Description of the larva of Pseudagrion decorum (Rambur, 1842) from central India (Zygoptera: Coenagrionidae)

5 Pages·1998·0.81 MB·English

by  Babu, B Suri

Odonatologica27(4):473-477 December I,1998
SHORT COMMUNICATIONS
Descriptionof thelarva ofPseudagriondecorum
(Rambur, 1842) from centralIndia
(Zygoptera: Coenagrionidae)
B. Suri+Babu
Forensic ScienceLaboratory,Police Control Room,Jagdalpur-494001(M.P.), India
ReceivedNovember 17, 1997/Revisedand AcceptedMay 20, 1998
The finalinstarlarva is described and figured,based onexuviae andlarvae from
Sagar, MadhyaPradesh. Briefnotes on itsbiologyareprovided.
INTRODUCTION
ThegenusPseudagrion Selys, 1876is widely distributedintheOriental, Ethio-
pian and Australianregions and, within Indianlimits, 11 species havebeen re-
corded(PRASAD& VARSHNEY, 1995). Pseudagrion decorum(Ramb.) is dis-
tributedthroughout continentalIndia,Burma,SriLanka(FRASER, 1933;KUMAR
& PRASAD. 1981)andNepal (ST. QUENTIN, 1970).FRASER(1919)described
thelarvaofP.hypermelasSel.andP. microcephalum (Ramb.)fromMadhyaPradesh,
India.KUMAR (1973) describedthefinal instarlarvaofP. rubriceps Sel.and P.
laidlawiFraser fromDehra Dun Valley, India.Thepresentpaperprovides some
basic informationon themorphology ofthefinalinstarlarvaofP. decorum.
MATERIALANDMETHODS
18 S and22 9finalinstar larvaeofP.decorumwerecollected from thelittoral zoneofSagarLake,
Sagar(M.P.)Indiaon30-VIII-1982 andreared inthelaboratorytoemergence.Speciesdeterminations
weremadefromteneralimagos.Bothexuviaeandlarvaepreservedin70%ethyl alcohol anddifferent
parts oflarvae and exuviae weregentlywarmed in 5% aqueousKOHsolution for 10to 15minutes,
washed inwater, dehydratedand stained with picro-indigo-carmine.The material wasleftovernight
in cedarwoodoilforclearance andmountedin Canadabalsam. Microphotographsweretaken with a
stereomicroscope and illustrations weredrawn with the helpofslides andphotographs.Measure-
ments were takenusing anocularmicrometer andwithaC.Reichert micrometer.Terminologyused
for thelabiumisadoptedfromCORBET(1953), for caudal gillsfrom MacNEILL(I960), and for
474 B.SuriBabu
tibialcombs fromMacNEILL (1967). Fieldobservations werecarriedoutthroughoutthe year 1982-
-83.
THESITE
Alllarvae werecollected fromthe littoral zoneofSagar Lake, which is situated inthe heart of
Sagar,M.P.Indiaat23°52’N and 78°45’Eat about533 mabovemeansealevel.Itissurroundedby a
number ofhouses, astony fencing wall, ametalled road oneastern, western, northernsides respec-
tively andonthe southern side by anopencultivated field.The eutrophicrain-fedlake coversanarea
of81hectares with acatchmentareaofabout 1410hectares. Thelakereceives domesticsewagefrom
acity bus-stand.There isaweironthe western side ofthe lake whichregulatesthe outflow andwater
level ofthelake. Apartfrom domesticsewage, pollutionofthe lakealso occursdue tobathing,clothes
washingandwallowingofcattle.ThecommongrassesParsicumproliferum,Oryzasativa, Paspalidium
germinatumandHydrorhiza aristata and somesedgeslike Scirpuslittoralis, Eleocharis palustrisand
Cyperusindicus weregrowingonthe banks ofthe lake. Hydrillaverticiliata, Potamogetoncrispus,P.
natans, P.pectinatus, Vallisneria spiralisare commonrooted submergedplants, Nymphaea stellata
andEichhornia crassipes form thefloating vegetation.Thepracticeof cultivatinghydrophytes of
economic valuelike Trapabispinosa,Nelumbo nuciferaiscommon.Asampleofwater wastakenand
analyzedonthesamedate asthelarval collection and theresultsofchemicalanalyses were:airand
watertemperature26.5°Cand25°Crespectively.Secchitransparency 40cm,pH 8.5,freecarbondioxide
nil,bicarbonates 84 ppm, carbonates 20 ppm, total hardness 118ppm, dissolved oxygen 7.2 ppm,
percent oxygen saturation 81.67%.
