Theisolatin geffec to fgreenhouse so narthropo dpest san dit ssignificanc efo rintegrate d pestmanagemen t
000003 1' J. van den Bos
Laboratory of Entomology, Agricultural University, Wageningen
The isolating effect of greenhouses on arthropod pests and its significance for integrated pest management: a case-study on Clepsis spectrana (Lepidoptera: Tortricidae)
Pudoc Wageningen 1983
UW>.Zobo 39f c CIP-GEGEVENS
Bos, J. van den
The isolating effect of greenhouses on arthropod pests and its significance for integrated pest management: a case-study on Clepsis spectrana (Lepidoptera: Tortricidae) / J. van den Bos. -Wageningen : Pudoc. - 111. - (Agricultural research reports;924) . Ook verschenen alsproefschrif t Wageningen. -Me t samenvatting in het Nederlands. - Met lit. opg. ISBN 90-220-0839-8 SISO 632.6 UDC 632.6/.7 Trefw.: planteziekten
ISBN 90 220 0839 8
The author graduated on 28 January 1983 as Doctor in de Landbouwwetenschappen at the Agricultural University, Wageningen, the Netherlands, on a thesis with a similar title and the same contents.
(C)Centr e for Agricultural Publishing and Documentation, Wageningen, 1983.
No part of this publication, apart from abstract, bibliographic data and brief quotations embodied in critical reviews, may be reproduced, re-recorded or published in any form including print, photocopy, microfilm, electronic or electromagnetic record without written permission from the publisher Pudoc, P.O. Box 4, 6700 AA Wageningen, Netherlands. Abstract
Bos, J. vanden , 1983.Th e isolating effect of greenhouses on arthropod pests and its significance for integrated pest management: A case study on Clepsis spectrana (Lepidoptera: Tortricidae). Agric. Res. Rep. (Versl. landbouwk. Onderz.) 924, ISBN 90 220083 9 8, (vii) + 92 p., 19 figs, 4 photographs, 33 tables, 159 refs, Eng. and Dutch summaries. Also: Doctoral thesis,Wageningen .
Clepsis spectrana is a tortricid that is indigenous to the Netherlands. It is a pest in several greenhouse cultures there. The greenhouse populations of this species have adapted to their environment,whic h has no cold period,b y losing their ability to enter diapause. Evenwhe n reared under outdoor conditions,n o diapause is induced in the greenhouse type. The field type enters a photoperiodically induced larval diapause, evenwhe n reared under greenhouse conditions. The instar inwhic h diapause is entered depends on the photoperiod. The duration of diapause ina greenhouse canb e shortened rapidly by selection. Reproductive isolation between the field type and the greenhouse type does not appear inan y form. The glass walls and roofs to a large extent limit free introgression of the field type into resident greenhouse populations by prohibiting immigrations into the greenhouse and by creating a different environment, inwhic h year-round development of the greenhouse type is possible. Based on this research, theperspective s of different non-chemical control methods of the greenhouse populations of C. spectrana are discussed.
Free descriptors: greenhouse cultures, Tortricidae, growth & development, diapause, sex pheromone, calling behaviour, pheromonal trapping, mating preference, allozymes, inter- strain crossings, non-chemical control. Contents
1 Introduction 1 1.1 The Clepsis spectrana problem 1 1.2 Rosecultur eunde rglas si nth eNetherland s 2 1.3 Thegreenhous ea sa necologica l island 2 1.4 Purposeo fresearc h 5
2 Literature 8 2.1 Morphologicalaspect s 8 2.2 Bionomics 8 2.3 Hostplan trang e 10 2.4 Distribution 13
3 Materials and methods 15 3.1 Technical 15 3.2 Experimental 16
4 Non-diapause development 17 4.1 Variabilityi nth enumbe ro flarva l instars 17 4.2 Rateo fdevelopmen ta tdifferen ttemperature s 22 4.3 Mortalityan dpupa lbod ywidt ha tdifferen ttemperature s 27
5 Diapause in field populations 31 5.1 Photoperiodicrespons ecurve s 31 5.2 Outdoorexperiment s 32 5.2.1 Inductiono fdiapaus e 33 5.2.2 Resumptiono fmoultin g insprin g 35 5.2.3 Post-diapausedevelopmen t 35 •5.3 Influenceo ftemperatur ean dphotoperio d onth einsta ri nwhic h diapause isentere d 37 5.4 Discussion 39
6 Photoperiodic response in greenhouse populations 40 6.1 Laboratoryexperiment s 40 6.2 Outdoorexperiment s 40 6.3 Discussion 48 7 Diapause of a field strain under greenhouse conditions 50 7.1 Maintenancean dterminatio no fdiapaus ewithou ta perio d ofchillin g 50 7.1.1 Greenhouseexperiment s 50 7.1.2 Laboratoryexperiment s 52 7.2 Heredityo fdevelopmen tduratio ni ndiapausin glarva e 54
8 Female sex pheromone 56 8.1 Compositiono fth efemal ese xpheromon e 56 8.2 Callingbehaviou ro fvirgi nfemale si nrelatio nt oth e light-darkcycl e 57 8.3 Pheromonaltrappin g 58 8.3.1 Outdoortrial s 59 8.3.2 Greenhousetrial s 60 8.4 Matingpreferenc e 62
9 Hybridization 64 9.1 Allozymefrequencie s 64 9.2 Crossingexperiment s 66 9.2.1 F1crosse s 67 9.2.2 F2crosse s 68 9.2.3 Discussion 69
9.3 Photoperiodicrespons ei nF 1hybrid s 70
10 Discussion 72
11 Prospects of non-chemical control of greenhouse populations 11
Summary 80
Samenvatting 83
Acknowledgements 86
References 87 1 Introduction
1.1TH E CLEPSIS SPECTRANA PROBLEM
Theleafrolle r Clepsis spectrana Treitschke (Lepidoptera:Tortricidae ,Tortricinae ) (syn.: Cacoecia costana F., Tortrix costana Schiff.)i sindigenou st oth eNetherlands .I n thefield ,i ti sbivoltin e (GraafBentinc k& Diakonof f1968) .Th esecon dgeneratio n hibernatesi nth elarva lstag e (Balachowsky1966) .I nth eope nair ,th elarva eonl y occasionallycaus edamag e (Alford1976) . InDutc hgreenhouses ,however ,th especie si sa n importantsourc eo feconomi cdamage .I ngreenhous erose s (Rosa hybrida) iti seve nth e mostimportan tarthropo dpes t (Vand eVri e 1976). C. spectrana isreporte dt odamag e greenhouserose si nothe rcountries :Denmar k (Pape 1964),German y (Feiter& Hensele r 1971), andEnglan d (Burges& Jarret t 1978),bu ti ncontras tt oth esituatio ni nth eNetherlands , inthes ecountrie si ti sconsidere donl ya mino rpest .
Ingreenhouse si nth eNetherlands ,growt han dreproductio no f C. spectrana continue withoutdiapaus edurin gwinter .Thi sha sbee nobserve do nroses , Gerbera, Alstvoemeria, andBromeliacea e (Vand eVri e1978 ,an dpers .comm.) .Thi sma yb edu et oa geneti c adaptationt oth eenvironmenta lcondition si nthes eheate dgreenhouses ,wher eth e differencebetwee nsumme ran dwinte rtemperature si ssmall ,an dsuitabl efoo di savailabl e allyea rround .Artificia lilluminatio ni sno tuse di nthes egreenhouses ,thu sth eda y lengthi salway sth esam ea soutdoors . Traps,baite dwit hsyntheti cse xpheromone ,tha tar eeffectiv efo rcapturin gmale si n thefiel d (Minkse tal .1973 )alway sgiv ever ypoo rresult si ngreenhouse s (Vand eVri e 1976).Thu sth epheromon erelease db yfemale soccurrin gi ngreenhouse sma yb edifferent .
Thesephenomen agiv eris et oth ehypothesi stha ta separat egreenhous etyp eo f C. spectrana exists.Whethe rthi styp eca nmaintai nitsel fdepend so nth edegre eo f isolationo fth efiel dpopulation san dth egreenhous epopulations .
Dutchgreenhous epopulation so f C. spectrana haveacquire dreduce dsensitivit yt o organophosphoruscompound san dtrichlörpho n (M.va nd eVrie ,pers .comm.) .Th e uninterrupteddevelopmen tan doverlappin ggeneration si ngreenhouse snecessitat eregula r treatmentswit hinsecticides . Anothermajo rpes ti ngreenhous eroses ,th etwo-spotte dspide rmite , letranychus urticae (Koch),ca nb econtrolle deffectivel y inros ehouse susin gphytoseii dpredator s (M.va nd eVrie ,pers .comm. )bu tbiologica lcontro lo f T. urticae isonl yfeasibl ei f C. spectrana iscontrolle d ina wa ytha tdoe sno taffec tth epredator ymites . 1.2ROS ECULTUR EUNDE RGLAS SI NTH ENETHERLAND S
Rosecultur eunde rglas si nth eNetherland sstarte da tth ebeginnin g ofthi scentur y (Augustijn 1953).Unti lth een do fth eSecon dhbrl dWar ,cultur ewa sconcentrate d inth e arearoun dAalsmeer .Sinc ethe nth eregio nroun dNaaldwij kha sals obecom eimportant , althoughth eros egraft sstil lcom efro mAalsmee r (M.va nd eVrie ,pers .connu.) . Everyphas eo fth emoder ncultur eo fgreenhous erose stake splac eunde rglass .Ne w graftsar eproduce dunde rglas s (Gclein 1965),an dne wcultivar sar edevelope di n propagatinghouses ,mainl yi nth eNetherlands ,Trance ,England ,an dGerman y (Van Marsbergen 1968) . Greenhouserose sar ecultivate dal lth eyea rround .Sometime sth erose sar e"rested " for4- 6week sdurin gwinter ,bu tneve ri nal lcompartment so fon eros ehous ea tth esam e time (Gelein 1965).Durin ga restin gperio da compartmen ti skep tfros tfre eonl y (W.va n Marsbergen,pers .comm.) .Th efirs tcultiva rsuite dfo rcultivatio nwithou tan yrestin g period,"Bette rTimes" ,wa sintroduce d inth esprin go f193 6 (Anonymus 1936).However , continuouscultivatio nonl ybecam ecustomar ylon gafte rth eSecon dWorl dWa r (W.va n Marsbergen,pers .comm.) .
1.3TH EGREENHOUS EA SA NECOLOGICA LISLAN D
Theecologica l conditionsi ngreenhouse sdiffe ri nman yrespect sfro mthos e inth e openfield .Th ecrop san dth eclimat ear edifferent ,an da fre eexchang ebetwee nth efaun a ofth egreenhouse san dth eope nai ri shampere db y theglas swall san droofs .
Themea ndail ytemperatur e inheate d greenhouses isalway shighe rtha noutdoors ,i n rosehouse si ti sabou t2 0C i nsumme ran d1 8C i nwinter ,whil eoutdoor si nth e Netherlandsi trange sfro mabou t 17C i nJul yt o2 G i nJanuar y (.Anonymus1982) . Thedifferenc e intemperatur e inan doutsid ea greenhous e isalway sgreates taroun d 1400h ,eve nwhe nth esk y iscloud y (Hiller 1956).Durin ga ho tsumme rday ,th esurfac e temperatureo fleave sperpendicula r toth esun' sradiatio nca nris et o35-3 7C i n aventilate dgreenhous e (Kanthak 1973). Ifthes etemperature slas tfo ran ylenght ho f time,the yar eletha lt oman yarthropo d species.I na neggplan tnurser y inth eSout ho f Franceth enumbe ro fth epeach-potat o aphid, Myzus versicae (Sulz.),wa sconsiderabl y reduced,withou tdamagin g thecrop ,simpl yb yclosin gth eventilator sfo rsom ehour sa t middayi nApril .Th eai rtemperatur eros eu pt o45°C ,whil e therelativ ehumidit y remaineda t70-80 % (Rabasse 1976). Insummer ,greenhouse sar eneve rheate ddurin gth eday ,onl y incidentallya tnight , tomaintai nth einsid etemperatur eabov ea certai nlevel .Greenhouse sar eheate d continuously inwinter .Sola rradiatio nonl yprovide spar to fth erequire denergy .A tnigh t thetemperatur e ismaintaine d ata certai nminimu m level,dependin g onth ecro p (Kanthak 1973).A commo nminimu mnigh ttemperatur e is1 5C . Ingreenhouse sth erelativ ehumidit yi susuall y lowertha ni ti soutside .Th evapou r pressure ina ventilate d greenhousean doutdoor s isabou tth esame ,bu tbecaus eo fth e highertemperature ,relativ eai rhumidit yi slowe ri nth egreenhous e (King 1970). Ina closed,heate dgreenhouse ,relativ ehumidit yi sals olowe rtha noutside .Th eevaporatio n rateo fth esoi lan dplant si susuall yno tsufficien tt okee pi thighe rtha n50% .Th e relativehumidit yi ssimila rt otha toutdoor swhe nheatin g iscu tdown ,an dma y occasionallyapproac h 100% (Kanthak 1973).Th ehumidit yi ssometime sincrease d artificially,dependin go nth erequirement so fth ecrop . Thespectra lcompositio no fth eradiatio ninsid egreenhouse sdiffer sfro mtha t outdoors.Th eglas swall stransmi tabou t90 %o fth eirradiatio no fwavelength sfro m 0.4 to2. 7pm ,wherea sshort-wav eultra-viole tligh ti salmos tcompletel yabsorbe d (Mackroth 1971).Th eabsenc eo fultra-viole tradiatio nfacilitate sth eus eo fbaculoviruse sa s controlagent sagains tnoxiou sinsect si ngreenhous eculture s (Vlake tal .1982) .
Theisolatin geffec to fgreenhouse so narthropo dpest scontribute st oth e effectivenesso fcontro lmeasures ,bu tals ot oth edevelopmen tan dmaintenanc eo f pesticideresistanc ei ngreenhouses .Becaus eo fth especia lcondition smentione dabove ,a specificfaun aexist si ngreenhouses ,an dth eus eo fexoti cpredator san dparasite sfo r biologicalcontro li spossible .Th egreenhous eenvironmen tact sa sa "sieve" ,onl yallowin g suchspecie st othriv etha tar eadapte dt othes econditions .
Sometimesthes ear eexoti cspecie stha tcanno tthriv ei nth eope ni nth eDutc h climate.Som eexample so feconomi cimportanc eare : a.Th ebee tarm yworm , Spodoptera exigua Hb.(Lepidoptera :Noctuidae) ,wa sprobabl y introducedfro mFlorid aint oDutc hgreenhouse so ninfeste d Chrysanthemum cuttings.A t present,i ti sa seriou spes ti nth eDutc hfloriculture ,especiall yo n Chrysanthemum and Gerbera (Vand eVri e 1977).Th especie sha sn odiapaus e (Fye& Carranz a 1973). Inth eNetherlands ,migrant sfro mth eMediterranea nare aar eoccasionall yfoun d outdoors (Lempke1963) ,havin gbee ntransporte dpassivel yi natmospheri cdepression s (French 1969).Sometime sthe yreproduce ,bu tth epopulation sinvariabl yd ono tsurviv e theDutc hwinte r (Lempke 1963). b.Th eleafmine r Lyriomyza trifolii Burgess (Diptera:Agromyzidae) ,i sa pes to ngreenhous e Chrysanthemum inNort hAmeric a (Spencer 1973),an do nceler yi nFlorid a(Spence r 1982). Itha sbee nobserve drecentl yi ngreenhouse s inth eNetherlands ,wher ei tcause s economicdamag et o Chrysanthemum, Gerbera and Gypsophila. Itha sals obee nobserve d ontomatoe s (M.va nd eVrie ,pers .comm.) .Th ecentr eo fdistributio no f L. trifolii atpresen tappear st ob eFlorid a (Spencer 1973).Th especie si sno tknow nt oente r diapause.I tca nsurviv ei narea swher eth ewinter sar einvariabl ysevere ,wit hsub zerotemperature sfo rextende dperiods ,bu ti tonl ythrive si nsubtropica lan dtropica l conditions.I nWester nEurop ether ei slittl elikelihoo do fi teve rbecomin g establisheda sa pes toutsid egreenhouse s (Spencer 1982). acosmopolita nspecie so fAmerica norigin ,an da well-know npes tinsec to na wid e acosmopoliti cspecie so fAmerica norigin ,an da well-know npes tinsec to na wid e varietyo fgreenhous ecrops .I ti sno tknow nt oente rdiapause .I nth eope ni nth e Netherlands,th especie si soccasionall yfoun doverwinterin go nfrost-hard yplant s insheltere dplaces .I ti sstil lno tclea rt owha tdegre eth especie sca nsurviv eth e Dutchwinte r (Binke tal . H
Indigenous speciesma ypenetrat egreenhous ecultures ,bu ti norde rt opas sth e "sieve"the yhav et oadap tt ogreenhous econditions . Anexampl ei sth etwo-spotte d spidermite , Tetranychus urtiaae (Koch). Itsdiapaus e isinduce db yshor tdaylength .A t2 0C ,a regim eo fshor tphotoperiod s evokesonl ya smallpercentag eo fdiapaus eform si nros ehous epopulations ,whil eloca lpopulation sfro m wildplant scompletel yente rdiapaus eunde rthes econditions .Thi sgeneti cadaptatio n enablesyear-roun ddevelopmen to fth emite si nheate dgreenhouses .Ros ehous epopulation s areresistan tt oorganophosphoru s compounds,wherea s localpopulation so nwil dplant sar e not. (Note:diapaus ean dresistanc ear eno tgeneticall y linked in T. urtiaae (Helle 1962)). Resistance tocompound stha twer eno tuse dafte r 1966wa sstil lpresen ti n1973 ,roughl y10 0 generations later.Thi sdemonstrate stha tros ehous epopulation so f T. urtiaae maintain themselvesfo rman yyear s inspit eo fintensiv echemica lcontro l (Overmeere tal . 1980). Thenatura lenemie so f T. urtiaae thatar efoun doutdoor sd ono toccu ri ngreenhouse s (M.va nd eVrie ,pers .comm.) . T. urtiaae ingreenhous ecucumber si seffectivel ycontrolle d byth ereleas eo fexoti cpredators , Phytoseiulus -persimilis A.-H. (Woets 1976).Geneti c exchangebetwee nfiel dan dros ehous epopulation so f T. urtiaae islimited ,fo rsevera l reasons (Overmeere tal . 1980): (a)th egreenhous eenvironmen thold sa necologica lparado x- shortday si nth eautum ninduc ediapause ,bu tth eperio do fchillin grequire dfo rdiapaus e terminationi sabsen ti nheate dgreenhouses ;immigran tmite sfro moutsid ear etrappe db y thepeculia renvironment , (b)Hybri dfemale sexhibi tpartia lsterility , (c)Loca lmite s fromwil dplant sar ever ysensitiv et oth ecurren tacaricides ,an d (d)immigratio no f localmite sfro mth efiel dma yb erestricted . Anotherexampl e isth epeach-potat oaphid , Myzus persiaae (Sulz.). Iti susuall y heteroecious,bu tanholocycli cform sar eofte nfoun d inWester nEurope .Thes eform s continuereproducin gb yparthenogenesi san dsurviv eth ewinte ro nsecondar yhosts ,eithe r inth efiel do nwinter-standin gcrops ,suc ha skal eo rcabbage ,o ri nmor esheltere dplaces , sucha sgreenhouse s ifsuitabl ehos tplant sar epresent .Simila rlif ecycles ,i nwhic h variousoverwinterin g strategiescoexist ,ma yappl yt oa numbe ro fothe r indigenousaphi d species (Blackman 1974).Wyat t (196S,1966 )consider stha tpopulation so f M. persiaae in Chrysanthemum nurseriesar estrongl yisolated .Th esam epatter no finsecticid eresistanc e wasfoun di ncolonie sfro msi xdifferen tnurseries ,an dfro ma cuttin gproducer ,i nth e Southo fEngland .Probabl ya singl eresistan tclone ,selecte db yth eintens einsecticid e programmesuse db yth ecuttin gproducers ,becam edistribute d throughoutth eEnglis h Chrysanthemum industry.Mos tcommercia lchrysanthemum sar eraise dfro mcutting ssupplie d bya smal lnumbe ro fspecialis tpropagators .
Boettger (1929)investigate dth efaun ao fdifferen thothouse s inBerlin .Beside s indigenousspecies ,h efoun dman yspecie so fnearctic ,Mediterranea no rtropical / subtropicalorigin .I nth eSout ho fItaly ,greenhous efauna smainl yconsis to findigenou s Mediterraneanspecie s (Boettger 1930).Th eadventiv efaun ai nheate dgreenhouse s inth e Netherlandsha sbee nsurveye db yMeeus e (1943),Va nOostro m (1944),Holthui s (1945), Meeuse& Huber t (1949),an dVa nde rHamme n (1949,1969) .
Arthropodsfro mth eope nfiel dca nente rgreenhouse si ndifferen tways : a.Winge dadult sma yente rthroug hth eventilators ,o rthroug hth edoor swhe nthe yar e leftopen .Th elikelihoo do fsuc ha neven tdepend so nth especies .Th echanc ema yb e highestamon ginsect stha tfl yi nlarg enumber san dar etransporte dpassivel yb y winddurin gth eday ,whe ngreenhouse sar eventilate d (e.g.aphids ,Thysanoptera) ,an d amongothe rkind so finsect swit hstron gfligh tactivity ,suc ha sbee san d bumblebees. DeBrouwe r& Va nDors t (1975)stat etha taphid so fth e Aphis gossypii (Glover) groupca ncoloniz egreenhous ecucumber sb yenterin gth ehouse sthroug hth eventilators .I n thepast ,cucumbe rgrower shav eha dt oprotec tthei rcro pagains tbee sb yscreenin gth e ventilatorswit hgauze ,t opreven tpollinatio no fth ecro p (DeBrouwe r& Va nDors t 1975). b.Wingles sarthropod sma ypenetrat egreenhouse sb yaeria ltransport .Bare l(1973 )state s thatyoun glarva eo fth esummer-frui ttortri xmoth , Adoxophyes orana (F.v.R.),floatin g inth eai ro nthei rthreads ,ma yb etransporte db ywind ,an dtha tthi smechanis mi s importantfo rth edispersa lo fth especies .Thi sma yals oappl yt oothe rtortricids . Vand eVri ee tal . (1972)hav ereviewe dth eliteratur eo nair-born etranspor to f tetranychidmites . c.Othe rspecies ,suc ha spredator ymites ,an dspecie stha tliv eunde rstones ,o nol dwalls , andtha tlik et openetrat ecellar s (Boettger 1932),ma ywal kint ogreenhouses ,fo r examplethroug hcrevice sbetwee nth epane so rthroug hth eventilators .Othe rspecie sma y penetratethroug hth esoil . d.Arthropod s (e.g.egg san dyoun glarvae ,tha tca neasil yb eoverlooked )ma yb ebrough t intogreenhouse swit hplan tmaterial ,tool so rmould .Specie sfro mforeig ncountrie sma y gainentr yt ogreenhouse so nplan tmaterial .
Migrationsfro mgreenhous et ogreenhous ema yoccu ri nth efollowin gways : a.Transpor twit hplan tmateria lfro mothe rnurseries ,notabl ypropagatin ghouses . b.Smal lleaf-dwellin g speciestha treadil yattac ht oclothin g (e.g.mites ,Thysanoptera , aphids,an dwhiteflie sma yals ob etransporte db yhumans . c.Occasionally ,activ emigratio nfro mgreenhous et ogreenhous ema yoccur ,sometime swit h anintermediat egeneratio ni nth eope nair . Lyviomyza tvifolii hasbee nfoun do nbeans , and Spodoptera exigua onbee tclos et oinfeste dgreenhouse s (M.va nd eVrie ,pers .comm.) .
1.4PURPOS EO FRESEARC H
Researchwa scarrie dou tt ofin danswer st oth efollowin gquestions : (a)doe sa separat egreenhous etyp eo f C. spectrana exist,an dwha tar eth echaracteristic s ofthi stype ? (b)Wha tmechanism sgover nth eisolatio no ffiel dan dgreenhous epopulations ? (c)T owha texten tar ethes emechanism so fimportanc efo rth enon-chemica lcontro lo f C. spectrana populationsi ngreenhouses ? Photo 1. Clepsis speatrana, femalemot ho na ros eleaf .Win gspa nabou t 20mm .Th e speciesdoe sno tsho wa pronounce d sexual dimorphism.
Photo 2.Lea fdamag e togreenhous e roses,cause db y Clepsis speatrana. Theresearc hcomprise dinvestigatio no fth efollowing discriminatin gpropertie so f fieldan dgreenhous estrain s (theter m"strain "refer st oth ecommo norigi nO fspecimen s rearedi nth elaboratory) :non-diapaus edevelopmen t (Chapter 4); induction,maintenanc ean d terminationo fdiapaus eunde rbot houtdoo ran dgreenhous econdition s (Chapters5-7) ; femalese xpheromon ean dsexua lbehaviou r (Chapter 8); andgeneti csimilarit y(allozym e frequencies,crossin gexperiments )(Chapte r9) . 2 Literature
2.1MORPHOLOGICA LASPECT S
Themorpholog yo f C. spectrana hasbee ndescribe db yKenne l (1910),Swatsche k (1958), Balachowsky (1966),Graa fBentinc k& Diakonof f (1968),Bradle ye tal . (1973),Razowsk i (1979),an dman yothers . Theforewin gcoloratio no fth eadul t (photo1 )i sextremel yvariable .Th egroun d colourvarie sfro mwhitis hochreou st oyellowis ho rreddis hbrown ,an dth ebrow n irrorationma yb eeithe robsolescen to rheavy .Th eforewing susuall yhav edar kbrow n markings,bu tmonochrom especimen sals ooccur .Thes evariation shav eals obee nobserve di n fieldpopulation so n Urtica dioica, andi ngreenhous epopulation so nrose san d Gerbera in theNetherlands . Thelarva eals ovar yi ncolour .Kenne l (1910)report stha tthe yar ebrown-gree n withwhitis hpinacul aan dblac khea dan dplates .Accordin gt oBradle ye tal . (1973)the yar e greyisholive-gree nvaryin gt obrown ,pale rventrally ,wit ha whitis hsubspiracula rline , cream-whitepinacul aan da concolorou sblac kirrorate dana lplate .Th ehea dan dth e prothoracicplat ear eblac kt oblackis hbrown .Accordin gt oSwatsche k (1958)th elarva e arebrow nwit hblack-brow nplate san dhead .I nbot hfiel dan dgreenhous epopulation si n theNetherlands ,i twa sobserve dtha tth ecolou ro fth elarva labdome nvarie sfro m brown-greent obrown . Wit (1978)compare da populatio no n Urtica dioica nearWageninge nwit ha non - diapausingpopulatio nfro ma ros ehous ei nAalsmeer .H einvestigate dth emorpholog yo f thelarvae ,pupa ean dmoths ,th eanatom yo fth eadul tgenitalia ,an dth echaetotax yo f thelarvae .H ecoul dno tfin dan ydifferenc ebetwee nth etw opopulations .
2.2BIONOMIC S
Theegg sar edeposite d insmal lbatches ,covere dwit ha gelatinou s layer,o nth e hostplan t (Bradleye tal . 1973).Specie so fth egenu s Clepsis (Guenée)usuall yla ythei r eggso nth euppe rsid eo fth eleave s (preferablyo na majo rlea fvei no rothe rsmal l depressionsi nth eepidermis) ,o nth estem so ro nth ebar k (Razowski 1979).Thi sha sbee n observedi nbot hfiel dan dgreenhous epopulation so f C. spectrana: inth efiel do n stingingnettle s (Urtica dioica L.);an di ngreenhouse so nrose s (Burges& Jarret t1978 ; ownobservation) , Gerbera, and Cyclamen. Theeg gmasse sconsis to freticulat eova legg s thatoverla plik eshingle so fa roof .
Inth efield ,th elarva efee do nth eleaves ,th elea fstems ,th eshoots ,th e Photo3 .Flowe rbu do fgreenhous erose stha tha sbee nattacke db y Clepsis gpeatrana.
