Live mass and length-mass allometry of adult odonates collected in east-central Mississippi, United States

2005·2.1 MB·English

by  Bried, J T

Odonalologica34(2):111-122 JuneI,2005
Livemassandlength-massallometry
ofadultodonatescollected ineast-central
Mississippi, UnitedStates
J.T.Bried¹,L.W.Bennet²tandG.N.Ervin¹’³
1DepartmentofBiological Sciences, MississippiStateUniversity,P.O.BoxGY,
MississippiState,MS39762,United States
e-mail:[email protected]
2CollegeofVeterinaryMedicine,MississippiStateUniversity, Box6100,
MississippiState,MS39762,United States
e-mail:[email protected]
3e-mail: [email protected]
ReceivedJune14,20041Revised andAcceptedOctober2,2004
Livemasswasrecorded forover290adult Odon. duringpeakflightseasonin Mis-
sissippi.Total livemassisreportedfor 19spp.,alongwithaquantitativespecies subset
analysisofinter-andintraspecificsexpartitionedmass.Freshmasswassignificantlycor-
related withspeciesandsexinAnisoptera(p=0.021)andZygoptera(p=0.001),based
onseparatespecies-levelanalysesoftheLibellulidae (n=6spp.)andCoenagrionidae(n
=4spp.),respectively.Totallivemassalso wascorrelatedwithtotalbodylengthinthe
libellulid dragonflies(r2=0.59-0.94,p<0.0001-0.03)andlength-massslopeswerenot
significantlydifferentamong species.Limitations andcautions ofmasspredictionvia
proportionatesizedimension(s)arediscussed,someadvantagesofworkingwithadults
asopposedtolarvae andmeasuringfresh massasopposedto drymassaredescribed,
andfurtherstudy oflength-massrelationshipsinadultOdon. isencouraged.
INTRODUCTION
Insectmassismeasuredeitherdirectlyasfreshorpreserved weight,orindirectlyas
anestimateofaclosely correlatedsizedimensionparameter,suchaslengthofbody
and/or wing. Length-mass regressions can yield useful mass predictiveequations
(MILLER, 1976;SAMPLEetah, 1993;BENKE etah, 1999;HALEetah,2004).
For example, they mayfacilitatemore efficient(rapid, non-laborious) determina-
tionof secondary production by circumventing theprocessing timeandneedfor
laboratory equipment thataccompanies directmassmeasurement (SAMPLE etah,
1993).Regressions foraquatic insectsinNorthAmericaarescarce(BENKE etah.
112 J.T. Bried, L.W.Bennett&G.N.Ervin
1999)andexist only fordriedor chemicallytreated larvalstages(SMOCK, 1980;
BURGHERR & MEYER. 1997;BENKE etal., 1999).
Measuring livemass ofadult Odonataandother aerialinsects has severalad-
vantagesformass prediction. Molting maycause a temporarydeclinein specific
gravityofaquatic insectlarvae, becausethecastexuviaereducesmass-volumera-
tiorelativetothatofthepremolt instar.Therefore, greaterlength-mass variability
anddiminishedaccuracy ofmasspredictionwillresultfrompoolingspecimen data
collectedbothnearanddistanttomolting periods (BENKE etal., 1999).Another
disadvantage to working withlarvalaquatic insects is that obtaining ashfree dry
massisrequired to negatetheeffectsofattachedsiltandotherwater-borneinor-
ganic materials(BENKE et al., 1999).Theprocedure is timeconsuming relative
tolive-massmeasurementandisunnecessary foraerialadults,except todetermine
gutcontents. Preservationmethodsoften destroy lipids(thus, induceloss oftis-
sue mass)anddifferenttechniques, such as acetonevs. alcohol,produce equations
thatare not interchangeable (DERMOTT&PATERSON, 1974;SMOCK, 1980;
GONZALEZetal.,2002). Inaddition, livemassmeasurementavoidsorminimizes
a deathtoll,unlikeallinsect preservation techniques.
