Kawada, Kazuo

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THE INFLUENCE OF CONSTANT TEMPERATURE ON THE DEVELOPMENT， LONGEVITY AND REPRODUCTION OF THE TURNIP APHID， RHOPALOSIPHUM PSEUDOBRASSICAE DAVIS Kazuo KAWADA The life-history and development of the tumip aphid， Rhoρalosiρhumρseudo-brassicae Davis， have been reported by Allen and Harrison (1941)， and Essig (1947). All of their studi田 werec訂 riedout under ∞nsiderably variable tem戸ra・tur白， but the eH配 tsof different constant tem戸ratur，白havenever been invl田tiga-飴d. The ex戸rimentsrepo此edbelow were conduct，吋 todetermine the influence of constant temperature on the development， longevity and reproduction of R. 抑制dobrassicaeunder clo配lycontrolled conditions. MAτ'ERIALS AND勘ffiTHODSThe vivi開rous， parthenogenetic turnip aphid was r伺 r吋 onkale leav伐Brassica oleracea 1. var. acethala， atten constant tem戸 raturl回 betw田n100 -32.50C. Each of the first instar larvae was put into a containeI' (4.5 X 2.0 cm) within two hours from its birth， with a fresh leaf of kale (2.5 in width and 2.5 cm in length) for f，αιFαxl was renewed every day. The aphids were examined every day; and their reproducti∞戸riod，longevity and the number of offsprings produced were record吋.Experiments at回 chconstant tem戸raturewere begun with four individuals and replicated five tim民 th凶 using20 first instar larvae in al， which were obtained from coloni田 ofthe viviparous， parthenogenetic tumip aphids that had been陀ared∞ntinuouslyfor more than three months on kale plants， the tem戸ra-ture in the r，伺ringr∞m being 200ー250C， and the photoperiod 16 hours. The aphids were reared in double-glass walled constant temperature and refrigera句dcabinets， inwhich the temperat町 ewas controlled at :! 0.50C of the prぽ ribedtem戸ra回re.Relative humidity of 50ー 70戸rcent was maintained at each tempera知reby placing a bottle ful of water in the cabinet. A fluore悶 ntlamp (T，伺hibaFL-20W)， 0戸ratedby a time switch， gave the daily photo戸riodof 16 hours; the light intensity on the surface of each container was 800-1000 lux. RESULTS Develoρment The relation be抑制1constant飽mperat町 eand time required to complete 244 Berichte d.Ohara Instituts. 日d.12， Ht. 3， TABLE.l The relation between development and constant tem戸raturesTem戸(OC田)tureNo.of larvae Ave. larval Coeff.of Advev.evleolp∞mitey n of Death rate full-grown period in days variation (鈎 t {第)32.5 。 100 30 15 6.67土0.15* 8.95 0.1499 25 27.5 17 7.18土0.22 12.86 0.1393 15 25 18 7.72士0.22 12.06 0.1295 15 22.5 19 8.11士0.21 11.24 0.1233 5 20 20 10.25士0.19 8.18 0.0976 。17.5 20 12.25士0.26 9.61 0.0816 。15 20 15.45士0.22 6.65 0.0647 。12.5 17 26.41:!::O.70 10.64 0.0379 15 10 13 37. 77:!::O.83 7.92 0.0265 35 * Standard eror. development from birth to the production of the first offspring is shown in Table 1， and Fig. 1. As temperature increased from 100 to 300 C， the average developmental days decreased from 37.77 days at 100 to 6.67 days at 300C. The writer was not able to determine exacdy the high白tlimit of temperature at which development was possible. At the constant tempera知reof 32.50 C none of the larvae used in the experiment attained to maturity; and only a few individuals were found to survive for田veraldays. That is， taking these facts into considera-tion， the writer believes that in the pre田ntexperiment the limit of high tempera-ture was田mewhereabout 310C. The constant temperature of 32.50C isinjurious to the larvae of the the aphid when this temperature acts upon them ∞ntinuously. 1n the experiments here p胞団nted，the writer was not able to caηy on rearing at a constant temperature lower than 100C. Therefore， itwas so far not possible to determine the temperature at which development cea関 s.If the r，配ipr，∞alsof the average time required for the development at each temperature are plotted against temperature， the curve of the average developmental vel，田itycan be obtained. With the rise in temperature the vel，∞ity of development increases at first very rapidly， but its rate of incr伺記出comesgradually smaller beyond about 22.50C. It is apparent出at，in the range of temperatures between 12.50 and 22.50C， the relation between the developmental vel∞ity of the aphid and temperatu問 wasvery nearly linear (Fig. 1). Shelford called this part where the vel∞ity of development makes a straight line the medial range of t疋mperature. By the method of least squares from the data of experiments in the medial temperature range， an equation， y = 0.0081 xー 0.0616was calculated. This equation repre記ntedvery well the temperョture・velocityrela-tion， and the th印 reticalthreshold of development proved to be 7.600C. 245 Kawada: Influence of temperature on the development of the turnip aphid 1964) 0.15 .