Further notes on Macromia Rambur from Hong Kong, with descriptions of the larvae (Anisoptera: Corduliidae)

8 Pages·1996·1.5 MB·English

by  Wilson, K D P

Odonatologica25(3): 275-282 SeptemberI, 1996
Furthernotes onMacromiaRambur from
HongKong, with descriptions of the larvae
(Anisoptera: Corduliidae)
K.D.P.Wilson¹ andG.Theischinge²r
' 6F, 25 Borrett Road,Mid Levels,Hong Kong
2 20 Leawarra Street,Engadine,N.S.W.2233,Australia
Received December20, 1995 /Reviewed andAcceptedFebruary 13, 1996
The larvaeofM.urania Ris, M.berlandi Lieft. andM. katae Wilsonare described
and illustrated;those ofthe latter 2spp. forthe firsttime. Details ofhabitat prefer-
encesandbiologicalnotes areprovided.
INTRODUCTION
Theadults ofthe3 Macromiaspecies known from Hong Kong were treatedin
detailby WILSON(1993). TheyareM. berlandiLieftinck, 1941,M. kataeWilson,
1993,andM. uraniaRis, 1916.Descriptions oftheirlast instarlarvaearegiven in
thispaper.Theywerebredoutforconfirmationofidentity.ThelarvaeofM. berlandi
andM. kataehavenot previously beendescribed.AllthreeMacromiaspecies can
befoundin thestreams whichdrainHong Kong’s ShaLoTung basin whereeach
species occupies a distincthabitattype. Detailsofhabitatpreferences andbiologi-
calnotes are provided.
MACROMIA BERLANDILIEFTINCK
Figures 1-7
Macromia borneensis Martin, 1906:69,fig.A: I d,Tonkin.
Macromia berlandi Lieftinck, 1941: 94-98, figs l(a,c): 1 d, type-loc. Tonkin;
Wilson, 1993:235-237,figs 1-5: 1 d,ShaLoTung,20-VI-1992;- Do.,26-VI-1992;
Wilson, 1995; 31 (key), 134-135 (photo’s; d, 2,larva), 139, 141, 143: HongKong.
Material.-2 larvae, ShaLo Tung,HongKong,8-V-1993 (1 2,1 d,emerged11-V-1993and
18-V-1993),4larvae,s.1.,27-11-1995 (1 d,emerged26-IV-1995, 2 d,emergedMay 1995);1 d,s,1.,
276 K.D.P.Wilson &G. Theischinger
24-V1-1995, 2 <J, s. 1„ 25-V1-1995, 1 9,s.1„2-VI1-1995; 1 9 (teneral),Sham TsengSettlement
Basin,HongKong,2-VII-1994,
DESCRIPTION OFLARVA. - Dimensions (inmm): Total length26.0-29.0,greatestwidth
ofhead 7.0-7.3, lengthofmetafemur 11.7-12.1,length ofabdomen 17.0-18.5,greatestwidth 10.4-
-11.0.
Head (Figs 1-4). - Wide, witheyes slightly protruding laterally and dorsally.
Postocular lobeswidelyroundedandwithsmallposterolateral tooth.Frontal shelf
low,obtusely angulated as seeninfrontalaspect. Prementummarkedly widerthan
long, withmarginofligula widely rounded,smooth, and set withshortthinsetae
more laterally, and shortspinoid setae more medially; labialpalps with 7 teeth
bearing large spinoid setae;4palpal setae, 1 setaofmoderatesize atbaseofpalp;
3-4pairsoflarge(primary) premental setae,2 pairsofsmall(secondary) premental
Figs 1-7. Macromiaberlandi Lieftinck, lastinstarlarva: (I)dorsal aspect;- (2)head, frontalaspect;-
(3)postocular lobe; - (4)labium,ventral aspect;- (5)prothoracic processes and nolal lobe;- (6)
middorsal abdominal spines,lateralaspect;- (7)lateralspinesofabdominal segments 8 and9, ventral
aspect.
Macromialarvae from Hong Kong 277
setae, thetwo groupswidely separated; numerousminutespinoid setae.
Thorax (Figs 1,5).-Prothoraxslightlynarrowerthanhead;lateralprothoracic
processes poorly differentiated,anteriorprocess a narrow lobe, posterior process
widely rounded; notal lobe widely rounded anterolaterally, narrowly rounded to
obtusely pointedposterolaterally. Synthorax widerthanhead.Legs withhairsand
smallspines; profemur slightly shorterthanwidthofhead, markedly shorterthan
widthofsynthorax. Wing sheathsreaching toor slightly beyond endofabdominal
segment5.
