oIII o... ell r0­ oO Z (I) (I) TE CHNICAL BULLE TIN No. 104 FEB RUARY 1980 (I) :l :::> ~ :0 THE APPARENT METAMORPHOSIS AND RELATED DEFENSE REACTIONS OF HAEMOCYTES IN THE LAWN ARMYWORM, SPODOPTERA MAURITIA ACRONYCTOIDES (Guene'e) GERALD H. TAKEI AND MINORU TAMASHIRO HAWAII AGRICULTURAL ExPERIMENT STATION, UNIVERSITY OF HAWAII THE AUTHORS Gerald H. Ta kc i is current ly with the Hawaii Epidemiologic Studies Program , Pacific Biomedical Research Center, University of Hawaii at Manoa. Minoru Tam ashiro is Professor of En tomology an d Entomo logist, Dep artment of Entomology, Co llege o f Tropical Agriculture and Human Resources, University of Hawaii. CONTENTS Page /\ BST RACT 2 INT RO DUCTI O N 3 MATER IA LS AN D METHODS. .. .. .... .. .. 5 RESULTS G Hacmocyt cs in Control S. mauritia G Hacmocy tcs in Armywo rm s Subject ed to Treatments of Pathogen s 19 SU~ IMARY AN D DISCUSS ION 27 R EF ERENCES 38 ABSTRACT Ph ysiop athol ogi cal studies in vo lvin g t he law n ar m y w orm, Spodoptcra m auri u a ac ro nyctoidcs [Gu en ce} and tw o pa t hogen s fo u nd asso ciated w ith it ill Ha ioai i, a nu clear poly hedr osis virus (N P V) and a microsporidian , Vairimorpha, have revealed th at th e hue m ocy tes in th is host ins ect change ill quantit y, f orm , and act iuit y ioith. growt h and devel opment du ring the larval and early pupal st ages. Th e blood ce ll changes in who le huem oly m pli samplcs co llectc d f ro m larvae and p upae were o bserved 10 fo llow a timet» pui tcrn wi th aging 'II gro w t h an d developm en t progressed, indicating an ap pn rcn! m etamorphos is of hucm o cv tes in th is moth. I.aruae whi ch are about 15 days old are characteriz ed hy individual pro hacm. ocytcs, cy stoc y tes, adipohuem ocylcs, an d spherule cells tha i multiply and in crease in quantities with gro w th and aging. Mor e f orms of hucmo cy tes may he o bserved wi th th e in creases in qu an ti ti es, until plasmatocv tes, ocnocvto ids. ver m if orm cells, granular haem ocytes, and podoc yt cs may also be diff erentiated. Th e multiplication and dif f eren tiation arc f ollowed b y aggregations and fusions of plasmulo cv tes and granu lar haem ocy tes, an d agglom erat ions of th ese and o ther hucmocy tcs f orm co m p lexes and nod ul es, respectively. Prio r to pupation th e individ ual an d co m plex es of haerno cy tcs begin vacuo lating and granu lating, these pro cesses believed to be indicating th e degen eration of tissu es. Du ring th ese ce llu lar pr ocess es, large numbers of small uacuo lelike glo bu les with som e larger blebs are produced alon g with increasing quantities of dar k gran u les. Phagocytosis of tissu e f ragm en ts is o bserv ed in th e individual and co m p lexes of liacmocvtes, while both p hago cy tosis an d enc ap sulation are believed to ta ke place during nodu lar f orm ation. l lyalin e huemo cy tes. o ther form s of ple omorphic plasrnatocy tes, an d inter m edi ate f orm s of hae m oc y te transforma tions an ' also o bse rve d du ring th is lat e larval period. In th e early pupal stage, th e degeneration con tinues until th e individual and c om plexes of hac mocvtes become filled and swo lle n with glo bules, granu les, an d p hago cy to zed tissu e f ragm en ts, and som e cells begin disru pting, By th e tim e Impae are three days old, the phago cytozed tissu es, alon g w ith all th e other materials that have accumulat ed within th e cells, tran sf orm in t o high ly refra ct ive sp h eres or balls. Th ese spheres do minate the haemolymph wh ile on ly ou tlines and remnan ts of blood cells remain . M an y phases in t he apparen t m etamorp hasis of huem ocy tes were accentuated during com parative studies between armyworms ex p ose d to treatments of p athogens an d ot h er stress situation s and untrea ted, con tro l armyworms. Armyworm.I' appearing normal th at are under