134 IRCFReptIles&AmphIbIAns•Vol18,no3•sep2011

Analternate,uncommondefensivebody-coilingconfigurationinAmphiuma tridactylum;notetheheadandtailprotrudingfromunderneath.Fooditems,earthworms(Lumbricussp.)andRedswampCrayfish(Procambarus clarkii)arepresent.

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body-coilingbehaviorhasbeenreportedinsalamanders,primarilyinplethodontids.however,the“tightness”ofthesecoilsispresumably

limitedbytheirskeletalmorphologyandrelativelyshortbody length.Coilinginplethodontidsisgenerally1–2looselycoiledbodyloops,orasan“s”shape.Avarietyofexplanationsforcoilingbehaviorhavebeensug-gestedforplethodontids,includingremovalofcover,springingorleaping(Wake1996),rollingdownhill(García-parísandDeban1995),exposure

totoxins(brodie1977),andreductionofevaporativewaterloss(hillmanetal.2009). body-coiling also has been reported for species in the familyAmphiumidae,andhasalwaysbeenassociatedwithreproduction.Allreportsdescribeapresumedfemalediscovered inmudunderaprevi-ouslysubmergedlog,coiledinasinglelooparoundeggsinbothA. means(Davison1895,Weber1944,seyle1985)andA. tridactylum(hay1888,

body-coiling behavior in the Three-toed amphiuma (Amphiuma tridactylum)

Cliffordl.Fontenot,Jr.1andWilliamI.lutterschmidt2

1Departmentofbiologicalsciences,southeasternlouisianaUniversity,hammond,louisiana70402,UsA(cfontenot@selu.edu)2Departmentofbiologicalsciences,samhoustonstateUniversity,huntsville,texas77341-2116,UsA(lutterschmidt@shsu.edu)

salamanderscoiltheirbodiesforavarietyofreasons,butprimarilyasaresponsetopredators.FortheaquaticsalamanderAmphiuma,allreportsoncoilingareassociatedwithnestattendance,althoughanothernotionhasmadeitintotheliterature,thatAmphiumacoilsitsbodytoreduceevaporativewaterlossoftheadult.Weinadvertentlytestedthisnotionviaanotherstudyontemperaturepreferenceinanaquaticthermalgradi-ent.becausenearlyhalfofourobservationswereoftightlycoiledindividualsunderwater,weconcludethatthisbehaviorisnotforreducingevaporativewaterloss,butmorelikelyadefensiveposture.

Fig. 1.non-nestingbody-coilingbehaviorinAmphiuma tridactylum.thistightcoilingoccursunderwater,ispresumeddefensive,anddiffersfromtheloosecoilingassociatedwithnesting.

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baker1937,baker1945,tinkle1959).Conversely,hillmanetal.(2009)and Duellman and trueb (1994), citing Ray (1958), indicated thatAmphiumatightlycoilsitsbodyandtailtoreduceevaporativesurfaceareaandthuswaterloss.however,theword“Amphiuma”doesnotoccurintheRay(1958)reference,andthuswebelievethisreferenceand/orconcepttobeinerror.here,wedescribethenatureofbody-coilinginAmphiuma,andtestthenotionofanevaporative-water-lossreducingfunction.

Materials and MethodsDuringthecourseofanotherstudyontemperaturepreferenceinalabo-ratorythermalgradient,weinadvertentlytestedwhetherbodycoilingisamechanismtoreduceevaporativewaterloss.WecollectedA. tridactylum(n=15)byhandatnightfromeastbatonRougeparish,louisianafromAprilthroughmay1990.Fordeterminingtemperaturepreference,anaquaticthermalgradientwascreatedbydividinganaquariumintofivewater-filledsectionsattemperaturesof22,26,28,31,and35°C.priortoeachexperi-mentaltrial,theaquaticthermalgradientwasdrainedandrinsedwithwellwatertoremoveanyolfactorycuesleftbyotheranimals.theaquaticgradi-entconsistedofanaquarium(125x38x34cm)withfivesections(25x38x9cm)formedbyfourglassdividers(9cmhigh).eachpoolwasaeratedtoprovidecirculationofoxygenatedwaterandtomaintainamoreuniformtemperaturewithineachpool.thegradientwaskeptinadarkroomtoeliminatepossiblelightcues,becausethesesalamandersutilizemostlyunder-waterburrowsinturbidwater.eachindividualwasplacedrandomlyinoneofthefivepoolsatthebeginningofeachtrial.eachexperimentaltrialcon-sistedofobservingoneindividualforbehavior,andrecordingtheselectedwatertemperatureandbodypositionevery30minfor6h(1100–1700h).

