Table Of Content©EntomologicaFennica.1June2018
Offspring sex ratio shifts of the solitary parasitoid wasp,
Trichopria drosophilae (Hymenoptera: Diapriidae),
under local mate competition
JingLi,YuWang,Cheng-JieZhu,MinZhang&Hao-YuanHu*
Li,J.,Wang,Y.,Zhu,C.,Zhang,M.&Hu,H.2018:Offspringsexratioshiftsof
thesolitaryparasitoidwasp,Trichopriadrosophilae(Hymenoptera:Diapriidae),
underlocalmatecompetition.—Entomol.Fennica29:97–104.
Localmatecompetition(LMC)modelspredictafemale-biasedoffspringsexra-
tiowhenasinglefoundressovipositsaloneinapatchandanincreasingpropor-
tionofsonswithincreasingfoundressnumber.Wetestedwhetherthesolitarypu-
palparasitoid,Trichopriadrosophilae(Hymenoptera:Diapriidae),adjustedoff-
springsexratiowithfoundressnumberwhenparasitizingDrosophilamelano-
gasterpupae.Meannumberoffemaleoffspringwashigherthanthatofmales,
withamaleproportionof26±16%whenonlyonefoundressoviposited.How-
ever,maleproportionreached58±26%,48±22%,and51±19%inthree-,five-
and seven-foundress cohorts. That the male proportion of offspring increased
withfoundressnumberisconsistentwithLMCmodels.
J.Li,Y.Wang,C.Zhu,M.Zhang&H.Hu*,KeyLaboratoryofBioticEnviron-
mentandEcologicalSafetyinAnhuiProvince,CollegeofLifeSciences,Anhui
NormalUniversity,Wuhu,Anhui,241000,China;*Correspondingauthor’se-
mail:[email protected]
Received8April2017,accepted18September2017
1.Introduction 1967,1979).Insuchahighlystructuredpopula-
tionwithinbreeding,wherematinghappensonly
Sexratiotheoriesaresometimesdescribedasone betweenfullsiblings,relatednessdifferbetween
of the most successful theories in evolutionary parentsandoffspring,sothatfemaleoffspringare
ecology(Fellowesetal.1999,Westetal.2000, morerelatedthanmaleoffspringtotheirmother
West 2009, Whitehorn et al. 2015). Sex ratio is (Hamilton1964,Herre1985).Withthisasymme-
adjustableinresponsetosuchbioticfactorsasin- tryinrelatedness,afemale-biasedsexratioisex-
teractions between relatives, out of which local pected(Herre1985).However,alessfemale-bi-
mate competition (LMC) is one of the most fa- ased offspring sex ratio does bring interests to
mous.LMCimpliesthatbrotherswouldcompete foundresseswhenmorethanoneofthemoviposit
witheachotherformatingwiththeirsistersinthe together,becausethevalueofsonsincreaseswith
strictlyisolatedpatchfoundedbyasinglefound- the increase in the possibility to mate with the
ress(Hamilton1967).Insuchapatch,afemale- daughters of the other foundresses (Hamilton
biased sex ratio adjustment would be adaptive, 1967, 1979, Herre 1985, 1987, Werren 1987,
becausetheLMCamongsonsdoesnotconform West2009).
tothefitnessinterestsofthefoundress(Hamilton LMC models were formed for populations
98 Lietal. (cid:127) ENTOMOL.FENNICAVol.29
thataresubdividedintolocalmatinggroups,such (Cancino et al. 2015), and the USA(Kacsoh &
asthepollinatingfigwasps,andnomaledispersal Schlenke2012,Wangetal.2016a,b).Trichopria
amonggroupsisoneofthekeyconditionsofthe drosophilaehasafemale-biasedsexratio(Wang
original models (Hamilton 1967, 1979). “Strict et al. 2016b). The distribution of the parasitoid
LMC” then happens when mating always hap- canbeexpectedtobeconsistentwiththatoftheir
pensinthenatalpatchwithrelatives,e.g.thepol- hosts. The drosophilid hosts breed in isolated
linating fig wasps, whose wingless males only patches such as orchards and dust heaps, and
mateinnatalfigsandfemalesfinishmatingbe- thereforeitispossiblethattheparasitoidhasalso
fore dispersing (Hamilton 1967, 1979). Cerato- astructuredpopulationandsexratioadjustment
solen solmsi (Mayr), the pollinator of Ficus under LMC could be assumed. Given this, we
hispida L. f., has wingless males, which mate predictthatT.drosophilaefemalesshouldadjust
with females in the figs and then dig holes the offspring sex ratio with foundress number,
through the wall of the figs to allow females to andthesexratioadjustmentshouldbeconsistent
disperse. Mating always happens between rela- withpredictionsofthe“partialLMC”models.