-園町、同 1>0h 、--0.10 言告白o u b 省、・40 b 'S u > u b ';: 咽Q) E凶0.05 O '0 ..・-・"0.'.唱白. . 目. . . 40 ??????? ，????? ? ? ??? ????〈10 15 20 25 Tempereture (oC) Developm阻匂1days (Y)卸 dvelocity of development (y) of Rhotalosithllm tselldobrassicae Davis at ∞nstant temperatures. 。30 10 4 5 Fig. 1. The relation between tem戸ratureand developmental time， which is the r，配iprocalof the developmental vel，凹ity，can be repr，間ntedby the formula， (xー t)Y = C where， Y is developmental time， C the砂 calledthermal constant， and t coη白・ponds to the theoretical threshold of development， 7.60oC. The values of x and Y were substituted in the eq'uation and the numerical value of C w部品もer-mined. 1t w出 foundto be 123.59. 1n terms of heat units， therefore， itmay be 臼idthat 123.59 day-degre田 onan average was required as the eH配 tiveaccumu-lated temperature for ∞mplete development of the s戸ci白 atconstant tempera加工白betw田 n12.50-22.50C. The value of t， 7.60oC， repre日ntsthe developmental 詑 ro. This value must be regarded as purely th田 retical，however， since validity for such extrapolation is dubious in the absence of experimental verification. The calculated curve conforms nearly to出eempirical valu回 withinthe medial tempera-ture range. The greatest variation was 2.24 days at 150C. Death rate The object of ex戸rimentsherein reported was primaril'y to inv，白tigatethe 246 Berichte d. Ohara Instituts. (Bd. 12， Ht. 3， TABLE 2 The relation between average longevity and constant temperatures T町 Ep{。eCm)hm No. of Imin gdeavyis ty Ave.lodnagyes vity Coeff. of individuals m va由tion(%l 30 15 12-17 14. 13:t0.36* 9.91 27.5 17 8-29 17.53土1.14 26.72 25 18 14-28 21.33土0.54 10.83 22.5 19 12-36 27.11土1.48 23.74 20 20 15-44 25.35土1.82 32.16 17.5 20 20-50 33.65土1.73 23.05 15 20 23-49 35.50土1.68 21.00 取 Standarderor. vel∞ity of development. The number of larvae reared was limited， so that it was 1m戸郡ibleto obtain very acculate data in regard to the death rate. But the writer believ，田thatthe r，白ultsobtained are sufficient to show general tendency of death rat田 inthe tumip aphid larva under a variety of constant tem戸ratures.The death rate obtained under the constant temperature experiment are shown in Table 1. It shows that the death rate is 0戸rcent in the range between 150-200C， but increa蹴 ac∞rdingas the ex戸rimentaltem戸raturedeviates from the above range， until it reach白 100per偲 ntat 32.50C. At a low temperature of 100C， the death rate was 35 per cent， but this figure記 emsto be somewhat t∞large. Judging from th聞 r白ultsit s田msthat the optimum tem戸ratureli田 somewherebetween 15。ー22.50C.The tem戸ratur，田higherthan 250C， or lower than 12.50C s田mto be unfavorable for the larva of the tumip aphid. Longevity The average number of days from birth to death of 20 larvae was deten泊nedat each temperature. As is apparent from the data in Table 2， the duration of longevity d配 reasedfairly regularly as the tem戸raturebecame higher up to 300C. Beyond this temperature， however， alrn田ta1 larvae di吋 beforereaching maturity. The minimum duration of longevity was found to be 8 days at 27.50C， and the maximum 50 days at 17.5 oC. (Table 2). The ielation between aαumulated mor-tality and tem戸ratureis shown in Fig.2. It is evident， that， as the 句mperatureincr回sed，the longevity d配 reased. The average number of days of survival at the time when 50戸rcent mortality∞cuη'ed was 14， 21， 24 and 36 days at the temperature of 300， 250， 200 and 150C.