Frequency of female colour morphs in populations of four coenagrionid damselflies (Zygoptera: Coenagrionidae)

2005·1.4 MB·English

by  Mckee, D

Odonatologica34(1):37-49 March1,2005
Frequency of femalecolourmorphsin
populationsof four coenagrioniddamselflies
(Zygoptera: Coenagrionidae)
D.McKee¹,I.F.Harvey²,D.J.Thompson² andT.N.Sherrat³t
1SchoolofBiologicalandBiomedical Sciences,UniversityofDurham,Durham,DH13LE,UnitedKingdom
2School ofBiologicalSciences,Biosciences Building,UniversityofLiverpool,Crown Street,
Liverpool,L697ZB,UnitedKingdom
3DepartmentofBiology,CarletonUniversity, 1125ColonelbyDrive,OttawaON,K1S 5B6,Canada
ReceivedMarch 9,2004/ReviewedandAcceptedMay5,2004
Knowledgeofnaturallyoccurringandromorphandgynomorphfrequenciesinpopula-
tions ofcoenagrioniddamselfliesisimportantforunderstandingtheevolution of2-limited
polymorphism.Herearereportedthe frequenciesofandromorphsandgynomorphsinpop-
ulations ofCoenagrionpaella,C. mercuriale,Xanthocnemis zealandica andIschnura u-
viatilisandareviewispresentedoftheliteratureforothercoenagrionidspp.Itisshownthat
ratios ofandromorphsto gynomorphsareoftenunequalwithandromorphsgenerallybeing
theuncommonmorph.Significantinter-andintra-populationvariationin morphfrequency
sometimesoccursbut isoflowmagnitude.No evidencewasfoundforspatialsegregation
ofandromorphsandgynomorphs.Andromorphfrequencycouldnotbesignificantlyrelated
withsexratioor6 density.
INTRODUCTION
Female-limitedcolourpolymorphism iswidespreadincoenagrionid damselflies.One
femalemorph, the andromorph, is usually quite brightly colouredandresembles the
maleofthespecies. Oneor more otherfemalemorphs, the gynomorphs, are usually
drabandlittleresemblemales.Howthisphenomenon ismaintainedwithinpopulations
iscurrently thefocusoftwocontrasting hypotheses: ‘learnedmaterecognition’ theory
(MILLER &FINCKE, 1999) and the ‘signal detection’model(SHERRATT, 2001).
Accordingtolearnedmaterecognition theory,malesshouldattempttomate mostoften
withthe most commonfemale morph inthe population. Ifmate-searching malesim-
pose afitnesscosttolonefemales(through excessive harassment)thenmalesthatcue
preferentially tothemostabundantmorph shouldimpose frequency-dependent selec-
tiononthatmorph. Incontrast,thesignaldetectionmodelisbasedonthepremise that
andromorphs gaina selectiveadvantage bylooking likemales(i.e. andromorphs) are
38 D.McKee,I.F.Harvey,D.J.Thompson&T.N.Sherratt
malemimics, (ROBERTSON, 1985). Inthis case, the levelofmalesexualattention
directedtowards andromorphs shouldincreaseas theperceived rate ofencounter be-
tween malesandandromorphs increases(sexualattentiondirectedtowardsgynomorphs
shouldnotchange withmaleperceivedrate ofencounter).
Recentresearchprovides varying degreesofsupportforboth hypotheses (e.g. COR-
DERO etal„ 1998;MILLER&FINCKE, 1999;VAN GOSSUM etal„ 1999;S1ROT
& BROCKMANN,2001; VAN GOSSUM etal, 2001;ANDRES etal„ 2002). One
consistentresulthoweveristhatselectivemechanisms,dependentonfemalemorphfre-
quency,appeartobeoperational inmostpopulations, atleast during someofthetime.
Detailedknowledge of andromorph frequencies indifferentpopulations ofdifferent
damselfly species is thereforeimportant. Here, wereportresultsofsurveysoffemale
morph frequencies inpopulations offourcontrasting coenagrionid damselfly species.