tives,andafemale-biasedsexratioevolvedinthe
manner predicted by LMC models (Hu et al. 2.Materialsandmethods
2013). Such a strict subpopulation is classic in
theories,butisunusualinnature.Butwhenmat- 2.1.Studyinsects
ingdoesnotoccurentirely locally,thesituation
termed “partial LMC” happens, which seems Strains of D. melanogaster and T. drosophilae
morecommoninnature(Hardy1994).Foralarge wereinitiatedfromfieldcollectionsonMay2015
number of species with winged males, e.g. at the Huiwang blue berry orchard in Nanling,
parasitoidwasps,“partialLMC”ismorerelevant, Anhui province, China (30.85° N, 118.40° E).
becausesomematingisalsolikelytooccuraway Drosophila melanogaster were cultured with a
fromthenatalpatch(Werren&Simbolotti1989, standardmedium(David&Clavel1965)inanin-
Nadel&Luck1992,Hardy1994,West&Herre cubatorwiththe14:10light:darkphotoperiodat
1998, Fellowes etal. 1999, Martel etal. 2010). 25±1°Candtherelativehumidityof60±5%.
“Partial LMC” selects for a less female-biased Adultfruitflieswererearedinacubecagemade
sex ratio compared to “strict LMC” (Nadel & ofnylonmeshof150-µmporesize,and90mm
Luck1992,Fellowesetal.1999,West&Herre petri dishes with the medium put into the cage.
1998). Every12h,thedishesweretakenoutofthecage
Trichopriadrosophilae(Perkins)(Hymenop- andplacedinaplasticbox,about50Linvolume,
tera:Diapriidae)isasolitarypupalparasitoidthat sealedwithnylonmesharoundtherim.Fourdays
attacksmanyspeciesofDrosophilidae(Wanget later, the dishes were sprinkled with water and
al.2016b).Thisspeciesofparasitoidhasbecome olderDrosophilalarvaecreptintotheboxandpu-
importantinrecentyearsinthefruitindustry,be- patedonthesmoothboxwall.Drosophilapupae
causeitmaybeapreferablecandidateasanagent weresprinkledandcollectedwithasoftbrushev-
for the biological control of the spotted wing eryday.
drosophila, Drosophila suzukii (Matsumura) Trichopriadrosophilaeweremaintainedwith
(Diptera:Drosophilidae),whichhasbroughtdi- pupaeofD.melanogasterashostsintheabove-
saster to soft and thinned fruits in Europe and describedincubatorforaboutoneyear.Parasitoid
North America (Lee et al. 2011, Hamby et al. waspswererearedinglassvials(25mmindia-
2013,Mazzettoetal.2016,Wangetal.2016a,b). meter,50mminheight)withDrosophilapupae
Trichopriadrosophilaeseemstobeacosmopoli- and honey-soaked cotton wool as food. Before
tanparasitoidwithawidedistribution.Itisasoli- experiments, Drosophila pupae that were less
taryparasitoidparasitizingpupaeofD.suzukiiin than2-d-oldandsimilarinsizewereprovided,in
France(Chabertetal.2012),Italy (Milleretal. ordertomaketheparasitoidwaspssimilarinsize.
2015,RossiStacconietal.2015,Mazzettoetal. Similar size was aimed at in order to produce
2016),Spain(Gabarraetal.2015),SouthKorea parasitoidsassimilarintheirlifehistorytraitsas
(Daaneetal.2016,Wangetal.2016b),Mexico possible.
ENTOMOL.FENNICAVol.29 (cid:127) SexratioshiftsofTrichopriadrosophilae 99
2.2.Offspringsexratioshifts toemerge,theywereaddeduptothetotalmale
withfoundressnumber andfemaleoffspring.
