Larval instars and development of the greater wax moth Galleria mellonella (Lepidoptera, Pyralidae)

9 Pages·1995·0.66 MB·

TThhee LLeepipdiopdteorpoltoegircaollSoocgieitycal Society ooff JJaapapnan
uetma 7be ns. IePid .Soc. 1mpan 46 <4):228-2 D3e6ce,mber 1995
Larval instars and development of the greater wax moth GaUeria
(LepidoptePryar,alidae)
melloneUa
Seiko MATsuMoTo' and K6ji YANo
Laboratory of Insec tManagement, Faculty ef Agriculture, Yamaguchi University,
Yamaguchi, 753Japan

Abstract The greater wax moth, Gallen' amellonegla, was reared at differe ntternperatures of
5"C interval bsetween 20:C and 350C to determine the number of larval instars and development.
The populations reared at 20`C and 25"C had eight larva linstars ,while those at 30"C and 350C
had seven. Temperatures experienced in the firs itnsta rwere critical and resulted in different
numbers ef instars . The temperature between 25℃ and 30"C will be critical dividing larvae in
differen mtoulting numbers. Head width within the same insta rreared at differen ttempera-
tures, however, showed no difference.
Key words Gallen' ameglonella, larval instars ,develepment.
Introduction
The greater wax moth, Galien 'maellonella (Linnae u(sL)epidopte Pryar,alidae )has been
widely used as an experimental insect for biologic amled,ical and other field sof study
throughout the world. The species is a famous pest of beehives from which its name
originated, and is common in Japan , Biology of this species has been reported (Paddock,
1918; Chase, 1921; Andrews, 1922; Milum and Geuther, 1935; Beck, 1960; Nielsen and
Brister ,1977), but litt lweork has been done on the number of larval instars ,especially
those under differen ttemperature regimes.
Anderson and Mignot (197 0an)d Plantevin (197 5r)eported the number of larva linstars
inNorth American French Chase (1921)
as seven or eight and populations. reported
instars These differencesin have
seven or eight with rare cases of six. number not yet
been
well explained.
The present work done in 1992 and 1993 was initiate dto make further studies on the
biology of this well-known pyralid species, particularly its larval instars ,since known
records vary and require defini tienterpretations.
Another object was to investigat ethe effects of rearing temperature on larva lsize,
Body sizes of some animals and insect sare known to vary in accordance with latitudinal
gradients (Kato 1,948; Park, 1949; Asahina, 1950; Hukusima and Kajita ,1960; Masaki
and Oyama, 1963) ,and arguments have been presented to interpret this phenomenon
(Park 1,949 ; Asahina ,1950 ; Masaki ,1966) , The Bergmann and the converse Bergmann
principles or other interpretations have discuss edthis problem. Asahina (1950)
mentioned that bedy sizes of some insects become larger when they Iive in an area other
than that where temperature is Qptimum for their development. Little has been done
experirnentally, however, to interpre tthis more detail.
' Present aclclress : Yamaguchi Agricultura lImprovement and Extensien OMce,
Yamaguchi, 753 Japan
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Larval Instars uf Gtzllen 'meallonellde 229
Materials and methods
The larvae of G. mellonella used were obtained frorn a stock culture of the Institute of
BiologicalControl,Kyushu University.They brood in
were reared with wax comb
rearing cases (12× 12×8cm) at 200C,250C,30eC and 350C under 16L: 8D photoperiod
Bofore use, wax brood comb was heated at high temperature to kil lany immature stages
of the moth. Experiments were started with eggs oviposited within 24 hours by the
individual rseared for two generations at each temperature. For this purpose, eggs were
obtained in separate oviposition cases until the third generation to avoid mixing genera-
tions.Larvae
were collected from rearing cases at each temperature threughout the study
period and were preserved in 70% alcohol. The width of the head capsule was measured
using an ocular micrometer. Younger insta rlarvae (hea dwidth less than O.4 mm) were
measured at higher micrometer magnitude. Similar numbers of eggs, approximately50,
were used for developmental studies since this species shows faste rdevelopment as
densityincreases(Skoptsov1,968).