， r，白戸ctively.Reρroduction Table 3 shows the average number of youngs produced during a life-time by a female at each constant temperature. Considerable variation in the number of offsprings was observed at each temperature， but the difference between the number at 250， 22.50， 200， 17.50 and 150C was not large. Significantly les youngs were produced at 27.50 and 300C than at any other tem戸ra卸r回.The constant tempera-ture of 300C s民 medωbenearly the uppermost limit for continuous repr吋uction.This result伺 nbe traced back to the unfavourable influence of high tem戸ratureon embryog町田is，or the shorter reproductive 戸riodon account of the earlier death of mothers at this temperature， or to a combination of these two factors. It is generally re∞gni田dthat the relation of the speed of development of in舵 tsto tem戸raturedαョsnot conform to a true straight line， but a sigmoid curve仕立ough-out the whole range of tem戸ra旬reat which the development is rx閣 ible.(Uvarov， 1931; David田n，1944; Andrewartha， 1961). In the ca田 ofthe turnip aphid， the above stated relations were also observed. The tem戸rature-vel∞itycurve obtained is very nearly a straight line at the tem戸ratur白 approximatelybetween 12.50-22.50C as is apparent from Fig. 1， but it d伺 snot seem to fit the ex戸n-mental data a∞ura総lywhen the rearing temperature is beyond the medial range， that is，出eobserved value of y is somewhat smaller at high temperature and larger at low tempera卸rethan the th即時ticalvalue， forming a sigmoid curve in the relation to the whole range of tem戸rature. As is already mentioned， in the medial tem戸aturerange，出etemperature -vel∞ity relation of the turnip aphid W邸 repre詑 ntedby the equation y = 0.0081xー 0.0616and the theoretical threshold of development by 7.60oC. But it is easily r配ognizedfrom the following facts that the value of 7.60 oC is the theoretical one and not the tem戸ratureat which development actual1y ceases， being fairly higher than the later. In the vicinity of Kurashiki the turnip aphid is usually found in the field， during winter (0配ember，January and February， where the m伺 ndaily tem戸ra-247 ?????? ? ?• ????????????????，????， ?????。。???，?????????，?? ?????。 ，???《?????，，、??，，? ???，??????????????????????? ???Kawada: Influence of t匂npemtureon the development of the tumip aphid 50 40 DISCUSSION JJ ， ， ?? ???，? ?。40 20 60 80 100 ???? ? ? ? ? ? ? ??〈Fig. 2. 1964J 248 Berichte d. Ohara Instituts. 但d.12， Ht. 3， TABLE 3 The relation between average fecundity and constant temperatures Tmn(p。eCm}ure No. of No. of Ave. no. of C偲 f.of individuals young produぼd young pr吋uα必 Variation (船30 21 5-23 13.05:t0.67* 23.67 27.5 25 10-60 29.00:t2.47 42.57 25 20 24-98 51. 35:t 1. 22 10.67 22.5 27 29-106 61.70土3.67 20.92 20 20 31-94 49・30:t3.叫 27.57 17.5 20 3ー 120 64.剖:t5.26 46.29 15 20 22-98 61.∞:t4.40 32.25 .< 辛Standarderor. ture is 5.90， 3.30， and 3.80C， and the minimum temperature 1.30， -1.10， and -0.90C， r回伊記tively)，and its development is continuous though very slow. The lethal temperature for the s戸ciesin the outd∞r must be considerablly below the tem戸ratureat which development cea錨.Though in summer there are many cruciferous plants (cabbage， kale， and tumip， etc.) in the field， the tumip aphid di岨ppearsthere. This seems to be chiefly due加 theatmospheric circumstance that the air temperature in the記aωnis not favorable to the metabolic activity of the larvae. Really， at a high temperature of 32.50C， no larvae could attain to full-growth in the rearing 位 periments.This fact indicat田 thatthe warmest period of the summer is the m部 tunfavorable for the tumip aphid. The results of oh町 vationson the death rate which was obtained at the con-stant temperature have already been stated. 1t shows血atthe death rate was 0 per cent from 150C up to 200C and then continued to increase until it reached 100 per cent at 32.50C. Judging from the death rate， it田emsthat the optimum temperature li田 somewherebetween 150ー22.50C. Temperature higher than 250C s田 msto be unfavorable to the nymph of the tumip aphid. on the other hand， atthe low tem戸ratur，回of100 and 12.50C， the death rat田 were35 and 15戸rcent， but th田evalu町田peciallythe former seem to be somewhat t∞large. Various factors are thought to be res伊nsiblefor this high mortality. The writer considers that the most impo抗antone of them must have been the low temperature. At the tem戸-rature of 32.50C， the ful1 development could not be expE詑tedbut the partial deve-lopment could be ob田rved. Takaoka (1960) re戸rtedthat the duration of survival of the gr田 npeach aphid， Myzusρersicae Sul詑 r，decreased wi血thetemperature rising from 150 to 250C; also that the number of offsprings produced at 250C was smaller than that at the lower tempera旬r田 of200 and 150C. Barlow (1961) observed that the duration of survival of the potato aphid， Macrosi.