Pemphigus spirothecae Pass. was inadvertently introduced into North America only recently. Upon hatching in spring on lombardy poplar, the fundatrix feeds on a leaf petiole, which bends and then spirals into a spiral gall. The fundatrix produces about 100 fundatrigeniae within the gall. These produce winged sexuparae which leave the gall and settle on the poplar bark, where they produce up to eight progeny, males and females. Each female lays a single large egg which overwinters on the bark. This aphid is thus monoecious and holocyclic

Chan, Cho-Kai

Forbes, A. R.

&lt;i&gt;Pemphigus spirothecae&lt;/i&gt; Pass. was inadvertently introduced into North America only recently. Upon hatching in spring on lombardy poplar, the fundatrix feeds on a leaf petiole, which bends and then spirals into a spiral gall. The fundatrix produces about 100 fundatrigeniae within the gall. These produce winged sexuparae which leave the gall and settle on the poplar bark, where they produce up to eight progeny, males and females. Each female lays a single large egg which overwinters on the bark. This aphid is thus monoecious and holocyclic

Journal of the Entomological Society of British Columbia

26 ,J. E ',r ()\J(II . S()C 11 1( 1'1' . COI.l I\ I II I.\ 72 (1975). I) I·T . ;~ I. 197;; LIFE-CYCLE OF A SPIRAL GALL APHID, PEMPHIGUS SPIROTHECAE (HOMOPTERA: APHID IDA E), ON POPLAR IN BRITISH COLUMBIA 1 CHo-KAI CHAN AND A . R. FORBES Resea rch Station , Agriculture Canada Vancouver , Britis h Columbia ABSTRACT Pemphig-us sllirollwcal' Pass. wa s inadvertentlv introduced into North America only recently . Upon ha tching in spring on lombardy poplar, the . fundatrix feeds on a lea f petiole, which bends and then spirals into a spiral galL The fund at rix produces about 100 fundatrigeniae within the galL These produce winged sexuparae which leave the gall a nd settle on the popla r bark , where they produce up to eight progeny , males a nd females . Each female lays a sing le large egg which overwinters on the bark. This aphid is thus monoecious and holocycl ic. 1\T1WDlTTION The gall aphid . P emphigus spiro th ecae Pass., wa s studied on lomba rdy poplar . Populu s nigra L. var. i talica, on the ca mpu s of t he Uni-vers ity of Briti sh Columbia during 1973 and 1974 . This aphid produces unique spiral galls (Fig. 1) on the petioles of the leaves . P. spiro-thecae is appa rent ly common in E urope but was found only recently in Nor t h America in Quebec (Alleyne & Morrison 1974) and at about t he sa me time in Bri t ish Columbia. Its life-cycle in Europe has been described by Tuth (1939 ). The present stydy was underta ken to deter min e t he life-c.ve le of t he ap hid in Briti sh Columbia and to describe t he aphid-host plant interaction . DEVELOPMENT OF TH E GA LL [n general. t he formation of a ga ll has a n early phase. a trophic phase. a nd a post-trophic phase (Mani 1964) . In t he spiral ga ll of P. spiro-thecae the early phase can be sub-di vided into three stages: bending. s piralling a nd s welling (G erhardt 1922); swelling of t he gall co nt inues t hroug h the trophic phase. Upon emerging from the egg, the fund atrix or s tem mother, begin s to feed on the petiole of a lea f produc-ing firs t bending (Fig. 2b) then spiralling until t hree loose spirals have been produced (Fig. 2. c & d) . Subsequent swelling of t he ga ll seals t he gall cavi ty and increases its size (Fig 2, e, f & g) . The time taken to prod uce the t hree coils on pet ioles of lombardy poplar outdoors at Vancouver was 3-4 weeks, cons idera bly longer t han the 6 days reported by Dunn (1960) for attain ing the sa me stage in the laboratory. If the first instar stem mother dies while the gall is forming. no further development takes place and incomplete galls result with one or 'Contri bu t ion no. 362, Hesearch S tat ion, Agricu ltu re Ca nad a. 6660 N. W. Marine Drive. Vancouver. Bri tis h Colum· bia. V6T I X2 . two coils . Subsequent feeding by the newly enc losed fun datr ix stimulates the co il s of th e gall to g row laterally. sealing the wa lls . In-crease in length of the coils expands the gall a nd increases the size of the cavity. The ga lls reach maturity in late Aug ust a nd September, g radually changing from green to ora nge- red or brown. When mature, the ga lls measure a bout 15 x 13 x 9 mm. The ga ll cav ity is lined by numerou s short, papi llate unicellula r hairs. with some longer multicellula r ones among them. When the gall is ma ture. one or two ost ioles develop (Fig. 3) between t he coils to serve as emergence holes for the a phids. or sometimes the coils loosen, producing a long sli t in the ga ll . allowing a mass escape of t he inh ab ita n ts. In t his post-trophic stage. the ga ll s dcteriorate and fa ll from t hc l rl'C wilh t he leaves. The tota l life of a ga ll is from 20-25 weeks. We could find no evidence that t he presence of a gall on a leaf weakened t he leaf or reduced its s ize. Ga lled leaves, however, fell from t he tree sooner t ha n non-galled ones. LI FE CYCL E OF THE APHID In lat.e Ma rch or Apri l at Vancouver t he fund at ri x emerges from the overwintered egg. at a time when t he young poplar leaves begin to appear. Th e fir s t instar funda t rix (Fig. 4) is small. brownish green. and ha s very well developed hind legs. 4-segmented antennae (Fig. 4a) and norma lly developed la bium and sty lets (F ig 5 ). In fact. its sty lets a re very much like t hose of M yZlls persicae (Sulzer ) (Forbes ]969) wit h each madibular stylet inner-vated by two dendrites. The funda t rix settles to feed on a lea f petiole. in itiating the forma tion of the ga lL The fundat rix moults for the first time as soon as t he spira lling of the petiole has been completed . or almost completed i.c" a bout 3-4 weeks after hatching. After the fourth moult the fund atrix is mature and s tarts to reproduce parthenogenetically. The mature J . E \T()\ I()I.. SCI(" H IlIT CCII. l l\ il\i \ 72 1197,,1 . D i';(' 3 1. 19r, g Pig. 1. Pully formed s pira l gall o f Pemphigus spiruthecat' Pass. on t he petiole of a lea f of lomba rdy popla r. Pig. 2. Stages in the form at ion of t he ga ll : a. a non-ga lled lea f: b. bend ing of t he petiole: c & d, s piralling of the petiole: e. f. &. g, s well ing of the ga ll. Fig. 3 Mature ga ll with a n ostiolc I a rrow I. 21' J . 1·;I': TI)\IOI.. Soc B HIT C()1.l \1111 \ 7:!. I I 97:'J\. DE C 3 1.197') 4 f~ ( " I J \ \ ',.,\ .. " \ j 6 6a 7 ~~ -8 Fig. 4. Firs t in sla r fund at rix of P. sp irolh l'tal' with an en largement of an antenna (4a). Magnification: whole aphid 1__ 1 = 0. 