Biomass dataof Odonata are used in studies of ontogeny,reproductive fit-
ness, flightbiophysics and energetics, physiological ecology, and behavioralecol-
ogy (MAY, 1976, 1984;ANHOLTetal., 1991;BAKER etal., 1992;DUNHAM,
1993;CORDERO, 1994;WAKELING, 1997). However,thereexistsapaucity of
descriptive odonatemass data(BECKEMEYER, 1999;butseeANHOLTetal.,
1991)andallometrybetweentotalmassandbody lengthhasnotbeenreportedfor
freshly captured adultstages. Theneedto fillthisinformationgapis underscored
byoverwhelming evidencethattheOdonataare strongcandidatesas indicatorsof
ecological integrity (e.g., SAMWAYS, 1993;SAMWAYS & STEYTLER, 1996;
CHOVANEC & RAAB, 1997;STEWART & SAMWAYS, 1998;CHOVANEC
& WARINGER, 2001;BRIERS& BIGGS,2003) andtheassessment ofecosys-
temfunctions, such as production, generally lags behind structuralinvestigations
(BENKE, 1984;AINSLIE, 1994;GESSNER &CHAUVET,2002).
Thespecific objectives ofthepresent studywere to (1) compile live-mass data
for adultdragonflies and damselfliesand quantitatively compare select species,
and (2) analyze relationships between fresh-body length and biomassin asmall
suiteof dragonflies as afirst-step feasibility testformass prediction. Our discus-
sion covers some finepoints ofmass prediction using length, both ingeneral and
as pertains to Odonata.
METHODS
On 11Julyand 19-20August2003,adultodonateswerecollectedfrom 17locationswithintheNoxu-
beeNational WildlifeRefuge,Noxubee Co.,MS,USA (33°17’N,88‘’48’W).Sampledhabitats included
reservoirlittoral zonesand spillways,bottomland hardwood forest,cypress-tupelo sloughs,roadside
ditches,andopenfieldsadjacenttolentic breedinghabitat,spreadacrossapproximately45km2.
Odonatemassanalyses 113
All encountered Odonata
were capturedwith aerialnets
duringa1hperiodateachloca-
tionandprocessedwithin0.5h.
Therefore,the amountoftime
between capture andweighing
ofanyindividual neverexceed-
ed1.5h.Nettedindividualswere
immediatelyinspectedtofacili-
tatepromptrelease ofanimals
inpoorcondition (e.g.,tattered
wings, missing body parts).
Specimens wereinserted into
separateglassineenvelopesand
transportedto a temperature-
-controlled facilitylocatedwith-
in9.6kmofallcollection sites.
Thecatchwassortedbyspecies
and by genderwithin species,
andindividualswereweighedto
0.01 mg(FisherScientificaccu-
124Delectronicbalance).Spec-
imensweregentlyblotted with
Kimwipes immediately prior
to weighingtominimize exo-
skeletalmoisture effects. Body
length(mm)wasmeasuredfrom
frons to abdominal apex, ex-
cludingthe caudal appendages
(i.e.,cerci,epi-,andparaprocts).
Odonatawerekept aliveandre-
turnedtocapturelocations im-
mediatelyafterprocessing. Col-
lectionsatagivenlocationwere Fig. 1.AveragetotalfreshmassofselectadultOdonatacollected
neverrepeated. in theNoxubee NWR.Panel Aaredamselflies: ARTI=Argia
Data werepooledacrossall tibialis;ENSI=Enallagmasignatum;ISHA =Ischnura hastata;
samplinglocations and forthe 1SPO= Ischnuraposita. Panel Baredragonflies: CEEP = Ce-
mid JulyandAugustdates.We lithemiseponina;ERSI=Erythemissimplicicolis; LIIN=Libellula
statisticallycrossedselectspecies incesta; LIVI=Libellula vibrans;PALO=Pachydiplaxlongipen-
withsexusingfactorialANOVA nis;PETE=Perithemistenera.Within panels,species/sexesshar-
and made LSDmultiplecom- inganylower-case letterarenotsignificantlydifferent (a=0.05).
parisonstorankmeanresponse Errorbarsare± 1SE.
(biomass).Separateanalyses wereconducted forthe suborders ZygopteraandAnisoptera.Biomass
isobviouslysize-dependent,but theaimhere wasto differentiatefreshmassvariabilitywithin species
and amongtaxonomicrelations. Length-masscorrelation inselectdragonflies(sexuallymature,n>5
replicates)wastestedwithaseriesofgendersegregatedsimplelinearregressions.Naturallog,log and
10
base-specifiedlogarithmictransformations ofdataproducedsimilar fits;natural logregressionsare
reportedhere.Analysis ofcovariance (ANCOVA)wasusedto comparesex-specificregressionslopes
amongspecies,usinglengthasthecovariate andmassastheresponse. Analyseswereperformedwith
SASV8.01(SASInstituteInc.,Cary) and DataDesk6.0 (DataDescription,Inc.,Ithaca).
