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Literature Citedbailey,l.l.,W.l.Kendall,D.R.Church,andh.m.Wilbur.2004.estimating
survivalandbreedingprobabilityforpond-breedingamphibians:Amodifiedrobustdesign.Ecology85:2456–2466.
bruce,R.C.1982.egg-laying,larvalperiodsandmetamorphosisofEurycea bislineataandE. junaluskaatsanteetlahCreek,northCarolina.Copeia1982:755–762.
Folkerts,G.W.1971.ecotypicvariationinsalamandersofthesoutheasternU.s.Herpetological Review3:106.
Forester,D.C.1977.CommentsonthefemalereproductivecycleandphilopatrybyDesmognathus ochrophaeus(Amphibia,Urodela,plethodontidae).Journal of Herpetology11:311–316.
Jones,t.R.1980.Areevaluationofthesalamander,Eurycea aquaticaRoseandbush(Amphibia:plethodontidae).Unpubl.m.s.thesis,AuburnUniversity,Auburn,Alabama.
Kozak,K.h.,R.A.blaie,andA.larson.2006.GenelineagesandeasternnorthAmericanpaleodrainagebasins:phylogeographyandspeciationoftheEurycea bislineatacomplex.Molecular Ecology15:191–207.
mount,R.h.1975.Amphibians and Reptiles of Alabama.AuburnprintingCo.,Auburn,Alabama.
pauley,t.K.andm.b.Watson.2005.Eurycea cirrigera,pp.740–743.In:m.lannoo(ed.),Amphibian Declines: Status of United States Species.UniversityofCaliforniapress,berkeley.
petranka,J.W.1998.Salamanders of the United States and Canada.smithsonianInstitutionpress,Washington,D.C.
Rose,F.l.andF.m.bush.1964.AnewspeciesofEurycea (Amphibia:Caudata)fromthesoutheasternUnitedstates.Tulane Studies in Zoology10:121–128.
sever, D.m. 2005a. Eurycea bislineata, pp. 735–738. In: m. lannoo (ed.),Amphibian Declines: Status of United States Species.UniversityofCaliforniapress,berkeley.
sever, D.m. 2005b. Eurycea wilderae, pp. 770–772. In: m. lannoo (ed.),Amphibian Declines: Status of United States Species.UniversityofCaliforniapress,berkeley.
timpe, e.K., s.p. Graham, and R.m. bonett. 2009. phylogeography of thebrownback salamander reveals patterns of local endemism in southernAppalachiansprings.Molecular Phylogenetics and Evolution52:368–376.
Wells,K.D.2007.The Ecology and Behavior of Amphibians.UniversityofChicagopress,Chicago,Illinois.
Perch Height Differences among female Anolis polylepis exhibiting
Dorsal Pattern PolymorphismJohne.steffen
pennstateerie,thebehrendCollege,erie,pennsylvania16563([email protected])
Female-limiteddorsalpatternvariationwithinaspecieshasbeenofinter-esttonaturalistsforyears,andhasbeenobservedinanimalsranging
fromspiders,damselflies,anddragonfliestofrogsandlizards.protectionagainstpredationbybirdshasbeenofferedasapreliminaryexplanationfortheevolutionofthesepatterns,especiallyfrombirdsthathaveacutecolorvisionandwhichpreferentiallypreyonfemalesbecausetheyarelessagileandmorenutritious(stampsandGon1983).
Fig. 1.maleAnolis polylepiswithdewlapextended(right)andfemaleA. polylepis(above)withthe“diamondstripe”(ds)dorsalpattern(seetext).Copyright©Davidlaurencio2010.Usedwithpermission.
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Female-limiteddorsalpatternvariationisobservedinmanyanolinelizards(savage2002,losos2009).Inanoles,multipledorsalpatternsoccurinfemalesthroughoutapopulation,andthesedorsalpatternsareherita-ble(Calsbeeketal.2008)andrelativelyfixedthroughoutafemale’slife(althoughtheintensityofthepatterncanchangedependingonlightavail-ability,humidity,andtemperature;pers.obs.).savage(2002)describedsomerecurringdorsalpatternphenotypesseenwidelyinspeciesofCostaRicananoles. FemaleAnolis polylepisfromlasCrucesbiologicalstationinCostaRicashowanumberofdorsalpatterns.AspartofademographicstudyofA. polylepis,Icapturedandrecapturedfemalesthatpossesseddifferentdorsalpatternsandmeasuredperchheightsandotherecologicalvariablestodeter-mineiffemaleswithdifferentdorsalpatternsdifferinmicrohabitatuse.