Photo4 . Clepsis speetrana larva.I tha s spunth eto pleave so f shoottogether . flowers,th eflowe rbuds ,th efruits ,an dth eseed so fth ehos tplan t (Spuler1910 ; Schütze 1931;Graa fBentinc k& Diakonof f 1968;Verno n1971 ;Bradle ye tal .1973 ; Razowski 1979). Larvalfeedin gbehaviou ro ngreenhous erose si sa sfollows .Th eyoun g larvaenibbl eth esuperficia ltissue sa tth ebotto mo fth eleaves .Olde rlarva efee do n theleave san dth elea fstems .The yals oburro wi nth estems ,flowe rbuds ,an dflowers , causingsever eeconomi cdamag e (Vand eVri e1978 ) (photos 2an d3) . Theolde rlarva ebuil dshelter sb yspinnin gth eleave so rth eflower so fth ehos t planttogethe r (Bradleye tal . 1973)(phot o4) .The yd othi smor etha nonc edurin g theirdevelopmen t (Burges& Jarret t 1978;ow nobservation) .Whe nyoun glarva ear e disturbed,the ydro po nsilke nstrand so nwhic hthe yma yb ecarrie dabou ti nth e surroundingsb yai rcurrents .Olde rlarvae ,whe ndisturbed ,ca nescap eabruptl yfro mthei r webbing,wit htwistin gmovement s (Balachowsky1966 ;Va nd eVri e 1978).Ros egrower si nth e arearoun dAalsmee rcal ltortricid so nthei rcro p"rozenijltjes" .Thi snam erefer st oth e characteristiclarva lescap ebehaviour . Pupationtake splac ewithi nth elarva lhabitatio n (Balachowsky 1966;Bradle ye tal . 1973; Vand eVri e 1978).Thi sha sbee nobserve ddurin gou rinvestigation so n Urtica dioioa inth efield ,an do nroses , Gerbera and Cyclamen ingreenhouse s inth e Netherlands.
Femalemoth sd ono tnee dan yfoo dfo rthei roviposition .Whe nnewl yemerge dmale s andfemale sar ebrough ttogethe ra troo mtemperature ,ovipositio nusuall ystart sdurin g thesecon do rthir dnight .Mos to fth eegg sar elai dwithi nthre enight s (Kuperus 1977).
Likeal lspecie so fth egenu s Clepsis (Guenée), C. spectrana overwinters inth e larvalstag e (Razowski 1979).Hibernatio nstart swhe nth elarva ehav ecomplete dabou t halfthei rdevelopmen t (Balachowsky 1966).Th ehibernacul aar emad ei nsheltere dplaces , ato rclos et oth ehos tplan t (Picard 1912;Va nRosse me tal . 1971;Verno n 1971).
Thefirs tfligh ti nth eNetherland susuall yoccur si nMa yan dJune ,an dth esecon d inAugus tan dSeptembe r (GraafBentinc k& Diakonof f 1968).Ligh ttra precord s fromth e experimentalorchar d"Schuilenburg " (from197 5unti l 1981),b yD eJon g (1966),an dA . vanFrankenhuyze n (from195 4t o1958 ,a t10-1 2differen t locations),indicat etha tth e firstfligh tusuall ystart si nth esecon dhal fo fMay. -Sometimes ,i na col dspring ,th e earliestmoth sonl yappea ri nth efirs twee ko fJune .Th efirs tan dth esecon dfligh t sometimesoverlap .Fligh tactivit ythe ncontinue sthroughou tJuly .Th esecon dfligh t sometimeslast sunti lmid-October .D eBrouwe r& Lempk e (1973)eve ncaugh t C. spectrana mothsa slat ea sth e2 5October .Durin gth esecon dfligh tperio dmor emoth sar ealway s caughttha ndurin gth efirst .
2.3HOS TPLAN TRANG E
Thespecie sha sbee nrecorde do nth efollowin gplants :
10 Wild planta
Fam.AQUIFOLIACEAE : Ilex aquifolium (Bradleye tal . 1973).Farn .BORAGINACEAE : Symphytum spp. (Schütze 1931).Fam .CCMPOSITAE : Artemisia maritima (Bradleye tal . 1973); Aster tripolium (Bradleye tal . 1973); Centaurea spp. (Balachowsky 1966); Cirsium arvense (collectionsMuseu mo fNatura lHistory ,Leiden) . Fam.CRUCIFERAE : Lepidium sp. (collectionsMuseu m ofNatura lHistory ,Leiden) ; nasturtium palustre (Schütze 1931); Rorippa spp. (Kostiuk1980) .Fam .CUPULIFERAE : Quercus sp. (Bradleye tal . 1973).Fam . CYPERAŒAE: Scirpus laaustris (Schütze 1931).Fam .EQUISETACEAE : Equisetum spp. (stemtop ) (Kostiuk 1980).Fam .EUPHORBIAŒAE : Euphorbia palustris (Schütze 1931).Fam .GRAMINEAE : Arundo phragmites (Balachowsky 1966); Glyceria speatabilis (Schütze 1931); Glyaeria maxima (Kostiuk 1980);gras s (Stange 1899); Phragmites spp. (Schütze 1931).Fam . IRIDACEAE: Iris pseudacorus (Schütze 1931).Fam .ONAGRACEAE : Epilobium angustifolium (Balachowsky 1966); Epilobium hirsutum (Schütze 1931); Epilobium palustre (Balachowsky 1966).Fam .PAPILIONACEAE : Medioago spp. (Kostiuk 1980); Trifolium spp. (Kostiuk 1980). Fam.PLUMBAGINACEAE : Limonium vulgare (Bradleye tal . 1973).Fam .POLYGONACEAE :Rumex spp. (Balachowsky 1966).Fam .POMACEAE : Crataegus sp. (Vand eVri e 1978).Fam . PRIMULACEAE: Lysimachia spp. (Stange 1899).Fam .ROSACEAE : Comarum palustre (Balachowsky 1966); Filipendula ulmaria (Kostiuk 1980); Potentilla spp. (Bradleye tal' .1973) ; Kubus sp. (Vand eVri e 1978); Spirea spp. (Schütze 1931).Fam .SALICACEAE : Salix sp.(Va n Poeteren 1941).Fam .UMBELLIFERAE : Ciauta virosa (Balachowsky 1966); Pastinaca sativa (collectionsMuseu mo fNatura lHistory ,Leiden) . Fam.URTICACEAE : Urtica dioioa (own observation); Urtica spp. (Balachowsky 1966).Fa mVALERIANACEAE : Valeriana sp. (collectionsMuseu m ofNatura lHistory ,Leiden) . Fam.VIOLACEAE : Viola spp.(Balachowsk y 1966).
Cultivated plants in the open air
Fam.CARYOPHYLLACEAE :carnatio n (Dianthus barbatus and D. caryophyllus) inth eope nai r inGerman y (Hahn1978) ,an di nth eNetherland s (VanFrankenhuyze n& D eJon g 1964).Fam . CHENOPODIACEAE:suga rbee t (Beta vulgaris) inth eNetherland s (VanRosse me tal . 1971). Fam.CONIFERAE : larch (Larix sp.)i nGerman y (Bodenstein 1955); Pinus radiata seedlings inEnglan d (Alford 1976).Fam .CRUCIFERAE : rapeseed (Brassica napus) inth eNetherland s (VanRosse m 1950);cauliflowe r (Brassica oleraced) inth eNetherland s (VanPoetere n 1930); sprouts (Brassica oleraced) inth eNetherland s (DeBrouwe r 1970).Fam .IRIDACEAE : Iris sp. inth eope nai ri nth eNetherland s (VanFrankenhuyze n& D eJon g 1964).Fam .LILIACEAE : onion (Allium cepa) inEnglan d (Alford 1976); Lilium candidum (Balachowsky 1966).Fam . PAPILIONACEAE:lucern e (Medioago sativa) inth eNetherland s (VanPoetere n 1935);pol e beans (Phaseolus vulgaris) inth eNetherland s (VanFrankenhuyze n& D eJon g 1964);broa d beans (Vicia faba) inth eNetherland s (filesPlan tProtectio nService ,Wageningen) .Fam . POLYGONACEAE:rhubar b (Rheumsp. )i nEnglan d (Alford 1976).Fam .POMACEAE :pea r (Pyrus communis) inth eNetherland s (VanRosse me tal . 1971);appl e (Pyrus malus) inth e Netherlands (Küchlein& Helmer s 1963;Va nFrankenhuyze n& D eJon g 1964;D eJon g1966 ;
11 VanRosse me tal .1971) .Farn .RIBESIACEAE :blac kcurran t {Ribes nigrum) inEnglan d (Dicker 1972);re dcurran t {Ribes rubrum) inth eNetherland s (filesPlan tProtectio nService , Wageningen).Farn .ROSACEAE :cultivate dstrawberr y {Fragaria sp.)i nEnglan d (Vernon 1971), inHungar y (Balâsz1968) ,an di nth eNetherland s (filesPlan tProtectio nService , Wageningen;ow nobservation) ;cultivate drose s [Rosa hybrida) inth eope nai ri nGerman y (Hahn1978) ,i nPolan dnea rPozna n (Dr.T .Baranowski ,pers .comm.) ,an di nth e Netherlands (VanPoetere n 1941).Fam .SALICACEAE :popla r {Populus sp.)i nGerman y (Hahn 1978).Fam .URTICACEAE :hop s {Humulus lupulus) inEnglan d (Vernon1971) .Fam .VITACEAE : vines {Vitis sp.)i nGerman y (Schwangart 1911,1912 ;Herin g 1963),an di nth eSout ho f France (Picard 1912),mainl yi nlo wlyin gpoorl ydraine dvineyards .
Plants in greenhouse cultures
Fam.ALSTROEMERIACEAE : Alstroemeria sp.i nth eNetherland s (Vand eVri e 1978)(Herber t (1837),Schen k (1855), Baker (1888)an dWettstei n (1935)attribut e Alstroemeria toth e familyAmaryllidaceae ;Buxbau m (1951,1954 )attribute si tt oth efamil yLiliaceae) .Fam . AMARYLLIDACEAE: Hippeastrum sp.i nth eNetherland s (filesPlan tProtectio nService , Wageningen).Fam .ARACEAE : Anthurium sp.i nth eNetherland s (Vand eVri e 1976).Fam . ARALIACEAE: Fatsia japonica inth eNetherland s (filesPlan tProtectio nService , Wageningen).Fam .BALSEMINACEAE :balsemin a {Impatiens sp.)i nGerman y (Bodenstein1952) . Fam.BEGONIACEAE : Begonia sp.i nth eNetherland s (Vand eVri e 1976).Fam .BROMELIACEAE : Bromeliaceaei nth eNetherland s (Vand eVri e 1978). Fam.CACTACEAE : Zygoaaotus trunoatus inth eNetherland s (VanRosse me tal . 1968); Rhipsalidopsis sp.i nth eNetherland s (files PlantProtectio nService ,Wageningen) .Fam .CARYOPHYLLACEAE :carnatio n {Dianthus caryophyllus) underglas si nth eNetherland s (VanFrankenhuyze n& D eJon g 1964).Fam . CCMMELINACEAE: Tradescantia sp.i nGerman y (Bodenstein 1952).Fam .COMPOSITAE :greenhous e Chrysanthemum inth eNetherland s (filesPlan tProtectio nService ,Wageningen) ; Gerbera sp. inth eNetherland s (Vand eVri e 1976)an di nGerman y (Hahn1978) ; lettuce {Laatuoa sativa) inth eNetherland s (VanFrankenhuyze n& D eJon g1964 )an di nEnglan d (Alford 1976).Fam . CRASSULACEAE: Kalanahoë sp.i nth eNetherland s (Vand eVri e 1978).Fam .CRUCIFERAE :stoc k {Matthiola incana) inth eNetherland s (VanFrankenhuyze n& D eJon g 1964).Fam . CUPRESSACEAE: Cupressus maerocarpa inth eNetherland s (filesPlan tProtectio nService , Wageningen).Fam .ERICACEAE :azale a {Rhododendron sp.)i nth eNetherland s (Vand eVri e 1978).Clas sFILICES :fer ni nEnglan d (Miles& Mile s 1948).Fam .GERANIACEAE :geraniu m {Pelargonium sp.)i nth eNetherland s (filesPlan tProtectio nService ,Wageningen) ,an di n England (Vernon 1971).Fam .LILIACEAE : Asparagus setaoeus inth eNetherland s (VanPoetere n 1940); Asparagus spp.i nGerman y (Pape 1955a); Lilium speciosum (var."Rubrum" )i nth e Netherlands (filesPlan tProtectio nService ,Wageningen) .Fam .MORACEAE : Ficus sp.i nth e Netherlands (Vand eVri e 1976).Fam .MUSACEAE : Strelitzia reginae inth eNetherland s (Van deVri e 1976).Fam .OLEAŒAE : lilac {Syringa vulgaris) inGerman y (Hahn 1978).Fam . PRIMUIACEAE:cyclame n {Cyclamen persicum) inGerman y (Bodenstein1952 ;Pap e 1955a),i n England (Vernon 1971),an di nth eNetherland s (VanPoetere n1936 ;Va nFrankenhuyze n& D e Jong 1964).Fam .ROSACEAE :greenhous erose s {Rosa hybrida) inDenmar k (Anonymus1942a ;
12 Pape 1964),i nGerman y (Feiter& Henseie r 1971),i nEnglan d (Burges& Jarret t 1978),i n Polandnea rPozna n (Dr.T .Baranowski ,pers .coram.) ,an di nth eNetherland s (VanPoetere n 1941;Va nFrankenhuyze n& D eJon g1964 ;Va nRosse me tal . 1965;Va nd eVri e1976 ,1978) . Farn.SCROPHULARIACEAE :snapdrago n (Antirrhinum majus) underglas si nth eNetherland s (Van Frankenhuyzen& D eJon g 1964).Fam .SOLANACEAE :greenhous etomat o {Solanum lycopersieum) inth eNetherland s (VanFrankenhuyze n& D eJon g 1964)an di nEnglan d (Alford1976) .Fam . VITACEAE:vine s (Vitis sp.)unde rglas si nth eNetherland s (VanFrankenhuyze n& D eJon g 1964).
Inth ecite dliterature ,ofte nonl yth enam eo fth ehost-plan tgenu swa sgiven .I n somecase si twa sdifficul tt odecid ewhethe rth erecorde dfoo dplan twa sa tru ehos t plant.I twa ssometime sdifficul tt oascertai nth ereliabilit yo fth eliteratur edata . Stillsom egenera lconclusion sca nb edrawn . Manyo fth ewil dhos tplant sar efro ma we tenvironment .Obviousl y C. speetrana prefersmois tbiotope s (Spuler1910 ;Balachowsk y 1966;Razowsk i1969 ,1979 ;Verno n1971 ; Bradleye tal . 1973;Kostiu k 1980).Th especie scertainl yi scommo naroun dAalsmeer ,whic h isa we tarea . Thespecie so fth egenu s Clepsis (Guenée)ar eusuall yoligophagous .Th ehos tplant s aremainl yshrub san dtrees ,includin gconifer s (Razowski 1979). C. speetrana, however,i s mainlyfoun do nherbaceou splants ,an di sextremel ypolyphagous ,bot houtdoor san di n greenhousecultures .Th elis tgive nabov eshow stha tth especie sha sbee nrecorde do n plantsfro ma tleas t2 8differen tfamilie si nth eope nair ,an d2 6differen tfamilie si n greenhouses.Th epolyphagou scharacte ro fth especie sincrease sit sdange ra sa pest .
2.4 DISTRIBUTION
According toBalachowsk y (1966)an dBradle ye tal . (1973), C. speetrana occursi n Northern,Centra lan dWester nEurope ,an di nth esouth-eas to fth eEuropea npar to fth e SovietUnion .Kostiu k (1980)add stha tth especie si swidel ydistribute di nth eEuropea n parto fth eSovie tUnion ,dow nt oth eBlac kSe aCoas tan dth eSe ao fAzov ,an da sfa ra s Daghestan,Talys han dth enorth-wester nUral ,an dtha ti tals ooccur si nAsi aMinor . In1969 ,Razowsk istate dtha tth especie si sfoun dal love rEurope ,excep ti nSpai n andPortugal ,an dtha ti ti sals ofoun di nSyria .Howeve ri n197 9Razowsk idi dno tinclud e southernEurop ean dSyria .Th edistributio ndat afro m196 9wer ebase do nth eliterature , andprobabl ywer ei npar tincorrect .I n197 9h einclude donl yth einformatio ntha tha d beenconfirmed .Hi sopinio ni stha tth edistributio nare ao fth especie sdoe sno texten d farsouth .Howeve rther ema yb eisolate dpopulation so fth especie si nnorther nYugoslavi a andnorther nItaly ,bu tthi sneed st ob econfirme d (Dr.J .Razowski ,pers .comm.) . Thespecie sha sonl ybee nrecorde da sa noxiou sinsec ti ncountrie slik eHungary , France,Germany ,Denmark ,England ,an dth eNetherland s (chapter 2.3).I nItal yth especie s isno tknow na sa noxiou sinsect ,an dpossibl ydoe sno toccu rther ea tal l (Prof.Dr.S . Zangheri,pers .comm.) .Dr .A .Diakonof f (pers.comm. )remember stha th ecaugh ta C. speetrana mothi na ligh ttra po nth eislan do fCorfu ,an dtha th efoun dth especie samon g
13 materialtha twa ssen tt ohi mfro mEgypt .Th especie sapparentl yoccur si nth e Mediterraneanregion .
Whenth einformatio nfro mth eMuseum.o fNatura lHistor yi nLeiden ,fro mth e ZoologicalMuseu m inAmsterdam ,fro mGraa fBentinc k& Diakonof f (1968),fro mD eJon g (1966),fro mA .va nFrankenhuyze n (unpublished),an dfro mth eexperimenta lorchar d "Schuilenburg" (unpublished)i scompared ,i ti sapparen ttha t C. spectrana hasbee n caughti nal lDutc hprovinces ,a t10 1differen tlocation sal love rth ecountry .Apparentl y thespecie s iswidel ydistribute d inth eNetherlands .Küchlei n& Helmer s (1963)ar eo fth e sameopinion .Th eearlies tspecimen si nth emuse ai nLeide nan dAmsterda mwer ecaugh tb y Snelleni n1857 ,nea rRotterdam .
14 3 Materials and methods
3.1 TECHNICAL
Fieldstrain swer ecollecte dfro mstingin gnettle s {Urtica dioioa L.)nea rWageningen , andgreenhous estrain sfro mros ehouse si nth eAalsmee rregion ,an didentifie da s C. speatrana byDr .A .Diakonoff .I nth elaborator ya tth emos t5 generation spe rstrai nwer e reared.A tleas tonc ea year ,ne wlarva eun dpupa ewer ecollecte di nth efiel dan dros e houses,an dne wmas srearing swer estarte dwit habou t12 5specimen spe rstrain .
Thelarva ewer ereare dsingl yi nglas svial s (height5 cm ,diamete r1. 5cm )o na n artificialdiet .Tw oPhilip sfluorescen ttube s (whitelight )o f2 0Wat teac hwer euse da s aligh tsource . Thedie twa sth esam ea suse db yAnkersmi t (1968)fo rth esummer-frui ttortri xmoth , Adoxophyes ovana (F.V.R.).Th eho tflui ddie twa smixe dfo r1 0minute si na Brau nmultimi x MX3 2kitche nmixe ra tmaximu mspeed .Thi swa ssufficien tt ogrin dth esoli dcomponent s andt opreven tthei rprecipitatio ndurin gcooling .Th esoli ddie twa scu tint opieces .Eac h vialreceive don epiec ean dwa sclose dwit ha wa do fcotto nwool .Th evial swit hthei r contentswer esterilize db ymaintainin gthe ma t11 2C i na stea mcontaine rfo r2 0minutes . Thevial swer eallowe dt ocoo lo na Monarc hclea nbenc h (typeMH-12-6) .A ssoo na sth e freewate rinsid eth evial sha devaporated ,newl yhatche dlarva ewer epu to nth edie to n theclea nbench .I nthi swa ygrowt ho fbacteri aan dfung io nth edie tcoul dfo rth emos t partb eprevented . Thevial swit hth elarva ewer ekep ti ntransparen tplasti cboxes ,whic hprevente dth e dietfro mdryin gou tprematurely .Usuall yi twa sno tnecessar yt otransfe rth elarva et oa newvia lbefor ecompletio no fthei rdevelopment .Moreover ,i nthi swa ytw ostrain scoul db e rearedi non eroo mwithou trunnin gth eris ko fmixin gthe mup . Thepupa ewer eremove dfro mth elarva lwebbin gt oensur eunhampere demergenc eo fth e moths.The ywer ekep to nmois tfilte rpaper . Themoth so feac hstrai nwer ebrough ttogethe ri na close dpolyethylen eba g (sizec a 15x30x45 cm),containin ga fres hros eshoo ttha twa splace di nwe tOasi st okee pi tfresh . Theegg swer edeposite do nth einne rsid eo fth eba gan do nth euppe rsid eo fth eros e leaves. Theeg gmasse swer ecollecte dan dallowe dt ohatc ho ngreenhous eros eleave si nPetr i dishesi nclose dplasti cbags .Th elarva ewer epu to nth eartificia ldie twithi n1 6hour s aftereg ghatching .
Thehea dcapsul ewidth so fth elarva linstars ,an dth epupa lbod ywidths ,wer e
15 measuredwit ha Wil dM 5stereomicroscop e (ocularx10 ,tota lmagnificatio nx25 ,on e micrometeruni trepresente d 0.04mm) .Hea dcapsul ewidt hwa sdefine da sth emaximu mwidt h ofth eexterio rskeleto no fth elarva lhea d (dorsallyo rventrally) .Pupa lwidt hwa s defineda sth emaximu mwidt ho fth ebod y (dorsallyo rventrally) .
3.2EXPERIMENTA L
Therat eo fdevelopment ,pupa lbod ywidth ,an dmortality ,i nlarva ereare do n artificialan dnatura ldiet swer ecompared ,t otes tth equalit yo fth eartificia ldiet . Thelarva ewer etake na trando mfro mon elo to feac hstrai nan dreare dsingl yi nglas s vialsa t25° Can dL D18:6 .Th ebotto mo fth eboxe si nwhic hth evial swer ekep twer e coveredwit hfilte rpape rsoake di nwater ,t opreven tprematur edryin gou to fth enatura l diets.Th ediet swer erenewe dtwic ea week,an dth emoult swer eassesse da tth esam etime . Pupationan dmot hemergenc ewer eobserve da t24-hou rintervals .Th enumbe ro finstar s betweeneg ghatchin gan dpupatio nwa svariable .Th e5-insta rgrowt htyp estrongl y predominatedi nbot hmal ean dfemal elarvae .Fo rthi sreaso nonl ylarva ewhic hha dbee n through5 instar sbetwee neg ghatchin gan dpupatio n (=5-insta r larvae)wer econsidered .
Nosignifican tdifference si ndevelopmen tduratio nan dpupa lbod ywidt h (testedwit h 2 thet-statistic) ,o ri nmortalit y (testedwit hth ex -statistic) ,wer efoun dbetwee nth e dietsi nbot hstrain s (2-sidedtest ,P>.05 ) (table 1). Differencesi ndevelopmen tbetwee n thestrain swil lb ediscusse di nchapte r4 .
Table 1.Duratio no flarva lan dpupa ldevelopment ,mortality ,an dpupa lbod ywidt ho fa field strainan da greenhous e straino nartificia l andnatura ldiet sa t2 5C an dL D18:6 .
Field strain Greenhouse strain
artificial Urtica artificial Rosa diet dioica diet hybrids leaf leaf mean development n=55 n=60 n=58 n=48 duration of 5-instar larvae 19.8 20.0 20.2 20.0 (days) (S.D.==2.3 ) (S.D.=2 0) (S.D.= 2.3) (S.D.=2.3) percentage larval 8% 5% 11% 14% mortality
86 2.41 2.40 2.35 2.37 pupal width (mm) V2 2.82 2.80 2.75 2.75 mean pupal development duration 6.4 6.5 6.9 6.8 (days) (S.D =0.5) (S.D.=C .6) (S.D =0.6) (S.D.=0.6) percentage pupal 7% 10% 5% 8% mortality 4 Non-diapause development
Developmentalrat ean ddiapaus ema yb egeneticall ylinked .Ho y (1978a)foun dtha ta non-diapausingstrai no fgyps ymoth , Lymantria dispar (L.),obtaine dthroug h purposefulselectio ni na laborator yculture ,exhibite dsignifican tdifference si n developmentalrat eo fsom elarva linstar swhe ncompare dt oa wil dstrai nfro mth efield . Greenhousepopulation so f C. speetrana mayhav eadapte dt odevelopmen ta thighe r temperatures.T odetermin eoptimu mtemperature ,dat ao nsiz ean dweight ,an dals oo n survival,unde rdifferen ttemperatur econdition sar emos tofte nuse d (Danilevskli1965 , pp. 152-153). Rateo fdevelopmen tan dmortalit yo feggs ,larva ean dpupa eo ffiel dan dros ehous e strainswer ecompared .Moreove rth enumbe ro flarva linstars ,th ehea dcapsul ewidth so f thelarvae ,an dpupa lbod ywidt hwer edetermined .
4.1VARIABILIT YI NTH ENUMBE RO FLARVA LINSTAR S
Variabilityi nth enumbe ro flarva linstar si sfrequentl yobserve di ninsec tspecies . Arevie wo fth eliteratur eo nthi ssubjec ti sgive nb yGruy s (1970):beside sgeneti c factors,severa lenvironmenta lfactor sca ninfluenc eth enumbe ro finstars ,suc ha s temperature,ai rhumidity ,quantit yan dqualit yo ffood ,crowding ,an dphotoperiod ;risin g temperatureprovoke smor emoult si nsom especies ,whil ei nothe rspecie si tcause sfewe r moults;i nsom especie sth esmalles tnumbe ro fmoult si sfoun da ta specifi cmedium-rang e temperature,an di tincrease sa thighe ran dlowe rtemperatures .
Thenumbe ro flarva linstar sfro meg ghatchin gt opupatio ni n C. speetrana varied between4 an d7 i nbot hfiel dan dgreenhous estrains .I nrearing so fa greenhous estrain , twoo fth elarva ewer eeve nobserve dt og othroug h8 instars .Thi svariabilit yma ymodif y therat eo flarva ldevelopment .
Infigure s1 an d2 th emea nhea dcapsul ewidth so fth eseparat einstar so fth e differentlarva lgrowt htype sar epresented .Th ereliabilit yinterval so fth emean s presentedi nthes ean dothe rfigure swer ecalculate daccordin gt oth efollowin gformula :
mean + S.E. x t (P=.0S, 2-sided test) — n '
Whenth enumbe ro fobservation sn exceede d100 ,fo r t thevalu e1.9 6wa suse di nth e ' n formula.