DESCRIPTION
Measurements (meanof30larvae,in mm): - Bodylength(excludingantennaand caudal
lamella): 13.16; — headwidth:3.05; - antenna;2.84; — prementum, length:2.47; — width:2.02;
—palpi;0.90;—wingsheath4.5;—prothoracicleg(femur-tibia-tarsus):2.2, 2.6,1.6;—mesothoracic
leg:2.7, 3.2, 1.4; — metathoracic leg: 3.1,3.8, 1.5; — median lamella:6.4; — laterallamella:6.5.
Theground colouris deep brown, some larvaegreenish brown with significant
Pseudagrion colourpattern ofcaudallamellae.
Head. — Anteriormargin round,posterior margin slightly concave, lateralside
bulging, posterolateral sides markedly narrow and beset with small setae. Eyes
prominent, colourgreyto blackish brown.Threeocelliprominently present.
Antennaefiliform(Fig. 1),7 segmented, pedicel abouttwiceas long as scapus,
allsegments besetwithpiliform setae.
Prementum (Fig. 2) extending posteriorly up to the base ofthe middlecoxae,
convexly roundeddistallyandprovidedwithafewsmallclaviformsetae.Prementum
provided with 1+1 premental setae and 6 scattered microsetaepresentnear the
baseofeachpremental seta.Arow ofspiniform setae presentonthelateralsidesof
prementum.Palpal setae 4+4.Distalendofpalpus(Fig. 3) dividedintotwo lobes,
theouter denticularregionpossessing fourteethandtheinnerlobeproduced intoa
curvedendhook. Movablehook slenderand sharp andabouthalfofthe length of
palpus. Mandibleas showninFigure 4.
LarvaofPseudagriondecorum 475
Thorax. — Hindwing sheaths reaching notably uptotheposterior halfofthe
fourthabdominalsegment. Proximaland distalparts offemoraandproximal part
ofthe tibiaofeachlegbanded withdarkbrown colour. Tibial comb(Fig. 5) con-
sists ofanumberofscatteredtridentateandafewunidentatesetae,whiletheinner
sideoftarsibeset withpectinate setae.
FigsI-8.LarvaofPseudagriondecorum(Rambur):(I)antenna; —(2)labiuminnerviewofprementum;
—(3)rightlabialpalpofprementum; — (4)rightmandible, dorsal view;— (5)tibialcomb andtarsi;
— (6)female gonapophysis,ventral view; — (7)malegonapophysis,ventral view; — (8)median(a)
and lateral (b)caudal lamella.
476 B. SuriBabu
Abdomen. — Femalegonapophysis (Fig. 6) comprising two pairs oflong
valvularprocesses arisingfromtheposterior margin oftheeighth abdominalseg-
mentandextending uptotheendofthetenthsegment. Innervalveis smallerthan
outer valve. Malegonapophysis (Fig. 7) consists ofapair ofequal-sized conical
processes presentonthe9th abdominalsegment.
Caudal lamellawith distinctpigmentation. Duplex nodate type, nodidistinctly
indicatedby atransverse line, apices rounded,postnodal region ofboth lamellae
possessing piliform setae. Tracheationwell developed. Thereis amediantrachea
fromwhich secondary andtertiarybranchesarise.
Median lamella(Fig. 8a), dorsal antenodal region possessing 25-28, ventral
antenodalregionbearing 6-8,andmediantracheapossessing 15-17spiniformsetae.
Laterallamella(Fig.8b),dorsalantenodalregionpossessing 5-7,ventralantenodal
region with 26-30andmediantracheapossessing 22-24spiniform setae.
NOTES ON BIOLOGY
The larvaeof P. decorumwere collectedfrom thelittoralzone ofSagar Lake,
perennial ponds andtemporary monsoonponds ofSagardistrict(M.P.), India.Lar-
vae remainattached tothe submerged vegetation. The associatedzygopteranlar-
vae were Ischnura senegalensis, I. rufostigma, Ceriagrion coromandelianum,
Enallagma parvumandCercion malayanum. Emergence occurred throughout the
yearexcept inextreme winter(water temperature 17-18°C)i.e.DecembertoFeb-
ruary. Endophytic oviposition takes place during theemergenceperiod. This is a
multivoltinespecies withfourgenerations in a yearin SagarLake.
