A new device to autonomously feed individualized mantids on extended periods of time

REVISTA

BRASILEIRA

DE

Entomologia

w w w . r b e n t o m o l o g i a . c o m

Biology,

Ecology

and

Diversity

A

new

device

to

autonomously

feed

individualized

mantids

on

extended

periods

of

time

Marcus

V.

Scherrer

_,

_Alexandre

_P.

_Aguiar

a_{UniversidadeFederaldoEspíritoSanto,CampusGoiabeiras,DepartamentodeCiênciasBiológicas,Vitória,ES,Brazil} b_{InstitutoFederaldoEspíritoSanto,CampusSantaTeresa,SantaTeresa,ES,Brazil}

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received18April2019 Accepted17June2019 Availableonline25June2019 AssociateEditor:EduardoAlmeida Keywords: Mantodea Prayingmantis Rearing Captivebreeding Cannibalism

a

b

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Mantisescanliveformanymonths,arenaturallyvoracious,andfeedinvariablyonliveprey.Manyspecies

haveapropensityforcannibalismandcannotbekepttogetherformostoftheirlifecycle,whichmakes

large-scalerearingtypicallytime-consuming,thuseasilybecomingprohibitive.Thisisparticularlytrue

forearlyinstars,becausetheyarethemostabundantstageofadevelopmentalcohort.Suchlimitation

hindersresearchonMantodeawhichdependonliveindividuals,suchasbehavior,physiology,ontogeny,

andothers.Inthiswork,asimple,low-maintenance“self-service”deviceisdescribed,whichisgreatly

effectiveinreducingthetimeneededforkeepinglive,individual,smalltomedium-sizedmantises.Trial

anderrorusageandmodificationsalongeightyearsleadtomanyimprovements,resultinginanearly

optimaldeviceforitstargetpurpose.Thefinalmodelallowsrearinglargenumbersofmantiseswhile

demandingonlyafractionofthetimedemandedbyconventionalrearingtechniques.Keyadvantages

includepreventionofcannibalism,thepossibilityofmonitoringmantisesindividually,andfull

function-ingautonomyofuptoseveralweeks.Thenewdevicehasamplepotentialinstimulatingandsupporting

Mantodearesearchondiverseareas.

©2019SociedadeBrasileiradeEntomologia.PublishedbyElsevierEditoraLtda.Thisisanopen

accessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction

RearingindividualsisacommonpracticeinMantodearesearch. Itisvitalforstudiesonethology(e.g.,BalderramaandMaldonado, 1973;Preteetal.,1992;Maxwell,1998;Hurdetal.,2004;Holwell, 2008),physiology(e.g.,Yager,2005;Preteetal.,2013;Schirmer etal.,2014;Nityanandaetal.,2016;Oufieroetal.,2016;Sutton etal.,2016),ontogeny(e.g.,Heitzmann,1960;Terra,1980;Yager, 1996;Avenda ˜noandSarmiento,2011),bionomy(e.g.,Travassos Filhoand Heitzmann, 1960; Urban,1964; Matsura etal., 1984; Kaltenpoth,2005;Ariza,2011;Maxwell,2014;RautandGaikwad, 2016),orevensystematics(e.g.,RiveraandSvenson,2016).

Thetraditional, standard rearing methodwas firstproposed byTravassosFilho (1945)andimprovedbyTravassosFilho and Heitzmann(1960)butwasapparentlyindependentlydevelopedby RobinsonandRobinson(1978)intothemodelnowwidelyadopted. Itconsistsinisolatingeachindividualinadisposableplastic recip-ient,toavoidcannibalism.Gravelsorplasticnetsareprovidedas aperchduringecdysis.Thelidispartiallyorcompletelyreplaced withfabrictoallowforgasexchangeswhileavoidingprey,nymphs

∗ Correspondingauthor.

E-mail:marcusscherrer@gmail.com(M.V.Scherrer).

oradultstoescape.Ifhumidityislow,waterspraysorwet cot-tonballsmustbeused.Sincemantisesdonoteatdeadspecimens, eachcontainermustbeopenedeverytwoorthreedaystobe provi-sionedwithliveprey,whichmustbecaptured,reared,orpurchased fromspecializedproviders.The mostusedpreyis thecommon fruitfly(DrosophilaFallén,1832),crickets,cockroaches,moths,and butterflies.Mantidhatchlingscanbekeptcollectivelyinthesame containerbutmustbeindividualizedafterthefirstorsecond ecd-ysis.

