Intergeneric variation in the external male genitalia of the subfamily Microgastrinae (Hymenoptera, Braconidae), with a reassessment of Mason's tribal system

15 Pages·1996·4.1 MB·English

by  K Maetô

J.HYM.RES.
Vol.5,1996,pp.3&-52
Inter-Generic Variation in the External Male Genitalia ofthe
Subfamily Microgastrinae (Hymenoptera, Braconidae),with a
ReassessmentofMason'sTribal System
KaoruMaetO
ForestBiologyDivision,ForestryandForestProductsResearchInstitute,P.O.Box16,Tsukuha
NorinKenkyuDanchi-nai,Ibaraki305,JAPAN
—
Abstract. Externalmalegenitaliaof39generaofMicrogastrinae,2ofCardiochilinaeandone
ofMiracinaewereexaminedtoreappraiseMason'stribalsystemofthebraconidsubfamilyMi-
crogastrinae.Volsellarstructuresofthemalegenitaliacametoprovideusefulnewcharacters.On
thebasisofmorphologicalcharactersincludingthoseofthemalegenitalia,monophylyofMason's
tribesandtheirgroupswasreassessed.ThetribesApanteliniandMicrogastrini(exceptforSathon)
mostlikelyformamonophyleticgroup,althoughmonophylyofeachtribeisnotsupportedby
theevidence.TheplacementofPrasmodonandSathonintheMicrogastriniisdoubtful,andthe
lattermaybelongtothemonophyleticassemblagecomposedoftheCotesiini,Microplitiniand
Fomicini.TheCotesiiniisprobablyparaphyleticsincesomeofthemembersseemtobecloseto
theMicroplitiniandFomiciini.
INTRODUCTION diochilinae, Khoikhoiinae and Miracinae,
wno19onu9rWdm1li)bdl,teawhrraigndeodeasft,bsiobtptureihtacsecioeoM1nsni3eic(0drSo0ofshguaatdbwshefetsaarcmnmiriodnilasbyHeteuiddiinsdmtlptseehopresremttcssoaienneco,st-f htW1199ahh98Cvoa43ueur),rg.trhonQeonuntittechtbekfaeerle.arname1lne9adw9ft2ioi,rrvomnkWalshnyhioitfpArfsecitshehotlealdemvgraeoebdnnenedrgrg(iMMcata1s9has9oeno0ndmn,
cmaAguoarsmnitpcyiounlnlteaeunnprtdeisdDo(aeop.nftgg.e,etrhraGefnaipuepallerdsdats1sia9t9nio2dn)i.dfBMoocreloetmmsobtpnrleyer1x9sa8n8ood,ff wtt1rh9aie6sb5a)llparirsnogytpeosot2seg3emedagnteubinscyesrMAapaoafasnnottdenhlere(es1c9Mo8i{1gcs)ner,nioszgiweiahdsotN5ri0sixpneloaxine-t
ttohiedssuobffalmeiplidyopatreerkaoninlaorbviaoentanedndaorpearaasssio-- ttealnitni,genMiecrraogaarsrtarnignie,diFnorfniivceiitnrii,besC,otAepsiainn-i
cW(ihSaihttafewidelawdnidt1h9H9u2sd,ydmlSbehisaotrtokinecy1p9o199l19y,3d,nStaWovlhitazrrutasonedns aqteunliedtseMdiceclfroiosnpeelidttoibntyih.eNHisipxseocngieen(s1e9gr6ir5co),ucpowsnhcioefcphtApwhaaansd-
1993). been largely taken from the idea ofWil-
ThemonophylyoftheMicrogastrinaeis kinson(1932).
firmlyestablishedbytheuniqueflagellum Mason's genericclassification hasbeen
withinvariably 16articles,mostofwhich adopted by many taxonomists (e.g., Wil-
typicallyhave2ranksoflongitudinalpla- liams 1985, 1988,Marshetal. 1987, Papp
codes (Mason 1981). Also, Mason (1981, 1988, Austin and Dangerfield 1992),
1983) suggested some additional autapo- thoughTobias(1986)andShawandHud-
morphies to define this subfamily. It is dleston (1991) withheld total approvalof
widely accepted that the Microgastrinae his generic proposals. Mason's phyloge-
formsamonophyleticgroupwiththeCar- neticanalysisandsupragenericclassifica-
Volume5,1996 39
HonoftheMicrogastrinae,however,have ne on slides. They were measured and
been criticized by Walker et al. (1990), photographed with a Nikon light micro-
whoconcludedthatMason'stribesarenot scope.
established on the basis of synapomor- Termsformalegenitaliaaretakenfrom
phies. Recent authors (Shaw and Hud- Snodgrass(1941).ThevolsellaoftheBra-
dleston 1992, Austin and Dangerfield conidae consists of lamina volsellaris (1)
1992)alsohesitatedtoadoptMason'strib- and twodistallobes,digitus(digitusvol-
alsystemoftheMicrogastrinae.Thereisa sellaris, d) and cuspis (cuspis volsellaris,
need of further intensive research to un- c)(Figs.1,3).Attheapexofamedianlon-
derstand the phylogenetic framework of gitudinal ridge (volsellar ridge, r), the
this large and economically important lamina volsellaris is distally articulated
subfamily. withthedigitus.Thecuspisiscontinuous
Mason's classification is principally with the lamina volsellaris in the Micro-
based on structuresofthe femalegenita- gastrinaeandrelatedsubfamilies(Quicke
lia. As shown by Tobias (1967), Marsh andvanAchterberg1990).