114 J.T. Bried,L.W.Bennett&G.N.Ervin
RESULTS
TOTALLIVEMASS
Atotalof296adult specimens among19species were weighed. Species having
n> 5 mature individualswere usedfor freshmass comparisons. Overall, gender
andspecies interactedsignificantly toaffectmass inbothlibelluliddragonflies (p
=0.021) and coenagrionid damselflies(p =0.001); overallp-values werecorrected
formissing sex levels(Fig. 1).
Reproductively mature Odonata can be sexually dimorphic in terms of fresh
mass. For the damselflies (Fig. 1A), Ischnuraposita sexes differed (p < 0.0001)
whereasthoseofI.hastatadidnot.FreshmassofArgiatibialisexceededallother
damselfliesandresults forthisspecies apply to immaturefemales. Withrespect to
dragonflies(Fig. 1B),maleandfemaleLibellulavibransweighedsignificantlymore
thananyotherspecies, including malesofthecongenerL. incesta,butgenders of
L. vibranswerenotsignificantly differentfromeachother.Pachidiplax longipennis
andPerithemisteneraalso didnotshowsignificant massdifferentiationbysex,but
malesandfemalesin CelithemiseponinaandErythemis simplicicoliswere dissimi-
lar(p =0.0071andp=0.0198, respectively). Interestingly, malesofC.eponina and
E.simplicicolisweremoresimilartomalesandfemalesofeachother’sspecies than
tofemalesoftheirownspecies (Fig. IB).C. eponina wastheonly species inwhich
malessignificantly outweighed females.
Live-mass datafor additionalspecies captured during this study are listed in
TableI.Matureadultswerethosefullyhardenedwiththecolorationtypicalofre-
Table I
Fresh(live)biomass ofadultOdonatacollected in east-centralMississippi,USA.
Dataaregivenasmeanmass(mg)foranyn> 1;values inparenthesesindicaten observations.
mM =maturemales;tM=teneral males;mF=maturefemales;tF=teneralfemales
SSppeecciieess BBiioommaassss
AArrggiiaaaappiiccaalliiss((SSaayy)) mmMM ==3377..8888((11))
AArrggiiaattiibbiiaalliiss((RRaammbbuurr)) mmMM==2266,.3300((11));;ttMM==2222..2255((11))
DDrroommooggoommpphhuussssppiinnoossuuss((SSeellyyss)) mmFF==557711..5577((11))
EEnnaallllaaggmmaassiiggnnaattuumm((HHaaggeenn)) mmFF== 1188..5588((33))
EEppiitthheeccaapprriinncceeppss HHaaggeenn mmMM==448866..7700((33))
EErryytthheemmiissssiimmpplliicciiccoolliiss((SSaayy)) ttFF== 113322..6699((11))
EErryytthhrrooddiippllaaxxmmiinnuussccuullaa ((RRaammbbuurr)) mmMM==8866..8877((11))
IIsscchhnnuurraarraammbbuurriiii ((SSeellyyss)) mmMM ==3322..0099((22));;mmFF ==4477..3311 ((33));;ltFF==2222..0055((11))
LLeesstteessddiissjjuunnccttuuss SSeellyyss mmFF==7777.1.111((1l))
LLeesstteessrreeccttaanngguullaarriiss SSaayy mmMM ==5555..7766((11))
LLiibbeelllluullaa iinncceessttaa HHaaggeenn mmFF==443322..5500((22))
LLiibbeelllluullaa llyyddiiaa DDrruurryy mmMM == 336622..4444((22));;mmFF==336622..4444 ((22));;ttFF==220066..8866 ((66))
PPaacchhyyddiippllaaxxlloonnggiippeennnniiss((BBuurrmmeeiisstteerr)) ttFF==7788..6633 ((55))
TTrraammeeaa cCaarroolliinnaa ((LLiinnnnaaeeuuss)) mmMM ==331199..3388((22))
Odonatemassanalyses 115
productively activeindividuals(ANHOLT etal., 1991),whereas teneralshadsoft
bodies, cryptic coloration, andglassy wings.