Wealsoprovideareviewof andromorph frequencies reported intheliterature.
MATERIALANDMETHODS
Coenagrionpuella(L.)
Thisspeciesoccursinsuitablehabitat throughoutEurope.Males arepredominantlyblue;andromorphfe-
maleshavesomebluecolourationbut arerelativelypoormalecolourmimics;gynomorphfemalesarepre-
dominantlybrown/olive.Andromorphand gynomorphfemalesdonotdiffersignificantlyin size(e.g,forew-
inglength)andfemales, overall,arelargerthanmales(THOMPSON, 1989a, 1989b).
Andromorphfrequencywasestimatedindetailin anadultpopulationatNessBotanicGardens (nearLiv-
erpool,U.K.;SJ303754;53°16.219,3”02.7'W),oneightdaysinJune2001,eightdaysinJuly2001andfive
daysinJune2002.Atransectwaswalkedthroughthegardensoneachofthese daysandallanimalsencoun-
teredwererecorded. Areasofornamental pondandassociatedwaterside vegetation(within5 mofwater),
aswellasextensivelengthsofhedgerow(distantfromwaterby 20-200m)wereincluded. Equaleffortwas
attachedtosearchingwatersideareasandthoseareasawayfromwater.
Coenagrionmercuriale (Charpentier)
This speciesisrestricted indistributionatbothaglobalandnationallevel.Itisconcentratedinthesouth
andwestofEuropeandhaspopulationsofunknown statusinnorthernAfrica.InBritainitoccursmainlyto
the southandwestofthe country.The gynomorphisolivegreen laterallywith smallpalemarksanteriorly
onsegments7-10. Intheandromorphthepalecolourismoreextensive andtherest ofthebodyisbluelike
themale.Femalesarelargerthanmales(THOMPSONetal.,2004).
Andromorphfrequency was estimated from mark-release-recapturestudies carriedoutin twoareasof
Hampshire,England:theItchenValley(populations1-3,Table II)andBeaulieuHeath(populations4-11,Ta-
bleII).Samplingwasconductedfrom 12Juneto 14July2001(ItchenValley)and 11Juneto 13 July2002
(BeaulieuHeath).Duringthesesamplingperiodsfield assistantswerepresentateach site forsevenhours
daily.Searchingwasrestrictedtothewatercourses.Fordataanalysis,thetwosummersamplingperiodswere
eachdividedintothreeconsecutivesub-periodsof10days.
Xanthocnemis zealandica McLachlan
This speciesisendemictoNewZealandwhereitiswidespread(ROWE, 1987).Malesarepredominantly
red;andromorphfemalesaresubstantiallyredandarereasonablemalecolourmimics;gynomorphfemalesare
predominantlybrown/olive.Andromorphfemalesandgynomorphfemales donotdiffersignificantlyinsize
(meanforewinglengthofmatureandromorphs=19.4mm,SD=1.1,n=50;meanforewinglengthofmature
gynomorphs=19.8mm,SD= 1.0,n=50;t= 1.6,df=98,p =0.111).Femalesarelargerthanmales(mean
overallmaturefemaleforewinglength= 19.6mm,SD= 1.1,n=100;meanmaturemaleforewinglength=
Coenagrionidcolourmorphs 39
18.1mm,SD=0.8,n=100;f=11.4,df=198,p<0.001)andthereisnosignificantcorrelationbetweenthe
forewinglengthsoftandempairs (r=0.09,n=100,p =0.355;datarecalculated fromMcKeeetal.,2003).
Androraorphfrequencyin adultpopulationsofX. zealandica was estimated atninepondslocatedin the
ChristchurchareaofNewZealand(locationreferencesinTable III).Eachsite wasvisitedthreetimes (be-
tween 15-12-01 and17-01-02; 10:00to 16:00)andall females in tandem andincopulationwererecorded
whilstwalkingaroundthewater’sedge(singlefemales wereveryrarelyencountered).