Severaladaptationshavebeeninformallyproposed(e.g.,among prayingmantis’enthusiasts)tohelpthisgeneralrearingmethod tobecomemore agile orpractical. It is reasonably popular,for example,theuseofbrachypterousdrosophilaflies,which mini-mizeslosseswhenprovidingspecimenstothemantises.Itisalso commontheuseofaholeinthecontainer,closedwithapieceof foam,tofacilitatetheprocessofinsertingnewprey.Analternative setupwasformallyproposedbyFyeandCarranza(1979)to sim-plifytheprocessofpreydeliveryforalargenumberofrearingcages atthesametime.Evenso,theavailableproceduresarestill time-consuming,discouragingorpreventingrearingoflargenumberof mantises(Rivera,2010).

Prete and Mahaffey (1993) proposed a 51.0cm×41.0cm× 22.0cmpolycarbonateandLucitechamberformasshatchingand earlyrearingofmantises. It issealedonce eggsareintroduced. https://doi.org/10.1016/j.rbe.2019.06.003

0085-5626/©2019SociedadeBrasileiradeEntomologia.PublishedbyElsevierEditoraLtda.Thisis anopenaccessarticleundertheCCBY-NC-NDlicense(http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Anaquariumpumpforcesfreshairthroughawaterbottlewithin thechamber.Theintroductionofprey,preyfood,andwateroccur throughholesthatarepluggedwithfoamrubber.Drosophilaand, forlaterstages,crickets,areprovidedasprey,andkeptaliveinside thechamberwithcommercialDrosophilafoodorslicesof vegeta-bles.Manymantisescanberearedtogetherthiswaybutmustbe removedandisolatedafterthefifthorsixthinstar.Preteand Mahaf-fey’sdevicewasanimportantimprovement,butrearingmantises inasinglechambermakesitdifficultorimpossibletouniquely identifyeachindividual,adrawbackformanystudies.For exam-ple,individualvariationsinthenumberand durationof instars wouldnotbeeasilyassessed.Temporaryremovalofindividuals, e.g.formeasurementsorphotos,wouldalsobealmost unattain-able.Furthermore,cannibalismremainsanissue,evenifabundant preyitemsareprovided(Preteetal.,1999).

Thepresentworkwascompletedwithouttheknowledgethat Suckling(1984) fed nymphs of Orthodera ministralis (Fabricius, 1775)(Mantidae)in“cellophane-coveredDixiecups(size104w) withperforatedbottoms,mountedintothetopofacardboardbox”, insideofwhich“bottlesofemergingDrosophilamelanogasterwere placed”.Thismatchesthemainideaproposedherein,butSuckling providesnofurtherdetailsaboutit.

Thisworkstartedpurelyoutofnecessity,namely, togetfair numbersofecdysesofalldevelopmentalinstarsofahostof Man-todeaspecies.Noneoftheknowndevicesatthetimeprovedviable forthetask.Afterseveraltrials,theendresultshowedclear poten-tialforgeneralized use,justifyingthechiefaimofthis work:to describeanew,low-maintenance,semi-automaticdeviceto simul-taneouslyfeedconsiderablenumbersofsmalltomedium-sized, individualizedMantodea,fromjuvenilesintoadults.

Materialandmethods

Materialandtools

Thefollowingquantitiesandmaterialisnecessarytobuildthe ModelAoftheautofeeder(Fig.1);dimensionsareabbreviatedas H(height),W(width),L(length),anddia(diameter):24 dispos-able,translucidplastic cups(145ml, 7.5cmdia, H5.0cm),with lid;onepieceofrectangularpolyvinylchloride(PVC)pipe(HWL 6.54cm×10.0cm×100.0cm);twotranslucentplasticsheets(LW 10.0cm×6.54cm),cutfromregularplasticfoldersfoundin gen-eralofficestores;12square,3.5cmpiecesofTullefabricofmesh size0.3mm;12round,5.0cmdiapiecesofTullefabricofmesh size2.0mm;one75gtubeofplasticadhesiveforPVC;threeglue sticks (thermoplastic adhesive).The following toolswere used: knifeforpaper;gluegun;electricdrillandholesawof4.0cmdia and6.0cmdia.ForModelB,36plasticcupsareneeded,alongwith 24cm×3.5cmand5.0cmpiecesofTulle.