LENGTH-MASS CORRESPONDENCE
Length-mass regressions aregivenforthesame6 anisopteran species asdepicted
inFigure 1B.Atotalof 118datapoints, spread unevenly amongthe6 Anisoptera,
wereusedforlength-massregressions byspecies and intraspecific sex (Fig. 2).
Allcorrelationsweresignificant andhadap-value rangefrom<0.0001 to0.03.
Totalbodylength accountedfor59-94%ofthevariationin biomass.Female Ce-
lithemiseponina andmale/femalePachydiplax longipennis displayed thestrongest
correlations(r2= 0.94and0.93/0.91, respectively) betweenbody length andfresh
Fig. 2.Transformedtotalbody lengthvs.fresh massforselect adultAnisopteracollected inthe
Noxubee NWR.Allcorrelationsaresignificant(a=0.05).
116 XT. Bried,L.W. Bennett&G.N. Ervin
mass. DatadistributionsinPerithemistenera andmaleLibellulaincestawerepoor
duetotiedlengthvaluesandoutliersandshouldthereforebeinterpretedwithcau-
tion.Lengths ofP. teneraandL. incestawere non-normal(p >0.2, Shapiro-Wilk
test,PROC UNIVARIATE, SAS). Length-mass patterns werecongruentamong
theremaining sexpartitionedspecies (Length XSpecies, p>0.05,Tab. II)andcor-
relationsforpooled datawerestrong(Fig. 3).
DISCUSSION
TOTALLIVEMASS
Aswithprevious studies(ANHOLT et al., 1991;DUNHAM, 1993;BECKE-
MEYER, 1999),ourresultsdemonstratethattotalfreshmassmaydifferinter-and
intraspecifically inadultOdonata.
All damselflyspecies usedinthecomparative mass analysis belonged toCoena-
grionidae (Fig. 1A)whileall dragonflies belonged toLibellulidae(Fig. IB). Both
familiesare highly speciose inNorth America, whichincreases thelikelihoodof
mass differentiationamongmembertaxa. Forexample, Argiaexhibitlargerover-
allbody size thanconfamilialIschnuraorEnallagma, thusexplaining why teneral
A. tibialisweremoremassivethanthethreemature coenagrionids (Fig. 1A).Sepa-
ratingspecimens by ageisatleastsomewhatsubjectiveandweelectedto minimize
potentialagebiaswithateneralvs. maturedichotomy. DUNHAM(1993)reported
littleintermediate-level(immature)massgaininPachydiplax longipennisandfound
strong dissimilarityonly betweenteneralandmature ageclasses.
Fresh mass heterogeneity was observed at the generic level, as exemplified by
thedifferencesbetweenLibellula vibransandmale L. incestaandbetweenthetwo
Ischnura, although only with respectto femaleI. posita. Meanmassofmature L.
lydia(362.44 mg average forbothsexes) is much less thanfor thetwo measured
congeners(Tab.I).Ofcourse,onemightexpect interspecificdifferenceswithinthese
particulargenerafromasmalldiversitysamplesincebothhavehighrepresentation
inNorthAmerica(23 Libellulaspp, 14Ischnuraspp).
Sexually dimorphic freshmass was observed in3 ofthe 7 species analyzed in-
traspecifically(Fig. 1).Sex-specific massdifferencesareknown fortheOdonata(AN-
HOLTetal., 1991;DUNHAM, 1993;CORDERO, 1994),aswellasvariousother
insecttaxa(e.g., wasps, MACKAUER,1996).ANHOLT etal.(1991) determined
thatin63%of54adultodonatespeciesexamined,femalessignificantlyoutweighed
malesatmaturity. Differentialmass gainamong males andfemalescorresponds
towheremass isallocatedforincreasing reproductive fitness. Infemales, increased
abdomensizemeansgreatercapacity forlargereggsandclutchsizes(CORDERO,
1994),whereasmalesizeandflightmusclelikelycorrelatetoterritorialabilityand
thus,indirectly, toreproductive success (ANHOLTetal., 1991;DUNHAM, 1993).