17 lg mean width
a 4 instars(n.16)
b 5 instars (n.187)
c 6 instars(n.13)
d 7 instars !n.8)
Larval instars lg mean width
a 5 instars(n.185)
b 6 instars (n.30)
c 7 instars (n.8)
Larval instars
Figure 1. lg of mean head capsule widths (mm)o f the separate instars of the 4-instar, 5-instar, 6-instar, and 7-instar larval growth type (field strains). Vertical bars represent the reliability intervals of themeans . Ig mean width
a 4 instars (n.13)
b 5 instars(n„203)
c 6 instars (n.67)
d 7 instars lg mean width a 5 instars(n.151) b 6 instars(n.100) c 7 instarsln. 22) d 8 instarstn. 2) Larval instars Figure2 .l go fmea nhea dcapsul ewidth s (mm)o fth eseparat einstar so fth e 4-instar,5-instar ,6-instar ,7-instar ,an d8-insta rlarva lgrowt htyp e (greenhouse strains).Vertica lbar srepresen tth ereliabilit y intervalso f themeans . 19 Therewa sa systemati cdifferenc e inmea nhea dcapsul ewidt hbetwee nth edifferen t larvalgrowt htypes :th ehighe rth enumbe ro finstars ,th esmalle rth emea nhea dcapsul e widtho feac hinstar .Thi swa susuall yth ecas eeve nfo rth efirs tinsta r (figures1 and 2). Thedifference s inmea nhea dcapsul ewidt hi neac hinstar ,betwee nth elarva lgrowt h types,wer estatisticall yevaluate dt odetermin e inwhic hinstar sthe ywer esignificantl y expressed. Theresult sar egive ni ntabl e2 .Th enumbe ro flarva linstar sma yb einfluence db y bothgeneti can denvironmenta l factors.I fenvironmenta lfactor sar einvolve d inth e determinationo fth enumbe ro finstar si n C. spectrana, theinfluenc eo fthes efactor s shouldb efel tbefor eth eegg shatch ,a sbot hi nfiel dan dgreenhous estrain sth e differencebetwee nth e4-insta r and5-insta r larvalgrowt htyp ewa salread ysignificantl y expressedwhe nth eegg shatche d (table 2). Thedifferenc ebetwee nth e5-insta ran d 6-instar typewa ssignificantl yexpresse dfro mth esecon d instar,an dth edifferenc e betweenth e6-insta r and7-insta r typefro mth ethir dinstar ,o reve nlater ,i nbot hfiel d andgreenhous estrain s (table 2). Thelowe rth eultimat enumbe ro finstars ,th eearlie r thedifferenc ebetwee nth elarva lgrowt htype swa sexpressed .A simila rpatter nwa sfoun d byGruy s (1970)i nth epin elooper , Bupalus piniarius (L.). Eggso fa fiel d strainan da greenhous e strain (1stlaborator ygeneration )wer ekep t at21° Can dL D18:6 .Larva ewer etake na trando mfro mon elo to feac hstrain ,withi n1 6 hoursafte rhatching .The ywer ereare da tdifferen ttemperature s (atL D18:6 ,t opreven t inductiono fdiapause) . Table 2. Statistical evaluation of the differences inmea n head capsule width between the different larval growth types of a field and greenhouse strain (1-sided t-test, P^.05). Field strains Greenhouse strains <3 LI NS NS NS NS 5-instar larvae L2 S S S S vs L3 S S s S 6--instar larvae L4 S S s s L5 s S s s LI NS NS NS NS 6-instar larvae L2 NS NS NS NS vs L3 NS S S NS 7-instar larvae L4 NS S S S L5 S s S s L6 S s S s * no females with 4 instars noticed 20 Table3 .Fraction s (%) of thelarva lpopulatio ngoin gthroug ha varyin gnumbe ro finstar s ina fiel dan dgreenhous e strain,a tdifferen t temperaturesan dL D18:6 . Number ofinstar s Meannumbe r Totalnumbe ro f 4 5 6 7 ofinstar s larvaeobserve d field 68 5% 87% 8% 5.0 63 greenhouse SS 14% 76% 10% 5.0 58 15°C field 99 86% 13% 2% 5.2 64 greenhouse 99 87% 13% 5.1 60 field SS 7% 93% 4.9 74 greenhouse SS 10% 90% 4.9 60 20°C field 99 98% 2% 5.0 64 greenhouse 99 97% 3% 5.0 70 field SS 4% 86% 11% 5.1 57 greenhouse OS 3% 90% 8% 5.1 78 25°C field 99 75% 25% 5.3 69 greenhouse 99 88% 12% 5.1 58 field SS 4% 78% 17% 5.1 46 greenhouse 3% 75% 22% 5.1 60 30°C sa field §9 56% 42% 2% 5.5 50 greenhouse 22 70% 30% 5.3 44 Table3 show sth enumber so flarva egoin gthroug ha varyin gnumbe ro finstar sfro m egghatchin gt opupation ,expresse da sproportion so fth etota lnumbe ro flarva eobserve d ateac htemperature .Th efollowin gconclusion sca nb edrawn : -Larva egoin gthroug h5 instar sfro meg ghatchin gt opupatio n (5-instarlarvae )wer e predominanta tal lrearin gtemperature si nbot hsexe si nbot hstrains . -Female stende dt odevelo pthroug ha highe rnumbe ro flarva linstar stha nmale si nbot h strains,bu tth edifference swer eno tsignifican texcep ti nth efiel dstrai na t30° C (2-sidedx 2-test,P>.05) . -Th emea nnumbe ro finstar swa sth elowes ta t20° Ci nbot hstrains ,bu tth eonl y significantdifferenc ewa sbetwee n20° Can d30° Ci nth efemale so fbot hstrain s (2-sided X2-test,P>.05) . Themea ndevelopmenta ltime so fth edifferen tlarva lgrowt htype so fa fiel dan da greenhousestrain ,a t2 SC an dL D18:6 ,ar egive ni ntabl e4 .Larva ldevelopmen twa s observeda t24-hou r intervals.Th ehighe rth enumbe ro finstars ,th elonge rth elarva l developmentaltim e (table4) .Th esam ephenomeno nwa sobserve di nman yothe rinsec t specieswit ha variabl enumbe ro flarva linstar s (Gruys1970) .Th etim erequire dfo r larvaldevelopmen tdi dno tdiffe rsignificantl ybetwee nth estrains ,i neac ho fth elarva l growthtype s (2-sidedt-test ,P>.05) .Amon gth elarva eo fth e4-insta rtyp eonl ymale swer e found,an damon gth e8-insta r type,onl yfemales .Larva ldevelopmen tduratio nwa sslightl y 21 Table 4.Mea n development duration (days) at 25 C and LD 18:6 of the different larval growth types of a field and a greenhouse strain. Field strain Greenhouse strain CÎO" n o"o" 59- n=9 n=7 4-instar larvae 16.4 — 15.9 (S.D.=1.5) (S.D.=1.3) n=69 n=3I n=72 n=41 5-instar larvae 18.9 20.3 19.8 20.8 (S.D.=2.4) (S.D.= 1.6) (S.D.=1.8) (S.D. =2.0 ) n=12 n=16 n=47 n=76 6-instar larvae 23.5 25.3 23.8 25.1 (S.D.=2.6) (S.D.= 2.0) (S.D.=1.9) (S.D. =2.1 ) n=8 n=9 n=6 n=12 7-instar larvae 29.4 31.8 28.3 31.2 (S.D.=2.0) (S.D.= 1.8) (S.D.=2.3) (S.D. =1.9 ) n=2 8-instar larvae 39.3 longer in females than inmale s in each of the larval growth types inwhic h both sexes were found. The difference was significant, except in the 5-instar larvae of the greenhouse strain (table4) . 4.2 RATE OF DEVELOPMENT AT DIFFERENT TEMPERATURES Developmental rates of a field and a greenhouse strainwer e compared in the egg stage, the larval stage (5-instar larvae,eac h instar separately), and thepupa l stage, at different temperatures and LD 18:6, in the first laboratory generation. Oviposition, egg Table 5. lleanduratio n of the egg stage (days) of a field and a greenhouse strain at different temperatures. 15°C 20°C 25°C 30°C 35°C 18.5 9.1 6.5 5.6 field strain (S.D.=0.9) (S.D.=0.6) (S.D.=0.1) (S.D.=0.4) n=203 n=234 n=216 n=243 18.7 9.6 6.2 5.4 greenhouse strain (S.D.=0.6) (S.D.=0.5) (S.D.=0.5) (S.D.=0.3) n=226 n=241 n=233 n=201 significance of difference NS S NS NS (2-sided t-test) 22 Table6 .Mea ndevelopmen tduratio n (days)o f5-insta r larvaeo fa fiel dan da greenhous e straina tdifferen ttemperature s (LD 18:6). 15°C 20°C 25°C 30°C 35°C 54.4 28.8 18.8 18.0 — - fieldstrai n 93 (S.D.=3.2 ) (S.D.=2.8) (S.D.=2.4) (S.D.=0 8) n=28 n=35 n=29 n=26 58.1 30.5 19.8 17.9 greenhousestrai n 56 (S.D.=7.3 ) (S.D.=3.8) (S.D.=2.8) (S.D.=1 3) n=22 n=28 n=37 n=21 significance ofdifferenc e S S NS NS (2-sided t-test) 59.7 31.7 20.2 19.9 fieldstrai n 99 (S.D.=3.6 ) (S.D.=2.1) (S.D.=1.6) (S.D.=2 1) n=33 n=35 n=29 n=24 61.0 31.5 20.6 19.4 greenhousestrai n 99 (S.D.=7.6 ) (S.D.=4.3) (S.D.=2.4) (S.D.=3 9) n-13 n=33 n=27 n=28 significance ofdifferenc e NS NS NS NS (2-sided t-test) hatching,moults ,pupation ,an dmot hemergenc ewer eobserve da t24-hou rintervals .Egg san d larvae,reare da tdifferen ttemperatures ,wer etake na trando mfro mon elo to feac hstrain . Theegg sfro mwhic hth elarva eoriginate dha dbee nreare da t21° Can dL D18:6 .Th epupa e originatedfro mth elarva euse di nth eexperiments . Intabl e5 th emea nduration so fth eeg gstag ear egiven .A temperatur eo f3 5C provedt ob eletha lt oth eembryo so fbot hstrains .Th emea nduratio no fth eeg gstag e decreased from18-1 9day sa t15° Ct o5- 6day sa t30°C .A t20° Cth egreenhous estrai n developedsignificantl yslowe rtha nth efiel dstrai n (table5) . Themea ndevelopmen tduratio no f5-insta r larvaea tvariou stemperature sdi dno t differsignificantl ybetwee nth estrains ,bu tgreenhous emale sa t1 5C an d20° Cwer e significantlyslowe ri ndevelopmen t (table 6).A temperatur eo f3 5C prove dt ob eletha l toth elarva eo fbot hstrains .Mea nlarva ldevelopmen tduratio ndecrease d from54-6 1day s at1 5C t o18-2 0day sa t3 0C (table 6). Themea ntim erequire dfo rdevelopmen twa s shorteri nmal elarva etha ni nfemal elarvae ,th edifferenc ewa salway ssignifican ti nth e fieldstrain ,bu tonl ya t3 0C i nth egreenhous estrai n(2-side dt-test ,P<.05)(tabl e 6). Asa nexample ,th emea ndevelopmenta ltime so fth eseparat einstar so f 5-instar larvae,reare da t15° Can dL D 18:6,ar egive ni ntabl e7 .Th emea nduration so fth e separateinstars ,expresse d asproportion so fth etota lmea nlarva ldevelopmen tduration , 23 didno tdiffe rsignificantl ybetwee nth estrains ,an dwer eno tsignificantl y influencedb y 7 sexo rtemperatur e (2-sidedx -test ,P>.05) . Table7 .Mea ndevelopmen t duration (days)o fth eseparat einstar so f5-insta r larvaeo fa fiel dan da greenhous estrain ,a t 15C an dL D18:6 . Fieldstrai n Greenhousestrai n LI 14.3 (S.D.=2.1) 15.2(S.D.=5.4 ) L2 9.4 (S.D.=0.9) 9.4 (S.D.=1.1) dtf L3L3 8.08. (S.D.=1.20 (S.D.=1.2) ) 8.8 (S.D.=1.1) L4 8.2 (S.D.=1.3) 9.6 (S.D.=1.5) L5 14.4 (S.D.=1.3) 15.3(S.D.=1.7 ) al 54.4 (S.D.=3.2) 58.1 (S.D.=7.3) n=28 n=22 LI 14.9 (S.D.=2.2) 15.9 (S.D.=5.0) L2 9.4 (S.D.=0.8) 9.2 (S.D.=0.7) 00 L3L 3 9.29. (S.D.=1.12 (S.D.=1.1) ) 9.0 (S.D.=1.3) L4 "9. -7 (S.D.=1.3•" s ) 10.2(S.D.=1.4 ) L5 16.5 (S.D.=1.4) 16.6 (S.D.=1.7) al 59.7 (S.D.=3.6) 61.0(S.D.=7.6 ) n=33 n=13 Table8 .Mea ndevelopmen tduratio n (days)o fpupa efro m5-insta rlarva eo fa fiel d anda greenhous estrai na tdifferen t temperatures (LD 18:6). 15°C 20°C 25°C 30°C fieldstrai n 98 23.6 11.7 7.2 6.1 (S.D.=1 .2) (S.D. =0 7) (S.D. =0.6) (S.D. =0 5) n=22 n=32 n=26 n=18 greenhousestrai n 0*0* 23.1 12.1 7.1 6.2 (S.D.=1 .3) (S.D. =0 8) (S.D. =0.6) (S.D. =0 6) n=19 n=27 n=34 n=16 significance ofdifferenc e NS NS NS NS (2-sidedt-test ) field strain 99 21.4 10.7 6.5 6.0 (S.D.=1 .0) (S.D. =0 7) (S.D. =0.5) (S.D. =0 5) n=26 n=29 n=27 n=16 greenhousestrai n 99 21.7 11.3 6.6 5.9 (S.D.=1 .2) (S.D. =0 7) (S.D. =0.6) (S.D. =0 6) n=14 n=30 n=25 n=20 significance ofdifferenc e NS NS NS NS (2-sidedt-test ) 24 Intabl e8 th emea ndevelopmen tduration so fpupa efro mS-insta rlarva ea tdifferen t temperaturesar egiven .Th edifference swer eno tsignifican tbetwee nth estrains .Th emea n timerequire dfo rpupa ldevelopmen tdecrease d from21-2 4day sa t1 5C t o5- 7day sa t3 0C . Malepupa egenerall yha da longe rmea ndevelopmen tduratio ntha nfemal epupa e (table 8). Thedifferenc ewa salway ssignificant ,excep ta t3 0C (2-sidedt-test ,P<.05) . Inth efigure s3-5 ,th emea ndevelopmenta lrate so fth eeg gstage ,larva lstag e (5-instarlarvae) ,an dpupa lstag ear eplotte dagains tth etemperature .Th eregressio n linesi nthes efigure swer ecalculate do nth ebasi so fth edat aa t1 5C ,2 0C ,an d2 5C . Theregressio ncoefficient sdi dno tdiffe rsignificantl ybetwee nth estrain s (t-statistic testing linearregression ,2-side d test,P>.05) .Extrapolatio no fth eregressio nline s (figures3-5 )indicate da developmenta lthreshol dclos et o1 0C fo rbot hstrains .Th emea n developmental rate temperature (C ) Figure3 .Mea ndevelopmenta lrat e(da y -l.) o fegg so fa fiel d anda greenhous e strain,plotte dagainagains st th etemperatur e (C ) Linearregressio no fdevelopmenta lrat e (y)an dtemperatur e(x) . 25 developmentalrat ea t3 0C wa salway slowe rtha ncoul db eexpecte do nth ebasi so fth e regressionline s (figures3-5) .Thi sindicate stha t3 0C wa sclos et oth euppe rtherma l limitfo rdevelopment . Broadlyoutlined ,developmen tduratio nwa sth esam ei nth efiel dan dth egreenhous e strain.Nevertheles ssometime ssignifican tdifference swer efoun dbetwee nth estrains ,i n theeg gstag ean di nth elarva lstag e (tables5 an d 6). Thesedifference sar edifficul tt o interprète.The yma yrepresen tcharacteristi cdifference sbetwee nfiel dan dgreenhous e populationso f C. spectrana, theyma yb edu et oth estrai ndifference son ema yexpec twhe n samplesar etake nfro mdifferen tgreenhous epopulation so rfro mdifferen tfiel d populations,o rthe yma yb edu et oinaccurac yo fth ethermostat sdurin gth eexperiments ,o r acombinatio no fthes efactors . developmental rate 5-INSTAR LARVAE 0,2Or y. 0.0034 f .0.999 y.0.0033 r.0 999 temperature ( C) Figure4 .Mea ndevelopmenta l rate (day )o f5-insta r larvae ofa fiel dan da greenhous estrain ,plotte dagains tth e temperature (C) . Linearregressio no fdevelopmenta lrat e (y) and temperature(x) . 26 developmental rate 0.2CV • Held strain y. 0.0102 x-O.1098 r. 0.998 - greenhouse slrain y.0.0101 x-0.1107 r. 0.994 temperature (C ) Figure5 .Mea ndevelopmenta lrat e (day )o fpupa eo fa fiel d anda greenhous e strain,plotte dagains tth etemperatur e ( C). Linearregressio no fdevelopmenta lrat e (y)an d temperature(x) . 4.3MORTALIT YAN DPUPA LBOD YWIDT HA TDIFFEREN TTEMPERATURE S Intabl e9 th emortalit yo feggs ,larva ean dpupa eo ffiel dan dgreenhous estrain s atdifferen ttemperature si sgiven .A temperatur eo f3 5C wa sletha lt obot hegg san d larvae.Pupa ewer eno texpose dt othi stemperature .I neac ho fth eimmatur estages , mortalitywa srelativel y lowa t2 0C an d2 5C ,a t1 5C i twa shigher ,an da t3 0C i twa s thehighes ti nbot hstrains .Th edifferenc ebetwee n1 5C an d 20C wa ssignifican ti nth e 2 pupaeo fbot hstrains ,an di nth egreenhous estrai negg s (2-sidedx -test ,P<.05) .Th e differencei nmortalit ybetwee n2 0C an d3 0C wa salway ssignifican t (P<.05)(tabl e 9). Thedifference si npupa lbod ywidt hwer eno tsignifican tbetwee nth estrain s (table 10).Th efemal epupa ewer esignificantl ylarge rtha nth emal epupa e (2-sidedt-test , P<.005).A t3 0C ,th epupa ewer esignificantl ysmalle rtha na tth eothe rtemperature si n bothstrain s (P<.05).A t1 5C ,femal efield-strai npupa ewer esignificantl ysmalle rtha n 27 Table9 .Percentag emortalit yo feggs ,larvae ,an dpupa eo ffiel dan dgreenhous e strainsa tdifferen t temperatures (LD18:6 ) 15°C 20°C 25°C 30°C 35°C fieldstrain s 26% 20% 16% 41% 100% eggs n=274 n=293 n=257 n=412 n=197 greenhousestrain s 24% 12% 14% 36% 100% n=297 n=274 n=271 n=314 n=127 fieldstrain s 15% 10% 13% 35% 100% larvae n=148 n=148 n=148 n=148 n=74 greenhousestrain s 18% 12% 10% 30% 100% n=148 n=148 n=148 n=148 n=74 fieldstrain s 21% 8% 7% 27% pupae n=109 n=132 n=100 n=64 greenhousestrain s 14% 5% 7% 19% n=96 n=122 n=121 n=76 at20° C (P<.05)(tabl e10) . Infigur e6 pupa lbod ywidt han doveral lsurviva legg-adul tar eplotte dagains tth e temperature.Widt han dsurviva lwer erelate dt oth etemperatur ei na simila rway ,i nbot h fieldan dgreenhous estrains . Bothi nfiel dan dgreenhous estrains ,3 5C wa sa letha ltemperature .Apparentl y 30C wa sclos et oth euppe rtherma llimi tfo rdevelopment : -A Att3 30 C0 C, mortalit, mortalit yway wa ssth th ehighese highes tti in ean eac c ho fth eimmatur estages .Th emortalit ya t2 0C wasalway ssignificantl ylowe r (table9) . Table 10.Mea nbod ywidth s (mm)o fpupa efro m5-insta rlarva eo ffiel d andgreenhous e strainsa tdifferen t temperatures (LD 18:6). 15°C 20°C 25°C 30°C field strain 00 2.38 2.40 2.39 2.29 n=55 n=69 n=48 n=36 greenhousestrai n0 0 2.37 2.39 2.36 2.30 n=44 n=54 n=70 n=45 significance ofdifferenc e NS NS NS NS (2-sidedt-test ) fieldstrai n CO, 2.74 2.84 2.79 2.63 n=54 n=63 n=52 n=28 greenhouse strain QQ 2.76 2.81 2.76 2.67 n=52 n=68 n=51 n=31 significance ofdifferenc e NS NS NS NS (2-sidedt-test ) 28 pupal body width (mm) survival(%) 100 field strain greenhouse strain temperature ( C) Figure6 .Th eeffec to ftemperatur eo nth eoveral lsurviva lfro m ovipositiont omot hemergenc ean dth epupa lbod ywidt ho ffiel d andgreenhous estrains . -A t3 0C ,pupa lbod ywidt hwa ssignificantl yreduce da scompare dt oth elowe rrearin g temperatures (table 10). -A t3 0C ,developmenta lrat ewa salway slowe rtha ncoul db eexpecte db yextrapolatin gth e linearregressio no fdevelopmenta lrat ean dtemperatur e (figures3-5) . Theuppe rtherma llimi tfo rdevelopmen tapparentl ywa sbetwee n3 0C an d3 5C i nbot hfiel d andgreenhous estrains . Survivalan dpupa lbod ywidt hwer esimila ri nfiel dan dgreenhous estrain si nth e temperaturerang e1 5C-3 0C (figure6) . Anadaptatio no fgreenhous epopulation so f C. speotrana todevelopmen ta thighe r temperaturesdi dno tappear .I tremain st ob eascertaine dwhethe rther ear edifference s indevelopmen tbetwee nfiel dan dgreenhous epopulation si nth etemperatur erang ebetwee n 29 thedevelopmenta l thresholdan d 15C ,a stemperature sbelo w1 5C wer eno tinvestigated .A s arule ,th enon-dorman tstage so finsec tspecie ssho wlittl egeographi cvariatio ni nthei r temperaturerequirement sfo rgrowt han ddevelopmen t (Danilevskii1965 ,pp .151-152) . 30 5 Diapause in field populations Diapause iscrucia li nannua lcycle so finsect sa si tlargel ydetermine swhethe ra speciesca nsurviv ecertai nconditions .Fiel dan dgreenhous epopulation so f C. speetrana seemt odiffe ri nthi srespect .T oestablis hthes edifferences ,an dt oasses sho wdiapaus e canb eeliminate di na greenhous eenvironment ,knowledg eo fth einduction ,maintenanc ean d terminationo fdiapaus ei nfiel dpopulation si srequired . 5.1 PHOTOPERIODICRESPONS ECURVE S Eggso fa fiel dstrai n (2ndlaborator ygeneration) ,an dlarva efro mthes eeggs ,wer e rearedi ndifferen tcombination so fphotoperio dan dtemperatur e (figure 7).Fo reac h combination16 5larva ewer eused . Larvaewer eonl yassume dt ob ediapausin gi fthei rhea dcapsul ewidt hdi dno texcee d themaximu mwidt h (0.88mm )note damon gdiapausin gfiel dstrai nlarva ei nth eoutdoo r experimentsdescribe d inSectio n5.2 . Extrapolationo fth eregressio nline sindicate dtha tth emea ndevelopmen tduratio no f non-diapausinglarva ea t1 3C i sabou t3 Imonth s (figure 4). Larvaetha tdi dno tdi eo r pupatewithi n6 \month swer eassume dt ob ediapausin g ifthei rhea dcapsul ewidt hwa sno t largertha n0.8 8mm . At 15C th emea ndevelopmen tduratio no fnon-diapausin g larvaewa sabou t2 month s (table 6). Whendiapaus ewa sno tinduced ,pupa ewer eusuall yforme dwithi n4 month safte r egghatching .Larva eremainin gafte r4 month swer eassume dt ob ediapausin gi fthei rhea d capsulewidt hdi dno texcee d0.8 8mm . At2 0C th emea ndevelopmenta ltim eo fth elarva ewa sabou t1 mont h (table 6).Thos e remainingafte r2 month swer eassume dt ob ediapausin g (headcapsul ewidt h< 0.8 8mm) . At2 5C th emea ntim erequire dfo rlarva ldevelopmen twa sabou t3 week s (table6) . Thelarva eremainin gafte r6 week s (headcapsul ewidt h< 0.8 8mm )wer eassume dt ob e diapausing. Theresult sar epresente d infigur e7 .A t 15C an d2 0C th ecritica lphotoperio dwa s between1 6an d1 7hours .I nth eNetherland sthes ephotoperiod s (daylength ,includin gcivi l twilight)occu rbetwee nmid-Jul yan dmid-Augus t (Beck1980 ,pp .3-6) .Th ephotoperiodi c responseo f C. speetrana waso fth e"long-day "type .A si nman yothe rinsec tspecie s (Beck 1980,pp . 127-128),hig htemperature stende dt oaver tphotoperiodi c inductiono fdiapaus e in C. speetrana (responsecurv ea t2 5C i nfigur e7) . 31 Diapause incidence (%) 100r O 13"C 15°C 20* 25°C 10 11 12 13 14 15 16 17 18 Photoperiod (h/day) Figure7 .Photoperiodi c responseo flarva eo fa fiel d straina tdifferen ttemperatures . 5.2OUTDOO REXPERIMENT S Inductionan dterminatio no fdiapause ,an dpost-diapaus edevelopmen to ffield-strai n larvae,wer estudie d inoutdoo rexperiments .Th elarva e (2ndan d3r dlaborator ygeneration ) werereare d inth eope nai ri na cag etha twa sprotecte dfro mth esun .Fiv erearing swer e performed,wit hegg stha thatche d inth eoutdoo rcag eo nAugus t 1,Augus t 17,Septembe r9 , September25 ,an dOctobe r 14,1978 ,respectively .Thi scover sth epossibl eeg ghatchin g periodo fth esecon dfligh ti nfiel dpopulations .Eac htim e8 0larva ewer ereared .Th e developmento fth elarva ewa sfollowe dindividually .Th ehea dcapsul ewidt ho feac hinsta r wasmeasured . Thetemperature ,recorde dwit ha thermohygrograp hplace dinsid eth ecage ,remaine d below9 C fro mDecembe r25 ,1978 ,unti lsprin g1979 .Thi stemperatur eca nb econsidere da s developmental zero (figures3-5) ,therefor en odevelopmen toccurre ddurin gthi speriod . AfterDecembe r25 ,th elarva ewer eobserve donc ea month .Fro mth ebeginnin go fApri l197 9 dailyobservation swer emad et oestablis hwhe nth elarva elef tthei rhibernacula .Afte r resumptiono ffeedin gan dgrowth ,th emoult swer eobserve da tweekl yintervals .Th ewidt h ofth ehea dcapsule so feac hinstar ,an dpupa lbod ywidth ,wer emeasured ;pupatio nan dmot h emergencewer eobserve da t2-da yintervals . 32 S.2. 1 Induction of diapause Table1 1show sth emea nnumbe ro fmoult su pt ohibernation ,an dth emea nhea dcapsul e widtho fhibernatin glarvae .Hibernatio nwa sassume dt ostar to nDecembe r25 ,1978 .Larva e enteringdiapaus ecoul db erecognize dbecaus ethe yusuall ymad ea hibernaculu mi nth e fissurebetwee nth ewal lo fthei rglas svia lan dth epiec eo fcotto nwoo lwit hwhic hth e vialwa sclosed . Thenumbe ro fmoult su pt ohibernatio nwa svariable .I tvarie dbetwee n1 an d6 ,bu t 1,5 ,an d6 moult swer eexceptional .Th emea nnumbe rwa slowe ra sth eegg shatche dlate r inth eseaso n (table 11).Tw oexplanation sar eoffered : a.Th einsta ri nwhic hdiapaus ei sentere di sfixed ,bu tth elarva eunderg o"stationar y moults"(postecdysia llarva eessentiall ybein go fth esam eweigh tan dfor ma sprecdysia l larvae)durin gdiapaus ea slon ga sth etemperatur ei sabov ea certai nthreshol d (compareBurge s1960 ;Chippendal e& Redd y1972 ;Scheite s 1978). b.Th einsta ri nwhic hdiapaus ei sentere di svariable ,an di scorrelate dwit hth emomen t inth eseaso ni nwhic hth eegg shatch . Table 11.Numbe ro fmoult su pt ohibernation ,an dmea nhea d capsulewidt ho fhibernatin g larvae.Outdoo rexperiment swit ha fiel d strain.Th edifferenc emales-female swit hrespec t toth enumbe ro fmoult su pt ohibernatio nwa sno t significant (2-sidedx 2-test,P>.05) . Dateo feg g Meannumbe ro f Percentageo flarva egoin g Meanhea dcapsul e hatching moultsu pt o throughdifferen tnumber s width (mm)o f hibernation ofmoult su pt ohibernatio n hibernatinglarva e (0*0*an d9 9combined ) ótf:4. 2 3moult s 3 1978-08-01 n=31 4 " 87 0.76 99:3. 