5 mm a ntenna 1 __ I = 0.1 mm Fig. 5 . Tra ns mi ssion electron mi crograph of a cross sect ion of the sty lets of a fir st in s tar fundatrix. f- ~ _ \ = 1 u Fig. 6. Matu re funda l rix with an enla rgement of a n antenna (Gal . Mag nificaLion : whole aphid I---- - - - _ _ I = 1 mill a ntenn a 1 - - 1 = 0.\ mm Fig. 7. Mature fundatrigeni a with an enlargement of an antenn a. Magnification a s for Fig. 6. Fig. 8 Sexuparac ins id e an o pened ga ll. J . E '\ [·()\l(ll. S() l" H ltl"!" Cc'I.[ I \ [ lIl.\ ,2 I 1 ~J7·-'I . 1) [.:(" :)1 . 197,-, 9 10 <. " t ,... 11 f ' , -(, I ; ' I" r I."" ",I I \ , • '\ Fig. 9 . Mature sex upa ra with an enlargement of a n an t pnna 19a1. Magnification as for F ig. 6. Fig. 10, \ l atun' ma le (sexliall'llI'i t h an enlargl'mE'n! of an antenna 11 0 a). l'\Oll' the rudimentar.\' mouthparts. \ lagnifil'ntion as 10f' I.'ig. Ii. Fig. 11. :\ latUl'l' fl 'll1a il' ISl'x uall'llI'ith an l'n largl'll1l'nt of ,[n antl'nnd I lia) . \Jotl' the rudiml'lltan' ll1ou th parts. \l agnifil'a!ion as for Fig . Ii. F ig. 12. Fl'nwll' la\'ing Iwr egg. Fig. 13 . .'\" l'gg with wool-lik l' wax. 29 30 .1, 1·:\To\ l()1. SIlt' 13111'1' C"I.I I\11 11 \ 7'21 1 ~)7:,). Ih ;I' :1 1, 197:,) fund atri x (Fig, 6) is pa le yellow a nd has s hort 4-seg mented a n tennae. I F ig, 6a) and well -d e-ve lo ped lab iu m and sty let s . At Va ncou ver t he fun datrices mature be-tween mid-june a nd t he beginning o f July , During July a nd Aug ust each fundatr ix pro-du ces abou t 100 p rogeny, t he fun dat rige niae, T he mature fund at rigen ia (Fig 7) is pa le a nd can be di s ti ng ui shed from . t he matu re fu nda-trix by its longer, 6-segmen ted antennae (Fig. 7a). The fun da trigeniae moult four t imes before t hey star t produ ci ng t he sexu pa rae. The se xupa l'ae ure p roduced in August and Septembe r a nd are prese nt in t he ga ll s I I.' ig. R ) from ea rh' August un t il la t NOH'mill'r. Th e m aLU re sex upa ra I Fi g, 9) is winged and ha s Ij-segmented anten nae with t ran sve rse seco ndary se nso ria on the third and fo ur t h antl'nnal seg-ments I Fi g. 9a). T he head a nd t ho rax aI"(' b lac k a nd t he abdome n is .H! llow-gl·el'n . I':ach sexupara p roduces a max imum of s ix fL' lllall's and t wo ma les on t he bark o f t he t rpc a nd I hen dies. The fema lcs a nd ma les mou lt t hrcl' limps in a pe r iod of :) (j .. 10 hOlll'S and t he n mall', T hl' ma le I Fig. 10 ) is s ma ll a nd pa le green wit h ·I-segmented antennae I Fig. IDa), T Ill' fema le I Fi g, II ) is a lso s lll a ll wi th ·I-segmen led a n ten-nae ( F ig, I la) but till' abdolllen is long and contains a s ing le. ve n ' la rge egg ( Fig. 121 which is l1.l id in the cre\' ices of th e bark o r undL'r till' lich en (Cetraria sp .) often found on th e ba r k. Th e newly la id egg I F ig, I :l) is 0 ,:,5 x O, 2t-1 Illm and is a lmost the s ize of the fema lp's abdomen, I t is whi te and cove red b.v wool-like' wax\' secre-tion s from t he abdomina l wax g la nd s. In :l or ·1 dav s th e egg cha nges to light green and then to a bright .vellow-IHoow n . Th e egg o \'(It'wi nters on th e ha r k . T he se xua les do not feed s ince t hey do not ha ve funcl io n <J 1 mouthpa r ts. T he l<J h ium is re-duced to a s ma ll papi lla a nd s ty lets arl' absent. T h(' rudi me n ta ry co nd itio n o