TurkJBiol 28(2004)79-83 ©TÜB‹TAK AMorphologicalStudyoftheVenomApparatusofthespider Allopecosafabilis (Araneae,Lycosidae) Külti¤inÇAVUfiO⁄LU,MeltemMARAfi,AbdullahBAYRAM DepartmentofBiology,FacultyofArtandScience,K›r›kkaleUniversity,71450,Yahflihan,K›r›kkale-TURKEY Received:24.05.2004 Abstract: ThemorphologicalstructureofthevenomapparatusofAllopecosafabrilis wasstudiedusingscanningelectronmicroscopy (SEM).Thevenomapparatusissituatedintheprosomaandiscomposedofapairofcheliceraeandvenomglands.Eachchelicera consistsof2parts,astoutbasalpartcoveredbyhair,andamovablefang.Avenomporeissituatedonthesubterminalparto fthe fang.Justbelowthefang,thereisacheliceralgroovenexttotheteeth.Eachsideofthegrooveiscoveredwithcuticular teeth. Thevenomglandsarelargeandroughlycylindrical.Eachglandissurroundedbycompletelystriatedmuscularfibers.Thevenom producedinthevenomglandsbycontractionofthesemuscularfibersisejectedintothefangthroughacanalandthevenompo re. KeyWords: Venomgland,chelicerae,scanningelectronmicroscope, Allopecosafabrilis,venom Allopecosafabrilis (Aranea,Lycosidae)Örümce¤inin ZehirAyg›t›ÜzerineMorfolojikBirÇal›flma Özet: Buçal›flmada,Allopecosafabrilis’inzehirayg›t›n›nmorfolojikyap›s›taramal›elektronmikroskobukullan›larak(SEM)incelendi. Zehirayg›t›prosomadayerleflmiflolup,birçiftkeliservezehirbezlerindenibarettir.Herbirkeliser,k›llarlakapl›kal›nbirbazalk›s›m vehareketlibirzehirdifliolmaküzereikik›s›mdanoluflur.Zehirdiflininaltk›sm›ndabirzehiraç›kl›¤›yeral›r.Zehirdifl ininhemen alt›nda,keliserdifllerineyak›nbirkeliseralbofllukbulunmaktad›r.Bofllu¤unherbirkenar›kutikulardifllerleçevrilidir.Zeh irbezleri büyükveflekilbak›m›ndansilindiriktir.Herbirbez,tamamençizgilikaslifleriileçevrelenmifltir.Bukasliflerininkas›lma s›ylazehir bezlerindeüretilenzehir,birkanalvezehiraç›kl›¤›vas›tas›ylazehirdiflineboflalmaktad›r. AnahtarSözcükler: Zehirbezi,keliser,taramal›elektronmikroskop, Allopecosafabrilis,zehir. Introduction situatedintheanteriorportionoftheprosoma.Thesize Thespidersarethelargestgroupofvenomous andshapeofthevenomglandsaredifferentinvarious animals,representedbymorethan38,000species speciesofspiders.Thevenomglandsof Loxosceles throughouttheworld.Thirtyspiderspeciesareknownto intermedia,Loxoscelesreclusa,Heteropodavenatoria, beharmfultohumans(1,2). Lycosanarbonensis,Lampanacylindrata and Agelena limbata speciesareintheprosoma(10,12),whilethose Manyspidersaresynanthropic.Thus,human-spider ofHognatarantula andPlesiophirctuscollinus speciesare encountersarenotinfrequentandbitesoccasionallyoccur inthechelicerae(8,13,14). (3,4).Forexample,ahighnumberofbitingeventsare observedinhumanpopulationsathighratesby Inthespiderembryo,thecheliceraeliebehindthe Phoneutrianigriventer becausethosespidersinfest mouthopening.Theyarelocatedintheanteriorportion clothingandshoes(5,7).Investigationsofspiders’ oftheprosomaatthenextgrowingperiod(2).Each venomsandvenomapparatushaveincreasedrecently cheliceraconsistsof2parts,astoutbasalpartanda (2,8,9). movablevenomfang(15).Therearematuremusclesin thebasalpartandvenomglandsinsomespecies.These Thevenomapparatusissituatedintheprosomaof musclesareinvolvedinmovingthefang.Ingeneral,the spidersandconsistsofapairofvenomglandsand