Thisexplanation iscongruentwiththefinding ofCORDERO (1994) inwhichfe-
Odonate massanalyses 117
males ofacoenagrionid damselfly exhibitedhigher abdominalmass relativeto
males, whilemalethoracicmass exceededthatoffemales.
Itshouldbenotedthatinthecurrentstudy, species massdatawerepooledforin-
dividualscollectedacross 17localizedhabitatareasduringmidJulyandAugust.As
such, observedmasspatterns mightreflectweighingmultiple cohortsofaspecies
withinoramongsites, whichmayinturnaddvariancetowatentissuemassratios.
However, norelevantinformation, at leastto ourknowledge, hasbeen published
foradultOdonata.Masspatterns are poorlyunderstoodamongspatially disjunct
populations ofaquaticinsects(SMOCK, 1980;DUNHAM, 1993:BENKEetal.,
1999).DUNHAM(1993) determinedthatPachydiplax longipennis malescaught in
Floridaexhibited greatermassgain relative tofemalesthrough to maturity,where
asthepresentstudy andANHOLTetal.(1991)foundnosignificant sexdifference
amongpopulations collectedin Mississippi andNewJersey, respectively. If mac-
ro-spatial scaleis aprimarymass regulatoryfactor, itseems Mississippi andFlor-
idaresults shouldbemore congruous,basedon latitudinalgeography aloneand
barring differencesinmethodsof weight measurement. Ofcourse our results do
not representactualmass gainoraveragemass over theadultlifespan,as maybe
attainedfrommark-recapture orother timeseries sampling methods.Apossible
causefor discrepancybetween thecurrent studyandthatofDUNHAM(1993) is
thatourdatawereobtainedfromthreecollectiondatesover~1moperiodandnot
throughout theflight season.
In general it is difficultto makecomparisons amongthetotalmass ofspecies
examinedinthisstudy with thatreported intheliteraturebecauseauthorseither
examineddifferent species, neglected total body mass measurement,orreported
dryweights forthefewtaxa thatoverlapped thisstudy.
Table II
Analysisofcovariance totestdeviationinlength-masspattern(slope)amongmalesandfemalesofseveral
libellulid dragonflies.Lengthandmassdatawerenormallydistributedineach species/sex.TypeI-IVsum
ofsquaresproducedthesameresults(a=0.05)
Source DF TypeISS MeanSquare FValue Pr> F
Males,y=mass
Length 1 14.2856 14.2856 3020.46 <0.0001
Species 3 0.5502 0.1834 38.78 < 0.0001
LengthxSpecies 3 0.0360 0.0120 2.54 0.0680
Females,y=mass
Length 1 4.3204 4.3204 1129.44 <0.0001
Species 2 0.0875 0.0438 11.44 0.0002
LengthxSpecies 2 0.0128 0.0064 1.68 0.2020
118 J.T. Bried,L.W.Bennett&G.N,Ervin
LENGTH-MASSCORRESPONDENCE
MAY(1981)summarizedallometryamongavarietyofbody dimensionsinadult
Odonata.However,alldatawerepooled foranuntoldvarietyofspeciesandtaxo-
nomiclevels,andbody lengthmeasurements werenot taken.
Our results suggeststronglinearrelationships betweenfreshbodylengthandto-
talmass inadultAnisoptera. Thesix testspecies provided awide rangeofmature
adultsizedifferencesandareamongthecommonNorthAmericanrepresentatives
ofthemostspeciose dragonflyfamily,theLibellulidae.Teneralswereomittedand
genders were analyzed separately within species because of known dissimilarity
betweensexually mature versus immatureageclasses(e.g., degreeofchitinization,
SMOCK, 1980)andbetweenmaleversusfemalemassgaininadultOdonata(AN-
HOLTetal., 1991;DUNHAM, 1993).
NotethatdatadistributionsforLibellulaincestaandPerithemistenera(Fig. 2)are
composed of overlapping
length values. This reflects
the coarse measurement
scale (i.e., nearest 1 mm)
necessary forfieldmeasure-
ment.SMOCK(1980)meas-
uredlarval odonatelengths
to 0.1 mm. In the interest
of quick and non-destruc-
tivecollectionoffreshmass
data,say as atoolforrapid
assessment of aquatic eco-
system function, 0.5 to 1.0
mm resolutionis probably
Fig. 3. Transformed totalbody lengthvs.fresh masspooled the finest foraccurate field
amongmales ofCelithemis eponina,Erythemissimplicicolis.