ResultsIn95ofthe205observations(46%)ofthermalselectionwithinthegradi-ent,individualswerepositionedinatightlycoiledpostureof3–4bodyloopswiththeheadpositionedatthebottomofthespring-shapedcoil(Fig.1).Wenotedsomevariations,includingaknot-likeconfiguration(figureonp.134),buttheheadwasalwaysunderneath.Intheother110observations,theindividualswerelyingacrossthebottominamorenaturalsprawledposition,typicalofthatobservedinthefield(Figs.2&3).

DiscussionAllofourlaboratoryandfieldobservationswereofanimalsinwater,sug-gestingthatthebody-coilingbehaviorobservedherewasnotbeingusedtoreduceevaporativewaterloss.thebody-coilingbehaviorweobservedinA. tridactyluminsteadwasprobablyattributabletoaninabilitytofindconceal-ment.Accordingly,thisbehaviormightbeadefensiveposture,asitreducesexposedsurfaceareafromanotherwiseveryelongatebodyposition.theseniorauthorhasobservedthisbehaviorhundredsoftimesovermanyyearswithindividualA. tridactylumandA. meansbeingtransportedtothelabinabucketorothercontainerwithwater,aswellasinanaquariumwithoutcover.Anecdotalobservationssuggestthatifacoveritemisprovided,theanimalsuncoilandusetheprovidedcover—andwehavenotobservedtightbody-coilingbehaviorwhencoverisavailable,norinthefieldunderanycondition.Virtuallyallindividuals,males,females,andjuveniles,foundundercoverinthefieldweretypicallyinamuddepressionwithasingleloosebodyloop,andgenerallyremainedthatwayunlessdisturbed(ClF,pers.obs.).ontheotherhand,theconceptthattightbodycoilingcouldbeusedtoreduceevaporativewaterlossisplausible.GiventhatAmphiuma

Fig. 2. Amphiuma tridactylum innaturalmud/muckhabitatinbatonRouge,louisiana.thisindividualwasplacedonthesurfaceforphotographicpurposesbecausethesesalamandersnormallyareaquatic/fossorialandnocturnal,anditindeedburrowedintothemudanddisappeared.notethebitemarksfromanotherAmphiumavisibleontheskin,aswellasanoldtailinjury.

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oftenliveinditches,ponds,andlakesthataresusceptibletodrying(ArescoandGunzburger2004,Gunzburger2003),itiseasytoimaginethebenefitofsuchabehaviorinadryingburrowduringaestivation.however,nocur-rentlyavailableevidencesupportsthatcontention.theverydifferentcoil-ingbehaviorassociatedwithAmphiumareproduction,withoneloosecoilaroundaneggmassonland,probablydoesreduceevaporativewaterlossoftheeggs.Inthatcase,theeggsareheldtogetherinapilesurroundedbytheadult,therebyreducingthesurface/volumeratiooftheeggmass(hayesandlahanas1987).becauseourobservationswereincidentalviaanotherstudy,wedidnotspecificallytesttheeffectofcoveravailabilityonbody-coilingbehavior,andwesuggestthisasafuturestudy.

AcknowledgementsWethankseanDoodyforassistanceinthefield.

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Fig. 3. Amphiuma liveincrayfishburrows,andoftenhuntwiththeirheadattheentrancetotakepassingprey.thisindividualwascoaxedoutoftheburrowbytwiddlingastickatthewater’ssurfacetomimicaninsect.

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