Abdomen(Figs 1,6,7).-About1.5timesas wideashead;middorsalspines
onsegments3-9, thoseonsegments3-5ratherslimandstraight, thoseon segments
6-9ratherstoutandmoreorless hooked;lateralspines on segments8and9,those
on9ratherstraight andabouttwiceas long as thoseon 8.
MACROMIA KATAE WILSON
Figures8-14
Macromia katae Wilson, 1993: 237-240,figs 11-17:Holotype <J, ShaLo Tung,
Hong Kong,3-VII-1992; Wilson, 1995: 3!(key), 130-131 (photo's; <J, 5, larva),
139, 143, 145; HongKong.
Material. - 1 exuviae, ShaLo Tung,Hong Kong, 16-V-1992, 1 exuviae, s.1.,5-VI-1992, 1
larva, s.1..8-V-1993 (emergedVI-1993),1 larva,s.i„27-11-1995, 4larvae, s. 1., l-XI-1995;3 9,Wu
Kau Tang, HongKong,31-V-1993.
DESCRIPTIONOFLARVA. - Dimensions (inmm):Total length21.0-23.5, greatestwidth
ofhead 6.2-6.8,lengthofmetafemur 10.2-10.9,lengthofabdomen 13.0-14.0,greatestwidth8.2-8.7.
Head (Figs 8-11). - Wide,with eyesslightly protruding laterallyand dorsally.
Postocularlobes widely rounded,withnarrow upright conenearmidlineandwith
large posterolateral tooth.Frontal shelfhigh, acutely conical as seen in frontal
aspect. Prementummarkedly wider thanlong, with margin ofligula very widely
rounded to almost slightly bilobed, smooth, and set with short thin setae more
laterally,andshortspinoid setaemore medially; labialpalps with6-7 teethbearing
large spinoidsetae;5 palpal setae,1very smallsetaatbaseofpalp; 5pairs oflarge
(primary) premental setae,2-3 pairsofsmall(secondary) premental setae,thetwo
groupsnot more widely separated than the individualsecondary setae fromeach
other; numerousminutespinoid setae.
Thorax (Figs 8, 12). - Prothorax slightly narrower than head; lateral
prothoracic processes hardly differentiated,anteriorprocess asmall angular lobe,
posterior process widely rounded;notallobeslightly rounded anterolaterally, dis-
tinctly pointed to hom-likeposterolaterally. Synthorax as wideas head.Legs long
and spiny; profemur longer than widthofhead or thorax. Wing sheathsreaching
closetoend ofabdominalsegment7.
Abdomen (Figs 8, 13, 14).- About 1.3 timesas wide as head; middorsal
278 K.D.P.Wilson &G.Theischinger
spines onsegment4-9,allratherstraightandslim,thoseonsegments4and5 short,
thoseon segments6-9ratherlong; lateralspines on segments8and9, those on9
less thantwiceas long asthoseon 8.
DISCUSSION.-TheclosestcongenerofMacromiakataeis M.arachnomimaLief-
tinck.BoththelarvaandadultofM. arachnomimawere describedandillustrated
by LIEFTINCK(1953) who remarked that, this new species [...] “is not closely
alliedtoanyofitscongeners”. Hefurtherremarkedthat[...he...]“was atfirstquite
unabletorecognize as belonging toanyknown genus.Theexcessively long wings
andenormouslegs ofthisstrange formwerereminiscentofsomelarge spider or
opilionidand didnotseemtoforeshadowtheproportions thesepartshaveinanyof
theknown species ofMacromia; the curious tubercles on the headand the stiff
spinybristlesonthefemorabeingadditionalornamentationsfoundinplaces where
Figs8-14. MacromiakataeWilson, last instarlarva: (8)dorsal aspect;- (9)head, frontalaspect;- (10)
postocular lobe;- (11) labium,ventral aspect;- (12) prothoracicprocesses and notal lobe;- (13)
middorsal abdominal spines,lateral aspect; - (14) lateral spinesofabdominal segments8 and 9,
ventral aspect.
MacromialarvaefromHongKong 279
nosuchoutgrowths wouldnormally beexpected”. Althoughappreciably larger,M.
kataeis clearly veryclosely relatedtoarachnomima,withthesamestream habitat
preference andsimilar larvalandadultforms.The larvaeofbothspecies possess a
pair ofcones or tubercles on thevertex near the midlineand afrontalhom.The
frontalhornofM. arachnomimaapparently projectsfrombetweentheantennae in
a forwarddirection whereas the frontalprojection ofM. katae is sharply angled
upward (see Fig. 9) (cf. LIEFTINCK, 1953:404, figs 7a, 7b). Adultsofthetwo
species have been compared atthe Leiden Museum where Dr van Tol has con-
firmedtheirdistinctness atspecies level. Oftheworld’s 117species ofMacromia
listedby BRIDGES (1994), apparently onlyM.arachnomimaandM.kataebelong
to thehighly specialized M.arachnomimagroup.