Assembling

AnassemblingschemaispresentedinFig.2(ModelA).There arethreemaincompartmentswhichmustbeinterconnectedand communicating:(1) A centralcirculation chamber fortheprey, composedbytherectangularPVCpipe(Fig.2,CII);(2)theattached rearingcupsfortheprey,connectedtothecentralchamberfrom below(Fig.2,CIII);and(3)theattachedrearingcupsforthe man-tises,connectedtothecentralchamberfromabove(Fig.2,CI).The rearingcupsforthepreyopenfreelyintothecentralchamber;the bottomoftherearingcupsforthemantisesarealsoopenintothe centralchamber,butseparatedfromitbya5.0cmpieceofTulle fab-ricof2.0mmmeshsize,whichisjustnarrowenoughtoavoidyoung mantisestoescapeintothecentralchamber,butlargeenoughto allowsmallpreyitemstoenter.

Thefirststepistodrilltheconnectingholes(Figs.1,2,numbers 1and2)ontherectangularPVCpipe(Figs.1,2,piecee).Twelve holesneedtobemadeononeofthe10.0cmsides,usingthehole sawof4.0cmdia,andanother12holesaremadeontheopposite sidewiththe6.0cmdiaholesaw.Theopeningsofbothsidesmust beverticallyaligned,andhorizontallyequidistantfromoneanother by8.2cmfromtheircenter(Figs.1,2,numbers1and2).Thelidsof thebottom(prey)cupsarethencutwiththeknifetoopena6.0cm diaholeonthecenter(Figs.1,2,number3).Eachlidisthenfixed withPVCadhesive,andsealedwiththermoplasticadhesive,aligned tooneofthe6.0cmdiaholesonthePVCpipe.Thebottomcupsare filledwithabout30mlofafoodmixforDrosophilaandsnappedinto placebypressingagainsttheirrespectivelids,nowfixedonthePVC pipe.A4.0cmcircularholeisnextcutonthebottomofthe12top cups(mantises’cups).Eachofthe5.0cmpiecesofTullefabricof meshsize2.0mmarethenpositionedoveroneofthe4.0cmdia holesonthePVCpipe;eachcupisthenalignedbyitsholewiththe equivalentholesonthePVCpipe,overtheTule,andthewholesetis gluedinplacewithPVCadhesiveandsealedwiththethermoplastic adhesive.A2.0cmsquareholeisthencutonthecenterofthe12 remaininglids.Theholesmustbefullycoveredwiththe3.5cm piecesof0.3mmmeshTulle,gluedexternally.Theselidswillclose themantises’cups.TheopenendsofthePVCpipearesealedbythe 10.0cm×6.54cmplasticsheets.

Insuchconfiguration,theautofeedercankeepupto12 indi-vidualizedmantisessimultaneously.Eachspecimencanbeeasily labeledorannotatedbyattachinganexternaltagtothecups.Itis importanttonotethattheholeonthelidsofthetopcupsarethe onlyventilationopeningsofthesystem.Theobjectiveofthefine meshhereistwofold;firstly,itpreventsthatbothyoungmantises andsmallpreyescape,andthenitalsoworksasafootholdforthe mantidstohangduringecdysis.Theclearplasticsheetsonthesides ofthePVCpipemakeiteasytoinspectthisarea,e.g.,whenchecking forpopulationdensityofpreyinthecourseoflengthenedusage.

Anexpandedautofeedermodel,with24mantises’cups,12on eachofthe6.54cmsidesofthePVCpipe,wasalsobuiltandtested (Fig.2,ModelB).Differencesintheoperationbetweenthetwo modelswereregisteredanddiscussed.

Experimentswereconductedinatropicalarea(21–29◦C aver-agemonthlytemperature,70–83%relativehumidity),sotherewas noneedtoregulatehumidity.Ifhumidityisanissue,thesolutionby PreteandMahaffey(1993)couldbeusedbutwasnottestedhere.