stress and infec ted arm y w orm s d emonstra te clear ly the pro gressive changes of huc mocy tes t ha t take place during th e apparen t m etamorphosis of these cells. Ilo w ever, in these sp ecime ns the changes are premature, occurring earlier in I he growt h and developmen tal periods of the army w orm th an in con tro l specimens. Th e pre co ciou s developments are conside red to be part of th e defen se reactions of S. mauritia. This and the apparent m etamorphosis of hue mocy les are discussed fro m different vie wp o in ts. THE APPARENT METAMORPHOSIS AND RELATED DEFENSE REACTIONS OF HAEMOCYTES IN THE LAWN ARMYWORM, SPODOPTERA MAURITIA ACRONYCTOIDES (Guene'el GERALD H. TAKE I AND ?\ IINORU T AMASHIRO INTRODUCTION Since the late nineteen th ce nt ury, an abundance o f res earch in vol ving ins ect bl ood cel ls has been reporte d. In additi on to studies co ncern ing t he morphology an d classifica tio n o f hacrnocyt cs, m ,U1 y investigatio ns have been co ncern e d wi th de fen se reac ti o ns and im munity of host insect s to p arasi tes an d pathogens. Sa lt ( 1963), Po inar ( 1969), and Shapiro ( 1969) have co m piled ex te ns ive reviews o n the immunity of inse cts to parasitic worms, w hile Hu ff ( 1940), St e inhaus ( 1949), Wagn er (196 1), Step he ns ( 1963), Briggs ( 1964), and Heimpcl and Harshbarger ( 1965) arc so m e o f th e au thors who have e mp hasize d thei r reviews o n insect im m uni ty and m icrobial infe ctions. T he activities or hacmocytcs in immune res ponses arc asso ciated wi th ph agocy tosis, ce ll tran sf ormat ion s an d melan ization. Basicall y , thes e arc re garded as cel lular defen se reactions, but Sa lt ( 1963) and Sha piro ( 1969) co nside r melan izati on to be a humo ral rea ction. Witt ig ( 1962) classifies a ctivitics or hac rnocy tcs in patho logy as hi stol ogical, cy to logica l, o r cy tochem ica l. Accord ing to this classifi ca­ tion , changes in total hacrn ocy tc co un ts (T HC) as reported by Wheeler ( 1963), Laigo and Paschke ( 1966), Witti g ( 1965, 1966), Shapiro ( 1967), and Bah adur and Pathak ( 197 1), as wel l as changes in differen tia l hacmocy tc co un ts (DI-IC) as re ported by Wittig (1 9 66 ) and Nappi (1 970a, lJ), arc h istol ogical change s. Some exam ples o f cy to log­ ica l ac tivit ies arc phagocy tosis (Wi tt ig, 19 65, 19 66, 19 68 ; We rn er and j ones, 19 ( 9 ), ce ll aggrega tion , and e ncaps ulatio n during pa rasiti zation (Van Den Bosch , 1964 ; Sa lt, 196 5, 1966 ; Poinar ct a l., 19 68 ; Na p pi and S t. o f'l'o lan o , 19 71 , 19 72 ), and wo un d clos ures by co agu lat ions (Ik ard , 195 0 ; Grego ire, 19 51 , 19 74) . Mclan izu t. ions as reported b y Rizki ( 195 7a, b, 19( 0 ) and Na p pi ( 19 70lJ) ar c cy toc hem ica l changes. 4 II AW AII AGR ICU LTU RAL E X I'E R I~ IENT STATION Interestingly, Arnold ( 1974) has or ganized the man y var ied p ro cesses o f hac mocytes, as re ported ove r t he years, in to hac rnocyt c funct io ns an d hacmocyte activi tics. In th e first ca tegory he has ac knowledged four basic fun ct ion s: ( I) ph agocy tosis of small parti cles the size of mi croo rgani sm s, (2) encaps ulatio n o f large, fo re ign o bjects suc h as parasites and parts o f parasi tes, (3) coagulatio n of the blood by cellu lar agglutina t ion and/or by co n trib u ting to p lasm a precipitat ion, and (4) stora ge and d istribution o f nutritive mat eri als. Included in th e hacmocytc activi tics ca tegory arc suc h pro cesses as healing 0 I' wo unds , nod ule formati on abo u t clum ps o f foreign particles, the removal o f lysed tissu es, membran e (ti ssu e) form at ion , con tro l o f hormone ac tio n and th e reg u la tio n o f gro w th, detoxication of che m ica ls, melani zation o f cu tic le, and other process es w hich may involve one or more o f th e Io u I' ack n owledged fun ct ions .