Parasitized Drosophila pupae were discernible
beforeparasitoidoffspringemergence,duetothe 2.3.Statisticalanalyses
darkpupaeoftheparasitoidsinside.Preliminary
studies showed that most T. drosophilae adults Countdataasnumberofparasitoidoffspringand
emerged15dafterlaidinhostpupae.Toobtain proportion data as sex ratio (male proportion)
newlyemergedvirginmaleandfemaleparasitoid have often non-normally distributed errors.
wasps,theparasitizedhostpupaewereindividu- Therefore, we used generalized linear model
ally selected and laid into a transparent tube (GLM)analysisofdeviancetothosedata,assum-
sealedwithafinenylonmesh,onthe14thdayaf- ingPoissonerrorsandaloglinkfunctiontothe
terhavingbeenexposedtoparasitoidfemales.On count data, and binomial errors and a logit link
thenextday,thetubeswerechecked,andthose functiontotheproportiondata.Weassessedthe
withparasitoidadultsinsidewereselected.Male appropriatenessoftheassumptionsofthePoisson
and female parasitoids were identified by their orbinomialerrorsbycomparingtheresidualde-
antennae(Romanietal.2008). viancewiththeresidualdegreesoffreedomafter
Inordertotesttheeffectsoffoundressnum- fitting the explanatory variables. Large relative
beronoffspringsexratioadjustment,fourtreat- values of the residual deviance indicated over-
mentsweredesigned,with1,3,5,and7newly- dispersion,whichmayresultinanoverestimation
emergedmale-femalepairsoftheparasitoid,re- ofsignificancelevels,andthereforewereplaced
spectively.Clearplasticcontainers(6cmdiame- Poissonorbinomialerrorswithquasipoissonor
ter, 8 cm height) were used as oviposition quasibinomialonesintheanalyses.Whenmore
patches,whichwereclosedatthesidewithafine thanoneexplanatoryvariablewasconsidered,a
nylonmeshforventilation.Asmallcottonwick fullmodelwasinitiallyfittedtothedata,includ-
soakedin10%honeysolutionwasplacedinside ing explanatory variables and their interactions.
thecontainertoprovideasourceofcarbohydrate Termswerethenremovedfromthefullmodelsby
foradultfeeding,and30laboratory-rearedDro- stepwisedeletion.Whethertheremovalofaterm
sophilapupaeaged1–3dwereprovidedashosts causedasignificantincreaseinthedeviancewas
ineachtreatment. assessedwitha¤2test,andthefinalmodelswere
After every 24 h, the host pupae exposed to tested by an F-test (Crawley 2007). All of the
theparasitoidswerechangedtoanothersetof30 above analyses were conducted in R2.13.0 (R
Drosophilapupae,togetherwiththecottonwick. DevelopmentCoreTeam2011).Incomparisons
Experiments lasted five days. Ten replicate ofthenumbersofmaleandfemaleoffspring,we
groupswerefinishedforeachoftheabovefour usedWilcoxontestinSPSS11.5(SPSSInc.,Chi-
treatments. cago,IL,USA).
After each exposure, the host pupae were The values of the degree of infestation (DI)
placedintransparentplastictubessealedwitha andthesuccessrateofparasitism(SP)amongdif-
fine nylon mesh. When adults of parasitoids or ferentfoundressnumberswerecalculatedandan-
fruit flies had emerged fromthe exposed pupae alyzed(Gibertetal.2010,Chabertetal.2012).
(somehadnotbeensuccessfullyparasitized),the NumbersofadultDrosophila(di)andparasitoids
number and sex of parasitoids, flies, and non- (pi)emergingfromeachgroupwerecounted.The
emergedhostpupaewererecorded.Alloftheex- DImeasurestheproportionofDrosophilakilled
perimentswereconductedinanincubatorunder bytheparasitoidandwascalculatedas(T–di)/T,
the photoperiod, temperature, and relative hu- with T being the average number of emerging
midityconditionsasdescribedabove.Aboutone fliesintheabsenceoftheparasitoid.TheSPmea-
weekaftertheemergence,alltheremainingpu- sures the probability that an infested host will
pae were dissected and the parasitoid offspring giverisetoanadultparasitoid,andthiswascalcu-
thatfailedtoemergewererecorded.Asitispos- latedaspi/(T–di)(ifpi>(T–di),wesetSP=1).