Operation

Beforeanyprayingmantiscanbetransferredintoanautofeeder, aDrosophilaculturemustbeestablishedonthepreycups.Atthis stage,thebottomofthemantises’cupsmustbecoveredwitha 5.8cmdiacardboarddisk,toavoidtheentranceofDrosophila spec-imens.Thefliescanbecapturedwiththesame145mlcups,and thenimmobilized with8sina freezer.Thesamecupsarethen attachedtothebottomoftheautofeeder;oncethefliesreanimate, theywillflyintothecentralchamber,andthecapturecupcanbe replacedwithacupwiththeculturemedium.Some10–20flies takeabouttwoandahalfweekstocolonizeallcups,generating enoughspecimenstoautonomouslymaintain12prayingmantises forseveralweeks.

Theculturemediumforthefliescanbepureripebananapuree, butamoreefficientformulaisachievedbyenrichingitwith corn-meal–oneteaspoonforeachmedium-sizebanana(about100g) makesoneportion.Themixwasprotectedwithaquarterteaspoon ofthefungicidemethylparaben(Nipagin®)perportion. Commer-cialorotherformulaswerenottested.Labelingthepreycupswith thedateofproductionoftheculturemediumwasquiteusefulin monitoringthequalityofthemedium.

Figs.1and2.Buildingschemesfortheautofeeders.1.Usedmaterial,measurementsandquantities.2.Assembling.Bottompanelcorrespondstoanexplodedviewdrawingof theModelA,withmantises’cupsonthetop.ThetoprightdetailisforModelB,withmantises’cupsinstalledlaterally,thusholdingtwiceasmanycups.CI,firstcompartment, therearingchamber,showinga4thinstar,2.0cmlongPhotinasp.(toscale);CII,centralorcirculationcompartment;CIII,thirdcompartment,thepreycup;a,squarepieceof Tullefabricwithmeshsizeof0.3mm;b,Lidwithasquarehole(5)inthecenter;c,translucentmantiscup,withcircularhole(4)onthebottom;d,circularpieceofTullefabric withmeshsizeof2.0mm;e,rectangularPVCpipewithcircularholesonthetopside(1)andbottomside(2)[serrationsonthesideisonlyaneffecttoshowinsidethepipe, andisnotmeanttobecarvedonpipe!];f,translucentplasticsheet;g,lidwithcircularhole(3)oncenter;h,translucentpreycup;i,culturemediumforDrosophilaFallén, 1832.Theconnectionsbetweencomponentsa+b,c+d+e,e+fande+garefixedwithPVCadhesiveandsealedwiththermoplasticadhesive(gluegun).Thesmallorangedots representdrosophilaflies,indicatingthattheymustcirculatefreelybetweenCI,CIIandCIII.

Mantiseswerecapturedinthewildorrearedfromtheeggcases producedbythecapturedorrearedspecimens.Eachspecimenwas placedinasinglecup,fromwhichtheprotectingcardboarddisk wasremovedmomentsbefore,allowingthefliestoenter.Actual autofeedersandsomedetailsofitsoperationarepicturedinFig.3.

Resultsanddiscussion

Theautofeederswereoperatedforovereightyears,supporting thedevelopmentofvariousprojects.Thenumberofautofeeders beingoperatedsimultaneouslyvariedfrom1to5,accordingto necessity.Atotalof381specimenswerereared:4Acanthops fal-cataria(Goeze,1778),45Acontistasp.,4Bantiasp.,73Cardioptera brachypteraBurmeister,1838,2Eumusoniasp.,40Miobantiaaptera Giglio-Tos,1917,85Miobantiafuscata(Giglio-Tos,1915),64Fuga fluminensis(Piza,1965),4 Hicetiasp.,1Parastagmatopterasp.,6

Photinasp.,25Pseudovatessp.,and28Thesprotiasp.Asexpected, thefliescirculatedandmatedfreelyinthePVCchamberandin thepreycups.TheamountoflightprojectedinsidethePVC cham-berfromthebottomopeningofthemantises’cupswasalsojust enoughtoregularlyattractsome,butnotallflies.Onceinthe man-tises’cup,thefliesrarelyreturnedtothePVCchamber,becauseit ismuchdarkerandbecausetheytrytoescapeflyingupwards.The numberoffliescapturedbythemantiseswasgenerallyefficiently counterbalancedbythecontinuousproductionofnewfliesinthe preycups.