IschnurafluviatilisSelys
This speciesseemstooccurthroughoutthepampasicecotoneofsouthernSouthAmerica(e.g.BULLA,
1973;VONELLENRIEDER,2000).Males have bluepost-ocularspots,ablue thorax with yellow/green
humeralstripesandabluetiptotheirabdomen.Matureandromorphfemalesareexcellentmalecolourmim-
ics.Maturegynomorphfemalesarebrown/olive,butyoungerfemales areorange.
AndromorphfrequencywasestimatedinfourpopulationsinUruguay(locationreferences inTableIV).
Twoofthesepopulations(PuntaCarretasandParqueMiramar)were each sampledforeighthoursovertwo
orthreeconsecutive daysofoptimumweatherduringNovember2002,December 2002, January2003and
February2003. Onepopulation(Mendoza)wassampledforfivehoursovertwo daysduringJanuary2003
andduringFebruary 2003 andthefinal population(PuenteSarandi)wassampledonceforfivehoursdur-
ingJanuary2003.Weattemptedtocaptureand mark(wing-spotofindelible ink)allindividuals encountered
whilstrandomlywalkingaroundtheponds.Aminimumperiodoftwoweeks elapsedbetweenallmonthly
estimates.
Forewinglengthsoftencopulatingpairs includinganandromorphfemaleandtencopulatingpairsinclud-
ingagynomorphfemale were measured(PuntaCarretas population,December2002).Andromorphsand
gynoraorphsdidnotdiffersignificantlyin size (meanforewinglengthofandromorphs= 16.3mm,SD=
0.9,n=10;meanforewinglengthofgynomorphs=16.7mm,SD=1.1,n= 10;1=0.9,df= 18.p=0.384).
Femaleswerelargerthanmales (meanoverallfemale forewinglength=16.5mm,SD =1.0,n=20;mean
male forewinglength= 14.7mm,SD =0.6,n=20;t=7.1,df=38,p< 0.001)andtherewasnosignificant
correlation between theforewinglengthsoftandempairs(r=0.07,n=20,p=0.774).
RESULTS
COENAGRION PUELLA
AtNess BotanicGardens during2001, C.puella andromorph frequency was40%
in Juneand 19% inJuly.During June2002 itwas26%. Theratioofandromorphs to
gynomorphs differedsignificantly from equality according to thelater two estimates
(Chi-square tests: x2 =2.9,p=0.087; x2= 10.7,p =0.001; \2= 37.4,p <0.001; re-
spectively). Therewas asignificant decrease inandromorph frequencybetweenJune
2001 and July2001 (x2=5.5,p =0.019); andasignificant increasebetweenJuly2001
and June2002(x2=5.6,p=0.018). Thesignificant inter-annualdifferencealsoholds
when theoverallmeanandromorph frequency during2001(35%) isusedinthecom-
parison (x2=5.2,p=0.023).
TableIshowsnumbersofanimalsencounteredalongthetransect.Thedataare divided
intothoseobservationsrecordedatwater (<5m distant)andthoserecordedawayfrom
water (20 - 200mdistant).Andromorphs and gynomorphs didnot segregateaccord-
ingtoareaofhabitat.Theratioofsingleandromorphs tosingle gynomorphs wasinde-
pendentofwhethertheanimalswereencounteredatorawayfromwater(contingency
Chi-square: June2001 x2=0.09,p =0.770; July2001 x2=0.38,p=0.537; June2002
40 D.McKee, I.F.Harvey, D.J.Thompson&T.N.Sherratt
TableI x2=0.07,p=0.788).Similarly,
C.puellarecorded atNessBotanicGardens theratioofpairedandromorphs
topairedgynomorphswas inde-
Atwater Away fromwater
pendentofwhethertheanimals
Males Jun-01 545 189 were encountered at or away
Jul-01 196 73 from water (contingency Chi-
Jun-02 247 206 square; June2001 \2=0.13,p
Singleandromorphs Jun-01 3 14
Jul-01 0 2 =0.723; July2001 x2=0.27,p
Jun-02 1 36 =0.607; June2002 x2 = 106.