MACROMIA URANIA RIS
Figures 15-21
MacromiauraniaRis, 1916:66,68-70,figs42-43&pi.3,fig.2-3: 2 <J, I 9,type-
loc. Tonkin; Wilson, 1993: 236-237, figs 6-10: 3 teneral 9,TaiTong (emergedVI-
-1992 fromfinal instar larvaecollected 24-VI-1992);1 S,PingYeung,30-V-1992; 1
9,ShaLoTung, 14-VI-1992;Wilson, 1995:31 (key), 132-133 (photo’s;6. 9,larva),
139, 141:HongKong.
Material.- 1 6.ShaLoTung,HongKong,24-VI-1995,3 6,s.I„2-VII-1995,4larvae,s. 1., 1-
-Xl-1995; 1 9,She Shan, HongKong, 15-V-1993; 3 larvae,Tai Tong,Hong Kong,24-V-1992, 4
exuviaes.I.,24-IV-1992, 3larvae,s. 1., 13-V-1995.
ThelarvaofMacromiauraniahas previously beendescribedby ISHIDA(1969)
and is illustrated in KAWAI (1985: 91, key 92, figs la-e). MATSUKI & LIEN
(1982: 19)haveprovided a larvalkey forthethreeTaiwanese Macromiaspecies
whichincludeM. chuiAsahina,M. clioRisandM.urania.ThelarvaofM. urania
fromHong Kong doesnot differsignificantly fromlarvaeofM. uraniafromJapan.
Itis describedhere forcomparison withtheothertwo species of Macromiafrom
Hong Kong.
DESCRIPTIONOFLARVA. - Dimensions (inmm):Total length21.5-23.5,greatestwidth
ofhead 5.8-6.1,lengthofmetafemur 8.7-93, lengthofabdomen 13.5-14.5, greatestwidth 8.0-8.8.
Head (Figs 15-18).- Moderately wide,witheyesstrongly protruding dorsally.
Postocularlobesnarrowly roundedandwithvery small posterolateraltooth.Fron-
tal shelf high, rather narrow and apically rounded as seen in frontal aspect.
Prementumhardly widerthanlong;threewelldeveloped ventrallongitudinal keels,
one anteromedialand two posterolateral; margin ofligula angulated, crenulate,
andset withshortthinsetaemorelaterally,andshortspinoid setaemore medially;
labialpalps with7 teethbearing large spinoidsetae;5 palpalsetae, 1 setaofmod-
erate size atbase ofpalp; 6 pairs of large (primary) premental setae, 2 pairs of
small (secondary) premental setae,thetwo groups notmore widely separated than
280 K.D.P. Wilson & G.Theischinger
theindvidualsecondary setae fromeachother; numerousminutespinoid setae.
Thorax (Figs 15, 19).- Prothoraxaboutaswide ashead;lateralprothoracic
processes poorly differentiated,anteriorprocess a larger angular lobe, posterior
process asmaller angular lobe; notal lobenot differentiated,almost rectangular.
Synthorax widerthanhead.Legs hairy;profemur shorterthanwidthofhead,mark-
edly shorterthan widthofsynthorax. Wing sheathsreaching approximately toend
ofabdominalsegment5.Fromanearlyinstaruntilfinalinstardistinctivediamond-
-shaped eye spots are locatedat thebase ofthe wing sheaths. The eye spots are
predominantly black withasmallerblack borderedferruginous orangespot occu-
pying theinnerhalfof thediamond.Thisfeatureis not easily discernibleinspeci-
mens preserved inalcohol.
Abdomen (Figs 15, 20, 21). - Almost 1.5 times aswide as head; middorsal
spines on segments 3-9,all ratherhooked, spine onsegment3 highandslim, re-
Figs 15-21. Macromia uraniaRis, lastinstarlarva: (15)dorsal aspect;- (16)head, frontalaspect;-
(17)postocularlobe;- (18)labium,ventral aspect;- (19)prothoracicprocessesand notallobe;- (20)
middorsal abdominal spines,lateral aspect; - (21)lateral spine ofabdominal segment 9, lateral as-
pect.
Macwmialarvae fromHongKong 281
mainingspines ratherlowandstout;lateralspines onsegments8 and9, spineon9
withtip strongly upcurved.