Results and discussion
1. Number of larval instars
Frequency distributi oonf head width of larvae reared at differen ttemperatures is shown
in Fig. 1. There were eight instar sin the populations reared at 2e"C and 250C, and seven
at 300C and 350C. Anderson and Mignot (1970 u)sing North American populations and
Plantevin (1975 u)sing French populations both reported seven and eight instars without
giving explanation of the differenc e.Plantevin (197 5me)ntioned, however, that the two
types of instars were separated during the firs tinstar larval period. The phenomenon
of these differen tnumbers is described ,in other words, as there being an extra insta rin
the eight instar population.
Several factors such as climate, sex or host plants causing extra instars in some insects
have been reported (Edward s1,881 ; Dimmock, 1888 ; Metcalfe ,1932 ; Gaines and Camp-
bell ,1935) .Differences in the moulting numbers seen in this study, however, c]early
suggest that the factor resposible is the rearing temperature experienced during the first
insta r; the temperature between 25"C and 300C seems to be critical in dividin glarvae
into the seven and eight insta rpopulations. Higher temperatures above that tempera-
ture reduce the number of moultings.
When the temperature mentioned is a causing factor ,some of the published data are to
be well interprete d.Beck (196 0r)eported that seven instar swere observed since he
reared at 35thC . PIantevin (197 5re)ported seven and eight instars as mentioned, and this
was because of the temperature of 27.50C he used. This temperature (27.5 'wCas)
intermediat ebetween 25"C and 30eC ,so that two types of larvae developed . The report
Chase (1921) infrequently instars 35'C
of who mentioned seven and eight and six reared at
is more dithcul tto explain since seven instar swould be expected at that temperature.
The differencein instar by (Chase,1921;
real numbers obtained single rearings
Plantevin,1975) frequencydistributiobny (Beck,1960)is
and mass rearings suspected as
the reason.
As seen ih Fig. 1, three instar swere recognized in the range below O.4 mm in the 20"C and
250C rearings, while two in the 30'C and 35"C rearings. Data of the firs tand following
instars in these temperature regimes also suggest that temperature before the first
moulting affects the differentiati oofn larval instars. Plantevin (1975 )referred to the
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230 Seike MATsuMoTo and K6ji YANo
4D
20
℃
3e
2a
ID
o
O.2 O.3 O,4 D,4 O.B 1.2 1.6 2.e 2,4

40
25℃
30
20
wki
10
ts. O.2 O.3 O.4 O.4 o.s L2 1.6 2.0 2.4

gz
4a 30
℃
30
20
10
o
O.2 O.3 e.4 o.4 O,8 L2 1,6 zo 2,4

4
3 35℃
2
O.2 e,3 e.4 0A O. 8 1.2 1,6 2.D 2.4
Head width (mm)

Fig. 1. Frequency distribution of head width of (inllen 'maelgonella larvaehreiagrehder at
differe nttemperatures. Younger instars were measured under magnitude
(seetext).

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LarvalInstar$ofGalten'amellonegta 231

separation into in thefirst instar, though he didnot point out the factor
responsible.twotypes
2. Range head
of width
As frequency distributio nosf head width obtained are considered empirically normal
distributien ,range of head width, its means and standard deviation of each instar were
statistically measured. The range within a 99% confidence limit is shown in Table 1.
The table shows that the width ef the firs tinsta rdoes not vary among differen ttempera-
tures, but does in the following instars ,although variation in the fift his slight. In the
200C and 250C rearings, width of the sixth and seventh instar sat 20"C is larger than that
at 25･C , In the 300C and 35'C ,width of the fifth and sixth instars at 30eC is larger than
that at 35'C.
Mean head width of each larva linsta robtained by analysis of variance is shown in Table
2. Head width of the first insta rat differen ttemperatures is not significantly different,
but in the following instars it is . This indicate sagain that the number of instars is
decide dby the second instar.
In the seven larval instar population, no significant differenc eis seen between the 30"C
and 350C temperature regimes in any instar .In the eight larval instar population (200C
and 250C) ,however, significant differenc earse seen between the two regimes in the
Table1. Range of head width (mm) of Gallen'ameilonellalarvae reared at
differe ntteniperatures.i}
Rearingtemperature

Instar
20 2s'c 3o"c 350C
℃
I O.1942-O.2036 e.1932-O.2004 O.1753-e.2015 O.1871-O.2161

IIIIIIVvVO.I2V3I2I5V-IO.I2I673 O.2645-O.2819 O.3037-O,3520 O.3136-O.3418
O.3087-O.3335 O.3503-O.3659 O.4586-O.5236 O.4851-O.5373
O.4791-O.5]41 e.5201-O.5641 O.7212-O.7790 O,7438-O.8058
O.7502-O.7994 O.7711-O.8051 1.08I3-1.1373 1.0649-1.1225
1,0419-1.0859 O.9896-1.0336 l.4358-1.4790 1.4193-1.4837
1.4465-1.4689 1.4153-1.4765 1.8908-1.9346 1.9111-1.9943
1.9069-1.9737 1.9337-2.0071
i) Numbers in table are confidence interval sfor popu]ation mean(p<O,Ol)
Table2.Mean headwidth ofGallen'ameilonellalarvaein each instar.i)
Rearing Instar
temperature
(oC) I II IIIIV v VIVIIVIII