Singlegynomorphs Jun-01 4 10 p=0.303).
Jul-01 1 5 Sex ratio was calculatedas
Jun-02 3 78 total number of males/total
Pairedandromorphs Jun-01 1) 3
Jul-01 1 2 numberof females. It as male
Jun-02 7 0 biased, ranging from 1.1 to
Pairedgynomoiphs Jun-01 25 7 12.2. Andromorph frequency
Jul-01 II 5 was not significantly correlat-
Jun-02 41 1
edwithsex ratio: r=0.40,n=
14,p = 0.151 (Fig. la, analy-
sis used allthe dailytransect estimates fromNess Gardens whereandromorphs were
recorded); nor was itsignificantly correlatedwith maledensity: r =0.27,n= 14,/?=
0.354(Fig. 2a).
COENAGRIONMERCURIALE
IntheItchenValleytherewerethreedistinctpopulations. Atthemostnortherly sites,
Mariner’sMeadowandHighbridge, andromorphs werenotfound(Tab.II).Inthelarg-
estpopulation. LowerItchen,meanandromorph frequency waslow,6% (Tab.II).The
ratioofandromorphs togynomorphs differedsignificantly fromequality intheLower
Itchenpopulation (Tab.II).
AroundBeaulieuHeath meanandromorph frequencyranged from9 to33% andthe
ratioofandromorphs to gynomorphs differedsignificantly fromequality in alleight
populations (Tab.II). However,betweenpopulations, andromorph frequency didnot
significantly differ(one-wayAnova,dataarcsinesquare-roottransformed:F? = 1.1,p=
0.394)andtheintraclasscorrelationcoefficientsuggested thattemporal variationwithin
populations wasrelatively high (r, =0,04).Thistemporal variationwassignificantintwo
cases butshowednoparticular pattern: HatchetStream(consecutive estimatesof9%,
9%, 0%),maximumlikelihoodx2=7.0,df=2,p =0.030;DeepMoor(consecutivees-
timatesof10%,35%,9%), maximumlikelihood\2=7.9, df=2,p=0.020.Therewas
nosignificant correlationbetweenandromorph frequency and sex ratio:r=-0.07,n-
27,p=0,712(Fig. lb).Neitherwas thereasignificantcorrelationbetweenandromorph
frequency andmaledensity; r=-0.34, n=27,p =0.080(Fig.2b).
Coenagrionidcolourmorphs 41
XANTHOCNEMIS
ZEALANDICA
Overall, andro-
morph frequency
was 9% (SD =4.5,
n = 27). Frequen-
cy in most of the
nine separate pop-
ulations was rather
similar (Tab. Ill)
and, although anal-
ysis of variancein-
dicated significant
difference between
populations (one-
way Anova, data
arcsine square-root
transformed:F =
g
5.9,p<0.001),this
was entirely dueto
population 2.Tuk-
ey-tests showed
that population 2
had a significantly
lower andromorph
frequency than all
other populations
except population
4. However, it is
possible thatpopu-
lation2 yielded an
anomalous result CFig. 1.Relationshipbetween andromorphfrequencyand.sexratio for: (a)
simply because it puella; —(b)C.mercuriale and - (c)I.fluviatilis.
was theleastdenseofallthepopulations surveyed andsample size was concomitantly
low.Theintra-class correlationcoefficientindicatedhighconcordancebetweenwithin-
population andromorph frequency estimates(r=0.61).Inallninepopulations theratio
of andromorphs togynomorphs differedsignificantly fromequality (Tab. HI).
ISCHNURAFLUVIATIUS
Populations ofI.fluviatiliswere widely distributedbutcharacterisedby lowdensity.