9 5 " 7 n=39 6 " 3 80: 3.4 3moult s 70 1978-08-17 n=36 4 " 28 0.62 99: 3.2 5 " 2 n=28 68: 2.8 2moults : 18 1978-09-09 n=47 3 " : 82 0.54 99: 2.8 n=29 88: 2.0 1moul t : 5 1978-09-25 n=43 2moults :8 9 0.42 99:2. 0 3 " : 5 n=33 88: 1.9 1moul t: 6 1978-10-14 n=36 2moults : 94 0.40 99:2. 0 n=35 33 lgmea n width Larval instars Figure 8. lg ofmea nwidth s of thehea d capsules (mm)o f the separate instars of larvae that hibernated after 2-4 moults,an d of 5-instar larvae that developed at 15C withou t diapause in the laboratory. Outdoor experiments with a field strain. Vertical bars represent the reliability intervals of themeans . Themea nhea d capsulewidth s of theconsecutiv e instars of larvae entering diapause deviated from ageometrica lprogression ,contrar y to those of 5-instar larvae going through non-diapause development (figure 8).Th edeviatio nwa s alwaysmos t pronounced after the lastmoul tbefor e hibernation. Themea n head capsule width of overwintering larvaewa s larger as theywen t throughmor emoult s up to hibernation (table 11, figure8) . Therefore larvae hibernating afterdifferin g numbers ofmoult s respectively allha d their own specific progression ofhea d capsulewidt h (figure8) . Larvae hibernating after 1moul t usually made ahibernaculum ,bu t did notmoul t within it.Larva e hibernating after 2-6 moults always underwent 1moul twithi n their 34 Table 12.Resumptio no fmoultin g inth esprin go f 1979 (outdoorexperiment swit ha fieldstrain) . Dateo feg g Percentagetha tha dmoulte donc ebetwee n 1979-04-13an d1979 - hatching 04-27,o rwer eo nth epoin to fmoultin g (whitecoloure dzon e behindth ehea d capsule)o n 1979-04-27 1978-08-01 97 1978-08-17 93 1978-09-09 92 1978-09-25 85 1978-10-14 91 hibernacula.Thi sconflict swit hth eassumptio no f"stationar ymoults "afte rth eonse to f diapause. Theseobservation ssuppor tth esecon dexplanatio nmentione dabove . 5.2.2 Resumption of moulting in spring Themaximu mtemperatur eremaine dbelo wT1° Cunti lApri l 13,1979 ,whe ni tros et o 19°Caroun dmidday .O nApri l 13,larva efro meac ho fth e5 rearing s (5differen teg g hatchingdates )wer eobserve dt ohav elef tthei rhibernacula ,an dwer efeedin go nth edie t atth ebotto mo fth eglas svials . Table1 2show sth epercentag eo flarva etha tha dmoulte donc ebetwee nApri l 13an d27 , orwer eo nth epoin to fmoultin go nApri l27 ,fo reac ho fth e5 rearings .Thes e percentagessugges ttha tth etim eo fresumptio no fgrowt han dmoultin gi nsprin gwa sth e samefo reac ho fth eS rearings ,an dwa stherefor eno tcorrelate dwit hth edat eo feg g hatchingi nth epreviou syear .I tha sbee ndemonstrate di nman yspecie stha tpost-diapaus e developmenti sprevented ,sometime sfo ra considerabl eperiod ,unti ltemperature sris e aboveth elowe rtherma lthreshol d fordevelopmen t (Tauber& Taube r 1976). 5.2.3 Post-diapause development Intabl e1 3th emea nduratio no fpost-diapaus edevelopmen ti spresente dfo reac ho f theS date so feg ghatching .I ntabl e1 4th emea nnumber so fmoult sdurin gpre -an dpost - diapausedevelopment ,an dth emea npupa lwidth safte rdiapause ,ar egiven . Theduratio no fpost-diapaus edevelopment ,bot hunti lpupatio nan dunti lmot h emergence,wa slonge ra sth eegg sha dhatche d lateri nth epreviou syea r (table 13).Th e relationshipbetwee nth edevelopmenta lperio do fpost-diapaus e larvaean dth edat eo feg g hatchingi nth epreviou syea rwa sals oexpresse d inth enumbe ro fmoult sdurin gpost - diapausedevelopmen t (table 14). Thetota lnumbe ro fmoult s (pre-diapause+ post-diapause) ,an dpupa lbod ywidth ,wer e notclearl ycorrelate dwit hth edat eo feg ghatching ,an dthu swit hth einsta ri nwhic h diapausewa sentere d (table 14). 35 Table 13.Mea nduratio no fpost-diapaus edevelopmen t (days)i n 1979 (outdoorexperiment s witha fiel d strain). Statisticalevaluatio no fth edifference sbetwee nmale san dfemale s (1-sided t-test,P^ .05) . Starto fpost-diapaus edevelopmen ta t1979-04-13 . Dateo feg g hatching Meandevelopmen t Meandevelopmen t Meandevelopmen t in197 8 durationunti l durationo fth e durationunti lmot h pupationi n 1979 pupaei n197 9 emergencei n197 9 dd 35.8(n=28 ) 17.8(n=25 ) 53.6 1978-08-01 S S S 99 42.7 (n=37) 13.9 (n=32) 56.6 o*3 53.7 (n=31) 16.3(n=27 ) 70.0 1978-08-17 S S NS 99 56.6 (n=25) 15.5(n=23 ) 72.1 do* 55.2(n=45 ) 15.4(n=40 ) 70.6 1978-09-09 S S NS 99 59.6 (n=32) 13.6 (n=29) 73.2 Table 14.Mea nnumbe ro fmoult sdurin gpre -an dpost-diapaus edevelopment .Mea npupa l widthafte rdiapaus e (outdoorexperiment swit ha fiel d strain). Statisticalevaluatio n ofth edifference sbetwee nmale san d females (1-sidedx ?-test,P^.05) . Dateo feg ghatchin g Meannumbe ro fmoult s Meantota lnumbe ro f Meanpupa l in197 8 duringlarva lpost - moults (pre-diapause bodywidt h diapausedevelopmen t +post-diapause ) (mm) in197 9 1.0 (n=28) 5.3 2.58 1978-08-01 S NS 99 1.6 (n=37) 5.5 2.94 ss 1.9 (n=31) 5.3 2.39 1978-08-17 NS NS 99 2.2 (n=25) 5.4 2.86 do* 2.3 (n=45) 5.2 2.46 1978-09-09 NS NS 99 2.5 (n=32) 5.4 2.95 2.6 (n=38) 4.6 2.50 1978-09-25 S S 99 3.2 (n=29) 5.2 2.86 dd 3.2 (n=22) 5.1 2.46 1978-10-14 S S 99 3.6 (n=23) 5.7 3.01 36 Thevariabilit yi nth enumbe ro flarva linstar s (Section4.1 )wa sprobabl yonl y expresseddurin gpost-diapaus edevelopment ,a sth enumbe ro fmoult su pt oth eonse to f diapausewa sstrongl ycorrelate dwit hth emomen ti nth eseaso ni nwhic hth eegg shatche d (table 11). Thelarva etha twer ediapausin goutdoor saverage don emor emoul ttha nnon-diapausin g larvaei nlaborator yrearing s (compareth etable s3 an d 14).Bonnemaiso n (1977)reporte da similarphenomeno ni nth esummer-frui ttortri xmoth , Adoxaphyes orana (F.v.R.),th elarva e goingthroug hsupernumerar ymoult safte rth eterminatio no fdiapause . Pupalbod ywidt hafte rdiapaus eoutdoor swa ssignificantl yhighe rtha nafte rnon - diapausedevelopmen ti nlaborator yrearing s (comparetable s1 0an d 14)(2-side dt-test , P<.05).Thi sma yb econnecte dwit hth ehighe rnumbe ro fmoult si nthi sdiapausin g generation (tables3 an d 14). Diapausingmal elarva etende dt odevelo pthroug ha lowe rnumbe ro fmoult stha n diapausingfemal elarvae .However ,th edifferenc ei nmea ntota lnumbe ro fmoult s(pre - diapause+ post-diapause )wa sonl ysignifican tfo rth eeg ghatchin gdate s 1978-09-25,an d 1978-10-14 (table14) .Th eduratio no flarva lpost-diapaus edevelopmen twa sshorte ri n males,bu ti nth epupa lstag emal edevelopmenta ltim ewa slonge r (table 13).Simila r phenomenawer eobserve d inth eexperiment so nnon-diapaus edevelopmen t (tables4 ,6 ,an d 8). Theresul twa sa sligh tprotandr yi nmot hemergence .Th edifferenc ei nmea ntota l durationo fpost-diapaus edevelopmen tunti lmot hemergenc ebetwee nmale san dfemale swa s significant,excep tfo rth eeg ghatchin gdate s 1978-08-17an d1978-09-0 9 (table 13).I n Lepidopteraan dman yothe rinsect sther ei sa genera ltendenc yfo rmale st oemerg ebefor e females (protandry).Differen texplanation shav ebee nadvanced .Thes ear esummarize db y Wiklund& Fagerströ m (1977).No tonl ynon-diapause ,bu tals opost-diapaus edevelopmen t canvar ywit hse x (Tauber& Taube r 1976). 5.3INFLUENC EO FTEMPERATUR EAN DPHOTOPERIO DO NTH EINSTA RI NWHIC HDIAPAUS EI SENTERE D Fromth eoutdoo rexperiment sdescribe di nSectio n5. 2 itappear stha tth einsta r inwhic hdiapaus ei sentere di svariable ,an dtha ti ti sstrongl ycorrelate dwit hth emomen t inth eseaso ni nwhic hth eegg shatch .I tma ytherefor eb edetermine db yphotoperio dand/o r temperature.Th einfluenc eo fthes etw ofactor swa sinvestigate d inlaborator yexperiments . Eggso fa fiel dstrai n (4thlaborator ygeneration) ,an dlarva efro mthes eeggs ,wer e reareda tdifferen tcombination so ftemperatur ean dphotoperio d (13C ,1 5C ,an d 20C ;5 , 8,13 ,an d1 6hour sligh tpe rday) . Inth eNetherland s (stationD eBilt )th emea ndail y temperaturei s16.4° Ci nAugust ,14.0° Ci nSeptember ,an d10. 3C i nOctobe r (Anonymus 1982).Th emea ndail ytemperatur e inDutc hros ehouse si sabou t1 8C i nwinte ran d 20C i n summer.Da ylengt hi nth eNetherlands ,includin gcivi ltwilight ,varie sbetwee n approximately8 an d 18hour s (Beck1980 ,pp . 3-6). Thedevelopmen to fth eindividua llarva ewa sobserved .Th emoult swer eobserve da t 24-hourintervals .Diapaus ewa sconsidere dt ob eentere da ssoo na sth efirs tmoul t withinth ehibernaculu mha doccurred .Fo reac hexperimen t 100larva ewer eused . 37 Table15 .Percentag eo flarva egoin gthroug hdifferen tnumber so fmoult su pt oth eonse t ofdiapause ,a tdifferen t temperaturean dphotoperio d combinations (laboratoryexperiment s witha fiel d strain). Diapause enteredafte r 2mo u Its 3mo u lts 4moult s 5moult s 6moult s 5hour s 13°C light 15°C n=89 100% perda y 20°C 8hour s 13°C n=85 100% light 15°C n=88 100% perda y 20°C n=95 100% 13hour s 13°C n=90 2% 92% 6% light 15°C n=81 2% 96% 1% perda y 20°C n=92 86% 14% 16hour s 13°C n=87 90% 8% 3% light 15°C n=94 96% 3% 1% perda y 20°C n=89 2% 90% 6% 2% Theresult sar egive ni ntabl e 15.Th ephotoperio dha da pronounce d influenceo nth e numbero fmoult sunti lth eonse to fdiapause .A t1 6hour sligh tpe rda ymos to fth elarva e entereddiapaus eafte r4 moults ,an da t1 3hour sligh tpe rda yafte r3 moults .A t8 an d5 hoursligh tpe rda yal lth elarva eentere ddiapaus eafte r2 moults .Occasionall ydiapaus e wasentere dafte r5 o r6 moult s (at1 6hour sligh tpe rday) ,bu tneve rafte r 1moult . Someo fth elarva ei nth eoutdoo rexperiment s (table 11)hibernate dafte r 1moult .The y wereprobabl yno tabl et oreac hcomplet ediapaus eo ntime ,befor ehibernatio nstarted . Theybuil ta hibernaculum ,bu tdi dno tmoul twithi nit .I ti sremarkabl etha tsom eo fthe m wereabl et osurviv ewinte ran dt opupat ei nsprin go fth enex tyear . Temperature,a tleas twithi nth erang einvestigate d (13C-2 0 C), didno tsee mt o influenceth enumbe ro fmoult safte rwhic hdiapaus ewa sentere d (table15) . Intabl e1 6th emea nduratio nfro meg ghatchin gunti lth eonse to fdiapaus e isgive n foreac hinvestigate d combinationo ftemperatur ean dphotoperiod .Th edat ai nthi stabl e confirmthat ,a tan ytemperature ,th etim erequire dt oente rdiapaus ewa sshorte raccordin g asth ephotoperio dwa sshorter . Table 16.Mea ndevelopmen tduratio nfro meg ghatchin gu pt oth eonse to fdiapaus e (days) atdifferen t temperature andphotoperio d combinations (laboratoryexperiment swit ha fieldstrain) . 5hour s 1 Lght 8hour s 1 Lght 13hour s light 16hour sligh t perda y perda y perda y perda y 13°C * 38.8 51.0 110.1 15°C 28.2 ^ 27.7 35.1 86.0 20°C 19.3 24.9 38.6 * noexperimen tconducte d 38 5.4DISCUSSIO N Fieldpopulation so f C. spectrana havea facultative ,photoperiodicall yinduce d larvaldiapause .Th ephotoperiodi crespons ei so fth e"long-day "type ,an dth ecritica l photoperiod isbetwee n1 6an d1 7hours .Th enumbe ro fmoult su pt oth eonse to fdiapaus e variesbetwee n2 an d6 ,an di sdetermine db yth ephotoperiod ,a tleas twithi nth e temperaturerang e1 3C-2 0C .I ti slowe ra sdaylengt hi sshorter .Outdoors ,th etim eo f resumptiono fgrowt han dmoultin gafte rdiapaus eterminatio ndoe sno tvar ywit hth edat e ofeg ghatchin gi nth epreviou syear ,an dthu swit hth einsta ri nwhic hdiapaus ei s entered.Th eduratio no fpost-diapaus edevelopmen ti slonge ra sdiapaus ei sentere dafte r a lowernumbe ro fmoults . Larvaefro megg stha thatc hlate ri nth eseaso nente rdiapaus eafte ra lowe rnumbe r ofmoults ,an dthu shav ea bette rchanc eo freachin gdiapaus eo ntime ,befor eth eleave s ofth ehos tplan tdeteriorat ean dth etemperatur edrop spermanentl ybelo wth elowe rtherma l thresholdfo rdevelopment .Becaus eth enumbe ro fmoult safte rwhic hdiapaus ei sentere di s variable,a nadditiona lvariatio ni nth eduratio no fpost-diapaus edevelopmen ti sinduced . Thiscounteract sth esynchronizin geffec to fresumptio no fgrowt han dmoultin gi nspring , andbring sabou ta longe rduratio no fth efirs tfligh tperiod . Thefunctiona lsignificanc eo fthes emechanism smigh tb et osynchronis eth eonse to f diapausewithou talterin gth eag estructur eo fth epopulation si nsprin gi nthi sbivoltin e tortricid.Multivoltin especie swoul db ebette rabl et ocop ewit ha los so fvariatio ni n theag estructure . Inothe rLepidopter ath einsta ri nwhic hlarva ldiapaus ei sentere dmigh tals ob e variable.SSringe r& Szentkirâly i (1980)foun dtha tlarva eo fth eplu mfrui tmoth , Grapkolitha funebrana (Tr.),tha tentere ddiapaus eearlie ri nth eyea rha dlarge rbod y weights.Geyspit s (1965)investigate dth epin emoth s Dendrolimus pini (L.)an d D. Sibiriens (Tschetw.)an dfoun dtha tdiapaus ewa sentere di na nearlie rlarva linsta raccordin ga sth e temperaturewa slowe ran dth ephotoperio dwa sshorter .Thi ssynchronise s theonse to f diapause.Geyspit sargue dtha ta mechanis mwhic hprevent sprematur einductio no fdiapaus e isneede di nthes especie swit ha lif ecycl etha texceed sa year ,an dwhos ediapaus ei s shortan di sterminate dwithou tcol dreactivation .Sh eals oargue dtha tth enee dfo r specialmechanism stha tsynchronis ebot honse tan dterminatio no fdiapaus ei sfel ti n specieswit ha nannual ,o rlonger ,cycle ,a swel la si nspecie swit ha polycycli ctyp eo f development. 39 6 Photoperiodic response in greenhouse populations 6.1 LABORATORYEXPERIMENT S Thephotoperiodi crespons eo f5 differen tgreenhous estrain s (1stlaborator y generation)wa steste di nth esam ewa ya stha to fa fiel dstrai n (Section5.1) .Th e5 strainsha dbee ncollecte da slarva ean dpupa efro mdifferen tros ehouse sa tdifferen t timeso fth eyea r (bothi nwinte ran dsummer) :fro mAalsmee ri nNovember ,fro mD eKaa gi n January,fro mRoelofarendsvee ni nFebruary ,fro mSlote ni nJune ,an dfro mEmmeloor di n June.Photoperiod so f8 ,10 ,12 ,14 ,16 ,an d1 8hour swer etteste da t15° Can d2 0C .N o diapausecoul db einduce di nan yo fth egreenhous estrains . 6.2OUTDOO REXPERIMENT S Thephotoperiodi crespons eo fon eo fth e5 greenhous estrain smentione d inSectio n 6.1,originatin gfro mth eros ehous ei nSloten ,wa sals oteste dunde routdoo rcondition s inth e2n dan d3r dlaborator ygeneration .Experiment ssimila rt othos ewit ha fiel dstrai n (Section5.2 )wer edone .Field -an dgreenhouse-strai nlarva ewer ereare di nth esam e outdoorcage .Th eexperiment swit hth egreenhous estrai nwer edon ewit hegg stha thatche d onAugus t1 ,Augus t 17,Septembe r25 ,an dOctobe r 14,1978 ,respectively .Thes eeg ghatchin g datescoincide dwit hthos eo fth efiel dstrain . Figures9 an d 10sho wth ecomparativ emeasurement so fth emea nhea dcapsul ewidt hi n eachrearin go ffield -an dgreenhouse-strai nlarva ei nth ecours eo fth eseason .Th ecurve s representingmea nhea dcapsul ewidt ho ffield-strai nlarva elevele dof fbecaus ediapaus e wasentered .Th ecurve so fth egreenhous estrai nalway sreache da significantl yhighe r leveltha nthos eo fth efiel dstrain ,an dcontinue dt oincreas eunti lth eonse to fcol d weatheri nDecember .Thi sindicate s thatno ,o ronl ysome ,greenhouse-strai nlarva e entereddiapause .Thi swa schecke db ystudying ,i nmor edetail ,th elarva ldevelopmen t aftereac heg ghatchin gdate . Egg hatching 1978-08-01 ByDecembe r 25,197 8 (onseto fhibernation ,se eSectio n5.2) ,90 So fth egreenhouse - strainlarva eha dpupated .Th elarges thea dcapsul ewidt hfoun damon gdiapausin glarva e ofth efiel dstrai nwa s0.8 8mm .However ,th ehea dcapsul ewidt ho fth eremainin g greenhouse-strain larvaewa sa tleas t1.0 4mm .Probabl ythe ywer eno tdiapausing ,bu tha d reachedth elas tinsta rbefor epupation .The yal ldie ddurin gwinter . 40 3th ol head capsules ,( iU^ _J_I_Ï—ï- -« greenhouse stra hing.1-8-1978 A-r\ "Tl" ,Ä /I I I T "E- i/ y}' / •—— »greenhouse sira m ƒ egg hatching^ 17-8-1978 // Dec.1978 Jan. 1979 Figure9 .Mea nhea dcapsul ewidt h (mm),i nth ecours eo f theseason ,o f larvaeo fa fiel dan da greenhous e strainreare doutdoors .Eg ghatchin g dates: 1978-08-01 and 1978-08-17.Vertica lbar srepresen t thereliabilit y intervalso fth emeans . 41 egg hatching: 25-9-1978 J Mean width of • • .-'Ï- -I _. ^ o^~ -'"^ ƒ . —- / // Figure 10.Mea nhea dcapsul ewidt h (mm)i nth ecours eo fth eseason ,o f larvaeo fa fiel dan da greenhous estrain ,reare doutdoors .Eg ghatchin g dates: 1978-09-25an d 1978-10-14.Vertica lbar srepresen t thereliabilit y intervalso fth emeans . 42 Egg hatching 1978-08-17 ByDecembe r25 ,1978 ,31 4o fth egreenhouse-strai nlarva eha dpupated .Th ehea d capsulewidt ho f46 4o fth elarva ewa s> ^1.0 4mm .The yha dgon ethroug h4 o r5 moults ,an d hadprobabl yreache dth elas tinsta rbefor epupation .Th eres to fth egreenhouse-strai n larvae (headcapsul ewidt h< 1.0 4mm )hibernate dafte r3 o r4 moults .Th emea nhea d capsulewidth so fth esuccessiv einstar so fthes elarva ear egive ni nth efigure s1 1an d12 . Theydi dno tessentiall ydeviat efro ma geometrica lprogression ,contrar yt othos eo f diapausingfield-strai nlarvae .Probabl ythes egreenhouse-strai nlarva ewer eo fth e6 - and7-insta rgrowt htype ,an dha dreache dth e4t ho r5t hinsta rb yth eonse to f hibernation,withou tenterin gdiapause .Th e5-insta r larvaeo fth egreenhous estrai n hadb ythi stim epupate do rreache dth eprepupa linstar .Th ewinte rmortalit yo fth e hibernatinggreenhouse-strai nlarva e (egghatchin g1978-08-17 )wa sno tdetermined . Igmea nwidt ho fhea dcapsule s —o field strj greenhouse strain Larval instars Figure 11.l go fmea nwidth so fth ehea dcapsule s (mm)o fth eseparat e instarso flarva e ofa fiel dan da greenhous e strain,hibernatin gafte r3 moults .Eg ghatching :1978-08-17 . Verticalbar srepresen t thereliabilit y intervalso fth emeans . 43 lgmea nwidt ho fhea dcapsule s greenhouse strain Larval instars Figure 12.l go fmea nwidth so fth ehea d capsules (mm)o fth e separate instarso flarva eo fa fiel dan da greenhous estrain , hibernatingafte r4 moults .Eg ghatching : 1978-08-17.Vertica l barsrepresen t thereliabilit y intervalso f themeans . Egg hatching 1978-09-25 Nopupatio noccurre di nth egreenhous estrai nbefor eDecembe r25 ,1978 .Th e frequencieso fth edifferen tnumber so fmoult stha toccurre dunti lhibernation ,an dth e mortalityo fhibernatin g larvae,ar egive ni ntabl e 17. Fieldpopulation so f C. speatvana enterdiapaus eafte ra tleas t2 moult s (Section 5.3).Thu sth egreenhouse-strai n larvaehibernatin gafte r 1moul t (table17 )wer e probablyno tdiapausing .Th emea nhea dcapsul ewidth so fth esuccessiv e instarso f greenhouse-strainlarva ehibernatin gafte r 2o r3 moult s (table17 )di dno tessentiall y deviatefro ma geometrica lprogression ,contrar yt othos eo ffield-strai nlarva eenterin g diapauseafte r2 o r3 moult s (figures1 3an d 14).Thi sindicate stha ta tleas tmos to f thesegreenhouse-strai nlarva edi dno tente rdiapause .Th emortalit yo fhibernatin g larvaewa smuc hhighe r inth egreenhous estrai ntha ni nth ediapausin g fieldstrai n (table 17). 44 Table 17.Frequencie so fth enumber so fmoult soccurrin gunti lhibernatio ni na greenhousestrain ,an dwinte rmortalit y (outdoorrearing ,egg shatche d 1978-09-25). Numbero fmoult s Proportiono fth etota l Mortalityo fhirbernatin g untilhibernatio n numbero flarva e larvaeunti lpupatio ni n (greenhousestrain ) (greenhousestrain ) thenex tsprin g 1 20% 2 33% greenhousestrain :94 % 3 46% n=69 fieldstrai n :12 % n=76 Larvaldevelopmen to fbot hstrain swa scompare dwit ha simulate dnon-diapaus e developmento f5-insta rlarvae .Th eus eo fthi ssimulatio nmode li sjustifie d inthi scase , asth elarva ei nthes eoutdoo rrearing s (egghatchin g 1978-09-25)di dno tdevelo pfurthe r thanth e4t hinsta runti lth eonse to fhibernatio n (tables1 1an d 17),an dth edifferenc e indevelopmen tduratio nbetwee nth e5- ,6- ,an d7-insta rgrowt htyp ei sstrongl yexpresse d onlyfro mth e5t hinsta ron .Th esimulation swer edon eaccordin gt oa metho ddesigne db y DeWi t& Goudriaa n (1974)("boxca rtrai nwit hcontrolle ddispersion") .Th esimulation swer e doneo nth ebasi so fth etemperatur erecorde db yth ethermohygrograph ,an dth erecorde d lgmea nwidt ho fhea dcapsule s Figure 13.l go fmea nwidth so f thehea dcapsule s(mm )o fth e separateinstar so flarva eo f greenhouse strain afiel dan da greenhous e strainhibernatin gafte r2 moults.Eg ghatching :1978 - 09-25.Vertica lbar srepresen t thereliabilit y intervalso f themeans . L5 L6 Larval instars 45 lgmea nwidt h ofhea dcapsule s Figure 14.l go fmea nwidth so f thehea dcapsule s (mm)o fth e separateinstar so flarva eo f —* greenhouse afiel dan da greenhous e strainhibernatin g after3 moults.Eg ghatching :1978 — 09-25.Vertica lbar srepresen t thereliabilit y intervalso f themeans . L1 L2 L3 Larval instars temperature+ 1 C,t oallo wfo rth einaccurac yo fth etemperatur emeasurement .Th e temperature indicatedb yth ethermohygrograp hwa scompare donc ea wee kwit hth e temperature indicatedb ya gauge dmercur ythermometer .Afte rsom etim eth ethermohygrograp h showeda lowe rtemperature .Th edeviatio nwa sneve rlarge rtha n1 C . Thesimulatio nresult sar epresente d infigur e 15.Larva ldevelopmen to fth efiel d andth egreenhous estrain ,an dth esimulate dnon-diapaus edevelopment ,coincide dfairl y welli nth e 1stan d 2ndinstar .I nth e3r dan d4t hinstar ,th edevelopmen to fth efiel d straindeviate dappreciabl y fromth egreenhous estrai ndevelopment ,an dfro mth esimulate d non-diapausedevelopment ,becaus ediapaus ewa sentered .Th emajo rpar to fth efiel dstrai n larvaeinterrupte d itsdevelopmen tan dentere ddiapaus eafte r2 moults . Egg hatching 1978-10-14 Nopupatio noccurre di nth egreenhous estrai nbefor eDecembe r 25,1978 .Th e frequencieso fth edifferen tnumber so fmoult stha toccurre dunti lth eonse to f hibernation,an dth emortalit yo fhibernatin g larvae,ar egive ni ntabl e18 .Th egreenhouse - -strainlarva eunderwen t1 o r2 moult sunti lhibernation .Th elarva ehibernatin gafte r1 moult (table18 )probabl ywer eno tdiapausing .I fther ewer ediapausin g greenhouse-strain 46 proportion of the larvae in L1 ' o field strain ——* greenhouse strain • simulated development (recorded temp.) • simulated development (recorded temp.+ 1°C) •-t^S^g.- , •**- December 1978 proportion of the larvae in L2 December 1978 proportion of the larvae in L3 10. 