ρhum euPhorbiae Thornas， decreased with the temperature rising from 50 to 300C， and the number of larvae produc吋 at250C was less than half the number at the low白ttempera加reof 50C. Noda (1951)， and Tanaka (1957) found that longevity 1964) Kawada: Influence of temperature on the development of the turnip aphid 249 of the apple-grain aphid， Rho，ρalosiρhumρrunifoliae Fitch， decreased from 25.0C with rising tem戸rature，becoming minimal at 300C. The r白ultsof the pr，田entex戸rimentalso indicates a similar tendency， namely that the longevity decreas錨 withthe tem戸raturerising from 150 to 300C， and the number of of-springs produced deα'ea配smarkedly at 300C than in the optimum tempera回rerange of 150 to 250C. This respon詑 totem戸rature，toge出erwith shorter longe-vity and smaller fecundity at higher temperature， may partly explain the often reported disapperance of this aphid in the field during summer. 1t is difficult to determine how many generations of the turnip aphid there are in a y伺 r. As has been already pointed out， the behavior of this s戸羽田inthe hot summer time has not yet been fully traced. Therefore， itis not yet p<国ibleto determine the number of generations in a year. However， ifwe ignore， for the moment， the number of generations in the summer time in which the behavior of the turnip aphid is not clear， there may be as many generations as ten or more during a y白色SUMMARY The results of the ex戸rimentsconducted on the relations of tem戸ratureto the development， longevity， and reproduction of the turnip aphid， Rho，ρalosiρhum ρseudobrassicae Davis， are summarized as follows: 1) The relation between temperature and vel配 ityof development was linear between 12.50 and 22.50C. and represented by the equation y = 0.0081xー 0.06162) The theoretical threshold of development was 7.6 oC， and the effective accumulated tem戸raturen配 es回 ryfor the complete development was 123.59 day-degre田 onan average. 3) The longevity d配 reasedwith rising temperature， the minimum longevity being 8 days at 27.5 oC， and the maximum 50 days at 17.5 oC. At 32.50C， al aphids died before maturity. 4) The average number of youngs produced戸rfemale decrea記dwith rising temperature. The maximum number of youngs produced were 120 at 17.5 oC， and the minimum only 5 at 300C. Acknow/edgJments. This study was carried out under the kind guidance of Dr. Yasunobu Yasue， to whom the author wish缶 toexpr田shis sincere thanks. The writer also wish白 toexpress sincere th釘lksto Dr. Chukichi Harukawa， Prof白田rEmeritus of Okayama University， for kindness in r，回dingthrough the manuscript and for kindly advice. The author is much indebted to Mr. Takashi Shiraga who carri吋 outrearing of the turnip aphid. 250 Berichte d. Ohara Instituts. 日d.12， Ht. 3， LITERATURE CITED Allen， N. & Harr包on，P. K. 1943.τbe turnip aphid in the southern stat白 andrnethods for its ∞ntro!. U. S. Dept. Agr. Farrners' BuI1. 1863: 1-9. Andrew直武ha，H. G. 1961. Introduction to也estudy of anirn且1populatiOl首・ London: Methuen. Barlow， C. A. 1961. Development， survival， and f伎undityof the potato aphid， Macrosithllm 611thorbiae (Thomas)， at constant temperatures. Can. Ent. 94: 667-671. Davidωn， J. 1944. On the relationship betw健 ntempera制問 andthe rate of developrnent of in舵 tsat∞nstant tern戸rratures.J. Anirn. Ecol. 13: 26-38. Essig， E.O. 1948.百lernωt irnpo巾 nt明覚iesof aphids attacking cruciferous crops in Califomia. Hilgardia 18: 407-422. Kawada， K. 1954. E∞>logiα1 studies of the cabbage aphid， Brlvicor，ne brassicae L (in Japan白e)NOgaku Kenkyu 42: 57-66. NはIa，I.1951. &氾，logicalstudy of Rhotalosithllm trll"ifolial Fitch. (in Japan間)Mern. Ehirne U凶v.5I:詑.2. 1: 55-63. Taka池a，1. 1960. Studi白 onthe differentiation of rnorphological and ecol唱icalcharacters f，ωnd in the life-cycle of the green戸沼.chaphid， MyzlIs tersicae Sulzer. (in Japan閤)Bull. Hatano Tobac∞Expt. Sta. 48: 1-85. Tanaka， T.1957. Effects of ∞n蜘 nt旬rnperatureon the biotic potential of the apple grain aphid. (in Japan匂e)Japan. J. Appl. Ent. Zool. 1: 268-271. Uvarov， B. P. 1931. Insects and clirnate. Trans. Ent. Soc. London 79: 1-247. 

THE INFLUENCE OF CONSTANT TEMPERATURE ON THE DEVELOPMENT, LONGEVITY AND REPRODUCTION OF THE TURNIP APHID, RHOPALOSIPHUM PSEUDOBRASSICAE DAVIS

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