Wesearchedextensively forpopulations inthedepartmentsofMontevideo,Canalones,
42 D.McKee,I.F.Harvey,D.J.Thompson&T.N.Sherratt
TableII
Meanandromorphfrequency(%) in elevenpopulationsofC. mercuriale. The significance ofChi-square
tests examiningwhethertheratio ofandromorphstogynomorphsdifferedfromequalityisshownusingas-
terisks (***p<0.001).Standarddeviation (SD)andthetotalnumberoffemales andmalesrecorded ateach
site areshown
Locality Latitude,Longitude U.K.National Mean% SD Females Males
GridReference
(1)Mariner’sMeadow 51° 1’N, 1°19’W SU476240 0 0 185 959
(2)Highbridge 50°59’N, 1°20’W SU465209 0 0 36 716
(3)LowerItchen 50°54’N, 1°22’W SU446117 6 **» 1.7 717 5492
(4)Roundhill 50°49’N, 1°32’W SU330019 23 *»* 1.2 379 1368
(5)HatchetStream 50°49’N,1°29’W SU359012 23••• 22.5 65 179
(6)Greenmoor 51"4rN,1°31’W SU338988 33 *** 15.7 34 118
(7)BagshotMoor 50°48’N, 1°29’W SU369000 g￿￿￿ 10.3 21 80
(8)DeepMoor 51042’N,1“30’W SU348999 19*** 8.1 256 1552
(9)Two BridgesBottom 51°42’N, 1“30’W SU343999 25 *** 3.8 182 961
(10)LowerCrockford 51°4rN, 1“29’W SU354989 23 1.2 310 1608
(11)PeakedHill 51°42’N,I°29’W SU361991 21 *** 2.1 609 2249
Lavalleja, MaldonadoandRochabuttypically encounteredonly afewindividualson
mostponds (includingonasmallpoolatapproximately 490maltitudeonCerroCate-
dral).Andromorph frequencyrangedbetween3and9%(Tab. IV).Itdidnotvary tem-
porallywithinthepopulations (Punta Carretas, maximumlikelihoodx2= TO,df=3,p
=0.799; Parque Mirramar,maximumlikelihoodx2=2.3,df=3,p=0.520; Mendoza,
maximumlikelihoodx2=0.9,df= l,p =0.337) orbetweenthepopulations duringany
month(November 2002, maximumlikelihoodx2= 1.9, df= 1,p=0.173;December
2002,maximumlikelihoodx2= 1•1,df= 1,p=0.287; January 2002,maximumlikeli-
hoodx2= 1.9,df=3,p=0.593;February 2003,maximumlikelihood\2=0.1, df=2,
TableIII
Meanandromorphfrequency(%)inninepopulationsofX. zealandica. ThesignificanceofChi-squaretests
examiningwhethertheratio ofandromorphstogynomorphsdifferedfromequalityisshownusingasterisks
(***p<0.001).Standard deviation(SD) andthetotalnumberoffemalesrecorded ateachsiteareshown
Locality Latitude,Longitude N.Z.National Mean% SD Females
GridReference
(1)TheGroynes 43°27’S,172°36’E M35783490 10*** 1.6 554
(2)LincolnGravelPit 43°38’S, 172°27’E M36&M37657298 2￿￿￿ 3.4 29
(3)StyxMill Reserve 43°28’S, 172°36’E M35 783490 14*** 3.5 276
(4)Halswell Quarry 43°36’S,172°35’E M36&M37757344 5*** 0.6 509
(5)HartCreekPond 43°47’S, 172°I9’E M36&M37545128 8*** 0.6 276
(6)ShagPond 43°42’S,172°26’E M36&M37644232 13 *** 1.5 239
(7)Fenland House Pond 43°43’S,172°27’E M36&M37633218 13*** 5.5 200
(8)KaipoiGravelPit 43°22’S,172°40’E M35826607 8 *** 4.0 94
(9)RegentsParkPond 43°28’S,172°36’E M35785485 9 3.2 58
Coenagrionidcolourmorphs 43
p=0.954).However,theintra-classcorrelationcoefficientdemonstratedsomeoverall
tendency formore variabilityofandromorph frequency estimatesbetweenpopulations
thanwithin populations (r( = -0.10).The dataas awhole showedthat single andro-
morphs werefarmorelikely tobeencounteredthansingle mature gynomorphs (con-
tingency x2=25.2, df= \,p <0.001).As someyoungerorangecolouredfemaleswere
observedcopulating wealsomadethe comparisonbetween andromorphs andorange
females,obtaining asimilarresult(contingency x2=99.0, df=!,/?<0.001).However,
when ratiosofsingle topaired animalswerecompared between andromorphs and all
otherfemalescombined, nosignificantdifferencewas apparent(contingency x2= 1.0,
df= 1,p=0.317).Sexratiowas biasedtowards males(range 1.1to 1.9).Andromorph
frequency was notsignificantly correlatedwithsex ratio; r=-0.16, n= 11,/;=0.639
(Fig. 1c). Itwas alsonotsignificantly correlatedwithmaledensity:r=0.42,n= 11, p
=0.195(Fig. 2c).