Libellula vibrans.andPachydiplax longipennisandfemalesof measurement.
C.eponina,E. simplicicolis,and P.longipennis.p < 0.0001 for Patterns of length-mass
bothsexes. gain(regression slope)were
congruentamongstanalyzed sex-specific libellulidspecies (Tab. II). Thissuggests
thatasingle collectivelength-mass equation is sufficientforpredictingfreshmass
ineachofthesetaxa. Thepooled length-mass correlationwas strong(Fig. 3)and
could provide rough mass estimationforthe tested sex-divided species, and for
other morphologically and taxonomically related species. Of course at familial
resolution, greater morphological variationshould exist thanat generic or spe-
cieslevels. Therefore, ifmass predictionis desiredthenanalyses oftoofewspecies
within a highly speciose family will reduceextrapolation powerdirectedtowards
thefractionof unsampled species withinthatfamily. Quality ofmass prediction
fromhigher taxonomiclevelregressions, suchas forfamiliesororders, islinkedto
Odonate massanalyses 119
adequaterepresentation ofspecies diversityandwillalways belesspowerful than
wellreplicatedspecies-level analyses. Suchconsiderationiscrucialforreliablemass
prediction fromlengthmeasurements (seenext section).
MASSPREDICTION USINGLENGTH
Reliablelength-mass equations mayacceleratebiomassandproductionestimates
forOdonataandother invertebratetaxa (e.g., earthworms, HALE etal., 2004).
JOHNSON etal.(2000)usedaspecies-specific mayflylength-mass equationpro-
videdin BENKEetal. (1999) toaidestimationofannualsecondary production
offreshwatermarshinWestVirginia, USA.SCHEFFER etal.(1984) usedequa-
tionspublished by SMOCK(1980)to linkinsectproduction withvegetative physi-
ognomy.GLADDEN&SMOCK(1990)andDUFFY&LaBAR(1994)wereable
toacceleratetheweighingprocessby performinglength-massregressions oninitial
collectionsto generateequations forpredictingmass in theirsubsequent samples;
samplingeffortherecouldhavebeenminimizedfurtherifcorresponding length-
-massequations werealready availablein theliterature.
Length-mass equations use constants derived from plotting mass as apower
functionofbody length:
[Eq. 1] M = aLh
or,inlinearform:
[Eq. 2] InM = Ina+hInL
whereMisorganismmass (mg),Lis length (mm),andaandbare constants. The
exponentb ofthe powermodelbecomes theslope in thelineartransformation,
whileInaistheinterceptorelevation.Equations usuallyare presented asa,bcon-
stants ± S.E. (see SMOCK, 1980;BENKEetal., 1999).
We provide regression parameters for the studiedrelationships in Table III.
Theseequations shouldonly beusedforcomparisons infuturestudiesandnotfor
predicting mass. Greaterreplication isneededbeforepredictive equations forthe
studiedtaxa maybe used in practice. Furthermore, unknowndifferencesin bio-
metricrelationships betweengeographically isolatedpopulations (SMOCK, 1980;
BENKE etal., 1999) couldaffectrobustness ofequations. Spatially and/ortem-
porally disparate populations ofaquatic insects are generally exposed to unequal
environmentalconditionsthatmay affect growthand length-mass relationships.
Odonatology needssystematic investigation ofadultlength-mass patternsacross
spatio-temporal gradients.
Predictingbiomass usingequations 1and2requiresthelineardimensionL(body
lengthinthisstudy), whichmaybeattainedfrom,(1)averaging lengthsfromasub-
set of liveindividualscaptured onsite, (2) the primary literatureas available, (3)
taxonomickeys, whichoften provide rangeand/ormeanlineardimensions, or(4)
preserved museumspecimens. Surrogate sizedimensionmetrics(e.g.,winglength)
mayalsobeusedinthecaseofadultodonates(see MAY, 1981;CORDERO, 1994).