f t he mouthp ar t s ca n be seen on t he hea ds in t he photom icro-graph s of t he antennal' in Figs. 10 a nd I I T hus a ll t he mor ph s o f P. s/liro/ill'('(/(, a re fo und o n the ha r k or in t he ga ll s on lomba rdy pop lar. Th e a ph id is LhL' rL'fon' monfH'cio us and holocyclic . DI S('lSS IO\; '1'11(' form a tio n o f the s p ira l ga ll o n the petio le o f lom bardy po pla r is a dra matic ex-;:lIn plp of t he wav in which a p hid s ca n change t he g l'Owth proc esses of p lants for their own ach':lIltage. The p la n t ti ssue L:omp lctely sur-round s and e nc loses the fundatri x a nd her pro-genv , Onh' late in t he season does the ga ll open a nd relea se t he Sl'xu parae, Othe r spl'cies of 1)f' lIIpilig(ls li v in g on po plar produc e markedly diffe rent ga ll s, Th e form of t he ga ll . therl'fore Illu s t be d ue to t he specifi c feedin g Ill'hav iour of the aph id when ga ll forma-tion is initiatpcl and to chemica l subs tances inj l'l'lL'd int.o p lants with the a phid 's saliva ,"liIL's 196H). The deta il s of t he feeding be-ha\' iou r of t he fund at rix of I) sfl i ro/il ec(Je ha ve hel'n descrihed In' Dunn 119(0). T he s pira l ga ll pro v ides the <lphid with a n e nv iro nment protected frolll para s itPs . preda-tors and we<lther condition s : on lv thl' se xuale s spend t he ir e n ti re life outside of the gall. Proh-ab h ' jus t 1.I S im portant to the a phid is the fa ct that t he g a ll ing apparenLl.\ ' s upplies the aphid with inlproveu nut r ition by ch a nging the ph ,vs io log \ ' of the p lant I Fo rrps l 19( 1), H .. r .. rt ' IH'l'S I\lle\'ne, E. II .. and F. 0 , r- lorri son, 197·1. Pe mphi g us s il irolhl'l'<l(' I II oll1optera : Aphido id ea) , an a phid which causes s pira l ga ll s o n poplar in Que bec. Cunad. I ~ nl. IIlIil ll ): 1'229-123 1. Dunn .. J. A. 19(j0. The formation o f ga ll s bv so me s pecil's of I' e mphig us I I-Iomop te l' a- Aphididae), '\l arce llia:\O ISupp l. ): I C,!) - IIi7, Fo rbes. ;\, R. 1969, T he s ty let s o f tlw green peach a ph id . ~Iyzus persicae I HOll1opte ra : Ap hididae) . Ca n ad. P.n L. 10 I I I ) <1 1 -4 I . 1·'o rrl'S l , ,J, i\ 1. S . 1971. T Ill' g ro wth of .\p his fa hal' as a n ind icator of t he nut ril io nal ac,,"a nlage o f ga llin g to the apple <Jph id Dysa ph is de\'('l'I a_ E: nt. ex p , & appl. II (4): 477 -483. C e rh a rdt . K, 1922. Uber die E nt wick lun g del' Spi ra llockenga ll e von Pemphig us spirolhl'(' at, ander I'.vramidenpa ppel. Z. P fl krank h, :12: 177-189, ISeen in I{e\,. appl. I~ n t. A I D: 492 (1922 )), Ma n i. M. S. 1964. EL:ology o f p lant ga ll s. Mo nogr. Bio I. 12, Ju nk (The Hague ), Mil es . p , W. 1968. Insect sec retion s in p la nts . Ann. Hev . Phytopatho l. Ii: J:l7- 164 . Toth. L. 1939. Uber die Biolog ic de l' Hlalt la us l' em phi g us spirolh l'l'al' Pass. Z. angl'w . En t. 2(12): 291-:31 J. 

English

Life-cycle of a spiral gall aphid, Pemphigus spirothecae (Homoptera: Aphididae), on poplar in British Columbia

https://journal.entsocbc.ca/index.php/journal/article/download/1867/1937

Life-cycle of a spiral gall aphid, Pemphigus spirothecae (Homoptera: Aphididae), on poplar in British Columbia

Abstract

Similar works

Full text

Available Versions

Journal of the Entomological Society of British Columbia