2e253035 O.1989aO.19O6.82a4O9.918O8.O42.a73O32.2210O01.O63.Oa2.39459586O16.OO3..254O749.2717117OO.4.7855O01.1217.O208.67837194118..10110.144685171.7.40569123.179.2425015

1.4459 1.9767

L9177 -

1.9527 -

1)Numbers in column followed by the same Ietter are not significantly
differen(tP>O.O ; lDuncan's multiple range test).
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fourth instars.
second, and sixth
It is thus possible to note that the differenc eof temperatures used to rear the seven larval
insta rpopulation does not greatly affect head width, but in the eight larval instar
itdoes. This does develop below 18"C 400C
population species not at or over as shown
by Sairs (1978 a)nd the present study, This fact of temperature limitin gdevelopment
may explain the above results. The 20eC temperature in this study is near 180C resulting
in a differenc eb,ut 30`C is not near 40"C so that there is no difference,
3, Coethcien tof variation and growth ratio of head width
The coeficient of variation of each instar at differen ttemperatures is shown in Table 3.
No regular tendency between temperature regimes was found, The values of the fourth
insta rin 2e"C and 25bC are high, as are those of the firs tand third instars in 300C and 350C.
The growth ratio of head width at differen tternperatures is shown in Table4. The
ratips between the third and fourth ,and the fourth and fift hin 200C and 25"C are large,
while those in 30eC and 350C seern to decrease with progressing instar .The ratio is,
however, somewhat variable to dravL Ta general character as seen in Beck (196 0an)d the
different
present study which shows results.
Table3. Coerncien tof variation ef head width of Gallen' ameilonella larvae.
Rearing Coethcient of variation <%>
temperature ±SD
CC) Instarl IIIIIIV VVI VII VIIIMean
20253035 4.725.0431.20.41 617.70.105 11.78 ll.07 5.SO 6.96 4.87 6.96±2,88
8.33 3.74 14.00 6.67 6.82 8.80 6.78 7.52 3.11
±
7.04 12.38 9.80 9.71 6.12 7.72 9.28 2.44
±
6.30 12.54 11.33 5.80 8.05 6.19 9.60 4.20
±
Table 4. Growth ratio of larva lhead width of Gallen' amellonella.
Rearing
ratio
temperature ±SD
("C ) Instarll/I III/IIGroIwVt/hIII V/IV VI/V VIIIVIVIII/VIIMean
20253035 1.25641.3818.2218.4754915.15.46720551.5602 1.3731 1.3701 L3186 1.3871 O.1212
±
1.3108 1.5182 1.4538 1.2836 L4293 L3671 L3930 O.0817
±
1.4900 1.5276 1.4787 1.3181 1.3158 1.4800 O.1601
±
1.5600 1.5156 1.4116 1.3271 1.3453 L4639 O.1091
±
4. Effect of temperature on larval size
The result of this study showed that around 30'C may be optimum for this species (see
later descriptio non percentage emergence). Head width of each instar reared at below
30"C or at higher ternperature regimes showed no distinc tdifferen cferom those at 30:C.
Field Anthonomms bisigniferP,hyllotveta Mamestra bnzssicae,
populations of striovald,
AJlamobiu sye2oensds, ]FYeris mpae crucivova and others show geographical variations of
sizes at differen tlatitude s(Kato ,1948; Park, 1949; Asahina, 1950; Nagasawa, 1954;
Masaki and Oyama, 1963 ; Hirata, 1962 ; Kitano, 1967) ,and temperature is suspected to
be one responsible factor . The habitat of the greater wax moth is beehives in any
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Larval Instars of GaUen'a mellonellke 233
Table5. Development of (lallen 'meaUonella at differen ttemperatures.i)
Developmental
Rearing Develepmental Percentage
t e mp ercat"ucr)e N roe.ar eedggs min pemarxiod (mdeaanys±)SD < 1ra1teda y s) emerge(nc%e)
20253035 45485150120
7156 837159802± 5.29 O.O12O.O15O.O1285.658.82e.e
65.0 4.33
±
50 54.1± 3.18
i) Data at 20"C were not obtained ewing to incubator trouble,
geographical area in the world, and many generation shave passed in this habitat,
Consequently ,the moth does not seem to vary in its response to temperature, with the
result we have found. It is suspected that this is the reason not many generations were
reared under each temperature regime in this study.
5. Development