0.8 . ><£*- December 1978 proportion of the larvae in L4 December 1978 Figure 15.Larva ldevelopmen t inoutdoo rrearing so fa fiel dan da greenhous estrain , and simulatednon-diapaus edevelopment .Eg ghatching :1978-09-25 . larvaeamon gthos ehibernatin gafte r2 moults ,the ycoul db eexpecte d tob e amongthos etha twer eabl et oreac hth epupa lstag ei nth enex tspring .Th emea nhea d capsulewidth so fth esuccessiv einstar so fthes elarva ear egive ni nfigur e16 .The ydi d notessentiall ydeviat efro ma geometrica lprogression ,contrar yt othos eo fth efield - -strainlarva ediapausin gafte r2 moults .Thu sa tleas tth emajo rpar to fthes egreenhouse - -strainlarva edi dno tente rdiapause .The yobviousl ysurvive da temperature-induce d quiescencetha tlaste dsevera lmonths .Quiescenc ei sa direc trespons et oadvers ephysica l 47 Table 18.Frequencie so fth enumber so fmoult soccurrin gunti lhibernatio n inth e greenhousestrain ,an dwinte rmortalit y (outdoorrearing ,egg shatche d 1978-10-14). Numbero fmoult s Proportiono fth etota l Mortalityo fhibernatin g untilhibernatio n numbero flarva e larvaeunti lpupatio ni n (greenhousestrain ) (greenhousestrain ) thenex tsprin g 1 7% greenhouse strain:72 % 2 93% n=74 fieldstrai n :44 % n=71 conditions,an ddiapaus ea nindirec trespons einduce db yperiodi ctoke nstimul isuc ha s photoperiod (Beck1980 ,pp.119-120) .Th emortalit yo fhibernatin g greenhouse-strain larvaewa sabou ttwic etha to ffield-strai nlarva e (table 18). 6.3DISCUSSIO N Fivedifferen trose-hous estrain sdi dno tente rdiapaus ea tan yphotoperio da t2 0C and1 5C o nartificia ldie ti nth elaboratory . Themea nhea dcapsul ewidth so fth esuccessiv e instarso foutdoo rreare dhibernatin g lgmea nwidth so fhea dcapsule s Figure 16.l go fmea nwidth so f thehea dcapsule s (mm)o fth e separateinstar so flarva eo f afiel dan da greenhous e straintha thibernate dafte r 2moult san d thatwer eabl e toreac hth epupa lstag ei n thenex tspring .Eg ghatching : 1978-10-14.Vertica lbar s represent thereliabilit y intervalso fth emeans . L1 L2 Larval instars 48 larvaeo fon eo fthes egreenhous estrain sneve rappreciabl ydeviate dfro ma geometrica l progression,contrar yt othos eo fdiapausin gfield-strai nlarvae .Thi swa svali deve nfo r thegreenhouse-strai nlarva efro megg stha thatche di nmid-October ,an dtha twer eabl et o reachth epupa lstag edurin gth enex tspring .Thu sfo rever yeg ghatchin gdat ei nth e outdoorrearing s itwa sprove dtha ta tleas tth emajo rpar to fth egreenhouse-strai n larvaedi dno tente rdiapause .Apparentl ythi sgreenhous estrai nha dt oa larg eexten t lostit sabilit yt oente rdiapause ,no tonl yi nlaborator yexperiment sbu tals ounde rth e testedoutdoo rconditions ,o nartificia ldiet . Inthei rnatura lenvironment ,rose-hous estrain so f C. spectrana arealmos t certainlynon-diapausing .Eve nunde rnatura lcondition si nth eope nfiel dn odiapaus ema y beinduce di nthes epopulations . 49 7 Diapause ofa field strai nunde rgreenhous e conditions Thephotoperiodi crespons eo ffiel dpopulation so f C. speatrana isdifferen tfro m thato fgreenhous epopulation s (Chapter 6). Possiblyfiel dpopulation schange dthei r photoperiodicrespons eunde rth einfluenc eo fspecifi cselectio npressures ,afte r immigrationint oheate dgreenhouses .T odiscer nho wthi sselectio nma ytak eplace , knowledgeabou tinduction ,maintenance ,an dterminatio no fdiapaus e infiel dpopulation s introduced intogreenhous eculture s isneeded . Theclimat ei nheate dgreenhouse s ischaracterise db yth elac ko fa perio do f chillingdurin gwinter .Man yinsect si na stat eo fdiapaus edi ewithou tdeveloping ,o r growi na protracte dan dirregula rmanner ,whe nexpose dt otemperature stha twoul db e expectedt ofavou rnon-diapaus emorphogenesi s (Lees1955 ,p .50) . 7.1MAINTENANC EAN DTERMINATIO NO FDIAPAUS EWITHOU TA PERIO DO FCHILLIN G 7.1.1 Greenhouse experiments Field-strainegg s (3rdan d4t hlaborator ygeneration) ,an dlarva etha thatche dfro m theseeggs ,wer ereare di na Gerbera houseo nartificia ldie ti na cag etha twa s protectedfro mth esun .Th egreenhous ewa sheate di nwinte r (meandail ytemperatur e 18C , minimumnigh ttemperatur e1 5C) . Pupationwa sobserve da t1- 3da yintervals .Th e experimentwa sdon etwice ,durin gth esecon dfligh tperio do ffiel dpopulations ,wit hegg s thathatche do nAugus t 24,an dOctobe r22 ,1979 .I neac htria l20 0larva ewer eused . Larvaldevelopmen tunde rthes econdition swa scompare dwith : a.Non-diapaus edevelopmen ti nth esam e Gerbera house (100field-strai nlarva efro megg s thathatche do nJul y6 ,1980 ;pupatio nwa sobserve da t24-hou rintervals) . b.Developmen to ffield-strai nlarva ewit hdiapaus eoutdoor s (Chapter5) . c.Non-diapaus edevelopmen toutdoor s (100fiel dstrai nlarva efro megg stha thatche do n July6 ,1980 ;pupatio nwa sobserve da t24-hou rintervals) . Infigur e 17,pupatio nrat ei nth ecours eo ftim eo fth elarva efro megg stha thatche d onAugus t 24,an do nOctobe r22 ,197 9i nth e Gerbera house,i sgiven .Abou t6 week safte r egghatchin gal lth elarva eha dmad ea hibernaculum .Th efirs tpupatio noccurre da tleas t 150day safte reg ghatching .Thu si twa scertai ntha tal lth elarva eentere ddiapause . Thetim eelapsin gbetwee nth efirs tan dth elas tpupatio nwa sextremel ylong .Th e larvaefro megg stha thatche do nAugus t24 ,1979 ,pupate dbetwee nJanuar y 28an dJul y1 5 ofth efollowin gyea r (figure17) .Th elarva efro megg stha thatche do nOctobe r 22,1979 , pupatedbetwee nMarc h2 1an dJul y1 8o fth efollowin gyea r (figure17) .Th enumbe ro f 50 Number of pupae formed per day egg hatching, 24-8-1979 -mi HI 1—i l l Qt 28-1-19 80 February July 15-7-1980 Date in 1980 Number of pupae formed per day egg hatching;22 -10-1979 h=Db= March 21-3-1980 Apri July 18-7-1980 Dale in 1960 Figure 17.Pupatio nrat eo fa fiel dstrai nafte rdiapaus ei na heate dgreenhouse .Eg g hatching:24-08-197 9an d22-10-1979 . pupaeforme dpe rda ywa sth ehighes taroun dmid-Ma yi nbot htrials ,bu ta larg epar to f thelarva epupate dbefor eo rafte rMa y198 0(figur e 17). Apparentlyth edevelopmen tduratio no fthes ediapausin glarva ewa sextremel y variable,an dneithe ra perio do fchillin gno rlong-da ycondition swer eprerequisite sfo r diapausetermination . Intabl e19 ,larva ldevelopmen t (diapausean dnon-diapause )outdoor san di nth e Gerbera housei scompared .Th eextremel ylon gperio dwhic helapse dbetwee nth efirs tan d thelas tpupatio nafte rth efiel d strainlarva eha dterminate dthei rdiapaus ei nth e greenhousei sals oeviden tfro mth edat ai ntabl e 19.Afte rdiapaus eoutdoor sthi sperio d 51 Table 19.Larva ldevelopmen t (diapausean dnon-diapause )o fa fiel d straino na nartificia l dietoutdoor san d ina Gerbera house. Rearing Dateo fe g Larvalmortalit y Timebetwee n Meandevelopmenta l situations hatching (egghatchin gu p firstan dlas t timeo ffemal e topupation ) pupation (days) larvaeminu smal e larvae (days) diapausei na 1979-08-24 23% 168 18 Gerbera house 1979-10-22 27% 119 21 1978-08-01 19% 38 7 diapause 1978-08-17 30% 52 3 outdoors 1978-09-09 10% 67 4 1978-09-25 16% 36 10 non-diapausei n 1980-07-06 17% a Gerbera house non-diapause 1980-07-06 33% 16 outdoors wasmuc hshorter ,althoug hth emea ndail ytemperatur ewa sconsiderabl y lowertha ni nth e greenhouse. Theextrem evariabilit yi ndevelopmen tduratio no fdiapausin g larvaei nth e greenhousecoincide dwit ha nincreas ei nth edifferenc e inmea ndevelopmenta l timebetwee n malean dfemal e larvae (table19) .Thus ,especiall y inth ebeginnin gan da tth een do fth e perioddurin gwhic hpupatio ntoo kplace ,th echanc eo femergin g field-strainmoth st ofin d amatin gpartne rwa sconsiderabl yreduced . Larvalmortalit ydurin gdevelopmen twit hdiapaus ewa sno tappreciabl y increasedi n thegreenhous ecompare dt oth eothe rrearin gsituation smentione d intabl e 19.Abou t75 1o f thelarva ei nth egreenhous ereache dth epupa lstage ,althoug hthe yha dt oterminat ethei r diapausewithou ta perio do fchilling .Th efertilit yo fth efemal emoth safte rterminatio n ofdiapaus ewa sno tinvestigated . Whena fiel dstrai ni sintroduce d intoculture si nheate dgreenhouses ,diapaus ewil l beentere da ssoo na sth eda ylengt hi ssufficientl yshort .Diapaus ewil lconsiderabl y decreaseth emultiplicatio nrat eo fth epopulatio npe rannum ,bu tth eabsenc eo fa perio d ofchillin gwil lno tessentiall yaffec tth esurviva lrat eo fth ediapausin glarvae . 7.1.2 Laboratory experiments Additionalexperiment swer edon ei nth elaboratory ,i nwhic hth edevelopmen to f individualdiapausin g larvae,withou tth einterferenc eo fa perio do fchilling ,wa s studied. Field-strainegg s (4thlaborator ygeneration) ,an d 250larva etha thatche d fromthes e eggswer ereare da t2 0C an d1 6h ligh tpe rda yunti lpupation .Larva etha tdi dno tdi e orpupat ewithi n2 month safte reg ghatchin gwer econsidere d tob ediapausing .Moult san d 52 Table 20.Frequencie s (%) of the numbers ofmoult s of diapausing larvae, from egg hatching up to death or pupation, larval mortality, and mean timeneede d by diapausing larvae to reach the pupal stage, indifferen t rearing situations,o f field strains. Number of Rearing situations moults from egg hatching outdoors laboratory laboratory until death (egg hatching Aug.1 (20°C and 16 h light (20°C and 16h light or pupation and 17, Sept. 9 and per day) per day; after 2 of diapausing 25, 1978) months: 20°C and 18 larvae h. light per day) larvae larvae larvae larvae larvae larvae pupating dying pupating dying pupating dying 2 6% 3 3% 5% 4 8% 64% 4% 1% 11% 5 61% 18% 7% 16% 9% 11% 6 27% 6% 18% 16% 41% 23% 7 3% 3% 11% 9% 24% 11% 8 J8 % 17% 15% 11% 9 22% 9% 5% 11% 10 9% 6% 2% 11% 11 9% 6% 2% 2% 12 4% 2% 13 3% 14 7% 6% 15 3% 16 _— 17 18 2% mean number 5.2 4.2 8.6 8.3 6.7 7.0 of moults n=260 n=33 n=45 n=90 n=147 n=44 mortality from egg hatching up 10-30% 77% 33% to pupation mean time needed by the diapausing larvae to reach 98 (S D.=48) 70 (S.D.=48) the pupal stage (days) pupationo tth ediapausin g larvaewer eobserve da t2-da yintervals . Ina secon dexperiment ,field-strai negg s (4thlaborator ygeneration) ,an d25 0larva e thathatche d from theseeggs ,wer ereare da t20° Can d1 6h ligh tpe rday .Th elarva e that didno t dieo rpupat ewithi n2 month safte reg g hatching,wer econsidere dt ob ediapausin g andtransferre dt o2 0C an dL D18: 6 (conditions thatd ono tinduc ean ydiapause) .Moult s andpupatio no fthes elarva ewer eals oobserve da t2-da yintervals . Larvaldevelopmen tunde rth econdition sdescribe dabov ewa scompare dwit hth e developmento flarva ediapausin g outdoors (experimentsi nSectio n 5.2).Th eresult sar e presentedi ntabl e20 . 53 Themea nnumbe ro fmoult sfro meg ghatchin gunti lpupatio no fdiapausin g larvaewa s 5.2unde routdoo rconditions .Th enumbe ro fmoult soutdoor sneve rexceede d 7(tabl e20) . Themea nnumbe ro fmoult sincrease dt o6. 7a t2 0C an dL D18:6 ,an dt o8. 6a t2 0C and1 6h .ligh tpe rda yi nth elaboratory .Th evariabilit y inth enumbe ro fmoult swa s muchgreate ri nth elaborator ytha noutdoors .I ti sremarkabl ethat ,contrar yt oth e situationoutdoors ,som eo fth elaboratory-reare ddiapausin g larvaetha tdie dbefor e pupationunderwen ta highe rnumbe ro fmoult stha nan yo fth ediapausin g larvaetha twer e ablet oreac hth epupa lstage .Som eo fthes elarva edie dafte r1 8moult s (table20) . Theabsenc eo fa perio do fchillin gapparentl ycause sprotracte d andvariabl e developmenti ndiapausin g larvaeo f C. speatrana. At 20C an dL D 18:6,diapausin glarva eo nth eaverag eneede d7 0day st oreac hth e pupalstage ,whil ethe yneede d9 8day sa t20° Can d 16h ligh tpe rda y (table 20).Th e differencewa ssignifican t (2-sidedt-test ,P<.05) . Long-daycondition sapparentl yhaste nth eterminatio no fdiapause . 7.2HEREDIT YO FDEVELOPMEN TDURATIO NI NDIAPAUSIN GLARVA E Undergreenhous econditions ,withou ta perio do fchilling ,a stron gvariabilit yi n thetim erequire d fordiapausin g larvaet oreac hth epupa lstag ei sexpresse d (Section 7.1). Ifthi svariabilit y isgeneticall ydetermined ,selectio ni nfavou ro fa shorte r diapauseduratio nma yoperat ei nheate dgreenhouse s ifa fiel dstrai ni sintroduced . Experimentswer ese tu pt odetermin ewhethe rth edevelopmen tduratio no fdiapausin glarva e canb eshortene db yselectio nunde rcondition swithou ta col dperiod . Fromth egreenhous eexperimen tdescribe d inSubsectio n7.1. 1 (egghatchin g 1979-08-24) threegroup so fpupa ewer etaken : group 1:pupa eforme dbetwee n 1980-01-28an d1980-03-0 3 group2 :pupa eforme dbetwee n1980-05-0 1 and1980-05-1 4 group3 :pupa eforme dbetwee n1980-06-1 2an d1980-06-1 7 Offspringo feac hgrou pwa sreare da t20° Can d1 6h ligh tpe rday .Eac htim e22 0larva e wereused ,fro megg stha tha dhatche do nth esam eday .Th elarva etha tdi dno tdi eo rpupat e within2 month swer econsidere d tob ediapausing ,an dtransferre d to2 5C an dL D18: 6(long - -daycondition stha td ono tinduc ean ydiapause) .Pupatio nwa sobserve da t24-hou rinterval s todetermin e thelengt ho ftim eth ediapausin g larvaeneede dt opupate . Group1 ha dpupate dearlies tafte rdiapaus ei nth egreenhouse .Fro mth ediapausin g offspringo fthi sgroup ,th eearlies t3 mal epupa ean dth eearlies t3 femal epupa ewer e taken(i.e .grou p1-1) .Afte remergence ,th emoth swer emate dan dthei roffsprin greare d asth eparenta lgeneration .Fro mth ediapausin goffsprin go fgrou p1-1 ,agai nth eearlies t 3mal epupa ean dth eearlies t3 femal epupa ewer etake n(i.e .grou p1-1-1 )an dthei r offspringreare da sth eparenta lgeneration .Th eresult so fthes eexperiment sar egive n intabl e21 . 54 Table21 .Photoperiodi crespons eo ffield-strai nlarva ea tdiapaus e inductionan dtim e required fordiapausin glarva et oreac hth epupa lstage ,i nselectio nexperiments . Proportiono fth elarva e Meantim erequire db y thediapausin g enteringdiapaus ea t20° C larvaet oreac hth epupa lstag e and 16h lightpe rda y (days)a t25° Can dL D18: 6 offspring 93% 71 (S.D.=39) group1 n=130 1st gene offspring 96% 73 (S.D.=56) ration group2 n=51 offspring 64% 74(S.D.=33 ) group3 n=54 2nd offspring 100% 54(S.D.=26 ) gene- group 1-1 n=147 3rd offspring 94% 43 (S.D.=23) gene- group 1-1-1 n=I17 Withinth e1s tgeneratio n (offspringgroup s1-3) ,a differenc ei nth etim eneede dfo r diapausinglarva et oreac hth epupa lstag edi dno tappea r (table21) .Th edifference s betweenth eoffsprin go fth egroup s1 ,2 ,an d3 wer eno tsignifican t (2-sidedt-test , P>.05). Inth e2n dgeneratio n (offspringgrou p1-1) ,th emea ntim erequire dfo rdiapausin g larvaet oreac hth epupa lstag ewa ssignificantl yshorte rtha ni nth epreviou sgeneratio n (1-sidedt-test ,P<.005) . Inth e3r dgeneratio n (offspringgrou p1-1-1 )th emea nnumbe ro fday sneede db y diapausing larvaet oreac hth epupa lstag ewa sagai nsignificantl yshorte rtha ni nth e previousgeneratio n (1-sidedt-test ,P<.005) . Theshortene ddevelopmen tduratio no fdiapausin g larvaei nth e2n dan d3r dgeneratio n didno tcoincid ewit ha chang eo fth ephotoperiodi crespons ea t2 0C an d1 6h ligh tpe r day (table21) . Geneticallydetermine d intrapopulationvariatio ni nth eduratio no fdiapaus ei sfoun d inman yinsec tspecie s (Tauber& Taube r 1976).Th eresult si ntabl e2 1indicat esuc ha geneticallydetermine dvariatio ni n C. spectrana. Themea ntim erequire dfo rdiapausin g larvaet oreac hth epupa lstag eunde rcondition swithou ta perio do fchilling ,rapidl y respondedt oselection .Consequently ,i fa fiel dpopulatio no f C. spectrana isintroduce d intoculture si nheate dgreenhouses ,th emea ntim erequire dfo rdiapausin glarva et oreac h thepupa lstag ewil lgraduall yb eshortened ,larva epupatin gearlie rcontributin gsoone r toth ereproductio no fth epopulation .I fwithi nth efiel dpopulation ssufficien tgeneti c variationi spresent ,th eabov emechanis mmay ,afte ra sufficien tnumbe ro fgeneration si s passedi nth egreenhouse ,lea dt oa los so fdiapausin gbehaviou ro fth ewhol epopulatio n underthes econditions . 55 8 Female sex pheromone Femalese xpheromon eplay sa nimportan trol ei narousin gmatin gbehaviou ri nman y insectspecies .Th ecompositio no fth epheromon e isusuall yspecifi cfo reac hspecies , thuscontributin gessentiall yt othei rreproductiv eisolation . Todetec tpossibl eisolatio nmechanism sbetwee nfiel dan dgreenhous epopulation so f C. spectrana, studieso nse xpheromon ean dcallin gbehaviou ro fth efemal emoth sar e important.Th efemal ese xpheromon eo ffiel dpopulation so f C. spectrana comprisesa t least2 components ,cis-9 -an dcis-11-tetradecen-1-o lacetat e (cis-9-an dcis-11-TDA) . Cis-11-TDAi sth emai ncomponen t (Minkse tal . 1973).Optima lattractio ni nth efiel di s obtainedwit ha mixtur eo fcis-11 -an dcis-9-TD Ai nth erati o9: 1 (Minkse tal . 1974). Poorresult swer eobtaine dwhe nthi smixtur ewa suse di ngreenhouse s (Vand eVri e 1976). Thisma yindicat ea deviatin gcompositio no fth epheromon eproduce db ygreenhouse-strai n females.I tma yals ob ecause db yth edeviatin gnatur eo fth eai rmovement si ngreenhouses . 8.1 COMPOSITIONO FTH EFEMAL ESE XPHEROMON E Thecontent so fa numbe ro fpheromon egland so fa fiel dstrai n (2ndlaborator y generation)an da greenhous estrai n (3rdlaborator ygeneration )wer eanalyse db yga s chromatography.Th ecooperatio no fW.J .Nooije n (Divisiono fTechnolog y forSociet yTNO , Departmento fChemistry ,Delft )i nperformin gthes eanalyse si sgratefull yacknowledged . Fiftygland so feac hstrai nwer eused .Th efemale swer eallowe dt oemerg ea t20+ 1C unde r artificialwhit elight :ligh tperio d 17hours ,"dusk "1. 5hours ,dar kperio d4 hours , "dawn"1. 5hours .Th eligh tintensit ychange dlinearl ydurin g "dawn"an d"dusk" . Observationsdurin gth edar kperio dwer emad epossibl eb yth eus eo fre dfluorescen t lights.Th egland swer ecollecte ddurin gth esecon dhal fo fth edar kperio dwhe nth e femaleswer e4 day sold .Th eglands ,togethe rwit ha ninterna lstandar d (octadecaneC1 8 alcohol),wer ekep ti na naluminiu mcapsul ei nflui dnitroge n (-196 C). Thecontent so f theglands ,togethe rwit hth einterna lstandard ,wer einjecte dwit ha Perki nElme rM S4 1 solidinjecto r (Décoins& Galloi s1979 )int oa stainles sstee l ?>% ov-101colum no n chromosorbWHP ,2 m longwit ha ninne rdiamete ro f4 mm .Th eeffluent swer ecollecte di n theC1 4acetat earea ,an dwit ha fallin gneedl einjecto rpu tint oa glas sc pwa x5 1 capillary,5 0m lon gwit ha ninne rdiamete ro f0.2 5mm . Thefemal ese xpheromon eo fbot hstrain scontaine dtw ocomponent s inth eC I4 acetat e area.Th eretentio ntime so fthes ecomponent scoincide dwit hthos eo fcis-9-TD Aan dcis - 11-TDA.Th erati ocis-9:cis-1 1 inth epheromon egland swa s2:10 0 inth efiel dstrai nan d 1:100 inth egreenhous estrain . 56 cis isomer s cisisomer s %EA Grespons e 100 transisomer s transisomer s 90- 80- 60- greenhousestrai n field strain 50- 40- 30- 20 10- • nifl.n.nifllrrnlfllll 2 3 4 5 6 7 8 9 10 H 12 2 3 4 5 6 7 8 9 10 11 t2 positiono funsaturatio no ftetradecen-1-ol-acetate s position of unsaturation of tetradecen-1-ol-acetates Figure 18.Mal eantetma lrespons eo fa fiel dan dagreenhous e straint omono-unsaturate d tetradecen-1-olacetat e standards.EAG=electro-antennogram . (Averagecontro lrespons ei s 0t o1 percent) . Themal eantenna lrespons et oa serie so fmono-unsaturate dTD Astandard swa s determinedb yelectro-antennograph y (EAG).Thank sar edu et oDr.Ir .C.J .Persoon s (Divisiono fTechnolog yfo rSociet yTNO ,Departmen to fChemistry ,Delft )fo rcarryin gou t theseexperiments .Eigh tmale so feac hstrai nwer eused . Theresult sar epresente di nfigur e 18.Th eelectro-antennogra mpatter nwa sidentica l forth emale so fbot hstrains .Thi sconfirm s thatth erati ocis-9-TDA:cis-11-TD Awa sno t oronl yslightl ydifferen ti nth etw ostrains . 8.2CALLIN GBEHAVIOU RO FVIRGI NFEMALE SI NRELATIO NT OTH ELIGHT-DAR KCYCL E Eveni fth ecompositio no fth efemal ese xpheromon ei sidentica li nbot hstrains , mutualattractio nma yb einhibite di fth efemale scal la tdifferen ttime sdurin gth enight . Thecallin gbehaviou ro fvirgi nfemale si nrelatio nt oth elight-dar kcycl ewa s investigatedi na nexperimenta lroo munde rstandardize dconditions :ligh tperio d 17hours , "dusk"1. 5hours ,dar kperio d4 hours ,an d"dawn "1. 5hours ;ligh twa sgive nwit h2 bulb s (whitelight )o f20 0W each ;th eligh tintensit ychange dlinearl ydurin g"dusk "an d "dawn"; duringth eligh tperio d2 fluorescen ttube s (whitelight )o f6 5W an d5 0H zeac hwer e additionallyused ;th eligh tsource swer eplace da taheigh to f1m abov eth emoth san d werearrange di nsuc ha wa ytha tbot hstrain sreceive dth esam eligh tintensity ; observationsdurin gth edar kperio dwer emad epossibl eb yth eus eo fre dfluorescen t lights;temperatur e2 3C (ligh tperiod )an d2 1C (dar kperiod) ;relativ eai rhumidit y70 - 801. Femalepupa ewer ecollecte d froma mas srearin ga t2 5Can dL D18:6.withi n1 6hour s afterpupatio nan dtransferre dt oth eexperimenta lroom .Th emoth swer eallowe dt oemerg e individuallyi nglas svial san dtransferre dt operspe xcylinder s (length1 5cm ,diamete r 10cm )close dwit hgauz ea tbot hend s (5moth spe rcylinder) .We tcotto nwoo lwa suse da s awate rsuppl yfo rth efemales .Callin gbehaviou rwa sobserve ddurin g2 successiv e"nights " with3- 4day sol dmoth s (50pe rstrai npe r"night") .Th eobservation swer emad ea t15 - 57 held s'rain O o * 9 dusk Figure 19.Callin gbehaviou ro fvirgi nfemale so fa fiel dan da greenhous e straini n relationt oth elight-dar kcycle . minuteinterval sdurin g"dusk" ,th edar kperio dan d"dawn" . Whenth efemale swer ei ncallin gpositio nth eabdome nwa sextende dan dben tventrally , wingswer eslightl yraise dan dhin dleg sstretched .Th etermina labdomina lsegment swer e protruded,exposin g thepheromon eglan dt oth eair .Othe rtortricids ,suc ha s Adoxophyes ovarici(F.v.R. )(Tamak ie tal . 1969)an d Fpiphyas postvitbana (Walker)(Lawrenc e& Bartel l 1972),an dth eEuropea nsmal lermin emoth s (Yponomeuba spp.) (Hendrikse 1978),behav ei n thesam eway .I nth epresen texperiments ,a C. speabrana femalewa sconsidere d tob ei n callingpositio na slon ga sit sabdome nwa sextended . Theresult sar epresente d infigur e 19.Unde rthes eexperimenta lcondition sth e callingbehaviou ro fvirgi nfemale swa sidentica l inbot hstrains .Th efirs tfemale s startedcallin gabou t1 hou rafte rth eonse to fdarkness .Callin gbehaviou rreache dit s maximumdurin gth esecon dhal fo fth edar kperio dan drapidl ydiminishe d at"dawn" . 8.3PHEROMONA LTRAPPIN G Fromth eresult so fth eexperiment sdescribe d inth eSection s8. 1 and8. 