Eachpreycuplastedforuptwomonthsefficientlyproducing adultflies.Oncetheculturemediumwasconsumed,someofthe preycupswerereplacedbynewones,withfresh,uncolonized cul-turemedium.Notmorethantwocupscouldbereplacedperweek. Suchprecautionisimportantbecauseeventhoughnewcupsare almostimmediatelycolonized,theeggstheyreceivetooktimeto

Fig.3. ModelBautofeederinoperation.(A)Overallview;emptyrearingchambershaveacardboarddiskblockingtheentranceofflies.(B)Four4thand5thinstarM.aptera Giglio-Tos,1917intherearingcupsalongwithsomeDrosophilaFallén,1832flies.(C)Frontviewofoneendoftheequipment,showingthepreycupwithculturemedium, andDrosophilalarvaeandflies;notecentralcompartmentwithpreyfreelycirculating,andtherearingcupwitha4thinstarM.apterahangingintheTullefabric.(D)Rearing cupseenthroughitscoverlid,witha4thinstarM.apteraandsomeprey.(E)Sideviewoftherearingcup,witha5thinstarM.apterafeedingonafreshlycaughtDrosophila fly.

developand producethefirstbatchofadults.Inthemeantime, thepopulationdensityoffliesissafelymaintainedbythecyclic productionofadultsintheremainingcups.

Adjustingforpreyavailability

Eveninspiteofregularreplacementsoffoodinthepreycups, thepopulationdensityoffliessometimesbecamequitelow.Such episodeswere more frequentwhen the autofeeders wereused in their maximum capacity, housing largeindividuals, and for extended periods of time. The adoptedsolution wasto have a numberofextraautofeedersinoperation. Whenthenumberof fliesbecame lowin one autofeeder,someof itsmantiseswere transferredtoavacantautofeederandmaintainedthereuntilthe originalflypopulationwasreestablished.Anequivalentstrategy wasemployedforautofeederswithhighdensitiesofflies,thatis, thesedeviceswouldreceivemoremantisspecimens.Such man-agementwasmoreeffectivewiththeModelBautofeeder,sincethe highernumberofmantisesitcanholdallowsforafinertuning.On bothmodels,theneedformanagingmantisesbetweendeviceswas

easilyassessedbycheckingthenumberoffliesinsidethemantises’ cups.Moreover,changingmantisesbetweenautofeederscreates theopportunitytoremovefecesandpreydebrisfromthe cham-bers. Oncethis dynamicwasobserved, problemswithshortage orexcessofflieswereconsistentlyavoided.Typically,however, theautofeedersrunautonomouslyforseveralweeks,withoutany intervention.

Models

Generally,Models Aand Bwere similarlyefficientfor semi-autonomous and simultaneous rearing of mantises. The used material,sizesandproportionswereadjustedempiricallythrough theyears,andcanbesafelychangedaccordingtonecessity(e.g., largercups orchambers,differentmaterials), providedthat the threeintercommunicatingchambers(Fig.2,CI,CII,CIII)are main-tained.

ModelA,withthemantises’cupsonthetop,accumulatesless fecesandpreydebris,becausetheremainspassthroughthemesh onthebottomandfellinthepreycups.Accumulationofdebrisin

thepreycupswasnegligibleanddidnotproduceanynoticeable effectongrowthandreproductionoftheflies.InModelB, how-ever,theremainsquicklyaccumulateonthelateralwallofthecup, requiringthemtobecleanedmoreoftenthancupsofModelA.

Regardlessofthemodel,thenumberoffliesinthecentral com-partment,andthereforeinthemantises’cups,wasproportionalto thenumberofrearingchambersinuse.ModelAishoweverprone toaccumulationoflivefliesiftheiravailabilityisnotmonitored. Thefliesalwaysseektoescapeflyingtowardlight,andupwards, andthereforewillnotgetbacktothedarkcirculation chamber below.In suchcases,thecuphadtobeslightlyopenedandthe fliesreleased.Theexcessivenumberoffliescandistressthe man-tises,particularlysmallnymphs,andallstagesofdevelopmentofF. fluminensis.Italsocanspreadmicroorganisms,whichcolonizethe wallsofthecup,requiringthemtobecleanedwithcottonsoakedin 92.8%ethanol.InModelB,mantises’cupsarelesslikelyto accumu-lateflies,becausetheycaneasilyreturntothecirculationchamber, whichispositionedlaterally.