sibletodeterminethesexofparasitoidsthatfailed DataofDIandSPwerealsoanalyzedwithGLM
100 Lietal. (cid:127) ENTOMOL.FENNICAVol.29
Fig.1.Offspringnumbers
ofthesolitaryparasitoid,
Trichopriadrosophilae,in
treatmentsofdifferentnum-
bersoffoundresseswiththe
fivedaysofoviposition
pooled.Outliersasdefined
byCrawley(2007).
models assuming binomial errors as described thirdday(Table1).Whenonlyonefoundressovi-
above. posited, the mean number of female offspring
(3.96±2.08,mean±SD)washigherthanthatof
3.Results male (1.68 ± 1.72) (Wilcoxon test, z = –5.53,
p<0.001, N = 50). In contrast, when three
The total number of T. drosophilae offspring foundressesovipositedtogether,themeannum-
summed across the four treatments and the five ber of male offspring (5.42 ± 4.55) was higher
ovipositiondaysincreasedwithincreasingnum- thanthatof female (3.34±2.71)(Wilcoxontest,
beroffoundresses(F =92.72,p<0.001)(Fig. z=–2.12,p=0.034,N=50).Themeannumberof
1,198
1).Thenumberoffemaleandmaleoffspringboth femaleandmaleoffspringwassimilarinthefive-
increased with foundress number on all but the foundress cohort (6.32 ± 3.35 and 6.22 ± 4.00)
Table1.Mean(SD)numberoffemaleandmaleoffspringofTrichopriadrosophilaeondifferentovipositiondays.
Numberof 1stday 2ndday 3rdday 4thday 5thday
foundresses
$ # $ # $ # $ # $ #
1 4.80 2.40 4.50 1.30 4.60 3.00 3.00 1.00 2.90 0.70
(1.93) (1.90) (2.01) (1.06) (2.27) (2.36) (1.89) (0.82) (1.79) (0.95)
3 3.60 11.40 2.50 3.20 2.40 2.90 2.80 3.70 5.40 5.90
(2.01) (4.43) (1.84) (1.62) (1.84) (2.81) (2.82) (3.97) (3.78) (3.31)
5 7.30 7.80 6.60 5.60 4.70 4.60 4.30 4.80 8.70 8.30
(2.87) (4.13) (2.46) (4.17) (3.33) (3.41) (2.67) (3.12) (3.71) (4.27)
7 7.50 10.60 9.10 5.80 6.50 7.00 6.20 5.90 7.00 9.00
(2.76) (3.75) (4.18) (3.16) (4.22) (4.69) (3.39) (3.38) (4.22) (4.03)
F 10.63* 9.59* 18.50* 17.92* 3.31NS 8.83* 8.59* 12.77* 9.36* 25.87*
1,38
*=P<0.01
NS=Notsignificant.Thetestsarefordifferencesamongtheclassesoffoundressnumbers.
ENTOMOL.FENNICAVol.29 (cid:127) SexratioshiftsofTrichopriadrosophilae 101
Fig.2.Proportionofmale
offspringproducedby
Trichopriadrosophilaein
treatmentsofdifferentnum-
bersoffoundresseswiththe
fivedaysofoviposition
pooled.BoxesasinFig.1.
Fig.3.Proportionofmale
offspringofTrichopria
drosophilaeondifferentovi-
positiondayswithtreat-
mentsofdifferentnumbers
offoundressespooled.
BoxesasinFig.1.
(Wilcoxontest,z=–0.32,p=0.750,N=50)and andovipositiondays,meaningthatsuchsexratio
in the seven-foundress cohort (7.26 ± 3.78 and adjustmentofoffspringalsoexistedonthediffer-
7.66±4.13)(Wilcoxontest,z=–0.36,p=0.719, entovipositiondays.Comparedwiththepropor-
N=50). tionintheone-foundresscohort,maleproportions
Male proportion increased with increasing inthethree-,five-andseven-foundressescohorts
foundressnumber(Fig.2;F =4.74,p=0.031). were each significantly higher (GLM, F =
1,190 1, 91
Thefinalgeneralizedlinearmodel(GLM)didnot 61.74,p < 0.001;F =22.73,p<0.001;F =
1,93 1,94
includetheinteractionbetweenfoundressnumber 29.28, p < 0.001; respectively). There was a fe-
102 Lietal. (cid:127) ENTOMOL.FENNICAVol.29
Table2.Mean(SD)degreeofinfestation(DI)andsuccessrateofparasitism(SP)ofTrichopriadrosophilaeon
differentovipositiondays.
