Hormonal Control of the Body-colour Change in Larvae of the Title Larger Pellucid Hawk Moth, Cephonodes hylas L. (1) Author(s) IKEMOTO, Hajime Citation 防虫科学 (1975), 40(2): 59-62 Issue Date 1975-05-28 URL http://hdl.handle.net/2433/158879 Right Type Departmental Bulletin Paper Textversion publisher Kyoto University IW !tt n ~ m' 40 ~-II Hormonal Control of the Body-colour Change in Larvae of the J,arger Pellucid Hawk Moth, Cephonodes hylas L. (1). Hajime IKEMoTo (Tokyo Prefectural Isotope Research Station, Fukasawa, Setagaya, Tokyo), Received January 27, 1975. Botvu-Kagaku 40, 59, (1975). 10. :t:tA:fJ:'-/~0)~fS~fl::l:ml9Q*J":s~t't:l1liIJaJ\ (1) 1lIl* Ml O+D;(WIL71'j 1--1' ffiaTtlf1'C/Yr, J,Jn;(WillUlu[KU11R) 50. 1. 27. )l:.flJ! :t:t A;IJ i/ I~O)f!U~t~.t!J!ttI:tMf5lJ:oL b1>-riJ;, ~~0*WllU,p~ C 1I[j1.Q;f5Il:~b o. V Ii ~ <-r 0 c ~;~f5~il:tlXroll:n~~v, ~~f5O)j)iJMIUJ: 1.>. Co 0) J: ? t.. lIHsl:tJJlWl* )v'£: ~ II: J: "? 't"illHll ~ n, .t!J~*b'£:~~J:"?'t"~.3no. mf5~M-r1.>~~*b'£:~O)~W.~R~O)~a~~~O) J: ? 11:.~bn 7.>. The integument of larvae of the larger pellucid remaining part of larval stage, prepupal, and hawk moth, Cephonodes hylas at the feeding age pupal stages. is green in colour, but before cocoon formation The gut content begins to turn red and red the colour turns in deep dark 'red owing to the pigment begins to vanish from the epidermal production of ommochromes. After a short time cells of the integument, within 12 hours after the they become into the pale green prepupae, red cocoon formation was completed. Further 12 pigments being vanished gradually. hours later, they become into the .pale green The present report deals with hormonal control pre pupae, the colour in the dorsal region from of the depigmentation phenomenon which was metathorax to terminal abdomen showing dark observed with the progress of prepupation in the green. mature larvae of the larger pellucid hawk moth. Prepupae molt to pupae 1-2 days after pre­ pupation. Body-colour change in the larvae of Cephonodes hylas Material and methods The last larval instar up to the larval-pupal molt Insect material: EA'A's or young instar larvae is divided into several phases, corresponding to of Cephonodes hylas were collected from Cape the developmental steps of metamorphosis. jasmine in Tokyo prefecture area, and they were During the first four days after the last larval individually reared under the constant range of molt, the integument of the larvae is bright temperature of 24-26'C in the laboratory. The green in colour and they feed vigorously. The last instar larvae were used for the present larval haernolymph in this stage is greenish blue experiments. in colour. , Isolated abdomens: Ligature was made at the On the fifth day after the last larval molt the back of the thorax of the last instar larvae and colour of the integument of the larvae turns into the anterior part of the body was cut off deep dark red, and the haernolymph changes its immediately after ligation. colour from greenish blue to yellowish green, Topical application of juvenile hormone (jH) keeping the same appearance to the stage of and its analogues: The following compounds pupal molt. The deep dark red larvae cease to kindly supplied by the late Prof. M. Fukaya , feed and come down from a trunk in nature and were used. they wander restlessly around in a feeding 1) Cecropia JH: methyl-12, 14-dihomojuvenate container (wandering stage). (Mori et al, 19.71) Then the larvae begin to spin a dark red 2) ZR 512: ethyl-S, 7, ll-trimethyl-2, 4-dode­ cocoon 12 hours after the body-colour changed cadienoate (purity 75 96) (Zoecon) into deep dark red. It, takes a few hours to 3) CT 5: 1-(3, 4-methylenedioxyphenyl)-7-epoxy build their cocoon in which they spend the -4,8-dimethyl-nona-l, 3-diene(purity 7096) (Chang 59 JlJj m M'~ m 40 ;@-II and Tamura 1971) pupation of' an isolated abdomen was apt to be These compounds, mixed, isomers, dissolved in proceeded. A large dose (20 pg), caused a pupal • .,.. fl'> 1_ ,11. ,I.ri: ' ...-" . 