DISCUSSION
KUMAR (1973)describedthefinalinstarlarvaofP. rubriceps and P.laidlawi.
Hereportedpalpalsetal formulaforbothP. rubricepsandP. laidlawias4+4.Palpal
setal formulaforthelarvaofP. decorumisalso4+4.Hementionedpremental setal
formulafor P. rubriceps as 1+1 and did not mentionthe numberofmicrosetae,
whichas hementionedforthelarvaofP. laidlawiis I/4+4/1.The premental setal
formulaforP. decorums 1/6+6/1.KUMAR(1973) foundlarvaeofP. rubriceps in
temporarymonsoonponds,slow-running marshy streams,amongtheaquatic veg-
etation near thebanks of large rivers and P. laidlawiin slow-running perennial
streamsandnearthebanks oflarge rivers inDehraDunValley, India.LarvaeofP.
decorum were found only in still-waterbodies like Sagar Lake,perennial ponds
and temporarymonsoonponds in Sagar district (M.P.), India.LIEFTINCK etal.
(1984) reported larvaeof P. microcephalum living in stagnantand slow-flowing
waters of various kind in Taiwan. KUMAR (1985) recorded P. rubriceps as a
multivoltinespecies withthreegenerations, whereasSURIBABU(1986)reported
P. decorum as a multivoltinespecies with four generations, two in the summer
Larva ofPseudagriondecorum 477
season, oneintherainy seasonandoneprolonged generation inthewinterseason.
It is concludedthat larvaeof Pseudagrion species flourish in a wide variety of
biotopes.
ACKNOWLEDGEMENTS
The author wishes tothank Dr B.K.SRIVASTAVA, Sagar,Indiafor criticallyreviewinganearly
draftofthe manuscript, Dr P.S.CORBET,Cornwall,U.K. for encouragement and literature,and Dr
M.PRASAD, ZoologicalSurvey ofIndia, Calcutta,forthe identification ofimagoes.
REFERENCES
CORBET, P.S., 1953.Aterminologyforthe labium oflarval Odonata. Entomologist86: 191-196.
*FRASER, F.C., 1919. DescriptionofnewIndian Odonata larvaeand exuviae. Rec. IndianMus. 16:
459-467.
FRASER,F.C., 1933. ThefaunaofBritish India, includingCeylonand Burma, Odonata, Vol. I.
Taylor&Francis, London.
KUMAR,A., 1973. Descriptionofthelastinstar larvae ofOdonata from theDehraDunValley(India)
withnotes onbiologyI.(Suborder:Zygoptera). OrientalInsects7(1): 83-118.
KUMAR,A., 1985.Areviewonthebio-ecologyoflndian dragonflies.Proc. 1stIndian Symp.Odonatol.,
pp. 73-92.
KUMAR,A.&M.PRASAD, 1981.Fieldecology, zoogeographyand taxonomyofOdonataofWest-
ernHimalaya,India. Rec. zool. Surv.India (Occ. Pap.)20: 1-118.
LIEFTINCK,M.A.,J.C. LIEN& T.C. MAA, 1984. CatalogueofTaiwanese dragonflies(Insecta:
Odonata). AsianEcol. Soc.,Taichung,Taiwan.
MacNEILL, N., 1960.Astudy ofthe caudal gillsofdragonflylarvaeofthesuborderZygoptera.Proc.
R. Irish Acad 61: 115-140.
MacNEILL,N., 1967.Pedalcombsofthelarvae ofthe dragonflies.Proc. R. Irish Acad 65(19): 391-
-406.
PRASAD, M. & R.K. VARSHNEY, 1995. A check-list ofthe Odonata ofIndiaincluding data on
larval studies. OrientalInsects 29: 385-428.
SURI BABU, B.,1986.Ecologicalstudiesonodonatelarvaeand theirrote inthebiologicalcontrol.
PhD.thesis,GourUniv.,Sagar(M.P.), India.
*ST.QUENTIN,D., 1970.Odonata ausNepal.KhumbuHimal3(3):389-411.
*=Originalpapers notconsulted.