Study Site and MethodsDuringthedryseasonof2003,Iperformedacapture-mark-recapturestudyofjuvenileandadultAnolis polylepis(Fig.1)ina10,000-m2plotofpri-maryforestwithintheboundariesofthelasCrucesbiologicalstation.thestationislocatedatanelevationof1,200mabovesealevelinsanVito,CotobrusCounty,puntarenasprovince,insouthernCostaRica(8°47’7’’n,82°57’32’’W).thismid-elevationsiteiscomprisedofmorethan300haofpremontaneWetForesthabitataccordingtotheholdridgeclassificationsystem. IsuperimposedaCartesiancoordinatesystemovertheplotandeveryfivemetersplacedasurveyflagthatcontainedtheCartesiancoordinates.Iperformedstandardizedsearchesforlizardsonthisplotbyenteringtheplotfromthesamepointduringeverysearch(thesoutheasternside)andslowlywalkingazigzagpatternfromoneendtotheotherendoftheplot.Icon-tinuallysearchedtheplotforlizardsinthiswayfrom0800–1130h.Whenalizardwasobservedduringastandardplotsearch,Inoteditslocationwithrespecttothenearestflag,andrecordedwhetherthelizardwasperchedonthegroundversusatrunkorbranchofatree.Imeasuredtheheightoftheperchandthediameteratbreastheight(Dbh)ofthetreeonwhichthelizardwasperchedwithahand-held5-mtapemeasure.Ithencapturedthelizard(byhandorwithanoose)andbroughtitbacktothelasCruceslab,whereImeasureditssnout-to-ventlength(sVl)inmillimeters,massingrams,and,ifthelizardwasafemale,Inotedifshewasgravid(i.e.,hadashelledeggintherightorleftoviduct)orhadyolkingfollicles.Icollecteddatafor19daysfrom3–24march.IestimatedhomerangesizesforfemalesusingthemethodsofJennrichandturner(1969). threedorsalpatternswerecommonamongfemaleA. polylepis. Idescribedanddrewthemindetailinmyfieldnotes(Fig.2),andtheyappearedtobeintermediatephenotypesofthatdescribedforfemaleCosta
Ricananolesbysavage(2002).Idefinedthethreecommondorsalpatternsas:(a)Diamondstripe(or“ds”),whichconsistsofblackdiamonds,andisthedorsalpatternlabeled“b”insavage(2002);(b)checkeredstripe(or“cs”),whichconsistsofawhiteandblackhyphen-ordash-likepattern,andappearstobeavariationofdorsalpattern“e”insavage(2002),withablackdashoverlyingthewhitestripe;and(c)whitestripe(or“ws”),whichconsistsofabrightwhitestripeborderedbyblackstripes,andisthedorsalpatternlabeled“e”insavage(2002). todeterminewhetherfemaleswiththethreedorsalpatternsdifferedinmass,sVl,perchheight,Dbh,andhomerangesize,Iperformedone-wayAnoVAsforeachvariable,withdorsalpatterntypeastheindepen-dentvariable.todeterminewhetherfemaleswiththethreedorsalstripepatternsdifferedinbeinggravidornotorinthenumberofhomerangeoverlapswithothermalesandfemales,Iusedchi-squaretestsforeachvari-able,withdorsalpatterntypeastheindependentvariable.
ResultsFemalesofthethreedifferingdorsalpatternsdidnotdifferinmass,sVl,Dbh,homerangesize,graviditystatus,ornumberofoverlappinghomerangeswithmaleorfemales(table1).however,adorsalpattern-specificdifferenceinperchheightswasevident.Femaleswiththedspatternperchedthelowest,femaleswiththecspatternperchedatintermediateheights,andfemaleswiththewspatternperchedthehighest(Fig.3).
Discussionthesedatasuggestthatfemalesthatpossessdifferentdorsalpatternsdif-ferinperchheightinAnolis polylepisatlasCrucesbiologicalstation.Furthermore,thesefemalesdonotappeartodifferaccordingtoothercom-monecologicallyrelevantvariablesthatweremeasured. Avianpredationhasbeenhypothesizedtobethekeyselectiveforceresponsiblefortheevolutionofthesedorsalpolymorphismsinmostspe-cies(stampsandGon1983).thatavianpredationhasaninfluenceonpopulationdensity (Andrews andRand1982), community structure(AdolphandRoughgarden1983),andhabitatchoice(Wunderle1981)inanoleshasbeenrecognizedforyears.Recently,Calsbeeketal.(2009)studiedfemale-specificdorsalpatternpolymorphisminCaribbeanislandpopulationsofthecloselyrelatedAnolis sagrei,andfoundthatpredationonparticularpatternswasfrequencydependentandactedasasignificantselec-tiveagentmaintainingthefrequencyofpatternvariantsinthepopulation.Unfortunately,thestudydidnotattempttostudyperchheightdifferencesindorsalpatternvariation.theauthorsspeculatedthatparticulardorsalpatternsappeardifferentiallyconspicuoustopredatorsincertainmicro-habitatconditions.Interestingly,thedorsalpatternvariationsobservedinA. sagreiaredifferentinshapeanddesignthanthoseinA. polylepis.
anolis polylepis
Fig. 2.DorsalpatternsobservedinfemaleAnolis polylepisinprimaryforestsnearlasCrucesbiologicalstation:ds=diamondstripe,cs=checkeredstripe,ws=whitestripe.