Numberof 1stday 2ndday 3rdday 4thday 5thday
foundresses
DI SP DI SP DI SP DI SP DI SP
1 0.56 0.52 0.51 0.48 0.56 0.54 0.42 0.41 0.45 0.33
(0.09) (0.19) (0.16) (0.20) (0.14) (0.29) (0.14) (0.28) (0.18) (0.23)
3 0.63 0.95 0.35 0.73 0.33 0.70 0.28 0.80 0.47 0.90
(0.15) (0.10) (0.22) (0.31) (0.15) (0.32) (0.21) (0.33) (0.22) (0.17)
5 0.82 0.75 0.59 0.80 0.50 0.73 0.41 0.88 0.68 0.96
(0.13) (0.18) (0.18) (0.21) (0.18) (0.31) (0.13) (0.13) (0.20) (0.07)
7 0.79 0.89 0.65 0.90 0.67 0.78 0.54 0.92 0.68 0.88
(0.13) (0.20) (0.16) (0.17) (0.13) (0.23) (0.22) (0.12) (0.22) (0.14)
male-biased sex ratio when only one foundress dani)(Pteromalidae)(Nadel&Luck1992,Liet
oviposited (one sample t-test, t = –10.18, al. 2014), Leptopilina heterotoma (Thompson)
45
p<0.001),butamale-biasedsexratiowhenthree (Eucoilidae) (Debout et al. 2002), and Tricho-
foundresses oviposited (one sample t-test, t = gramma euproctidis (Girault) (Trichogramma-
46
2.20, p=0.033).Sexratiowasnotsignificantly tidae)(Marteletal.2010).Males’abilitytomate
differentfrom50%withfiveorsevenfoundresses inanoff-natalpatchhasalsobeenstudied(Nadel
(onesamplet-test,t =–0.63,p=0.534;t =0.53, &Luck1992,Marteletal.2010).Forexample,
48 49
p=0.603,respectively). malesofT.euproctidisdisperse,andtheoverall
Male proportion across all the foundress- off-patchmatingproportionreaches40.5%(Mar-
number treatments differed among the five ovi- teletal.2010).WingsofT.drosophilaemalesare
positionbouts(Fig.3).Comparedtothepropor- almostaslongasthoseoffemales(Romanietal.
tiononthefirstovipositionday,theproportionof 2008),suggestingthatoff-patchmatingislikely.
male offspring on the 2nd day was significantly Our results showed that this solitary pupal
lower(F =13.30,p<0.001),butsimilarwith parasitoidshifteditsoffspringsexratiowithdif-
1,77
thatonthe3rd,4th,and5thday(F =3.65,p= ferentnumbersoffoundresseswhenovipositing
1,76
0.060;F =3.74,p=0.057;F =3.44,p= in a patch. A female-biased sex ratio was pro-
1,74 1,77
0.071;respectively).Moremaleswerelaidonthe duced by lone T. drosophilae females, but off-
firstovipositionday. spring number ofboth sexestended to beequal
Trichopria drosophilae foundresses in- withtheincreasingnumber offoundresses. The
creased the degree of infestation (DI) with in- sexratioadjustmentofT.drosophilaeisconsis-
creasingnumber offoundresses(F =28.91, tentwiththepartialLMCmodels.
1,198
p < 0.001) (Table 2). Less adult flies emerged Sex ratio theories attract attention in evolu-
with increasing number of foundresses. The tionarybiologyinexplainingadaptation,butalso
meansofDIloweredwiththeprogressoftheovi- asbasesofmethodstoobtainahighlyfemale-bi-
positiondays(F =14.14,p<0.001).Thefinal asedmassofparasitoidsforthepurposesofpest
1,197
GLMmodelshowedthatonlyfoundressnumber control.Asmentionedabove,T.drosophilaeisa
affectedsignificantlythesuccessrateofparasit- preferablecandidateforthebiologicalcontrolof
ism(SP)(F =5.47,p=0.019).Themeansof theinvasivespottedwingdrosophila,D.suzukii.