2 itca nb e expectedtha tther ewil lb eunhampere dmutua lattractio nbetwee nmal ean dfemal emoth so f bothstrain swhe nthe yar ebrough ttogether .T ochec kthis ,release-recaptur e trialswit h trapscontainin g livevirgi nfemale swer econducted .Thes eexperiment swer edon ebot h outdoorsan di na greenhouse ,becaus eth enatur eo fth eai rmovement s insidea greenhous e differsgreatl yfro mtha toutdoors ,whic hma yaffec tpheromone-mediate dcommunicatio n amonginsect si ngreenhouses . 58 8.3.1 Outdoor trials 2 Onese to frelease-recaptur e trialswa sconducte d ina noutdoo rcag e (area7x6=4 2m ; height2. 5m )o fpolyamid egauz e (meshwidt h1.2 5mm ,threa ddiamete r0.31 5mm) ,plante d withrow so f Prunus triloba (L.).Ai rcurrent si nth ecag eresemble dthos ei na natura l situation. Threekind so ftraps ,eac hi nduplicate ,wer eused : - Stickytrap s (deltashape) ,baite dwit h2 virgi nfemale so fa fiel dstrai ntha twer e keptinsid eth etra pi na tub e (length5 cm ,diamete r2. 5cm )close da tbot hend swit h gauze.We tcotto nwoo lwa suse da sa wate rsuppl yfo rth efemales . -Trap so fth esam etyp ebaite dwit h2 virgi nfemale so fa greenhous estrain . -Unbaite dtrap so fth esam etyp ewer euse dt oasses swha tproportio no fth ecatche si n thefemale-baite dtrap sha dt ob eattribute dt oothe rfactor stha npheromona lattraction . Thetrap swer eplace d 1m fro mth ewall so fth ecage ,a ta heigh to f0. 5m .Th edistanc e betweenadjacen ttrap swa s2.5- 4m . Malean dfemal emoth swer etake nfro ma mas srearin ga t2 5C an dL D18: 6 (greenhouse strain2n dan d3rd ,fiel dstrai n3r dan d4t hlaborator ygeneration) .Th emoth swer e allowedt oemerg eindividuall yi nglas stubes .Female swer etransferre dt oth etrap s within1 6hour safte remergence .Male swer erelease dinsid eth ecag ewithi n1 6hour s afteremergenc ewhe nth efemale si nth etrap swer ea tleas t2 day sold .Field-strai nan d greenhouse-strainmale swer erelease dalternatel ya tinterval so fa tleas t2 weeks ,t o preventthe mgettin gmixe dup .Recapture si nth etrap swer erecorde ddaily ,an ddea do r dyingfemale swer ereplaced .Th earrangemen to fth etrap swa schange ddail yt opreven t effectso fpositio ni nth ecatches .Th etrial slaste dfro mJun eunti lOctobe r1980 . Theresult sar epresente di ntabl e22 .Difference si nth erelease-recaptur etrial s 7 wereteste db yth ex -metho d (1-sidedtest) .Recapture si nth efemale-baite dtrap swer e alwayssignificantl ylarge rtha ni nth etrap swithou tbai t (P<.005)(tabl e 22).Thi s demonstratesth erol eo fpheromona lattractio ni nthes eexperiments .Ther ewer en o Table22 .Percentag erecapture dmale si nfemale-baite dan dunbaite d trapsi n fieldcage . Trapsbaite dwit h Trapsbaite dwit h Unbaited virginfemale so fa virginfemale so fa traps greenhousestrai n fieldstrai n males 3.8% 9.2% 0.6% greenhouse n=27 n=66 n=4 strain males 4.2% 8.5% 0.7% field n=18 n=36 n=3 strain Totalnumbe ro fmale sreleased :Greenhous estrain = 715;Fiel dstrain =426 p. 59 significantdifference si nrecapture sbetwee nth emale so fbot hstrain s (P>.0S),thu s femaleso fbot hstrain sattracte dmale so fbot hstrain si nequa lproportion s (table22) . Thisconfirm sth eunhampere dmutua lattractio nbetwee nth estrains ,whe nbrough ttogethe r underoutdoo rconditions . Field-strainfemale sattracte dabou ttwic ea sman ymale so feac hstrai ntha n greenhouse-strainfemale s (table 22).A tpresent ,a nexac texplanatio nfo rthi sphenomeno n cannotb egiven .Th egreenhouse-strai nfemale smigh tfo rexampl ehav ecalle dles s frequentlytha nfield-strai nfemales ,o rth eamoun to fpheromon eproduce dpe rfemal e mighthav ebee nlowe ri nth egreenhous estrain . 8.3.2 Greenhouse trials Anotherserie so frelease-recaptur etrial swa sconducte d ina Gerbera house(are a 8x10=80m ;ridg eheigh t5 m) . Theventilator swer escreene dwit hgauz et opreven tmot h escape.Th etrial swer ese tu pi nexactl yth esam ewa ya sthos ei nth eoutdoo rcage .Th e numbero ftrap spe rm wasabou tth esam ea si nth eoutdoo rcage :2 trap so feac hkin d wereplace dbetwee nth e Gerbera beds,an danothe r2 o feac hkin dalon gth ewall sinsid e thegreenhouse ,a ta heigh to f0. 5m .Th edistanc ebetwee nadjacen ttrap swa s 3-4m .Th e trialswer econducte ddurin g3 week si nJanuar y 1981,whe nth egreenhous ewa scontinuousl y heated (greenhousestrai n1st ,fiel dstrai n5t hlaborator ygeneration) ,an ddurin g3 week s inJun e 1981,whe nth egreenhous ewa sonl yincidentall yheate ddurin gth ecoldes tpar to f thenigh t (greenhousestrai n3rd ,an dfiel dstrai n 1stlaborator ygeneration) .Release d malemoth sal lbelonge d toa greenhous estrain .Th erecapture swer ecompare dwit hthos e ofgreenhouse-strai nmale si nth eoutdoo rcag e (Subsection 8.3.1).Th eresult sar epresente d inth etable s2 3an d24 . Table23 .Percentag erecapture dmale s (greenhousestrain )i nfemale-baite d andunbaite d trapsi na greenhouse . Trapsbaite dwit h Traps baitedwit h Unbaited virginfemale s ofa virginfemale s ofa traps greenhouse strain field strain alongth e 1.4% 2.0% 1.0% walls n=14 n=20 n=10 January 1981 betweenth e 0.4% 0.6% 0.2% plantbed s n=4 n=6 n=2 alongth e 3.4% 1.7% 0.8% walls n=25 n=12 n=6 June 1981 betweenth e 0.8% 0.8% 0.3% plantbed s n=6 n=6 n=2 Totalnumbe ro fgreenhous e strainmale sreleased :Januar y 1981= 1010;Jun e 1981=726 . 60 Therecapture so fgreenhouse-strai nmale si nth egreenhous ewer elo wcompare dt o thoseo fgreenhouse-strai nmale si nth eoutdoo rcag e (tables2 2an d 23).Althoug hth e recapturesi nth etrap sbaite dwit hgreenhouse-strai nfemale sdi dno teve ndiffe r significantlyfro mthos ei nth eunbaite dtrap si nth etrial so fJanuar y198 1 (P>.0S)(tabl e 23),i ti sjustifiabl et oconclud etha tbot hgreenhouse-strai nfemale san dfield-strai n femalesattracte dgreenhouse-strai nmale si na greenhous eenvironment . InJanuar y1981 ,field-strai nfemale sattracte dmor emale stha ngreenhouse-strai n females,bu tth edifferenc ewa sno tsignifican t (P>.05)(tabl e 23). InJun e1981 ,field - strainfemale sattracte dsignificantl y lessmale stha ngreenhous estrai nfemale s (P<.05) (table 23).Th erecapture si nth egreenhous ewer esignificantl yhighe ralon gth ewall s thanbetwee nth eplan tbed s (P<.05) (table 23).Thi swa sth ecas efo rbot hfemale-baite d andunbaite dtraps .A tpresent ,a nexac texplanatio nfo rthes ephenomen acanno tb egiven . Intabl e24 ,recapture so fgreenhouse-strai nmale si nth egreenhous ean di nth e outdoorcag ear ecompared .A significantlylowe rproportio no fmale swa srecapture di nth e greenhousecompare dt oth eoutdoo rcage ,bot hbefor ean dafte rcorrectio nfo rth ecatche s inunbaite dtrap s (P<.005).Apparentl ypheromona lattractio nb yvirgi nfemale swa sles s effectivei nth egreenhous etha ni nth eoutdoo rcage . Airmovement si ngreenhouse sdiffe rgreatl yfro mthos eoutdoors .I ngreenhouse sther e aren ohorizonta lai rcurrents ,bu tth eai ronl ycirculate sb ywar mai rrisin gan dcol d airfallin g (Kanthak 1973).Th ewin dspee di sver ylow .I tusuall yvarie sbetwee n5 an d 20cm/ s whenth eventilator sar eclosed ,an dbetwee n5 an d4 0cm/ s whenope n(G.P.A . Bot,G.A .va nde nBerg ,pers .comm.) . Thereduce deffectivenes so fpheromona lattractio ni nth egreenhous ema yhav e differentcauses .Basi cmal efligh tactivit y (notelicite db ypheromone )ma yb elowe ri n greenhousestha ni nth eope nair ,an dfemale sma ycal lles sfrequently .A mor elikel y explanationi stha tpheromone-mediate dlong-rang ebehaviou ro fth emale si sdisturbe di na greenhouseenvironment .I nth efield ,male sreac tb yflyin gu pwin dwhe nthe yencounte r pheromonemolecule s (Kennedy& Mars h 1974).Th especifi cnatur eo fth eai rmovement si n Table24 .Compariso nbetwee nrecapture so fmal emoth s (greenhousestrain )i na n outdoorcag ean di na greenhous e (release-recapture trialsusin gfemale-baite dan d unbaited traps). Greenhouse Greenhouse Outdoor cage (January) (June) (summer) •alongth ewall s 4.4% 5.9% %male s •betweenth eplan tbed s 1.2% 1.9% recaptured •totalrecaptur e 5.6% 7.8% 13.6% %male srecapture d aftercorrectio n 4.5% forth ecatche si nunbaite dtrap s 2.0% 11.9% numbero fmale srelease d 1010 726 715 61 greenhousesma yreduc eth eeffectivenes so fthi sanemotacti cbehaviour .Thi sma yb eth e reasonfo rth epoo rcatche so f C. speatrana intrap si ngreenhouse stha twer ebaite dwit h syntheticpheromone ,a sreporte db yVa nd eVri e (1976).However ,mal esexua lbehaviou ri n short-rangeorientation ,clos et ocallin gfemales ,ma yb eunaffecte di ngreenhouses . C. speatrana isa seriou spes ti ngreenhouses .Th echanc eo fa mal egettin gclos e toa callin gfemale ,wit ho rwithou tpheromone-mediate danemotacti cflight ,an dtherefor e thechanc eo fa femal egettin gfertilized ,i sapparentl ysufficientl yhig ht oensur ea considerablepopulatio nincrease .Behavioura lobservation sshoul drevea lwhethe rgreenhous e populationso f C. speatrana haveadapte dthei rsexua lbehaviou rt oth especifi cgreenhous e conditions,e.g .i nth esens etha tothe rtha npheromona lstimul ipla ya mor eimportan t roletha ni nfiel dpopulations . 8.4MATIN GPREFERENC E Roelofs& Card é (1977)suggeste d thatth efunctio no fsecondar ypheromon ecomponent s mayb et oreleas emal eshort-rang eresponse s (landing,win gfanning ,glan dextrusion , mating). Thefemal ese xpheromon eo fth esummer-frui ttortri xmoth , Adoxophyes orana (F.v. R.),an dtha to f C. speatrana, isthough tt ocontai nth esam ecomponent s (cis-11-TDAan d cis-9-TDA),bu ti na differen trati o (Minkse tal . 1973).De nOtte re tal .(1978 )an dDe n Otter& Klijnstr a (1980)suggeste d thatth epheromon erelease db yfemale so f A. orana containson eo rmor eadditiona lcomponent stha tar eneede dt oinduc eth ecopulator yact . Thusth efac ttha ta fiel dstrai nan da greenhous estrai no f C. speatrana mutually attracteac hothe rwhe nthe yar ebrough ttogethe rdoe sno tnecessaril y implytha tinter - strainmating sca noccur .Experiment swit ha fiel dstrai nan da greenhous estrai nwer ese t upt ochec kwhethe rinter-strai nmating sar epossible . Malean dfemal emoth so fa fiel dstrai n (1stlaborator ygeneration )an da greenhous e strain (3rdlaborator ygeneration )wer etake na trando mfro mon egrou po feac hstrai n reareda t2 5C an dL D 18:6.The ywer ebrough ttogethe rwithi n1 6hour safte remergenc ei n polyethylenebag s (sizeca .10x15x3 0cm ,eac hcontainin ga fres hros eshoo tplace di nwe t Oasis).Th ebag swer ekep ta t2 5C an dL D18:6 ,an deac hreceive d 1femal ean d3 male s inth efollowin gcombinations :greenhous eÇ x greenhous e0*0 ;greenhous e Qx fiel d00 ; fieldÇ x greenhous e(53 ;fiel d0 .x fiel d3(5 .Ther ewer e 10bag spe rcombination .Matin g wasconsidere dt ohav eoccurre di fa femal elai dfertilize deggs . Table25 .Occurrenc eo fintra-strai nan d inter-strainmating s betweena fiel dan da greenhous estrain . Femalex Male s Numbero ffemale slayin g fertilizedegg s greenhousex greenhous e 6(n=10 ) greenhousex fiel d 5(n=9 ) fieldx greenhous e 5(n=10 ) fieldx fiel d 7(n=10 ) 62 Successful inter-strainmating sreadil yoccurre d (table 25). Inthes eexperiments ,a difference inmatin gpreferenc ebetwee nth estrain sdi dno tappear .I fonl ya mino r differenceexists ,i tma y onlyb edetecte d ina situatio n inwhic hmale s could actually choosebetwee nfemale so fbot hstrains . 63 9 Hybridization Noisolatin gmechanism swer efoun di nth epheromona lattractio no rmatin ghabit s betweenfiel dan dgreenhous epopulation so f C. speotvana (Chapter 8).Allozym e frequencieswer edetermine d inorde rt oge ta nindicatio no fth edegre eo fgeneti c differentiationbetwee nthes epopulations .Crossin gexperiment swer edon et odetermin e whetherhybri doffsprin gar eviabl ean dfertile .Th ephotoperiodi crespons eo fF 1hybrid s wasdetermined . 9.1ALLOZYM EFREQUENCIE S Onehundre dlarva ewer ecollecte dfro mstingin gnettles , Urtica dioioa (L.),nea r Wageningeni nMa y 1979,an danothe r 100larva efro ma ros ehous ei nRoelofarendsvee n(nea r Leiden)i nAugus t 1979.Fift ylarva eo feac hpopulatio nwer epreserve da t-2 5C .Th eres t ofth elarva ewer ereare do na nartificia ldie tan dth emoth spreserve da t-2 5C . Allozyme (electromorph)frequencie so f1 8differen tloc ii nbot hstrain swer edetermine d byelectrophoresis .Th ecooperatio no fDr .S.B.J .Menke n (Departmento fZoogeography ,Fre e University,Amsterdam )i nperformin gthes eexperiment si sgratefull yacknowledged .Th e methodsapplie db yMenke n (1980)fo r Yponomeuta spp. (Lepidoptera:Yponomeutidae )wer e used.Th eabbreviations ,name san dEnzym eCommissio nNumber sfo rth eenzyme sassaye dar e asfollows :ACPH ,aci dphosphatase ,E C3.1.3.2 ;ALD ,aldolase ,E C4.1.2.13 ;EST-ß-1 , esterase,E C3.1.1.2 ;FUDH ,fucos edehydrogenase ,E C1.1.1.122 ;GLUO ,glucos eoxidase , EC1.1.3.4 ;GOT- 1an dGOT-2 ,glutamic-oxaloaceti c transaminase,E C2.6.1.1 ;G6DPH , glucose-6-phosphatedehydrogenase ,E C1.1.1.49 ;HDBH ,hydroxybutyrat edehydrogenas e (runs cathodally),E C1.1.1.30 ;LAP-1 ,leucin eaminopeptidase ,E C3.4.11.1 ;MDH- 1 (runs anodally)an dMDH- 2 (runscathodally) ,malat edehydrogenase ,E C1.1.1.37 ;ME ,mali c enzyme,E C1.1.1.40 ;NDH ,"nothin gdehydrogenase "(run scathodally) ;PGI ,phosphoglucos e isomerase,E C5.3.1.9 ;PGM ,phosphoglucomutase ,E C2.7.5.1 ;PT- 1an dPT-2 ,"genera l proteins"wit hunknow nfunction . Eightenzym eloc iwer efixe dfo rth esam eallel ei nbot hpopulations :ACPH ,FUDH , GOT-1,GOT-2 ,G6PDH ,ME ,NDH ,an dPT-2 .Th eallozym efrequencie so fth eothe r1 0loc iar e giveni ntabl e26 . Theseelectrophoreti cdat awer euse dt oestimat eth eaverag eheterozygosit ype rlocu s (II),th egeneti cdistanc e (D), an dth egeneti c identity (I)o fth etw opopulations . H estimatesth eproportio no fheterozygou s locii na singl eindividua lo rpopulation . Itamounte dt o0.09 8i nth efiel dpopulation ,whil eth egreenhous epopulatio nha da 64 Table 26.Allozym e frequencies at 10loc i ina field population anda greenhouse population. Locus Allozymes Field population Greenhouse population ALD 100 97% 96% 103 3% 4% n=38 n=28 EST-ß-1 97 9% 100 91% 100% n=38 n=28 GLUO 100 71% 73% 101 2% 102 29% 23% 104 2% n=38 n=28 HDBH •9 4 9% -100 91% 100% n=23 n=28 LAP-1 98 4% 100 92% 91% 102 5% n=38 n=28 MDH-1 97 1% 100 84% 75% 107 14% 25% n=38 n=28 MDH-2 -9 8 1% -100 99% 82% -102 18% n=38 n=28 PGI 94. 10% 96. 7% 100 88% 90% 105. 5% n=88 n=66 PGM 94 1% 97 1% 12% 100 91% 78% 106 8% 9% n=68 n=43 PT-1 100 92% 100% 102 8% n=38 n=28 similar value (0.104). D estimates thenumbe r ofne tcodo ndifference s per locusbetwee npopulation s (Nei 1971, 1972). Thevalu ewa s 0.006 +_0.01 8 inth epresen t investigation. Themea n distance values (D)i nth egenu s Speyeria (Lepidoptera: Nymphalidae) are0.01 3+ 0.003fo r conspecific populations,an d0.18 2 *_0.01 3betwee n species (Brittnacher et al. 1978). 65 Comparedwit hsimila rstudie so fspecie sgroup sno tbelongin gt oth eorde rLepidoptera , the Speyeria valuesar elow .The ycorrespon dver ywel lwit hth edistanc evalue sfoun di n thegenu s ïponomeuta (Menken1980) .Th evalu eo fD i nth epresen tinvestigatio nindicate s aconspecifi cstatu so ffiel dan dgreenhous epopulation so f C. spectrana. Theinde xI measure sth emea ngeneti csimilarit ybetwee ntw ogroup s (Nei1971 ,1972) . Thevalu ewa s0.99 4i nth epresen tinvestigation .Fo rsiblin gspecies ,I generall yrange s from0.9 8t oles stha n0.7 0 (Ayala1975) .Th egeneti cidentit yo fconspecifi cloca l populationsrange sfro m0.9 7t o1.0 0i n Drosophila spp.(Powel l 1975),fro m0.9 4t o0.9 8 in Aedes aegypti (Munstermann 1979),an dfro m0.98 9t o0.99 7i n Aedes triseriatus (Matthews& Crai g 1980).Th emea nidentit yvalue s (I)i nth egenu s Speyeria are0.98 7+ 0.003fo rconspecifi cpopulations ,an d0.83 3+ 0.01 1betwee nspecie s (Brittnachere tal . 1978).Thes ecorrespon dver ywel lwit hth eidentit yvalue si nth egenu s ïponomeuta (Menken 1980).Whe nconspecifi cpopulation sar epanmictic ,thei rgeneti csimilarit yi sexpecte dt o begreate rtha n0.9 9 (Matthews& Crai g 1980).Thu sth egeneti cidentit yo fth etw o populationsi nth epresen t investigationwa sa tth eleve lo fpanmicti cpopulation so fon e species. Fieldan dgreenhous epopulation so f C. spectrana arealmos tcertainl ystil l conspecific. 9.2CROSSIN GEXPERIMENT S Firstan dsecon dgeneratio ncrosse swer eperforme dwit ha fiel dan da greenhous estrai n at25° Can dL D18:6 .Th efiel dstrai n (1stlaborator ygeneration )originate dfro mlarva e collectedo n Urtica dioica nearWageningen ,an dth egreenhous estrai n (3rdlaborator y generation)fro mlarva ean dpupa ecollecte di na ros ehous ei nD eKaa g (nearLeiden) .Th e strainsha dbee nreare da t1 5C an dL D18:6 . Ineac hP an dF 1crossing ,1 5mal ean d1 5femal emoth swere ,withi n1 6hour safte r emergence,take na trando man dconfine di non epolyethylen eba g(siz eca .15x30x4 5 cm), containinga fres hros eshoo tplace di nwe tOasis . Theduratio no fdevelopmen to fa numbe ro fegg slai do nth einne rsid eo fth e polyethyleneba gwa sdetermine d (atleas t20 0viabl eegg spe rcrossing) .Th eeg gmasse s werecu tou twithi n1 6hour safte rlayin gan dpu to nmois tfilte rpape ri na petr idis hi n aclose dplasti cbag .Eg ghatchin gwa sobserve da t24-hou rintervals . Theres to fth eeg gmasse swer edivide da trando move rpetr idishe scontainin gfres h roseleaves .Th edishe swer ekep ti nclose dplasti cbags .Withi n1 6hour safte reg g hatching,22 0larva ewer ecollecte da trando man dtransferre d toglas svial scontainin ga n artificialdiet .Th evial swer ekep ti nclose dtransparen tplasti cboxes . Eggmortalit ywa sdetermine db ycountin gth eempt ychorion s (representinghatche d eggs)an dth enon-hatche deggs . Pupationan dmot hemergenc ewer eobserve da t2 4h intervals ,afte rpupatio nth e dietsan dlarva lweb swer eremove dt oensur eunhampere dmot hemergence .Th ebotto mo fth e boxeswer ecovere dwit hwe tfilte rpape ri norde rt oensur ea hig hai rhumidity . Table27 .Fecundit yan dfertilit yo fth eparent san d sexrati oo fth eprogen y inP crosse s at25° Can dL D18:6 . Femalesx Male s Numbero fegg slai d Numbero fegg shatche d %mal e perfemal e perfemal e pupae Fx F 467 322 45% Fx G 476 324 50% Gx F 394 256 49% Gx G 375 236 59% F=fieldstrai nG=greerihous estrai n 9.2.1 P crosses Thefirs tse to fcrosse sinvolve dth efield -an dgreenhouse-strai nmatings ,an dth e twopossibl ehybri dcrosses .Th eresult sar epresente di nth etable s27 ,28 ,an d29 . Fecundityan dfertilit ydi dno tsee mt ob eaffecte db yth estrai no fmal e participatingi nth ematin g (table 27).Th ese xratio so fth ehybri dan dpure-strai n progenydi dno tsignificantl ydeviat efro m1: 1 (2-sidedx -test ,P>.05) .O nth ebasi so f theseexperiment si tcanno tb edecide dwhethe rth epur estrain ssignificantl ydiffere di n fecundityo rfertility ,a sth enumbe ro fegg slai db yeac hseparat efemal einvolve di na crossingwa sno tknown .Th enumbe ro fegg spe rfemal ewa scalculate db ydividin gth etota l numbero fegg spe rcrossin gb y 15 (thenumbe ro ffemale sinvolve di neac hcrossing) . Mortalityo fth eprogen ydi dno tdiffe rsignificantl ybetwee nth eP crosse si neac ho f theimmatur elif estage s (2-sidedx 2-test,P>.05 )(tabl e28) . Comparedt oth efiel dstrai n (FxF),th emea nlarva ldevelopmen tduratio ni nth e greenhousestrai n (GxG)wa ssignificantl y longer (2-sidedt-test ,P<.005 ) (table29) . Possiblyth emea nnumbe ro finstar su pt opupatio nwa shighe ri nth egreenhous estrain . Thenumbe ro finstar swa sno tdetermine di nthes eexperiments .Larva ldevelopmen tduration s inth etw ohybri dclasse s (FxGan dGxF )range dbetwee nthos eo fth epur estrain s (table 29). Inth eeg gstag ean dpupa lstag en osignifican tdifference sbetwee nth eprogen yi nth e Pcrosse swer efoun d (P>.05)(tabl e29) . Table28 .Percentag emortalit yo fvariou slif e stageso fth eprogen y inP crosse sa t25° C andL D18:6 . Femalesx Male s %no nhatche d %larva l %pupa l %overal lmortalit y eggs mortality mortality fromeg gt oadul t FxF 31 5 4 37 Fx G 32 3 5 37 Gx F 35 4 4 40 Gx G 37 7 3 44 F=fieldstrai nG=greenhous estrai n 67 Table29 .Mea nduratio no fdevelopmen t (days)o fth eprogen y inP crosse sa t2 5C an dL D 18:6. < Femalesx Male s Eggs Larvae Pupae Total egg-adult femalesx male s eggs SS 98 SS 29 SS 92 Fx F 6.2 20.9 23.5 6.2 5.8 33.3 35.5 Fx G 6.5 22.4 25.4 6.4 6.0 35.3 37.9 Gx F 6.4 21.1 23.5 6.1 5.9 33.6 35.8 Gx G 6.9 26.4 28.4 6.4 5.9 39.7 41.2 F=field strainG=greenhous estrai n 9.2.2 Fl crosses Sixdifferen tF 1crosse swer ese tu pt otes tth ereproductiv ecapacit yo fhybri d femalesan dth eviabilit yo fth eprogeny .Th eresult sar epresente d inth etable s30 ,31 , and32 . Fecundityan dfertilit yo fth eparent si nth eF Tcrosse swer evariabl e (table30) . Sometimesthe ywer ehigher ,an dsometime s lower,tha ni nth eP crosse s (tables2 7an d30) . These xrati oneve rsignificantl ydeviate dfro m1: 1 inth eprogen yo fth eF 1crosse s (2-sidedx 2-test,P>.05 ) (table30) . Mortalityo fth eprogen yi nth eF 1crosse swa svariabl e inth eeg gstag ean di nth e pupalstag e (table 31).Tota lmortalit yu pt omot hemergenc ewa ssometime ssignificantl y lower,an dsometime ssignificantl yhighe rtha ni nth epoole dcontro lcrosse s (FxFan d GxGcombined) .Th emea ntota lmortalit yo fth eprogen yamounte d to48° 6i nth epoole dF 1 crosseso fhybrids ,whic hwa ssignificantl yhighe rtha ni nth epoole dcontro lcrosse s (P<.05).I nth epoole dF 1backcrosse s itwa s39°6 ,whic hwa sabou tth esam ea si nth epoole d controlcrosses . Developmentduratio ndi dno tdiffe rsignificantl ybetwee nth eprogen yo fal lF 1an dP crossesi nth eeg gan dpupa lstag e (2-sidedt-test ,P>.05)(table s 29an d 32). Inth elarva l Table30 .Fecundit y andfertilit yo fth eparent san d sexrati oo tth eprogen y inF lcrosse s at25° Can dL D18:6 . Femalesx Male s Numbero fegg s Numbero fegg s %mal e laidpe rfemal e hatchedpe rfemal e pupae Fx (FxG) 428 321 51% back- Fx (GxF) 392 188 52% crosses (FxG)x G 499 429 47% (GxF)x G 464 329 57% crosses (FxG)x (FxG ) 478 311 52% ofhybrid s (GxF)x (GxF) 295 162 48% F=fieldstrai nG=greenhous estrai n 68 Table31 .Percentag emortalit yo fvariou slif estage so fth eprogen yi nF lcrosse sa t2 5C andL D18:6 . malesx Hale s %no n hatched %larva l %pupa l %overal l eggs mortality mortality mortality egg-adult Fx (FxG ) 25* back- Fx (GxF) 52* 58 crosses (FxG)x G 14 i; 18* * ! 3t 31* (GxF)x G 29+ 4 5 36 crosses (FxG)x (FxG) 35 18 49 ofhybrid s (GxF)x (GxF ) 45 19 58 pooledcontro lcrosse s (FxF+ GxG ) 34 40 F=fieldstrai n +doe sno tdiffe rsignificantl y frompoole dcontro l crossdat a (2-sidedx -test ,P>.05 ) G=greenhousestrai n * differs significantly frompoole d controlcros s data (P<.05) stage,th edevelopmen tduratio no fth eprogen yi nth eF 1crosse srange dbetwee nthos eo fth e purestrain so rwa seve nshorte r (tables2 9an d32) .A ninterpretatio no fthes edifference s cannotb egiven ,a sth enumbe ro flarva linstar swa sno tdetermine d inthes eexperiments . 