Fig. 3.perchheightdifferencesamongfemaleAnolis polylepiswithdifferingdorsalpatternsatlasCrucesbiologicalstation.ds=diamondstripe,cs=checkeredstripe,andws=whitestripe.barsrepresentonestandarderror.one-wayAnoVAshowedthesedifferencestobestatisticallysignificantatp≤0.05).
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thedataIpresenthereareconsistentwithanavianpredationexpla-nation—ifthedifferentdorsalpatternscouldbeshowntobedifferentiallyconspicuoustoavianpredatorsindifferentmicrohabitats,andifdifferentdorsalpatternsexperiencedifferentialmortalityasaresultofthisconspicu-ousness.Futureresearchonfemaledorsalpatternsinanolesshouldthere-forefocusontheecologicalsignificanceofthefemaledorsalpatternswithrespecttoavianvisualsystems.
AcknowledgementsIthankCraigGuyer,ots,andtheAndrewmellonFoundationforfinan-cialsupport.Ialsothankluis-DiegoGomezforinvitingmetostaywithhimuntilaroombecameavailableatthelasCrucesbiologicalstation.thisinvitationwasextendedforaweekandledtothedevelopmentofafriendshipuponwhichIhavereliedforyears.hisenthusiasmfortropicalresearchandhissenseofhumorwerecontagious,andhewillbegreatlymissed.Finally,IthankhenryFitch.Iconsiderhimtobethe“foundingfather”ofmainlandanoleecologicalresearch,andhisinterestinmyworkgavemegreatconfidence.healwayswelcomedvisitorsand,asaresult,Iwasabletogleanagreatdealofknowledgefromhim.Idedicatethispapertothelivesofbothofthesegreatmentors.
Literature CitedAdolph,s.C.andJ.Roughgarden.1983.ForagingbypasserinebirdsandAnolis
lizardsonst.eustatius(neth.Antilles):Implicationsforinterclasscompeti-tion,andpredation.Oecologia56:313–317.
Andrews,R.m.andA.s.Rand.1982.seasonalbreedingandlong-termfluctua-tionsinthelizardAnolis limifrons,pp.405–412. In:e.G.leigh,Jr.andA.s.Rand(eds.),The Ecology of a Tropical Forest: Seasonal Rhythms and Long-term Changes.smithsonianInstitutionpress,Washington,D.C.
Calsbeek,R.,C.bonneaud,andt.b.smith,2008.Differentialfitnesseffectsofimmunocompetenceandneighborhooddensityinalternativefemalelizardmorphs.Journal of Animal Ecology77:103–109.
Calsbeek,R.,l.bonvini,andR.m.Cox.2009.Geographicvariation,frequencydependentselection,andthemaintenanceofafemalelimitedpolymorphism.Evolution,earlyview,publishedonline3August2009.
Jennrich,R.I.andF.b.turner.1969.measurementofnon-circularhomerange.Journal of Theoretical Biology22:227–237.
savage,J.m.2002.The Amphibians and Reptiles of Costa Rica: A Herpetofauna Between Two Continents, Between Two Seas.theUniversityofChicagopress,Chicago,Illinois.
stamps,J.A.ands.m.GonIII.1983.sex-biasedpatternvariationinthepreyofbirds.Annual Review of Ecology and Systematics14:231–253.
Wunderle,J.m.,Jr.1981.AvianpredationuponAnolislizardsonGrenada,WestIndies.Herpetologica37:104–108.
steFFen
Table 1.Resultsofseparateone-wayAnoVAsandChi-squareanalysestestingdorsalpatterndifferencesinecologicallyrelevantdependentvariablesamongfemaleAnolis polylepis.Dorsalpatterntypewastheindependentvariable.FemaledorsalpatternscommonlyobservedatlasCrucesbiologicalstationwere“ds”(diamondstripe),“cs”(checkeredstripe)and“ws”(whitestripe).nreferstonumberofindividualfemalesrepeatedlyobservedwithaparticulardorsalpattern,andthenumberinparenthesesreferstothetotalnumberofsightingsfortheparticulardorsalpatternsighting.Dbh=treetrunkdiameteratbreastheight.Anasterisk(*)marksresultssignificantatp≤0.05.
Dependent variable F df P N (ds) N (ds) N (ws)
mass 0.500 14 0.613 6(26) 3(20) 6(21)
svL 1.431 14 0.259 6(26) 3(20) 6(21)
Perch height 3.955 14 0.039* 6(26) 3(20) 6(21)
DBH 0.200 14 0.821 6(26) 3(20) 6(21)
Home range 0.714 14 0.502 6(26) 3(20) 6(21)
c2 df P N (ds) N (cs) N (ws)
gravid / not-gravid 4.611 14 0.330 6(26) 3(20) 6(21)
# male HR overlap 5.220 14 0.516 6(26) 3(20) 6(21)
# Female HR overlap 5.882 14 0.443 6(26) 3(20) 6(21)