(1965),Quicke(1988)andQuickeandvan Length of the lamina volsellaris was
Achterberg (1990), themalegenitaliacan measuredfromthebasalendofthelami-
provide useful characters for the higher navolsellaristotheapicalendofthevol-
levelclassificationofbraconids.Exceptfor sellarridge. Digitallengthwasmeasured
Williams' (1988) revisional study of Sa- fromtheapicalendofthevolsellarridge
tlion,however,mostsystematicstudieson totheapexofthedigitus.
theMicrogastrinaehavegivenlittleatten-
tiontothemalegenitalia.Thepresentpa- RESULTSANDDISCUSSION
ptheererxetpeorrntaslomnaltehegevnoiltsaellilaarisntrtuhcetuMriecsroo-f DescriptionsofVolsellae
gastrinae to elucidate their inter-generic Microgastrinae: Apantelini. Lamina
variations. 1 haveexamined 39 outof53 volsellariswith 1-8(usually2-5)setaeor
extant genera of the Microgastrinae, and setal alveoli (Table 1). Cuspis glabrous,
also several genera ofthe Cardiochilinae separated fromdigitusexceptforMiropo-
andMiracinaeasoutgroups.Onthebasis tcs, in which they were fused with each
ofmorphologicaldata including thoseof otherandsovolsellabecameasingleplate
the male genitalia, I will reappraise Ma- (Figs. 7-8). Relative length of digitus to
son'stribalsystem. laminavolsellaris0.39to0.69(Table1).In
MATERIALSANDMETHODS Apantcles,Austrocotesia,Dolichogenidca,Pa-
pmntties,Pholetesor,PromicrogasterandSen-
ThespeciesexaminedarelistedinTable dnplnic, digitus arched dorsally or cres-
1.ThemicrogastrinesarearrangedinMa- cent-shaped, distinctly convex ventrally,
son's tribal system;Austrocotesia is tenta- with a pointed apex directed dorsally or
tively placed in the Apantelini. As out- laterally (Figs. 1-5, 9, 11-13); in Illidops,
groupsofthe Microgastrinae,Cardiochiles digitus tubiform apically and strongly
andHartemila (Cardiochilinae)andMirax archeddorsally(Fig.6);inMiropotes,dig-
(Miracinae)wereexamined. itusconvexventrallywiththeapexrather
weMreetiamsmomeartsaedoffort2h-e3ddariyesdins5pe%ciKmOenHs rinouPnedlic(oFpieg,. 7d)igoirtucsreosncleynt-sslihgahpteldy(cFiogn.ve8)x;
at40°C.Genitaliawereremovedfromthe ventrally, not crescent-shaped, while the
restofthemetasomaandrinsedwith70"() apical portion obviously bent dorsally
ethanol. (Fig.10).Apexofdigituswith1-4(usuallv
Volsellae were torn away from sur- 2-3)teeth(Table1).
roundingcuticleandmountedinglyceri- Microgastrinae: Microgastrini. Lamina
40 JournalofHymenopteraResearch
Table1. LaminavolsellarisanddigitusofMicrogastrinae,CardiochilinaeandMiracinae.
Volume5,1996 41
Table1. Continued
Prn^nioiionsp.
Pscminpaiilck'siiniuiliconus
Ashmead
Rhygop^litisaciculatmAshmead
Sathonlateralis(Haliday)
SathotimasoiiiWilliams
Sathonneomexicanus(Muesebeck)
Xanthomkrogastersp.
Fomiciini
Fcirnicaarata(Enderlein)
FornicaceylonicaWilkinson
Cotesiini
BulukaachterbergiAustin
Qift'SMaffinis(Nees)
Cotesiaaiicilla(Nixon)
Cotesiaflavip^esCameron
Cotesiaglomerata(L.)