9.2.S Discussion Whenheterosi so fF 1hybrid soccurs ,i ti scause db yincrease dgeneti cvariabilit y ofth ehybrid scompare dt oth econtro lcrosses ,allowin gth emos tefficien tdevelopmenta l pathwayst opredominat edurin ggrowth .I ti spossibl yexpresse db ya faste rdevelopmen t anda highe rsurviva lrat ewhe ncompare dt oth econtro lcrosse s (Liebherr& Roelof s1975) . TheF 1hybrid sdi dno texhibi ta highe rsurviva lrat etha nth econtro lprogen yi nan yo f theimmatur estage s (table 28).Th eduratio no fdevelopmen to fth eF 1hybrid sdi dno tdiffe r significantlyfro mtha to fth econtro lprogen yi nth eeg gan dpupa lstage ,bu ta definit e Table32 .Mea nduratio no fdevelopmen t (days)o fth eprogen y inF lcrosse sa t2 5C an dL D18:6 . Femalesx Male s Eggs Larvae Pupae Total egg-adult 0*0* 99 « 99 0*3 99 Fx (FxG ) 6.3 19.5 22.0 6.6 6.2 32.4 34.5 back- Fx (GxF) 6.8 19.6 22.2 6.6 6.2 33.0 35.2 crosses (FxG)x G 6.4 20.4 22.3 6.5 6.3 33.3 35.0 (GxF)x G 6.4 21.8 23.5 6.7 6.4 34.9 36.3 crosses (FxG)x (FxG) 6.5 22.3 25.4 6.7 6.5 35.5 38.4 ofhybrid s (GxF)x (GxF ) 6.7 23.2 25.5 6.4 6.1 36.3 38.3 F=fieldstrai nG=greenhous estrai n 69 conclusionabou tth erat eo fdevelopmen to fth elarva ei shampere db ypossibl evariation s inth emea nnumbe ro finstars . Oliver (1972)consider stha thybri dincompatibilit y ina specie scros si sshow nb y reducedfecundity ,reduce dembry oviability ,a distorte dse xrati oan dmor easynchronou s eclosiono fth etw osexe si nth ehybri dcrosse swhe ncompare dwit hth econtro lcrosses . Moreasynchronou seclosio no fth etw osexe sdi dno toccu ri nF 1o ri nF 2hybrid s (tables2 9an d32) . These xrati oneve rsignificantl ydeviate dfro m1: 1 (tables2 7an d 30).Reduce d embryoviabilit yoccurre d inth eprogen yo fsom eo fth eF 1crosses ,bu ti nothe rF 1crosse s itwa ssignificantl yincrease d (table 31). Meanfecundit yo fpur estrai nfemale samounte dt o422 ,an dmea nfertilit y27 5 (derived fromth etable s2 7an d 30).Fo rhybri dfemales ,thes evalue swer e43 4an d301 ,respectivel y (derivedfro mtabl e 30). Fecundityan dfertilit yo fhybri dfemale sdi dno tsee mt ob e reduced,bu ta definit econclusio ni shampere db yth efac ttha tth enumbe ro fegg slai db y eachseparat efemal einvolve di na crossin gi sno tknown . Thequestio nwhethe rhybri dincompatibilit y inan yfor mexist scanno tb eanswered , butwhe na fiel dstrai nan da greenhous estrai nar ebrough ttogether ,hybridizatio nan d introgressioncertainl ywil loccur . 9.3PHOTOPERIODI CRESPONS EI NF 1HYBRID S Fieldan dgreenhous epopulation so f C. spectrana canb ereadil yintercrosse d (Section 9.2).Thu sdiapaus echaracteristic sca nb ecrosse d intogreenhous epopulation sb y introducingfield-strai nmoths .T odetermin eth eeffectivenes so fthi sprocedur ea sa geneticcontro lmethod ,knowledg eabou tth ephotoperiodi crespons eo fth eF 1hybrid stha t areformed ,i sneeded . Photoperiodicrespons eo fth ereciproca lF 1hybrid swa sdetermine da t2 0C an d1 6h lightpe rda yi ncrossin gexperiment susin ga fiel dstrai n (3rdlaborator ygeneration )an d agreenhous estrai n (2ndlaborator ygeneration) .Th estrain sha dbee nreare da t1 5C an d LD18:6 .Fo reac hcrossing ,1 5mal emoth san d 15femal emoth swer etake na trando mfro mon e loto feac hstrai nan dconfine di non epolyethylen eba gcontainin ga fres hros eshoot . Table33 .Percentag eo flarva eenterin gdiapaus ea t2 0C an d 16h ligh tpe rda y inth eprogen yo fP crosses . Femalesx Male s FxF FxG GxF GxG %diapaus e 86 52 18 0 n=208 n=203 n=214 n=210 70 Eggswer ecollecte dan dkep ti npetr idishe so nfres hros eleaves .A sampl eo f22 0larva e wastake na trando mwithi n1 6hour safte reg ghatching ,an dreare dsingl yo na nartificia l diet.Larva etha tdi dno tdi eo rpupat ewithi n2 month safte reg ghatchin gwer econsidere d tob ediapausing . Thepercentag eo fdiapausin glarva ei nth eprogen yo feac ho fth e4 possibl eP crosse s isgive ni ntabl e33 .Th ereciproca lF 1hybrid sshowe da nintermediat ephotoperiodi crespons e compared toth epure-strai nprogeny .Thei rreactio nincline dt oth ematerna lcharacteristics . 71 10 Discussion Fieldan drose-hous epopulation so f C. spectrana differessentiall ywit hrespec tt o diapause.Fiel dpopulation shav ea facultative ,photoperiodicall y induceddiapaus e inth e larvalstag e (Chapter 5).Rose-hous epopulation s lackedth eabilit yt oente rdiapaus e underth econdition s tested,bot hi nlaborator yan doutdoo rexperiment s (Chapter6) . Non-diapausingbehaviou r isadvantageou si nheate dgreenhouses ,wher esuitabl efoo di s availablethroughou tth eyear ,an dth etemperatur ealway sallow sfo rgrowt han d reproduction. Morphologicaldifference sbetwee nfiel dan drose-hous epopulation sdi dno tappea r (Wit 1978).N odifference swer efoun di nth ecompositio no fth efemal ese xpheromone ,th e pheromone-mediatedbehaviou ro fth emales ,th ecallin gbehaviou ro fvirgi nfemale si n relationt oth elight-dar kcycl ean dmatin gpreferenc e (Chapter 8).Fiel dan drose - housepopulation sca nb eintercrosse dwit ha viabl eF 2generatio n (Section9.2) .Thei r genetic identity (I)amounte dt o0.994 ,whic hi sth eleve lfo rpanmicti cpopulation so f onespecie s (Section9.1) . Fieldan dgreenhous epopulation so f C. spectrana are certainlystil lconspecific .I t isadequat et ospea ko fa "fiel dtype "an da "greenhous etype" . Whenth etw otype sar ebrough ttogether ,the ysee mt ointerbree d freely,withou ta greatdea lo fhybri dincompatibilit y (Section9.2) .Developmen tduratio nan dtemperature - dependentmortalit ydi dno tdiffe rbetwee nth etw otype s (Chapter 4).Th esurviva lo f diapausing larvaewa sno tessentiall yaffecte db yth eabsenc eo fa perio do fchillin gi n aheate dgreenhous ean dwa sno tlowe ri ncompariso nwit hth esurviva lo flarva egoin g throughnon-diapaus edevelopmen ti na greenhous ean doutdoors .Thu sth esurviva lo fth e twotype sma yno tdiffe ressentiall yi na greenhous eenvironmen t (Subsection 7.1.1). Adifferenc ei nsensitivit yt oth esyntheti cpyrethroid stha tar ecommonl yuse dfo rleaf - rollercontro li ngreenhouse s inth elas tfe wyear si sa tpresen tunlikel yt oexis t (M.va nd eVrie ,pers .comm .) . Diapauseappreciabl ydecrease sth emultiplicatio nrat epe rannu mi nheate d greenhouses (Subsection 7.1.1).Thi sseem st ob eth eonl yfacto rlimitin ggeneti cexchang e betweenth etw otypes ,afte rth eimmigratio no floca lwil dleaf-rollers . Greenhousepopulation shav eoverlappin ggenerations .Al ldevelopmenta l stagesar e alwaysfoun dsimultaneousl y (Vand eVri e 1978).Thi smean stha tth efligh tperiod so fth e twotype soverla peac hother .Eve nthei rphenolog ydoe sno tprohibi tinterbreeding . Yetth egeneti cexchang ebetwee nfiel dan dgreenhous epopulation s issufficientl ylo w tomaintai na separat egreenhous etype .Sample sfro mrose-hous epopulation s lackth e 72 abilityt oente rdiapause ,regardles so fwhethe rthe yar etake ni nsumme ro ri nwinte r (Chapter6) .Apparentl yth eglas swall san droof st oa larg eexten tlimi tfre e introgressiono fth efiel dtyp eint oresiden tgreenhous epopulations ,b yprohibitin g immigrations intoth egreenhouse ,an dals ob ycreatin ga differen tenvironment ,i nwhic h aperio do fchillin gi slacking . Theorigi no fth egreenhous etyp emigh tb ea non-diapausin ggeographi crac eo f C. spectrana, fromth ewarmes tpart so fit sdistributio narea ,importe dwit hplan tmateria l intoth eDutc hgreenhous ecultures ,o rperhap s thefiel dtyp ewa sintroduce dint oheate d greenhouses,an dsubsequentl ylos tit sabilit yt oente rdiapaus eunde rth einfluenc eo f specificselectio npressure si nth egreenhous eenvironment .Thes etw opossibilitie swil l nowb ediscussed . C. spectrana isa palaearcti cspecies .Th eare ao fdistributio nprobabl yinclude sth e Mediterraneanregion ,bu tth especie si sonl yknow nt ob enoxiou si ncountrie swit ha colderclimat e (Section2.3) . C. spectrana belongst oth egrou po farthropo d speciestha t diapauses inwinter ,diapaus edevelopmen ttakin gplac ea ttemperature sbelo wth ethreshol d foractiv edevelopment .Thes especie susuall yd oente rdiapaus ei nth eMediterranea n region (Danilevskii 1965,pp .22-24) .I nsom eo fthes especie sMediterranea npopulation s havebee nshow nt ob epartl ynon-diapausing ,e.g .i nth elacewin g Chrysoperla cornea Steph. (Alrouechdi& Canar d 1979). C. speotvana hasbee nrecorde di nvineyard si nth eHéraul t districti nth eSout ho fFrance .Thi sdistric tha sa Mediterranea nclimate ,bu tth elarva e enterdiapaus ei nautum n (Picard 1912).Nothin gi sknow nabou tth eexistenc eo fnon - diapausingpopulation so f C. spectrana undernatura lconditions .A nintroductio no fsuc ha populationint oth eDutc hgreenhous eculture si stherefor eunlikely . Hoy (1978b)review sa nimpressiv enumbe ro farthropo dspecie si nwhic ha non - diapausingstrai nwa sobtaine db yinadverten to rpurposefu lselectio ni nlaborator y cultures.Som estrikin gexample sare :Lyo ne tal . (1972)foun dtha ta colon yo fth e Westernspruc ebu dworm , Choristoneura occidentalis (Freeman),ha dinadvertentl ylos tit s abilityt oente rdiapaus eafte ri tha dbee nreare dfo r2 0generation sunde rcontrolled , nondiapause-inducin g conditions;Ho y (1977)selecte dwithi n8 generation sa strai no f gypsymoth , Lymantria diepar'(L.), thatcoul db ereare dcontinuousl ywithou tit snorma l "obligatory"diapause . Rosesbelon gt oth eearlies tcutflower stha twer ereare dunde rglas si nAalsmeer .Th e firstros ehous ewa sconstructe di n189 8 (Augustijn 1953).Th eflowe rauctio ni nAalsmee r wasfounde di n1912 ,ros ehouse swer ethe nalread yofte nheate di nwinte r (Anonymus 1930). Tortricid larvaeo nrose sar ecalle d"rozenijltjes "b yth egrower si nth eAalsmee rregion . Oldros egrower sstat etha tth enam ei sa sol da sth eros ecultur ei nthi sregion .Fro m theliteratur ei ti scertai ntha tth enam ewa salread ycommonl yuse di n194 1 (VanPoetere n 1941). Itma yb eassume dtha ttortricid shav eoccurre do ngreenhous erose ssinc eth estar t ofth ecultur eunde rglass .Th eearlies tmentio no ftortrici ddamag e (speciesunspecified ) inDutc hros ehouse stha tcoul db efoun di nth eliteratur ewa si n192 9 (VanPoetere n 73 1929).Th efirs ttim e C. speatrana wasrecorde d ingreenhouse sb yth eDutc hPlan t ProtectionServic ewa si n1936 ,o n Cyalarnen (VanPoetere n1936) .I n1941 , C. speatrana causedconsiderabl edamag et ogreenhous eroses .Unti ltha ttim eth especie sha dbee n considereda rar einsec ti nfloricultur e (VanPoetere n 1941).Sinc ethe nth enam e"rozen - ijltjes"ha sregularl yappeare di nth eliterature :Anonymu s (1942b),Augustij ne tal . (1945),Va nDor t (1948),Va nRaalt e (1950),Gelei n (1965). InFebruar y 1964, C. speatrana causedheav ydamag et ogreenhous erose s (VanRosse me tal . 1965),indicatin gtha ti n196 4 anon-diapausin gpopulatio nalread yexisted .I fi ti sassume dtha tselectio ni nfavou ro f non-diapausewa spossibl ea ssoo na sth eros ecultur eunde rglas swa sstarted ,greenhous e populationso f C. speatrana haveha da perio do fa tleas t6 0year st oadap tt othei r environment.Thi sperio dcomprise s360-54 0generation so fth egreenhous e type.I ti s likelytha ta non-diapausin gpopulatio nca nb eselecte dou twithi nsuc ha period .Developmen t durationo fdiapausin g larvaecoul db eshortene drapidl yb yselectio nunde rcondition s withouta perio do fchillin g (Section7.2) .A sth egeneti cidentit y (I)o fth etw otype s waso nth eleve lo fpanmicti cpopulation so fon especie s (Section9.1) ,i tma yb e speculatedtha tth egreenhous etyp ei sno to fexoti corigin . Itseem st ob equit epossibl etha tth efiel dtyp eimmigrate dint oheate dgreenhouses , andsubsequentl y lostit sabilit yt oente rdiapause . Ifi ti sassume dtha tth egreenhous etyp eoriginate sfro mth eloca lfiel dpopulations , fourquestion sarise : 1.Ho wca nfiel dpopulation sente ra greenhouse ? 2.Ho wca na non-diapausin gpopulatio nb eselecte dfo ri na heate dgreenhouse ? 3.Ho wman ygeneration sar erequire dt oobtai nsuc ha population ? 4.Ho wdoe sa non-diapausin gpopulatio nmaintai nitself ,an dho wdoe si tmigrat efro m greenhouset ogreenhouse ? Question1 :fiel dpopulation sca nente ra greenhous ei ndifferen tways : a.Femal emoth so rairborn eyoun glarva ema ypenetrat ethroug hth eventilators .Thi s probablyhappen srarely . Fieldpopulation smainl yfee do nlo wherbaceou splant s (Section 2.3),whic hlimit s thechanc etha tth eyoun glarva ear etransporte daeriall yove rlonge rdistances . Thefligh tactivit yo f C. speatrana islikel yt ob elow .Mal efligh trang eo fth e summer-fruittortri xmoth , Adoxophyes orana (F.v.R.),a relate dspecie swit ha simila r lifecycl ean dabou tth esam ewin gspa n (GraafBentinc k& Diakonof f 1968),i susuall y notmor etha n20 0m ,an dofte nles stha n10 0m .Female sprobabl yfl yeve nles s(Bare l 1973).A differenc ebetwee ndispersin gan dmigratin gfligh tbehaviou r (Johnson1969 ) wasno tfoun d in A. orana (Barel 1973).Moder nros ehouse sonl yhav eventilator sa t ridgeheigh t (ca.5 m )(Va nMarsberge n 1968),an dthes ear eno talway sope na tnight . Severaltortrici d speciesregularl ycaus edamag et ocultivate drose si nth eope n airi nWester nEurop e (e.g.Richte rvo nBinnentha l 1903;Pap e 1955b).A tpresent ,non e ofthes especie soccur so ngreenhous erose si nth eNetherland s (Vand eVri e 1978), whichillustrate sth eisolatin geffec to fmoder nros ehouse so ntortrici dspecies . 74 Isolationma yhav ebee nles si nth epast .Th ewall so fth eearlies tros ehouse s wereonl yma nhigh ,an dth eglas sroo fwa sremove di nsumme r (Spaargaren 1908).Ros e houseswit ha permanen tglas sroo fwer eintroduce dlater ,wit hventilator sbot ha t ridgeheigh tan di nth eside-wall s (Anonymus 1926).Thi styp eprevaile dunti llon g afterth eSecon dWorl dWa r (W.va nMarsbergen ,pers.comm.) . b.Eggs ,larvae ,an dpupa ema yb ebrough tint oa greenhous ewit hplan tmateria lfro mth e openair .Thi sprobabl yhappen srarel ya swell .Ros eshrub sar ekep t5- 7year si na greenhousebefor ethe yar ereplace d (W.va nMarsbergen ,pers .comm.) .Formerl y thisperio dwa s 7-10year s (Wasscher1955 ;Gelei n 1965).Ne wshrub sar eproduce db y graftingunde rglass ,th egraft soriginatin gfro mgreenhous erose s (Gelein1965) .A secondmetho d isb yinoculation ,th einoculate dplant sar ekep ti nth eope nai rfo ra yearbefor ethe yar ebrough tint oa greenhous e (VanMarsberge n 1968).Th efiel dtyp e mayoccasionall ypenetrat ea ros ehous ewit hthes eplants .Mos tgreenhous ecrop sar e rearedcompletel yunde rglass . Question2 :studie so nth egeneti cbasi so fdiapaus ei narthropo dspecie shav eofte n beenfragmentar yan dhav esometime syielde dconflictin gresults .N oclea rconclusion sca n bedraw nabou tth egeneti cbasi so fdiapaus ei nth ebroa dsense ,althoug husuall ysevera l genessee mt ob einvolve d (Hoy 1978b). Thegeneti cvariabilit yexhibite dwit hrespec tt odiapaus eb ymos tarthropod si s impressive.Severa lelement so fdiapaus ear egeneticall ydetermined .Th ecritica l photophase,th eduratio no fdiapause ,th eda ydegree srequire dfo rdiapaus etermination , andth edegre eo fcold-hardines sexhibite ddurin gdiapaus eal lrespon dt oselection ,a s demonstratedb ysevera lspecie s (Hoy 1978b). Thequestio narise sho wnon-diapausin gpopulation so f C. spectrana mayhav ebee n selectedfo ri nheate dgreenhouses .Th eanswe rca nonl yb egive ni fmor einformatio n aboutth egeneti cbasi so fdiapaus ei nthi sspecie si savailable .Onl ysom esuggestion s canb egiven . Asi nman yothe rarthropods ,th ephotoperiodi crespons eo f C. spectrana ismodifie d byth etemperatur e (Section5.1) .Genotype stha tlac kphotoperiodi c inductiono f diapauseunde rth etemperatur econdition si na heate dgreenhous ear ea ta nadvantag eove r diapausinggenotypes ,a sthe ycontribut emor efrequentl yt oth ereproductio no fth e population.I nthi swa yth ephotoperiodi crespons eo fimmigrate dwil dleaf-roller sma y shifttoward snon-diapause . Theduratio no fdevelopmen to fdiapausin g C. spectrana larvaei nheate dgreenhouse s isstrongl yvariabl ean dgeneticall ydetermined .I tca nrapidl yb eshortene db yselectio n (Section7.2) .Whe na fiel dpopulatio ni sintroduce dint oa heate dgreenhouse ,diapaus e mayb eterminate dmor equickl yafte ra certai nnumbe ro fgenerations ,specimen swit ha shorterdiapaus eduratio ncontributin gsoone rt oth ereproductio no fth epopulation . Thesemechanism sca nonl ygiv eris et oa los so fdiapausin gbehaviou ri fwithi nth e fieldpopulation ssufficien tgeneti cvariatio ni spresen tt oenabl ethes epopulation s toadap tt oa nextremel ywid erang eo fenvironmenta lconditions .Th ecost ,i nterm s ofreduce dfitnes so fa populatio nassociate dwit hth eproductio no fles stha noptimall y 75 fitindividuals ,i scalle dth e"geneti cload" .A sHaldan e (1957)reflected ,"thi si sth e pricea populatio nmus tpa yfo rth eprivileg eo fevolution" . Anotherpossibl emechanis mpresuppose sth eexistenc eo fa "switc hgene "controllin g theabilit yt oente rdiapause .Th eactio no fsuc ha gen ecause sa switc ho fth eepigenotyp e toa differen tdevelopmenta lpathwa y (Mettler& Greg g 1969,p .62) .I fth eabilit yt oente r diapausei scontrolle db yth eactio no fon esingl egene ,a non-diapausin gpopulatio nwil lb e formedsimpl ybecaus enon-diapausin g specimenscontribut esoone rt oth ereproductio no f thepopulation . Question3 :th enumbe ro fgeneration srequire dt oobtai na non-diapausin gpopulation , cannotb eestimate dexactly ,althoug hth eduratio no fdevelopmen to fdiapausin g larvaeca n beshortene drapidl yb yselectio nunde rcondition swithou ta perio do fchillin g (Section 7.2). Question4 :a non-diapausin gpopulatio nma ymigrat e fromgreenhous e togreenhous eo n youngplant sproduce d inpropagatin ghouses ,i nspit eo fth espra yprogramme sapplie db y thepropagators .Activ emigratio nfro mgreenhous et ogreenhouse ,an dtranspor tb yhuman s (younglarva eattache dt oclothes) ,ma yonl ypla ya rol ei fth egreenhouse sar eadjacen t andbelon gt oth esam egrower . Oncea non-diapausin gpopulatio nha sbecom eestablishe d ina greenhouse ,i tma y maintainitsel ffo rman yyear sb ymovin gfro mon ecompartmen tt oanother ,o rt oadjacen t greenhouseso fth esam egrower .A flowe rgrowe rneve rreplace sal lhi splant sa tth esam e time. 76 11 Prospects of non-chemical control of greenhouse populations Theexistenc eo fnon-diapausin gpopulation so f C. speotrana indicatesa stron g isolatingeffec to fgreenhouse so nthi sspecies .Th egreenhous eact sa sa n"ecologica l island".Thi ssituatio noffer sprospect sfo rsom econtro ltechnique stha tca nonl yb e effectivea tlo wimmigratio nrates ,suc ha sth ecommunicatio ndisruptio ntechniqu ean dth e sterile-maletechnique .Moreove rbiologica lcontro lb yus eo fnatura lenemie sma yoffe r prospectsi nthi sislan dsituation . Pheromonaltrappin go f C. speatrana isles seffectiv ei ngreenhouse stha ni nth eope n air(Sectio n8.3) .Simila rphenomen ahav ebee nobserve di nothe rLepidopter a (Vande n Bos 1983).Probabl yth elong-rang epheromone-mediate dbehaviou ro fmale si sles seffectiv e ina greenhous eenvironmen tbecaus eo fth especifi cnatur eo fth eai rmovements .However , malesexua lbehaviou ri nshort-rang eorientation ,clos et ocallin gfemales ,ma yb e unaffected (Subsection 8.3.2). Thisdecrease sth eeffectivenes so fsyntheti cpheromone suse dfo rmonitorin gan dmas s trapping.Th equestio narise swhethe rpheromone-baite dtrap sca nb eeffectiv ea tall ,whe n usedagains tinsect slivin gi nenclose dspaces .Hopp e& Levinso n(1979 )an dLevinso n& Levinson (1980a,b )stat etha tpheromone-baite dtrap sca nb euse dsuccessfull yfo rlong - termmonitorin gan dmas strappin go fstorag emoth s (Phycitinae)an d Tvogodevma spp.i n granaries,flou rmill san dfoo dfactories . Decreaseo fth eeffectivenes so fth emale' slong-rang esexua lresponse si ngreenhouse s may,o nth econtrary ,contribut et oth eeffec to fapplicatio no fth ecommunicatio n disruptiontechnique : innocturna lmoths ,th emale' sresponse st ofemal ese xpheromon eusuall yconsis to fa sequenceo fdistinctiv ebehavioura lsteps .Ther ei sevidenc etha teac hste prequire sa higherpheromon econcentration .Thi sha sbee ndemonstrate di nth elaborator yb ySchwinc k (1955)wit hth eChines esilkwor mmoth , Bombyx movi (L.),an db yBartel l& Shore y (1969)wit h thelight-brow nappl emoth , Epipkyas postvittang. (Walker)•I ti sals oknow nt ooccu ri n maleAmerica ncockroaches , Periplaneta amevioana (L.)