fangrestsinagrooveofthebasalsegmentliketheblade chelicerae.Venomisproducedinapairofvenomglands 79 AMorphologicalStudyoftheVenomApparatusoftheSpider Allopecosafabilis (Araneae,Lycosidae) ofapocketknife.Whenthespiderbites,thevenomfang movesoutofthegrooveandpenetratestheprey.Atthe sametime,thevenomisinjectedintothepreyfroma tinyopeningatthetipofthevenomfang.Bothsidesof thecheliceragroovehavecuticularteeth.Spiderswith teethinthegroovemashtheirprey.Thosewithoutteeth canonlysuckouttheirvictimsthroughthesmallbite holes(2).Thenumberandsizeofcheliceralteethare veryimportantdiagnosticcharacteristicsfortaxonomists. Spidersusetheircheliceraefordefense,seizingprey, Figure1.Thegeneralappearanceofvenomgland(vg). carryingeggcocoons,makingnoiseanddigging(2,15). Spidervenomisobtainedforuseinmedicaltreatmentof lengthoftheglandswas1.38mmandthewidthwas suchdiseasesascardiacdisturbanceandforproducing 490µm(Figure2).Theoutersurfacesoftheglandsare newantibacterialreagents(16,17).Theaimofthisstudy surroundedbynumerousspirallyarrangedstriate wastoinvestigate,themorphologicalstructureofthe muscularfibers(Figure3). venomapparatusofAllopecosafabrilis. MaterialsandMethods Twentyspecimensof Allopecosafabrilis (18)were collectedfromthetownofYahflihannearK›r›kkalein July.Thespiderswereanesthetizedwithetherandtheir venomglandsintheprosomaweredissectedundera stereomicroscope(NikonSMZ10A).Thevenomglands andcheliceraewerewashedwith0.2Msodium phosphatebuffer.Thevenomglandswerefixedin3% Figure2.Theappearanceofdiameterandlengthofvenomgland. gluteraldehydebufferat4°Cfor2h.Afterrinsingin sodiumphosphatebuffer(pH7.2)3timesfor10min, theywerefixedin1%osmiumtetroxidewiththesame bufferat4°C.Sampleswereleftinsodiumphosphate buffertoremoveosmiumtetroxide,andthenwere dehydratedinthefollowingalcoholseriesfor10min; 50%,60%,70%,80%,90%,95%and99%.After dehydration,thesamplesweretransferredtopetridishes anddriedonair.Driedsampleswereplacedonstubs, thencoatedwithgoldusingaPolaron500sputtercoater andexaminedusingascanningelectronmicroscope Figure3. Theappearanceofnumerousstriatedmuscularfibers(m) (19,21). surroundingvenomgland. Eachchelicerawasobservedtohave2parts,astout Results basalpartandamovablevenomfang(Figure4).The basalpartiscoveredbylonghairs.Eachfangisobserved Inourstudies,thevenomapparatusof Allopecosa tositinagrooveatthebaseofthechelicera.Outsidethis fabrilis consistsofapairofvenomglandsintheprosoma groove,justbelowthevenomfang,cheliceraeteethare (Figure1).In Allopecosafabrilis,thevenomglandsare reciprocallyarranged(Figure5).Theseteethareusedfor cylindrical.Theglandiscomposedofacylindricalstem holdingandcrushingprey.Thereisaporetoreleasethe andacanalconnectedit.Thecanalextendsthroughthe venomproducednearthetipofthevenomfang(Figure outersurfaceofthechelicerae.Theglandswere 6). determinedtobeonelobed(Figure1).Theaverage 80 K.