HABITATPREFERENCES. - None of Hong Kong’s three Macromia species have
been foundin boulderstreams withhigh torrentialflows,whichis thedominant
habitatinHongKong’s mountainousterrain.Larvaewerecollectedonly fromsmall
wooded, or partially wooded streams, 3-6 m wide, with shallow gradients and
substratesdominatedby coarse sand.Althoughsubjected totorrentialflowsduring
heavy rainfallperiods inHong Kong’s May toOctoberwetseason, themeancur-
rent speeds ofthesestreams are low.
LarvaeofMacromiaberlandiare restrictedto slow flowing stream sections in
pools andslacks andare foundon substratescomprised ofmuddy sand.
LarvaeofMacromiakatae arenot foundinor onbottomsubstratesofany kind
butareexclusively associatedwithsubmergedroots inwaterwithmoderateor fast
flow.Themajorityoflarvaeweretakenfromtreeroots butonespecimen was taken
fromtheroots ofginger lily, Hedychium coronariumKoen.Larvae transferredto
tanks forobservation andbreeding out adopt a verticalposition clinging to plant
stems,sticks and matting.Thelong spines onthelegs ofM. kataeare no doubtof
assistanceto thelarvain maintaining itsposition attachedto tree roots infastcur-
rents.
LarvaeofMacromiauraniapreferrelativelyfast flowing waterandarefoundon
thesubstratesurfaceofsandy reaches inmoderatelyfastruns, insandy gravel,and
atstream margins withsand,gravel, leaves androot material.
BIOLOGICALNOTES. — InHong Kong the adults ofallthree Macromiaspecies
emergefromlateMayto July,withpeak activity occurring in Juneandearly July.
The beginning oftheemergenceperiodcoincides withthecommencement of the
wet season andthemarked increaseinmeantemperatures.
Thehabitatpreferenceofthelarvaeisareflectionofthemales’choiceofterrito-
ries andtheoviposition sites usedby the females.
MatureMacromiaurania malesare thefirstof the three Macromiaspecies to
arriveatthestream atapproximately 07:30hinthemorning. Theirpatrols are5-15
mlong and centeredover gravelriffles sections. Thefirstauthorhas observed M.
uraniaovipositing atthree sites in Hong Kong (Tai Tong, She Shan andSha Lo
Tung) and one in Guangdong (Dinghu Shan), all duringthe morning. The sites
adopted foroviposition weregravelriffles.Theeggs are dislodgedbymaking brief
contactwiththewatersurface.Maleterritorialactivityis muchreducedafter10:00h.
MatureMacromiaberlandimalesarrive atthestreamfromapproximately 09:00
h, and territorialactivity is reduced after 10:00h. The patrols ofthe males are
longerthanMuraniabeatsandincludeentireslowflowing streamsections, which
occurbetweenriffles,aboveweirsandnaturalstreamimpoundments suchas fallen
trees. Thelengths ofpatrols andslowflowing sections measure upto20m atSha
Lo Tung whereobservations ofM. berlandiwere made. Oviposition occurs,im-
mediately afterpairing, in theslowflowing sections.
282 K.D.P. Wilson &G.Theischinger
ThemalesofMacromiakataearelasttoarrive atthestream,withhighest activ-
ityobserved from09:30to 11:00h.Oviposition occurs atthe stream margin with
eggs dropped over thickmatsofsubmerged tree roots.
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KAWAI,T, 1985. An illustrated bookofaquaticinsects ofJapan.TokaiUniv. Press.
LIEFTINCK,M.A., 1941. Une espece nouvelle deMacromia duTonkin. Revuefr.Ent. 8(2): 94-98.
LIEFTINCK,M.A., 1953. New dragonflies(Odonata)from Borneo, with notes ontheirhabitats and
larvae. Treubia 22(2):381-406.
MARTIN, R„ 1906. Cordulines. Colins tool. SelysLongchamps17: 1-94,pis 1-3excl.
MATSUKI, K.& J.C. LIEN, 1982. Descriptions ofthelarvae oftwo Macromia species in Taiwan.
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R1S, F, 1916. H.Sauter’s Formosa-Ausbeute. Odonata. (MitNotizenliberandere ostasiatische Odo-
naten.)Suppltaent. 5: 1-81, 3pis excl.
WILSON,K.D.P., 1993. Notes onMacromia fromHongKong,withadescriptionofMacromiakatae
spec. nov.(Anisoptera:Corduliidae).Odonatologica22(2):233-241.
WILSON,K.D.P., 1995. HongKong dragonflies.Urban Council ofHongKong.