(Rus t1976 ;Silverma n 1977).I n laboratoryessay sDe nOtte r& Klijnstr a (1980)pointe dou ttha tfemal ese xpheromon ei s indispensablet oevok ematin gattempt si nmale so fth esummer-frui ttortri xmoth , Adoxophyee ovana (F.v.R.).Shimiz u& Tamak i (1980)studie dth ematin gbehaviou ro fth esmalle rte a tortrix (Adoxophyes sp.).The ystate dtha tth efemal ese xpheromon ei sindispensabl et o releasemal esexua lbehaviou ri nshort-rang eorientation ,eve nafte rinitia lcontac twit h afemale .Castrovill o& Card é (1980)state dtha tonl yfemal ese xpheromon ema yevok emal e short-rangesexua lbehaviou ri nth ecodlin gmoth , Laspeyresia pomonella (L.).Femal ese x pheromonema yb eindispensabl ei never yste po fth esequenc eo fmal esexua lbehaviour , 77 bothi nan doutsid egreenhouses . Whenth ecommunicatio ndisruptio ntechniqu ei sapplie di nth efield ,th eoveral l concentrationo fth esyntheti cpheromon ei nth eai ri susuall yinsufficien tt ooverflo w thepheromon eplume sproduce db ycallin gfemales .I ngreenhouses ,th emale' ssexua l responses inlong-rang eorientatio nar ealread y lesseffectiv ewithou tapplicatio no fth e communicationdisruptio ntechnique .I ngreenhouses ,i tma yb epossibl et omak eth eoveral l concentrationo fsyntheti cpheromon esufficientl yhig ht ooverflo wth epheromon eplume s producedb ycallin gfemales ,an dthereb yt oachiev ecommunicatio ndisruption .Greenhouse s seemt ob ewell-suite dfo rth eapplicatio no fth ecommunicatio ndisruptio ntechniqu ea s acontro lmeasur eagains tnoxiou smot hspecies ,provide dmot hdensit yi sno tto ohig ht o ruleou tth echanc eo frando mencounter san dmatings .Studie so nth eapplicatio no fth e communicationdisruptio ntechniqu e ingreenhouse sshoul db eencouraged . Applicationo fth esterile-mal etechniqu eagains t C. spectvana hassevera ladvantage s ina greenhous eenvironment .Immigratio no fne wadult sfro moutsid e isalmos tcertainl y negligible.A tpresent , C. spectvana isth eonl ytortrici d speciesoccurrin g inth eDutc h floriculturalgreenhouse s (Vand eVri e 1978).Th edange rtha tothe rleaf-roller swil l takeove rwhe nchemica lcontro lagains t C. spectvana isstoppe dseem stherefor esmall . Applicationo fth esterile-mal etechniqu eagains tth esummer-frui ttortri xmoth , Adoxophyes orana (F.v.R.),i norchard si sto ocostly .Ther ear etw obottlenecks .B y releasingsteril emale sth epopulatio nca nb ereduce dt oa nextremel ylo wlevel ,i t remainsnecessary ,however ,t ocontro lothe rleaf-roller schemically ,whic hdefeat sth e purpose.Moreover ,th emetho drequire sa continuou sreleas eo flarg enumber so fsteril e malespe rgeneration ,t odea lwit himmigrants .A sthi spolyphagou sspecie sthrive so na widevariet yo fperennials ,immigratio nfro mth esurroundin gwil dvegetatio ncanno tb e prevented (Ankersmit 1975,1980) . Geneticcontro lo f C. spectvana byth ereleas eo fsteril emale showeve ri sno t impededb ythes etw ofactors .I nth eros ecultur eunde rglas shighe rpes tcontro lcosts , butlowe rlevel so fdamage ,ca nb etolerate d thani nfrui tgrowing .Th efollowin gprocedur e mayb epracticable :firstly ,a greenhous epopulatio nshoul db ereduce dt olo wnumber sb y insecticidest opreven teconomi cdamage ;thi sshoul db efollowe db yth ereleas eo flarg e numberso fsteril emales ,i norde rt oachiev eeradicatio no fth epes tseparatel y ineac h greenhouse.Studie so nth eapplicatio no fth esterile-mal etechniqu eagains tgreenhous e populationso f C. spectvana arerecommended . Interferencewit h thelif ecycl eo finsec tpest sb ymanipulatio no fth ediapaus e responseha sbee nsuggeste d asa mean so fcontro l (LaChance& Kniplin g1962 ;Klasse ne t al. 1970a,b ;Hoga n1971 ,1974 ;Foste r& Writte n 1974). Diapausecharacteristic sca nb ecrosse dint ogreenhous epopulation so fC . spectvana, withoutincreasin g theinfestation ,b yreleasin gmale so fth efiel d type.Thi sprobabl y isineffectiv et ocontro lthes epopulations ,an deve ninsufficien tt osuppres sgrowt han d reproductiono fth epes tdurin gth ewinte rseason : (a)th eabsenc eo fa perio do fchillin g doesno taffec tth esurviva lrat eo fdiapausin g larvae (Subsection7.1.1) . (b)F 1hybrid s 78 exhibita nintermediat ephotoperiodi cresponse ,inclinin gtoward sth ematerna l characteristics (Section9.3) ,thu sonl ypar to fth eoffsprin gwil lente rdiapause ,an d (c)th ediapaus echaracteristic sar eprobabl ysoo nlost . Biologicalcontro lo f C. speotrana ingreenhouse sma yhav einterestin gprospects .A rosehous ei nRoelofarendsvee nwa svisite di nth efirs twee ko fFebruary ,an di nAugus t 1979.I nFebruary ,26 3o fC . speotrana larvaewer eparasitised ,an di nAugus t 52%.Th e larvaeha dbee ncontinuousl ypresen tbetwee nFebruar yan dAugust ,bu tthe yremaine da ta lowpopulatio ndensity .Chemica lcontro lwa sno tnecessar ydurin gthi speriod .Th e parasites,whic hwer eno tidentified ,wer eals oactiv edurin gwinter .Apparentl ythes e parasiteswer eno tdiapausing .A surve yo fth eparasit efaun ao f C. speotrana in greenhouseculture sshoul db emade . 79 Summary Chapter 1: th eenvironmenta l conditions ingreenhouse sdiffe ri nman yrespect sfro m thosei nth eope nfield .Bot hth eclimat ean dth ecrop sar edifferent .A freeexchang e betweenth efaun ao fth egreenhouse san dth eope nai ri shampere db yth eglas swall san d roofs.Th eisolatin geffec to fgreenhouse so narthropo dpest scontribute st oth e effectivenesso fcontro lmeasures ,bu tals ot oth edevelopmen t andmaintenanc eo f pesticideresistanc e ingreenhouses .Becaus eo fth especia lcondition sa specifi cfaun a existsi ngreenhouses ,an dth eus eo fexoti cpredator san dparasite s forbiologica l controli spossible .Th egreenhous eenvironmen tact sa sa "sieve "onl yallowin gsuc h speciest othriv etha tar eadapte dt othes especia lconditions .Thes ear esometime sexoti c speciestha tcanno tthriv ei nth eope ni nth eDutc hclimate .Nativ especie sma ypenetrat e intogreenhous e cultures,bu tt opas sth e"sieve "the yhav et oadap tt ogreenhous e conditions. Theleaf-rolle r Clepsis spectrana Tr.i snativ e inth eNetherlands .I tgive sa n exampleo fth edevelopmen to fgreenhouse-adapte dpopulations .I nDutc hgreenhouses , especiallyo nroses ,i tcause smuc hdamage .I nheate dgreenhouses ,wher eartificia l illuminationi sno tused ,growt han dreproductio no f C. spectrana continuewithou t diapausedurin gwinter ,whic h isadvantageou s forth especie si nthi senvironment ,a s thedifferenc ebetwee nsumme ran dwinte rtemperature sdoe sno texcee da fe wdegree san d suitablefoo di savailabl eal lth eyea rround . Chapter2 deal swit hth emorphology ,bionomics ,host-plan trang ean ddistributio n areao f C. spectrana. Chapter3 describe sth ematerial san dmethods . Chapter4 :th enumbe ro flarva linstar sfro meg ghatchin gt opupatio nvarie d between4 an d8 i nbot hfiel dan dgreenhous estrains .Eac hlarva lgrowt htyp eha dit s ownspecifi cprogressio no fhea dcapsul ewidth .Th edifferenc e inhea dcapsul ewidt h betweenth e4 -an d 5-instar typewa salread yeviden ti nth e 1stinstar ,betwee nth e5 - and6-insta rtyp ei nth e2n dinstar ,an dbetwee nth e6 -an d7-insta rtyp eonl yi nth e3r d instaro reve nlater .Female stende dt odevelo pthroug ha highe rnumbe ro finstar stha n males,bu t5 instar swa sth emos tusua l inbot hsexes .Th edevelopmen tduratio nwa sth e samei nfiel dan dgreenhous estrain si neac ho fth eimmatur estages .Th euppe rtherma l limitfo rdevelopmen twa sbetwee n3 0C an d3 5C i nbot hfiel dan dgreenhous estrains , whereasth edevelopmenta l thresholdwa sclos et o1 0C .A nadaptatio no fgreenhous e populationso f C. spectrana todevelopmen ta thighe rtemperature sdi dno tappear . Chapter5 :shor tda ylengt hinduce ddiapaus ei nfiel dstrain si n thelarva lstage . Thecritica lphotoperio dwa sbetwee n1 6an d1 7hours .Th enumbe ro fmoult su pt oth eonse t ofdiapaus evarie dbetwee n2 an d6 ,an dwa sdetermine db yth ephotoperiod .Larva efro m eggshatchin glate ri nth eseaso nentere ddiapaus eafte ra lowe rnumbe ro fmoults .I n outdoorexperiments ,th etim eo fresumptio no fgrowt hafte rdiapaus eterminatio ni nsprin g wasno tcorrelate dwit hth edat eo feg ghatchin gi nth epreviou syear .Th elarva eunderwen t supernumerarymoult safte rterminatio no fdiapause .Th eduratio no fpost-diapaus e developmentwa slonge ra sdiapaus eha dbee nentere dafte rles smoults .Th enumbe ro f moultsafte rterminatio no fdiapause ,an dth eduratio no fpost-diapaus edevelopment ,wer e sex-linked.Th efunctiona lsignificanc eo fthes ephenomen ai sdiscussed . Chapter6 :th ephotoperiodi crespons eo f5 differen tgreenhous estrains ,originatin g fromlarva ean dpupa ecollecte di ndifferen tros ehouse sa tdifferen ttime so fth eyea r (bothi nsumme ran di nwinter) ,wa steste di nth elaboratory .Thes egreenhous estrain sdi d notente rdiapause ,a tbot h2 0C an d 15C ,regardles so fth ephotoperiod .On egreenhous e strainwa sals oreare doutdoors .Eg ghatchin gdate swer eAugus t1 ,Augus t 17,Septembe r 25,an dOctobe r 14.A tleas tth emajo rpar to fth elarva edi dno tente rdiapause . Chapter7 :field-strai nlarva eentere ddiapaus ei na heate dgreenhouse ,bu tth e absenceo fa perio do fchillin gcause da nabnorma lgrowt hpatter ni nthes elarva e comparedt olarva eterminatin gthei rdiapaus eoutdoors : (a)larva ldevelopmen tduratio n wasextremel yvariabl e (larvaefro mfield-strai negg stha thatche do nAugus t2 4i nth e greenhouse,pupate dbetwee nJanuar y2 8an dJul y1 5o fth efollowin gyear) ; (b)th e differencei nmea ndevelopmenta ltim ebetwee nmal ean dfemal elarva ewa sgreatl yincreased ; and (c)th emea nnumbe ro fmoults ,an dth evariatio ni nth enumbe ro fmoults ,wer e increased.Th esurviva lo fdiapausin g larvae,however ,wa sno tessentiall yaffecte db yth e absenceo fa perio do fchilling .Th etim erequire dfo rdiapausin g larvaet oreac hth e pupalstag eunde rcondition swithou ta col dperio dwa sgeneticall ydetermine dan dcoul d beshortene drapidl yb yselection . Chapter8 :a differenc ei nth ecompositio no fth efemal ese xpheromon ebetwee n fieldan dgreenhous estrain scoul dno tb eshown ,no ri nth ecallin gbehaviou ro fvirgi n femalesi nrelatio nt oth elight-dar kcycle .Release-recaptur etrial sreveale dtha t femaleso fbot hstrain sattracte dmale so fbot hstrain si nequa lproportions .Ther edi d notappea rt ob ea differenc ei nmatin gpreference . Chapter9 :th einde xo fgeneti cidentit y (I)o fa fiel dpopulatio no nstingin g nettlesfro mth emiddl eo fth ecountry ,an da rose-hous epopulatio nfro mth ewes to f thecountry ,amounte dt o0.99 4(base do nallozym efrequencies) .Thi si sth eleve lfo r panmicticpopulation so fon especies .Fiel dan dgreenhous estrain scoul dreadil yb e intercrossedwit ha viabl eF 2generation . Chapter10 :fiel dan dgreenhous epopulation so f C. spectrana arecertainl ystil l conspecific.I ti sadequat et ospea ko fa "fiel dtype "an da "greenhous e type".Th e greenhousetyp ei scharacterise db yabsenc eo fth eabilit yt oente rdiapause .Whe nth e twotype sar ebrough ttogethe rhybridizatio nan dintrogressio ncertainl ywil loccur . Immigrationo fth efiel dtyp eint oheate dgreenhouse si sapparentl ysufficientl ylo w tomaintai na separat egreenhous etyp ewit hconstan tcharacteristics .Th eorigi no fth e greenhouse typemigh tb ea non-diapausin g geographicrac eo f C. speatrana, fromth e warmestpart so fit sdistributio narea ,o rth efiel dtyp etha tha simmigrate d intoheate d greenhouses,subsequentl ylos tit sabilit yt oente rdiapause .Th elas tpossibilit y seemsth emos tlikely . Chapter 11:pheromona ltrappin go f C. speatrana isles seffectiv ei ngreenhouse stha n inth eope nair .Probabl yth especifi cnatur eo fth eai rmovement si ngreenhouse sreduce s theeffectivenes so fth elong-rang epheromone-mediate dbehaviou ro fth emales .However , malepheromone-mediate dbehaviou ri nshort-rang eorientation ,clos et ocallin gfemales , mayb eunaffecte d (Section8.3} .Thi sdecrease sth eeffec to fsyntheti cpheromon euse d formonitorin gan dmas strapping .However ,applicatio no fth ecommunicatio ndisruptio n techniquema yb esuccessfu lunde rglass ,becaus eth eoveral lconcentratio no fsyntheti c pheromone inth eai rca nb emad emuc hhighe r ingreenhouse stha ni nth eope nfield . Furtherresearc hi srecommended . Controlling C. speatrana ingreenhouse sb yreleasin gsteril emale sseem sfeasible ,as : (a)immigratio no fne wadult sfro moutsid ealmos tcertainl yi snegligible ,an d (b) C. speatrana isth eonl ytortrici doccurrin g inth eDutc hfloriculture ;th edange rtha tothe r leaf-rollerswil ltak eove rwhe nchemica lcontro lo f C. speatrana ceasesseem stherefor e small. Diapauseca nb ecrosse d intogreenhous epopulation so f C. speatrana byreleasin g maleso fth efiel dtype .Thi sprobabl y isa nineffectiv ewa yo fcontrollin gthes e populations. Parasitised C. speatrana larvaewer efoun di nsevera lgreenhouses ,eve ni nwinter . Theparasites ,whic hwer eno tidentified ,apparentl ywer eno tdiapausing .I ti srecommende d tomak ea surve yo fth eparasit efaun ao f C. speatrana ingreenhous ecultures . &2 Samenvatting Hoofdstuk1 : He tkasmilie uverschil ti nvee lopzichte nva nda ti nhe tvrij eveld .E r wordenander egewasse ngekweek te nhe tklimaa ti sanders .Ee nvrij euitwisselin gtusse n kasfauna'se nveldfauna' sword tbelemmer ddoo rd ewande ne nhe tda kva nd ekas .He tiso lerendeeffec tva nkasse no pinsekten -e nmijtenplage nka nbijdrage naa nd edoeltreffend heidva nbestrijdingsmaatregelen ,maa roo kaa nd eontwikkelin ge nhandhavin gva nresis tentietege nbestrijdingsmiddele n inkassen .Al sgevol gva nhe tspecial ekasmilie u bestaatee nspecifiek efaun ai nkassen ,e nword the tgebrui kva nuitheems eparasiete ne n predatorenvoo rbiologisch ebestrijdin gmogelijk .He tkasmilie ufungeer tal see n"zeef " dieallee ndi esoorte n"doorlaat "di eaa nd especifiek eomstandighede nzij naangepast .I n kassenworde ntropisch ee nsubtropisch e insekten-e nmijtensoorte ngevonde ndi ezic hi nd e buitenluchti nhe tNederlands eklimaa tnie tkunne nhandhaven .Som skome ninheems esoorte n binnen,maa ro md e"zeef "t ekunne npassere nmoete nz ezic haanpasse naa nd ekasomstandig - heden. Debladrolle r Clepsis spectrana (Tr.)i sinheem si nNederlan de nheef tee nafzonder lijkkastyp eontwikkeld .I nkasse ni shi jee nbelangrijk eplaag ,met.nam eo prozen . Inverwarmd ekasse nwaa rgee nkunstmatig ebelichtin gword tgegeven ,gaa tzij nontwikke lingoo kgedurend ed ewinte rverder ,nie tonderbroke ndoo rdiapauz e (winterrust).Di ti s voordeligvoo rd esoor ti ndi tmilieu ,waa rhe tverschi ltusse nzomer -e nwintertempera - turenslecht senkel egrade nbedraag te nhe tgehel ejaa rdoo rgeschik tvoedse laanwezi gis . Inhoofdstu k2 worde nd euiterlijk ekenmerken ,d elevenswijze ,d ewaardplantreek se n hetverspreidingsgebie dva n C. spectrana besproken.I nhoofdstu k3 worde nd emateriale n enmethode nbeschreven . Hoofdstuk4 : He taanta llarvestadi avana fhe tuitkome nva nhe te ito td everpoppin g liepuitee nva n4 to t8 i nzowe lveld -al skasstammen .El kva ndez egroeitype nha dzij n eigenspecifiek everloo pva nkopkapselbreedte s (iederlarvestadiu mheef tzij neige n specifiekegemiddeld ekopkapselbreedte) .He tverschi li nkopkapselbreedt etusse n4 -e n 5-stadia-rupsenkwa ma li nhe teerst elarvestadiu mto tuiting ,tusse n5 -e n6-stadia - rupseni nhe ttweed estadium ,e ntusse n6 -e n7-stadia-rupse npa si nhe tderd estadiu mo f later.D evrouwtje smaakte ngemiddel dmee rvervellinge ndoo rda nd emannetjes ,maa rhe t 5-stadia-typewa soverheersen d inbeid egeslachten .E rwa sgee nverschi li nontwikkelings- i duurtusse nveld -e nkasstammen .Di tgol dvoo rzowe leieren ,rupsen ,al spoppen .D eboven grensvoo ractiev eontwikkelin gla gtusse n3 0C e n3 5C i nveld -e nkasstammen ,terwij ld e ontwikkelingsdrempel ind ebuur tva n1 0C lag .Ee naanpassin gva nkaspopulatie sva nC . spectrana aanontwikkelin gbi jhoger etemperature nwa snie taantoonbaar . 83 Hoofdstuk5 :Veldstamme nhadde nee ndiapauz e inhe tlarvestadium ,geïnduceer d doorkort edaglengte .D ekritisch edaglengt ela gtusse n 16e n1 7uur .He taanta lvervel lingento the tintrede nva nd ediapauz e liepuitee nva n2 to t6 ,afhankelij kva nd e daglengte.Rupse ndi elate ri nhe tseizoe nui the te ikwamen ,ginge nn aee ngeringe r aantalvervellinge ni ndiapauze .He ttijdsti pva ngroeihervattin gn abeëindigin gva nd e diapauzei nhe tvoorjaa rwa snie tafhankelij kva nd edatu mwaaro pd eeiere ni nhe tvoor gaandejaa rware nuitgekomen ,bi jproeve ni nd ebuitenlucht .D erupse nmaakte nextr a vervellingendoo rn abeëindigin gva nd ediapauze .D eduu rva nd epost-diapauze-ontwikke - lingwa slange rnaarmat ed ediapauz en aee ngeringe raanta lvervellinge ningetrede nwas . Hetaanta lvervellinge nn abeëindigin gva nd ediapauz ee nd eduu rva nd epost-diapauze - ontwikkelingverschilde ntusse nmannetje se nvrouwtjes .D ebiologisch ebetekeni sva n dezeverschijnsele nword tbesproken . Hoofdstuk6 :D ereacti eo pdaglengt eva n5 verschillend ekasstamme nafkomsti gva n rupsene npoppe ndi ei nverschillend erozenkasse ni nverschillend e tijdenva nhe tjaa r (zoweli nd ezome ral si nd ewinter )verzamel dwaren ,wer di nhe tlaboratoriu monde r geconditioneerdeomstandighede ngetoetst .Dez ekasstamme nginge nbi j zowel2 0C al s1 5C bijgee nenkel edaglengt e indiapauze .Ee nva ndez ekasstamme nwer doo ki nee nkoo ii nd e buitenluchtgekweekt .D eeiere nkwame nui to p 1augustus ,1 7augustus ,2 5septembe re n 14oktober .E rtra dgeen ,o fnagenoe ggeen ,diapauz ein . Hoofdstuk7 :Rupse nva nee nveldsta mginge ni nee nverwarmd eka si ndiapauze ,maa r deafwezighei dva nee nkoudeperiod everoorzaakt eee nabnormaa lgroeipatroo ni ndez erupsen , vergelekenme trupse ndi ehu ndiapauz e ind ebuitenluch tbeëindigden : (a)D evariati ei n deontwikkelingsduu rva nd erupse nna mster kto e (rupsendi eo p2 4augustu sui the te i kwamen,verpopte ntusse n2 8januar ie n1 5jul iva nhe tvolgend ejaar) , (b)He tverschi l inontwikkelingsduu r tussenmannelijk ee nvrouwelijk erupse nna mster ktoe .(c )He t gemiddeldaanta lvervellinge ne nd evariati e inhe taanta lvervellinge nname nster ktoe . Deoverlevingskan sva ndiapauzerend erupse nwer devenwe lnie tnoemenswaardi gbeïnvloe d doorhe tontbreke nva nee nkoudeperiode .D etij ddi ediapauzerend e rupsenonde rkas - omstandighedennodi ghadde no mhe tpopstadiu m tebereike nwa serfelij kbepaal de nwer d onderinvloe dva nselecti esne lkorter . Hoofdstuk8 :Ee nverschi l ind esamenstellin gva nhe tvrouwelijk esexferomoo n tussenveld -e nkasstamme nko nnie taangetoon dworden ,noc hi nhe tlokgedra gva nmaagde lijkewijfje si nrelati eto td elicht-donker-cyclus .Ui tterugvangproeve nme twijfjes - vallenblee kda tvrouwtje sva nbeid estamme nmannetje sva nbeid estamme ni ngelijk emat e aanlokken.Ee nverschi li nparingsvoorkeu rkwa mnie tnaa rvoren . Hoofdstuk9 :D einde xva ngenetisch e identiteit (I)va nee nveldpopulati eo p brandnetelsi nhe tmidde nva nhe tland ,e nva nee npopulati eo pkasroze ni nhe tweste nva n hetland ,bedroe g0,99 4(gebaseer do pallozymfrequenties) .Dez ewaard ekom toveree nme t dieva npanmictisch epopulatie sva néé nsoort .Veld -e nkasstamme nkonde ngemakkelij k onderlinggekruis tworde ne nd eF 2generati ewa slevensvatbaar . 84 Hoofdstuk10 :Veld -e nkaspopulatie sva n C. spectrana behorenzeke rno gto téé nsoort . Menka nhe tbest espreke nva nee n"veldtype "e nee n"kastype" .Hs tkastyp eword t gekenmerktdoo rhe tontbreke nva nhe tvermoge no mi ndiapauz et egaan .Ifennee rd ebeid etype n samengebrachtworden ,zulle nz ezeke ronderlin gkruisen .D eimmigrati eva nhe tveld typei nverwarmd ekasse ni skennelij kgerin ggenoe go mee nafzonderlij kkastyp eme t constanteeigenschappe nt ehandhaven .D eoorspron gva nhe tkastyp eka nee ndiapauze-vri j geografischra sva n C. spectrana zijn,ui td ewarmst edele nva nzij nverspreidingsgebied . Heti soo kmogelij kda the tveldtyp ei nverwarmd ekasse nimmigreerd ee nvervolgen s zijnvermoge no mi ndiapauz et egaa nverloor .D elaatst emogelijkhei d lijkthe tmees t waarschijnlijk. Hoofdstuk11 :D etoepassin gva nferomoonvalle ntege n C. spectrana isi nkasse nminde r effectiefda ni nd ebuitenlucht .Vermoedelij ki sal sgevol gva nd especifiek eaar dva nd e luchtbewegingeni nkasse nd eeffectivitei tva nhe tdoo rferomoo nopgewekt elange-afstands - gedragva nd emannetje sverminderd .He tdoo rferomoo nopgewekt ekorte-afstands-gedrag , dichtbi jlokkend ewijfjes ,za lechte rnie tgestoor dzij n(hoofdstu k8.3) .Di tdoe t afbreukaa nd eeffectivitei tva nferomoonvalle nvoo rhe tsignalere nva nee naantastin gi n eenvroegtijdi g stadium,o fvoo rhe tmassaa lwegvange nva nmannetjes .Toepassin gva nd e verstoringstechnieki nkasteelte nbied twaarschijnlij kwe lkan so psucces ,omda td e algeheleconcentrati eva nhe tsynthetisch eferomoo ni nd eluch ti nkasse nvee lhoge r gemaaktka nworde nda ni nhe tvrij eveld .Verde ronderzoe kword taanbevolen . Toepassingva nd esteriele-mannetjes-technie k tegen C. spectrana inkasse nlijk t veelbelovend:immigrati eva nnieuw emotje sva nbuite ni svrijwe lzeke rt everwaarloze n en (b) C. spectrana isd eenig ebladrollersoor ti nd eNederlands ebloementeel tonde rglas , zodate rgee ngevaa rbestaa tda tander esoorte ni naanta ltoeneme nal sd echemisch e bestrijdingva n C. spectrana gestaaktwordt . Diapauzeka ni nkaspopulatie sva n C. spectrana ingekruistworde ndoo rmannetje sva n hetveldtyp elo st elaten .Di ti sontoereiken dal sbestrijdingsmethode . Inverschillend erozenkasse nblee kee ndee lva nd e C. spectrana rupsengeparasiteer d tezijn ,zelf si nd ewinter .D eparasieten ,di enie tgedetermineer dwerden ,ginge nblijk baarnie ti ndiapauze .He tverdien taanbevelin gee ninventarisati et emake nva nd e parasietenfaunava n C. spectrana inkasteelten . 85 Acknowledgements Theresearc hfo rthi srepor twa spropose db yProf.Dr .J .d eWilde ,Mr .M .va nd eVrie , andDr.Ir .G.W .Ankersmit .I twa scarrie dou tfo rth eLaborator yo fEntomolog y (AgriculturalUniversity ,Wageningen] ,whil e Iwa sseconde dt oth eResearc h Stationfo r Floriculture,Aalsmeer ,th eNetherlands . Iwis ht othan ksincerel yan dprofoundl yal lthos ewh ohav econtribute d inan ywa yt o thispublication .I woul d liket omentio nsom eo fthe m inparticular . Firsto fal lI woul d liket othan km ypromotor ,Prof.Dr .J .d eWilde ,fo rgivin gm e theopportunit y tod othi swork .Hi sinterest ,continuou sencouragement ,an dcomment so n themanuscrip twer eo fgrea thelp . Thanksar eals odu et oth eboar do fth eresearc hstatio ni nAalsmee rfo rthei r hospitalityan dcooperation . Theinteres tan dsuppor to fMr .M .va nd eVri ean dDr.Ir .G.W .Ankersmi tthroughou t thework ,thei rvaluabl e suggestionsan dcomment so nth emanuscrip tar egratefull y acknowledged. Ia mindebte dt oDr.Ir .C.J .Persoon sfo rmakin gth eelectro-antennograms ,t oMr .W.J . Nooijenfo rgaschromatographica l analysiso fth econtent so fpheromon eglands ,t oDr . S.B.J.Menke nfo rprovidin gth eelectrophoreti c data,t oDr .A .Diakonof ffo rtaxonomi e workan dprovidin gliteratur eo nhos tplant san ddistributio no f C. spectrana, toDr .H.H . Evenhuisfo rtaxonomi ework ,t oMr .G .va nRosse mfo rallowin gm et ous eth efile so fth e PlantProtectio nService ,t oIr .A.K.1I .Wi t forassistanc e incollectin g leaf-rollersi n thefield ,an dt oDr.Ir .R .Rabbing cfo rassistanc e incompute rmodellin gan dreadin g partso fth emanuscript . Amongother sDr.Ir .A.K .Minks ,Drs .C .va nde rKraan ,Dr .L.H.M .Blommers ,Dr .W.M . Herrebout,Drs .A .llendrikse ,Prof.Dr .J.C .va nLenteren ,Ir .J .Woets ,Ir .P.M.J . Ramakers,Dr .D .llill eRi sLumbers ,an dDr.Ir .M.W .Sabeli shav econtribute db ythei r interestan dstimulatin gdiscussion . Ireceive d indispensableassistanc efro mMr .M .Boogaar dan dMrs .B .Overdcves t (takingove ro froutin eobservation sdurin gm yholidays) ,Mis sC.C.M ,d eBoe r (drawings), Mr.M.J . 'tHar t (adviceo nlay-out) ,Mr .H .Stepha n (photographs),an dMrs .S .Kerkhoven - Hodges (improvemento fth eEnglis h text). Lastbu tno tleas tI woul d liket othan km ywife ,Cob yva ndo rLubbe ,withou twhos e carean dmenta lsuppor tthi swor kwoul dno thav ebee ncompleted . 86 References Alford,D.V . (1976).Th ehos trang eo f Clepsis speotrana (Treits.)(Lepidoptera : Tortricidae).PI .Path .25 :166 . 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