120 J.T.Bried,L.W,Bennett& G.N.Ervin
TableIII
Parameterestimatesforlength-massrelationshipsinthetaxastudied. Equationsareshownstrictlyfor
demonstrativeand comparativepurposes andshould notbe used foractualestimation ofmass (see
text).ParametersfortheLibellulidae areaveragesacrossthesixspeciesshown,nreferstothenumberof
individuals usedand rangerepresentsthemin-max lengths(nearest 1.0mm)ofeachsample
PPoowweerrMMooddeell LLiinneeaarr((IInn))MMooddeell
TTaaxxaa SSeexx aa bb aa±±lS1SEE bb±ilS1SEE rr22 nn RRaannggee
CCeelliitthheemmiisseeppoonniinnaa MM 00..00001133 33..226688 66..337788 ±± 22..882244 33..1199771±00..778855 00..7766 77 3355--3388
FF 00..00330077 22..444400 33..992266±100..885555 22..556633±100,,223399 00..9944 1100 3333--4400
EErryytthheemmiissssiimmpplliicciiccoolliiss MM 00..11993399 11..887744 11..668877±1 11..111199 11..888866±100..229988 00..7755 1155 4411--4455
FF 00..00000088 33..442244 55..997788±1 11..777766 33..111111 ±100.,447711 00..7766 1166 4400--4466
LLiibbeelllluullaa iinncceessttaa MM 00..11009944 22..008833 22..338888 ±122..666655 22..1122771±00..667744 00..5599 88 4488--5544
FF nnaa nnaa nnaa nnaa nnaa nnaa nnaa
LLiibbeelllluullaa vviibbrraannss MM 00..00000022 33..668800 33..9922661±00.8.85555 22..5566331±00.2.23399 00..7766 1122 5544--6600
FF nnaa nnaa nnaa nnaa nnaa nnaa nnaa
PPaacchhyyddiippllaaxxlloonnggiippeennnniiss MM 00..00002277 33..009999 66,,1122661±00..771155 33..1155771±00..220011 00.,9933 2211 3300--4411
FF 00..00887777 22..117766 22..7755221±00.7.72277 22,,226677 ±100..221100 00..9900 1144 2288--3366
PPeerriitthheemmiisstteenneerraa MM 00..00004444 33..007755 55..118877±1 11..336622 33,.0000221±00.4.45533 00..8855 88 1199--2211
FF 00..00000099 33..773311 77..334411 ±144..339955 33..885511 ±1 11..445500 00..5599 77 2200--2211
LLiibbeelllluulliiddaaee MM 00..00552200 22..884477 44..2288221± 11..555566 22..6655551±00..112266 nnaa 66 1199--6600
FF 00..00330000 22..994433 44..999999±122.1.10077 22..994488 ±100..772277 nnaa 44 2200--4466
Winglengthmaybeaneasierfieldmeasurementthanbodylengthforlivingdragon-
fliesbecause wings areeasierto immobilizeandmeasure withoneset ofhands.
Itisrecommendedthatmassbeestimatedusingavailablespecies-level predictive
equations involvingalineardimension(BENKE etal., 1999), namely bodylength
foradultdragonflies. Family levelequations havelowerpredictive ability and are
only recommendedforusewhengeneric orspecies-specific equations arenotavail-
ablefor thetaxa under study (SMOCK, 1980;BURGHERR & MEYER, 1997;
BENKEetal., 1999)andtheresearcheristooconstrainedbylogisticalmatters(e.g.,
lack oftimeorpersonnel) togeneratespecificequations. Ifhighertaxonomicequa-
tionsmustbe used,thencombinedlength-width measurements,ratherthanlength
alone,shouldhelpcontrol formorphological variation(SAMPLEetal., 1993).
Freshandpreservedinsectspecimens differintotalbiomass.Estimatingbiomass
fromcollectionsof preserved specimens is metwith the following uncertainties
and potential disadvantages: (1) differentpreservation techniques may yielddif-
ferentspecimen weights (GONZALEZetal.,2002); acetonetreatmentiscommon
inadultdragonflypreservation andlikely extractslipids (ANHOLT etal., 1991),
(2) specimen quality, including mass,is probably associated with length of time
instorage,(3) geographic identity ofthecollection(SMOCK, 1980;DUNHAM,
1993;BENKE etal., 1999), and(4) logistical concerns, such as finding thesame
species in collections, andenough replicates ofthose species, thatwere observed
onsite. Creating dry-mass equations for eachpreservation methodis impractical
butnecessary in orderto havereliablespecies-specific equations. Currently there