Rearingsuccess

Theautofeederwasdeveloped,andused,exclusivelyasa solu-tionfor onespecific problem(seeIntroduction). Theresultson rearingsuccessprovidedbeloware,therefore,availableonlyfor thespecificcaseswherethedevicewasused.Itisnottheaimof thisworktopresentafull-blowntestontheoverallefficiencyof theautofeeder.Theprovideddata,however,offersaninformative reportof8yearsofannotatedresultsandobservations.

Specimensof Acontista sp.werereared fromhatching upto theend of adult life in theautofeeder (maximumbody length ∼20mm). Nymphs of A. falcataria, C. brachyptera, Hicetia sp., Parastagmatopterasp.,Photinasp., Pseudovatessp.,and Thespro-tiasp.wereefficientlyreareduptothelastorpenultimateinstar (∼35mm).Atthispointtheavailablespacewasinadequatefora normalecdysis,andthespecimenshadtobetransferredtolarger containersunderthetraditionalrearingmethod.Evenso,adultsof Hicetiasp.,Photinasp.,andThesprotiasp.weresuccessfullyreturned andrearedintheautofeedersafterecdysis(∼65mm).Adultsof Bantiasp.andEumusoniasp.werealsoefficientlyreared(∼43mm). SpecimensoffirstinstarofMiobantia spp.wouldnottakeD. melanogaster.Thismightberelatedtotheirsmallsize,near2.5mm (Scherrer, 2014), not much larger than the flies. Yager (1999) reportedthesamerejectionbyverysmallfirstinstarnymphsof someAmelinae, Oligonicinae,and Thespinae.Theonlyavailable solutionistorearthefirstinstarsofthesetaxainchambers con-tainingestablishedculturesofCollembola,asproposedbyUrban andTravassosFilho(1954).SecondstagenymphsofMiobantiaspp. weresuccessfullyrearedintheautofeedersuntiltheadultstage.

SpecimensofF.fluminensislivedtheleastintheautofeeder. Sev-enteenofthenymphscollectedonthefieldlivedlongenoughto undergooneorafewecdyses.Oneofthesenymphscompletedsix ecdysesandreachedadulthood.Othercollectednymphs, allthe nymphshatchedonlaboratory,andalltheadultslastedonlyafew days.Thishoweverdoesnotseemtobeaninherentlimitationof thedevice,sincereducedlongevitywasalsotheoutcomewhen wetriedtokeepF.fluminensisusingthetraditionalmethod.This mightsimplymeanthatF.fluminensisisdifficulttorear.Indeed, theyare,mostofthetime,notoriouslyagitatedinthecontainers,a behaviorwhichdoesnotcorrespondtowhatisobservedinnatural condition.

Adults of A. falcataria, C. brachyptera and Parastagmatoptera sp. (body length ∼40–50mm) are not adequately fed with D. melanogasterandthereforecouldnotbemaintainedin the aut-ofeeders as designed. Adults of Pseudovates sp. (body length ∼70mm)alsocouldnotbemaintainedinitduetospace limita-tionsoftherearingchambers.Thisshouldobviouslyalsobethe

caseforadultsorlateinstarsofothersimilarorlargersized man-tises(e.g.,Stagmatoptera Saussure,1871,Macromantis Saussure, 1871,andAngelaServille,1839).Thiswashoweveraplanned limi-tation,infavorofsavingspaceandbecauseofthefocusonrearing juveniles.Thisisrelevantbecause,inMantodea,itistheearlystages ofdevelopmentwhichareoftennumerous,andthereforedifficult torearoneby one.Adultsaremuch less ofa problemin what regardsmaintenanceforscientificpurposes.

Adaptingtheautofeedersforlargeindividualswouldbe rela-tivelyeasy,e.g.,byreplacingoneormoreoftheoriginalcupswith largerones.Forlargespecimens,however,largerfooditemswould alsoberequired.Supplyingthepreycupswithculturesofthe com-monhousefly,oranyofthemothspecieswhichinfeststoredgrains (Pyralidae),alongwithalargermeshsizeTulle,couldbeaviable alternative,butthiswasnottested.