1 {11 of acetone were applied to dorsal integument molt, being not accompanied by. colour change of the thorax of the larvae. To the control 1 pi in appearance. of acetone alone was applied. It is concluded therefore that the depigmentation Injection of molting hormone: Effect of molting and pupal molt are induced by the same kind of hormone on the depigmentation as before men­ molting hormone, a concentration at which the tioned was examined by injecting fi-ecdysone hormone is effective to the two processes being into the isolated abdomens. ,a-Ecdysone dissolved different.' in 2 III of distilled water was injected into an 2) Effect of time of ligation on the depigmen­ isolated abdomen in proper concentration through tation: The ligation was made at various times the 4th abdominal leg. An equal amount of during the period from the onset of dark redden­ distilled water alone was injected to the control. ing stage to shortly after completion of cocoon formation in order to determine the critical period Results for the production of molting hormone effective 1) Effects of injection of ,a-ecdysone on the to the depigmentation. developmental process: In order to ascertain the Results of ligation experiments showed that effects of various titers, ,a-ecdysone solution was the depigmentation in the deep dark red larvae injected into isolated abdomens of the deep dark was .controlled by molting hormone which was red larvae. produced until the middle stage of cocoon The ligature was performed on green larvae formation (Table 2). about 6 hours before the onset of dark reddening All of the isolated abdomens were unable to in order to obtain deep dark red isolated pupate. Only in a few specimens ligatured shortly abdomens. Preliminary experiment showed that after cocoon formation the pupal integument was the ligature performed at this time caused the observed partially at the dorsal region. whole body to keep deep dark reddening, and 3) Effect of juvenile hormone and its analogues abdomens of the ligatured animals survived at on the depigmentation: The effect of Cecropia least 2 weeks with no signs of depigmentation JH and its analogues on the depigmentation was and pupation. tested by topical application of the chemicals to As shown in Table 1, a small dose (1-3pg) the deep dark red larvae over several stages caused to vanish red pigment from the integument from wandering to shortly after cocoon formation. without pupal molt. As dose increased, the As shown in Table 3, both Cecropia JH and Table 1. Effects of ,a-ecdysone injected into isolated deep dark red abdomens". No. of Response to j3-ecdysone** I No. of isolated····· Dose isoloted i--- .----,----,--,---,--~---abdomens which pg abdomens IDepigmentation I Prepupation Pupation did not response --- used I 20 5 0 3 5 0 1 1 0 0 10 5 I {: 1 4 4 0 I 0 0 1 5 I 5 9 {: 3 3 1 1 I i 4 3 5 ,i . 3 0 1 1 5 I 3 0 0 2 Control 5 I 0 I 0 0 5 * Received j3-ecdysone 2-3 days after ligation. ** Evaluation was made 5 days after the injection. 60 Table 2. Effect of time of ligation on depigmentation. • ~f Time of No. of' larvae Response I Change of mean" ligation used 1-' No depigmentation Depigmentation I colour Onset of dark reddening stage 7 7 0 I 4.9-)4.9 I I : I Wandering stage 9 8 I 5.0->4.7 (3)" Cocoon building I stage 7 I 2 5 5.0-)4. 1 (3. 7) Shortly after formation of 13 12 5.0-)1.5 (1.1) cocoon building I * Type 1: Pale green with darkening dorsal region. Type 5: Deep dark red. Type 2-4: Indermediate between 1 and 5. ** The number in parentheses indicates mean value in depigmentated individuals only. Evaluation was made 3 days after ligation. Table 3. Effect of JH and its analogues on eventually raising pale green prepupae, has not the depigmentation in the deep dark been studied in this species. ,red larvae. The results of the present experiments demon' com:~::~--IN~~f I Mean colour just strate that such depigmentation as in the deep larvae used after prepupation* dark red larvae of Cephonodes hylas is induced CT 5 50fig 7 1.7 by a considerable amount of molting hormone ZR 512 20jlg 8 3.1 and inhibited by JH and its analogues. It seems 10 3 3.3 likely that the depigmentation in the deep red Cecropia JH 20fig 4 3.3 larvae of Cerura vinula may be induced by 10 6 2.5 molting hormone and inhibited by JH and its Control 10 1.6 analogues as in the case of Cephonodes larvae. ---------_.-----' The change in colour from green to dark red * Symbols as the same in Table 2. in the larvae of Cephonodes hylas at the end of ZR 512 inhibited the depigmentation in the deep the last instar is induced by molting hormone dark red larvae of Cephonodes hylas, not only at and inhibited by JH and its analogues (Ikernoto, the treated part of the integument but also at in press and unpublished data). It is concluded the other part of the integument, when tested at that dark reddening, depigmentation and pupal 10-20 fig level per individual.