ÇAVUfiO⁄LU,M.MARAfi,A.BAYRAM callinus andHognatarantula (13,22,26)theyareinthe chelicerae.Inthisstudy,thevenomglandof Allopecosa fabrilis speciesissituatedintheprosomaandextends throughtheoutsideofthecheliceraewithapairof canals. Previousstudiesshowedthatthevenomglandsvary inshapeandposition(27).Forexample,inthegenus Atypus theglandsarecomposite,in Filistata theyare multilobularandin Scytodes theyarebilobular Figure4.Theappearanceofbasalpart(bp)andvenomfang(vf). (11,28,29).Thevenomglandsof Loxoscelesreclusa and Loxoscelesintermedia arebulbous;in Heteropoda venatoria,Latrodectusmactans,Lycosaindagastrix they arecylindrical;in Ctnedusmedius theyarepurse-like;in Plesiophirctuscollinus theyarecarrot-like;andinAgelena labyrinthica theyareaubergineinshape(11,30,32).The venomglandsof Allopecosafabrllis haveonelobeasis alsothecaseinLoxoscelesintermedia,Lycosaindagastrix, Heteropodavenatoria,Loxoscelesreclusa,Cuppiennius salai,Dolomedestenebrosus,Agelenalimbata, Latrodectusmactans and Lycosanarbonensis Figure5.Theappearanceofcheliceraeteeth(ct). (11,12,23,25),andtheyarecylindrical. Thesizeofthevenomglandisnotnecessarilyrelated tothesizeofthespider.Forexample,largetheraphosid spidersandtarantulashaveverysmallglands,whereas mostsmalllabidognathspeciespossesscomparatively largeglands(1,2).Inourresearch,although Allopecosa fabrilis hasasmallbody,thesizeofitsvenomglandis ratherlarge. Themovementofthecheliceraediffersbetweenin the2largesubordersLabidognathaandOrthognatha. Thecheliceraearesituatedundertheprosomainthe Labidognathamembers.Thecheliceraeareopposite,like Figure6. Theappearanceofthepore(p)throughwhichvenomis thearmsoftheletterV.IntheOrthognathamembers, released. thecheliceraeareconnectedwiththeanteriorofthe prosomaandthevenomfangslieparalleltoeachother. Discussion Theymoveupanddown(33).Basedonitschelicera movement, Allopecosafabrilis belongstothesuborder Kaston(22)statedthatthevenomglandsofspiders Labidognatha. aregenerallyfoundintheprosoma,andrarelyinthe chelicerae,exceptforthefamiliesUloboridaeand Collatz(34)reportedthatalthoughsomespiders Holarchaidae,whichlackvenomglandsentirely.Inthe havecheliceralteeth,somedonot.Forexample,the species Loxoscelesintermedia,Ctnedusmedius,Lycosa Araneidae,Tetragnatidae,AgelenidaeandAvucularidae indagastrix,Heteropodavenatoria,Loxoscelesreclusa, membershavecheliceraecoveredwithlargeteeth, Cuppienniussalai,Dolomedestenebrosus,Agelena whereastheTheridiidaeandThomisidaemembersdonot limbata,Latrodectusmactans and Lycosanarbonensis haveteeth.Intermsofthesizeoftheteeth, Allopecosa narbonensis (11,12,23,25)itwasreportedthatthe fabrilis issimilartotheAraneidae,Tetragnatidae, venomglandsareintheprosoma,andin Plesiophirctus AgelenidaeandAvicularidaemembers. 81 AMorphologicalStudyoftheVenomApparatusoftheSpider Allopecosafabilis (Araneae,Lycosidae) Studiesshowedthatthenumberofchelicerateeth Correspondingauthor: playsanimportantroleintaxonomy.Forexample,while Külti¤inÇAVUfiO⁄LU thereisonlyonetoothattheposteriorofthechelicera K›r›kkaleUniversity,FacultyofArtandScience, toothgrooveinthefemale Enoplognatha (Theriididae), DepartmentofBiology, thereare6-7largeteethinthe Tapinopa (Linyphiidae) (22).Fourpairsofteetharepresentonthecheliceraeof 71450,Yahflihan,K›r›kkale-TURKEY Allopecosafabrilis inanoppositearrangement.Inthis E-mail:[email protected] study,itwasdeterminedthatthemorphological structureofthevenomapparatusof Allopecosafabrilis resemblesthoseofrelatedspecies,buttherearesome smalldifferences. 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