WhitneyU‐test:U=9757.5,Nabsent=76,Npresent=402,p<0.001).

Figure2:Red‐bellyturtlesaresocialwhentwoanimalsareobservedbasking(t=3.71,df=37,p<0.001)aswellaswhenthreeanimalsbasktogether(t=2.03,df=26,p=0.05).

Figure3:Thepropor,onofred‐bellyturtlesbaskingsociallyforpopula,onsof4–15animalswasmorethanexpected(t=4.43,df=91,p<0.001).