Theuseofthedeviceforrearinganimalsotherthanpraying mantiseswasnottested,butitclearlyhaspotentialforrearingother predatoryarthropodssuchasspiders,earwigs,somebeetles,bugs, lacewings,andothers.

Advantages

TableIsummarizesthemaindifferencesbetweenthetraditional rearingmethod,thePreteandMahaffey’smasshatchingchamber, andthenewdevice.Buildinganautofeederconsumesclearlymore timethanassemblingatraditionalcage.However,thisisquickly paid-offbythefactthatthedemanding,highlyrepetitiveand time-consumingprocedureof transferringfood itemsintoindividual rearingchambersisfullyavoidedwiththeautofeeder.Themore mantisesrearedsimultaneously,andthelongerthecolonieslast, themoretime-rewardingtheuseoftheautofeederwillbe.If free-domtodootherthingsisanissue,theautofeedermightstillbethe bestchoice,evenifasinglemantisistobereared.

By definition, an autonomous feeding mechanism does not allowprecisecontroloverhowmanypreyitemsthemantiseswill take.Unlessrigorouscontrolofthedietofeachmantisisrequired, suchmonitoringcanbeperformed,forexample,byobservingthe degreeofabdominalswellingofthespecimens(usuallyquite con-spicuousinMantodea),orbyobservinghowmuchpreyisleftin thecentralchamber.

Themass-hatchingchamberproposedbyPreteandMahaffey (1993),aswellasothermethodsofrearingmantisescommunally (Preteet al.,1999),will,generally,generate similarresults.The keyadvantagesofthenewdevice,however,layonthefactthat itisdesignedformass-rearingofindividualizedmantids, prevent-ingpredation/cannibalism,andallowingforsafeandsimultaneous rearingofdifferentorincompatiblespecies.Taggingisalsoeasy, promotingtheprecisefollow-upofeachindividual.

Finalcomments

Thedescribeddeviceisnot intendedasasubstitute for pre-vious methods. Instead, it presents a unique, and finely tuned setoffeaturesthatmakesitapotentiallyadvantageous alterna-tiveformass-rearingof individualizedmantises. Thespecimens canbeleftfullyunattendedforextendedperiodsoftime,freeing theresearcherforotheractivities.Ithasasolidpotentialfor sup-portingMantodearesearchonareassuchasbehavior,physiology, ontogeny,biologicalcycles,immaturestages,taxonomy,andany otherinvestigationwhichdependonrearingormaintaininglive Mantodeaindividuals,especiallyduringitsearlystagesof devel-opment.

TableI

Differencesbetweenthenewdevice,themasshatchingchamber(PreteandMahaffey,1993),andthetraditionalrearingmethod(e.g.,RobinsonandRobinson,1978).Typical autonomyandtypicalsetuptimedataareforrearing12mantises.

Method Typicalautonomy Typicalsetuptime Preyconsumptionmonitoring Cannibalismprevention Individualmonitoring

Autofeeder 1–3weeks 4–5h Subjective Total Possible

Mass-hatchingchamber Weeksa _Hoursa _{Subjective Partial Impossible}

Traditional 2–4days <30min Objective Total Possible

a_{Noprecisedataavailableintheliterature.}

Conflictsofinterest

Theauthorsdeclarenoconflictsofinterest.

Acknowledgments

This study was financed in part by the Coordenac¸ão de Aperfeic¸oamentodePessoaldeNívelSuperior–Brasil(CAPES)– FinanceCode 001, and bytheFundac¸ãodeAmparo àPesquisa eInovac¸ão(FAPES),Brazil[Process80708846/18].YuriL.R.Leite (UFES)providedhelpfulsuggestionsonaninitialversionofthe manuscript.HenriqueM.Rodrigues(CaseWesternReserve Uni-versity,USA)andJulioM.RiveraC. (UnidaddeInvestigaciónen EntomologíayMedioAmbiente,UniversidadSanIgnaciode Loy-ola,Peru)assistedwiththeliterature.Anonymousreviewersand theeditorsprovidedusefulcommentsandsuggestions.

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