1,198
SPwerehigherwhenmorefoundressesoviposit- Rearingandreleasingofthisparasitoidinfields
ed. may be important in controlling D. suzukii
(Mazzettoetal.2016)andthenafemale-biased
4.Discussion sexratiowouldbeuseful.Ourresultssuggestthat
reducingcrowdingoffoundressesandavoidance
Partial LMC has been observed in many para- oftheirinteractionwouldincreasetheefficiency
sitoids,e.g.Pachycrepoideusvindemmiae(Ron- ofT.drosophilaeasabiologicalcontrolagent.On
ENTOMOL.FENNICAVol.29 (cid:127) SexratioshiftsofTrichopriadrosophilae 103
theotherhand,degreeofinfestation(DI)andsuc- Kang,T.,Yi,H.,Jung,C.,Lee,D.W.,Chung,B.K.,
cessrateofparasitism(SP)decreasedwhenfewer Hoelmer,K.A.&Walton,V.M.2016:Firstexplora-
tionofparasitoidsofDrosophilasuzukiiinSouthKo-
foundresses oviposited, meaning less efficient
reaaspotentialclassicalbiologicalagents.—Journal
hostutilization.
ofPestScience89:823–835.
Trichopria drosophilae produced a greater David,J.R.&Clavel,M.F.1965:Interactionentrelegé-
proportionofsonsonthefirstdayofoviposition notypeetlemilieud’élevage.Conséquencessurles
than on thesecond to fifth day. Thismay result caractéristiquesdudéveloppementdelaDrosophile.
—BulletinBiologiquedelaFranceetdelaBelgique
from a male-first strategy (Bayram et al. 2004,
99:369–378.
Huetal.2012);thatis,insomespecies,maleoff-
Debout,G.,Fauvergue,X.&Fleury,F.2002:Theeffectof
springtendtobeproducedatthestartofovipo- foundressnumberonsexratiounderpartiallocalmate
sitionbouts,followedbymostlyfemales,asseen competition.—EcologicalEntomology27:242–246.
for some pollinating fig wasps (Kjellberg et al. Fellowes,M.D.E.,Compton,S.G.&Cook,J.M.1999:
Sex allocation and local mate competition in Old
2005,Mooreetal.2005,Rajaetal.2008,Huet
Worldnon-pollinatingfigwasps.—BehavioralEco-
al. 2013). An egg parasitoid wasp, Telenomus
logyandSociobiology46:95–102.
busseolaeGahan(Scelionidae),alsohasahigher Gabarra,R.,Riudavets,J.,Rodríguez,G.A.,Pujade-Vil-
proportion of females with increasing egg mass lar,J.&Arnó,J.2015:Prospectsforthebiological
size(Bayrametal.2004).AsLMCmodelspre- controlofDrosophilasuzukii.—BioControl60:1–9.
Gibert,P.,Allemand,R.,Henri,H.&Huey,R.B.2010:
dict,afemale-biasedsexratiowouldconformto
Localadaptationandevolutionofparasitoidinterac-
the interests of a single parasitoid. Such a
tionsinaninvasivespecies,Drosophilasubobscura.
parasitoidshouldproducetheminimumnumber —EvolutionaryEcologyResearch12:873–883.
ofmalesrequiredtoinseminateallherdaughters. Hamby,K.A.,Kwok,R.S.,Zalom,F.G.&Chiu,J.C.
Layingmoremaleoffspringatthebeginningof 2013:Integratingcircadianactivityandgeneexpres-
sionprofilestopredictchronotoxicityofDrosophila
oviposition may result in males that have
suzukii response to insecticides. — PloS one 8:
emergedandarereadytomatebythetimethatfe-
e68472–e68472.
malesemerge. Hamilton,W.D.1964:Thegeneticalevolutionofsocial
behaviour.II.—JournalofTheoreticalBiology7:17–
Acknowledgments.Wethanktheanonymousreviewersfor 52.
manyusefulcomments.Thisprojectwassupportedbythe Hamilton,W.D.1967:Extraordinarysexratios.—Scien-
National Science Foundation of China (31172145, ce156:477–488.
31672351).Allexperimentsreportedherecomplywiththe Hamilton,W.D.1979:Winglessandfightingmalesinfig
currentlawsofChina. waspsandotherinsects.—In:Blum,M.S.&Blum,
N.A.(eds.),Reproductivecompetition,matechoice
andsexualselectionininsects:167–220. Academic
Press,NewYork,463pp.
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