Cotesiakariyai(Watanabe)
Cotesiamelanoscelus(Ratzeburg)
Cotesiaofella(Nixon)
Cotesiaplutellae(Kurdjumov)
Cotesianibecula(Marshall)
Cotesiatatehae(Watanabe)
Cotesialeiiebrosa(Wesmael)
Deiitenxyscarbonaria(Wesmael)
Deuterix\/spacificaWhitfield
Diolcogastcrabiioininalis(Nees)
Diolcogasterduris(Nixon)
Diolcogastercf.spreta(Marshall)
Distatrixpmpiliouis(Viereck)
ExixmexicanaMason
Gh/ptapaiitelesaliphera(Nixon)
Clyp'tapantelesfulvipes(Haliday)
GlyptapantclesUparidis(Bouche)
Gh/ptapaiitelesxvebsteri(Muesebeck)
LathrapiintetesfiiscusWilliams
ProtapaiilelesalaskeiisisAshmead
Protapantelesaiichisiades(Nixon)
Protapanteleslymantriae(Marsh)
Protoynicroplitiscalliptera(Say)
Protomicroplitismediatus(Cresson)
Rasivalvarugosa(Muesebeck)
Rasivalvastigmatica(Muesebeck)
VetianidesxesteMason
VeiniiiuspinicolaMason
WilkinsonelhisstriatusAustin&
Dangerfield
Microplitini
AllopliliseompletusNixon
MicroptitisalanuensisAshmead
Microplilisdepnnuitor(Fabricius)
42 JournalofHymenopteraResearch
Table1. Continued
Taxon
Volume5,1996 43
Cardiochilinae.Laminavolsellariswith siomorphic. The digitus found in the
3-8setae(Table1).Cuspisseparatedfrom Apantelini and Microgastrini is apo-
digitus, and bearing a group of alveoli morphic,beingcrescent-shapedwitha
without seta (Fig. 52). Relative length of sharp (occasionally slightly obtuse)
digitus to lamina volsellaris 0.44-0.52. apexdirecteddorsallyorlaterally.
Digitusroundapicallyandnotorweakly 5. Number ofapical teeth of digitus. A
arched dorsally (Figs. 51-53), with 5-10 plesiomorphicconditioncannotbede-
apicalteeth. fined,becausetheteethvaryinnumber
Miracinae. Lamina volsellariswith4-6 from 2in theMiracinaeto5-10inthe
alveoli, invariably without seta. Cuspis Cardiochilinae.
lgleanbgrtohuso,fsedpiagriattusedtforolmamdiigniatusv.olRseellaltairvies ReassessmentofMason'sTribalSystem
0.40-0.46. Digitus broadly truncated api- AlthoughMason(1981)poshalated that
cally,slightlyarcheddorsally,andinvari- his tribes Apantelini and Microgastrini
ablywith2apicalteeth(Figs.54-55). form a monophyletic group, he did not
suggestanycrediblesynapomorphiesfor
PolarityofCharacterStates theassemblage(Walkeretal. 1990). Aus-
Basedontheconditionsobservedinthe tin (1990), however, pointed out that the
outgroups,CardiochilinaeandMiracinae, ventromedially membranous, folded and
ctrhoegaposltarriintayeoisfscuhgargaecstteerdsatsatfeosllionwst:heMi- omafotssetyn,nedaxeppfoiannmidotireblplyheynhotyfpoarlolp,ayogfciMluaamdseoinsi'pnsrcolAbupadabinln-yg
1. Numberofsetae (orsetal alveoli) on telini -I- Microgastrini.
lamina volsellaris. The plesiomorphic Moreover,themonophylyofApantelini
conditionisperhaps3-6. Lossandac- -I- Microgastrini ismostlikely tobesup-
quisitionofsetaearefoundbothinthe ported by the crescent-shaped or arched
Microgastrini and Cotesiini. Cotesia is digituswithitssharp (orslightlyobtuse)
aberrant in always having numerous apex being directed dorsally or laterally.
volsellarsetae(Fig.56),andalsosome Insomeaberrantgenera (lllidops,Miropo-
other genera of the Cotesiini (Glypta- tes, Pelicope and Xanthomicrogaster), the
panteles, Lathrapanteles, Protapanteles) digitus is not typically crescent-shaped,
andSathon(Microgastrini)oftenhave7 buttheapicalportiontendstobepointed
ormoresetae. dorsallyorlaterally.
2. Articulation of digitus with cuspis. Mason's tribe Apantelini hasbeendis-
Separationofthedigitusfromthecus- tinguishedfromhisMicrogastrinibyhav-
pis is apparently plesiomorphic. The ing no percurrent median carina on the
fusion of these lobes is found only in propodeum. Most genera of the Apante-
thegenusMiropotes(ApantelLni). linidoubtlessformamonophyleticgroup
3. Relative length of digitus to lamina supportedbytheanteriorlyprojectinglat-
volsellaris.Mediumsizeddigitus,0.4- erallobeofthemetanotum(Mason1981).
0.5 ofthe lamina volsellaris in length, However, somegenera (Miropotes,Senda-
is probably plesiomorphic. A compar- pliiie, Pelicope, etc.) of the Apantelini are
ativelylongdigitus(0.55ormoretimes devoid of the apomorphy. At the same
as long as the lamina volsellaris) was time,somegenera{Oweras,Clarkiriella,Ico-
foundinsomegeneraoftheApantelini lu'lla) oftheMicrogastrinishowasimilar
and Microgastrini. ifnothomologouscharacterstate(Mason
4. Shapeofdigitus.Thedigitus,notdis- 1981). The percurrent median propodeal
tinctlyarcheddorsally,witharoundor carina of the Microgastrini may be apo-
broadlytruncatedapexisprobablyple- morphic,butthesameconditionisfound
44 JournalofHymenoiteraResearch
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