DISCUSSION
Ratiosof andromorphs to gynomorphs often deviatefrom equality. For 97% (31/
32)ofour population surveys (whereandromorphs wererecorded)theratioofandro-
morphs to gynomorphs differedsignificantly fromequality. TableVshows otheran-
Table IV
Numbers ofandromorphs,mature gynomorphsandorange females in fourpopulationsofIi.fluviatilis.Fe-
males wererecorded asbeingsingle(Single)orincopulation(Paired).Total number ofmalesrecorded and
andromorphfrequency(%)arealsoshown.ThesignificanceofChi-squaretests examiningwhethertheratio
ofandromorphstogynomorphs(includingorangefemales)differedfromequalityisshownusingasterisks
(￿p <0.05;**p<0.01;***p<0.001;nsp>0.05)
Locality Andromorphs Gynomorphs Orange Males %
Single Paired Single Paired Single Paired
(1)PuntaCairetas Nov-02 4 1 21 57 24 1 122 5 ***
38°41’S,62°80’W Dec-02 1 14 0 179 13 10 343 7￿**
K-29663362 Jan-03 2 7 3 158 9 2 310 5 ***
Feb-03 2 7 4 124 9 3 202 6***
(2)ParqueMirramar Nov-02 5 4 3 71 10 2 140 9***
38°74’S,62°27’W Dec-02 1 1 6 34 16 1 96 3***
J-29779423 Jan-03 0 11 11 119 18 2 235 7 ***
Feb-03 3 7 23 105 8 1 199 7 ***
(3)Mendoza - - - - - - - - -
38°67’S,62°4rW - - - - - - - - -
K-29660493 Jan-03 0 2 2 39 23 3 106 3 ***
Feb-03 2 4 10 56 28 0 186 6 ***
(4)PuenteSarandi - - - - - - - - -
38°58’S,61°58’W - - - - - - - - -
G-28346594 Jan-03 0 3 0 63 8 0 139 4 ***
__ __ __ „ __ __
44 D.McKee, I.F.Harvey,D.J.Thompson&T.N.Sherratt
TableV
Andromorphfrequencies(%)reported in the literature. For aparticularspecies, estimatesfrom different
populationsareindicated as1,2,3etc. Different estimatesfromthe samepopulationareindicated asa,b,c
etc.Totalnumberoffemales recorded isgiven(Females).Thesignificance(p)ofChi-squaretests examin-
ingwhethertheratio ofandromorphstogynomorphsdifferedfromequalityisshownusingasterisks(*p<
0.05;**p<0.01;***p<0.001;nsp >0.05).fTwotypes ofgynomorpharerecognisedforthese species.
nFrequenciescalculated from agraph
SSppeecciieess SSoouurrcceeooffddaattaa FFrreeqq..((%%)) FFeemmaalleess Pp
AArrggiaiavviivviiddaa CCOONNRRAADD&&PPRRIITTCCHHAARRDD((11998899)) llaa 6644 7788 **
llbb 6666 444488 ******
22aa 4488 3333 nnss
CCeerriiaaggrriioonntteenneelllulumm* AANNDDRREESS&&CCOORRDDEERROO((11999999)) I1 1122 2266 ***￿**
22 00 3344
33 1199 1166 ￿*
44 2277 115522
55aa 1155 5544 ****»*
55bb 1199 552255 »*****
55cc 1144 222211 •**
66aa 1133 665577 **»
66bb 1100 666622 ￿**￿*￿
66cc 1100 226633 ***
66dd 1122 336622 ￿*￿*￿*
66ee 1111 115588 ￿*￿*￿*
77 00 4433
88 1122 8822 ￿*****
99 99 5533 ******
CCooeennaaggrriioonnppuueellllaa TTHHOOMMPPSSOONN((11998899aa)) llaa 1122 117700 ***
llbb 1155 220099 ***
IIcc 66 117744 ***
EEnnaallllaaggmmaabboorreeaallee FFIINNCCKKE£((11999944)) 11 4455 555544 ￿*
FFOORRBBEESS((11999944)) 11 6688 448855 ￿*￿*￿•
EEnnaallllaaggmmaacciivviillee MMIILLLLEERR&&FFIINNCCKKEE((11999999)) 11 1177 331122 ￿**￿*￿
EEnnaallllaaggmmaaeebbrriiuumm MMIILLLLEERR&&FFIINNCCKKEE((11999999)) 1I 1155 7700 ***
EEnnaallllaaggmmaahhaaggeennii FFIINNCCKKEE((11999944)) llaa 2266 337700 ***
llbb 3311 116666 ***
11cc 3366 110033 ***
22 2266 3399 ￿***
IIsscchhnnuurraaddaammuullaa JJOOHHNNSSOONN((11996644)) llaa 1144 6633 *****￿
llbb 1144 5522 ￿**￿*￿
11cc 1100 5588 ******
IIdd 1111 7722 ***
llee 1144 5500 ***
IIff 1144 6655 ***
Ilgg 1133 4488 ￿**￿»￿
IHhi 1144 5511 ￿*****
l1i1 1122 4433 •￿￿•￿•
22aa 1111 5533 ￿*****
22bb 1122 4422 ***
Coenagrionidcolourmorphs 45
TableV,continued
22cc 1144 4422 ***
22dd 99 5544 ￿*****
22ee 1122 6600 ￿*￿**￿
22ff 1122 5588 ￿*****
22gg 1122 5500 **￿
22hh 1144 4422 ￿***￿*
22ii 1133 3399 »**
33aa 1188 4400 ￿*****
33bb 1166 3388 ***
33cc 1166 3322 ￿**￿*￿
33dd 1177 3300 »**
33ee 1166 4433 *****￿
33ff 1155 4400 ******
33gg 1166 3322 ￿**￿*￿
44aa 1177 4488 *****￿
44bb 1166 5511 ******
44cc 1144 4422 ￿**￿*￿
44dd 1155 3322 ￿**￿
44ee 1155 3399 ***￿**
44ff 1166 4444 ***
44gg 1166 3377 ￿**￿*￿
IIsscchhnnuurraaeelleeggaannss* PPAARRRR((11996699)) 11 3366 9999 ￿***
22 3344 221177 ￿**￿*￿
33 2233 111111 ******
VVAANNGGOOSSSSUUMMeettaall..((11999999))tt" 11 77 1133 ￿***
22 2277 1177 nnss
33 1122 1155 ****
44 7700 1100 nnss
55 1188 1111 nnss
CCOORRDDEERROOeettaall..((11999988)) 11 5555 995577 ￿**￿
IIsscchhnnuurraaggrraaeellllssii*ii CCOORRDDEERROO((11999900)) 11 1188 552233 *****￿
22aa 2211 2299 ￿***
22bb 1177 6655 ￿**￿*￿
22cc 1144 668855 ***
22dd 88 8855 ******
22ee 1188 110077 »*»
33 77 4466 ******
44aa 1188 9944 ***
44bb 1111 9977 »**
55 3300 3377 **
IIsscchhnnuurraarraammbbuurrii RROOBBEERRTTSSOONN((11998855)) 11 3311 9900 ***
22 2255 4444 ***
SSIIRROOTTeettaall..((22000033)) llaa 4488 4488 nnss
llbb 3399 8833 **
11cc 3366 9944 ****
IIdd 3399 4499 nnss
llee 5500 4488
Iiff 4488 7755 nnss
46 D.McKee, I.F.Harvey, D.J.Thompson&T.N.Sherratt
TableV,continued
NNeehhaalleennnniiaa iIrreennee FFOORRBBEESSeettaall..((11999955)) i1 33 3311 ******
22 77 1155 ***
33 22 4488 *￿****
44 1122 3344 ******
55 33 3300 ***
66 2288 3311 **
77 2266 114455 *￿****
88 2244 115566 ***
dromorph frequency estimatestakenfromthe literature. For91%(86/94)ofthesees-
timates(whereandromorphs wererecorded)theratioofandromorphs to gynomorphs
differedsignificantlyfromequality.
Ifaspecies displaysfemale-limitedpolymorphism thenmostpopulations appearto
possessandromorphs. Theyoccurredinallbuttwo ofthepopulations weexaminedand
inallbuttwo(Ceriagrion tenellum:ANDRES&CORDERO,1999)ofthepopulations
listedinTable V. However,although andromorphs are almostalways present within
populations, they oftenoccur withrelatively lowfrequency. Weencounterednositua-
tionswhereandromorphs were more commonthangynomorphs. Forthepopulations
inTableV there are only fourinstances whereandromorph frequency canbe shown
statisticallytobesignificantly greaterthan50% (TableV). Thissuggests thatinstanc-
es whereandromorphs are more frequentthangynomorphs may beatypical. Ifmale
encounterrate withdifferentfemalemorphs is directlyproportional tooverallfemale
morph frequency, then implications forthelearnedmaterecognition modelare clear:
caseswheremalespreferentiallychoosetomatewithandromorphs maybeinfrequent
becauseandromorphs are infrequentlythemost commonmorph.
Variationinandromorph frequencysometimesexistswithinandbetweenpopulations.
We foundmarginally significant variationinandromorph frequency withinthe Ness
Gardenspopulation ofC.puella, withintwopopulations of'C.mercurialeand between
populations ofX.zealandica.WedidnotfindsimilarvariationforI.fluviatilis.FORBES
etal.(1995)determinedsignificantdifferencesbetweenandromorphfrequencies inpop-
ulationsofNehalenniaireneduring asingle seasoninCanadaand,although ANDRES
&CORDERO (1999) didnotfindintra-population variationforC. tenellum,evidence
forinter-population variationexists(ourcalculationsfromTableVmakingcomparisons
withinyears: populations 1 and5a, maximumlikelihoodx2= 0.2, df= 1,p =0.686;
populations 5band6a,x2=8.6, df= 1,p=0.003;populations 2,3and meanof6b,6c
and6d, x2=8.6, df=2,p=0.014;populations 4,5cand6e,x2= 14.8,df=2,p<0.001;
populations 7,8and9,\2- 9.0,df=2,p=0.011).Incontrast,datareported by CORD-
ERO(1990)forSpanishIschnura graellsiipopulations doesnotshowintra-population
variationinandromorph frequency (ourcalculationsfromTableV:population 2,max-
imumlikelihoody2 =5.4, df=4,,p=0.252;population 4,x2= 1.7,df= l,p=0.186);
FINCKE (1994)foundnosignificant inter-annualdifferencesinandromorph frequency
forEnallagma hageniataMichiganpond;andSIROTetal.(2003)didnotfindsignificant