Developmental parameters at differen ttemperatures are shown in Table5. Develop-
mental zero and total effective temperature from egg to adult emergence calculated
based on the data of developmental rate were 5.0℃ and 1,666. 7day-degrees ,respectively
(Fig 2.) , Since this species rnates and oviposits within 24 hrs after emergence (Nielsen
and Brister ,1977) ,total effective temperature for one generation is about 1,670 day--
degrees.
As seen in Table5, developmental period decreased as temperature increased .Percent-
age emergence, however, was highest at 30bC and that at lower or higher temperature
regimes was much lower. Published data on the developmental period are variable even
at the same rearing teniperature. This may be partly due to differen tdiet and rearing
O,025
･EB'xasv
O.020
×
vysi
O.O15
ggfig98 .OO06X
O.OIO
O,O05
o 5 ID 15 20 25 30 35 4D
Rearing temperature
Fig.2 . Developmental rate of Gatlett mellonella reared at differen ttemperatures.
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234 Seiko MATsuMeTo and K6ji YANo
densities.
Judgin fgrom the result and data of the temperature in beehive s(Sasa k1i98,1), around
30eC may be optimurn temperature for this species. Individua lvariation in develop-
mental period at each temperature regime is decrease das temperature increased suggest-
ing there are concentrations of emergence periods.
6. 0thers

Comparing the head width of the seven and eight insta rpopulations, that of the second
insta rof the former population is almost the same as that of the third instar of the latter.
Subsequen tinstar sof respective populations show a similar combination, so that the
head width of the last insta rof the two populations is the same,
The second insta rof the eight insta rpopulation is thus an extra instar which is lacking
in the seven instar population. This interpretati osnupports the argument of Plantevin
(1975).
Acknowledgments
We would like to thank Dr M. Ohba (Instit uotfe Biologica lControl ,Kyushu University)
and Mr E, lwase (Yamaguchi City) for giving us G. mellonella and beehives . Our thanks
also go to Mr S, Hamasaki (Yamaguchi University )for his help in rearing experiments.
Referenees
Anderson, M. A, and E. C. Mignot, 1970. The number of larva linstars ef the greater wax moth, Gallen'a
mellonella (Lepidopter aPy:ralidae )w,ith characters for the identificat ioofn instar s.f Georgia
ent. Soc. 5: 65-68.
Andrews, J. E. ,1922 , Some experiments with the larva of the wax moth Galleri amellonella L. 7beans,
PVis ,itlcad, Sci .Arts Lett .20 : 255-261.
Asahina,S.,1950.PreliminarynetesonthedistributionofJapaneseinsects. Correlationbetweenbody-

size and latitudin adlistributi orenpresented by southern and northern forms . Kbntyf i18 : 23-24 (in
Japanese).

Beck, S.D., 1960 . Growth and development of the greater wax moth, (]aller imaeilonella <L. )(.Le-
pidoptera: Galleriidae ).T),ans ,VVis ,Acad. Sci. Arts Lett. 49: 137-148.
Chase, R,W., 1921. The length of lif eof the larva of the wax moth, Gallent amelionella L. ,in its
different stadia. Ibid, 20: 263-267,
Dimmock, K. A,, 1888. Variable nurnber of rnolts of insects . Il!yche 5 (141-14 2: )28-29.
Edwards, W. H., 1881 . 0n the number of molts of butterfli ewist,h some histor yof the moth Qillosamia
Promethea (Drury )I.bid. 3 (81 :) 159-161.
Gaines ,J. C. and F. L. Campbell, 1935 . Dyar's rule as related to the number of instar sof the cern
earworm, Hlaliothi sobsoZeta (Fab. )co,llected in the fiel d.Ann. ent, Soc. Am. 28 : 445-461.
Haydak, M. H., 1940. The length of develepment of the greater wax moth. Scienc e91 : 525.
Hirata ,S. ,1962 . Local variations in certain characters of the cabbage moth, Mamestra b,assic aCeLinne).
ko. J EcoL 12: 133'140 <i nJapanes ewith English surnrnary).
Hirata ,S. ,Fukushi, K,, Mikami, A., Takayashiki, E and T. Yamauchi, 1967 . Comparative studies on
the population dynamics of important lepidopterou psests on cabbage. VI. Growth and variation
of the head capsule width of larvae of Pien' smpae cracivova Boisd . Ili pI.L cipPL Ebet .Zbol .11 : 1-
8 Ci nJapanes ewith English summary).
Hukushima, S. and H. Kajita ,1960. Note on the elytral dimension in the fiea beetle R,h]:llotret satn'olata
Fabriciu sin Gifu Prefecture .Ibid .4: 182 (i nJapanese).
Kato, M., 1938 . Geographical variation of Antizonomus bisignif eSrchenkling . Qyo-Dobutstrgaku
Zdsshi 10: 186-189 (i nJapanese).
Kitano ,H., 1967. Studies on the seasonal differenc ein the head width of the larvae of the common
cabbage butterfi yP,ien's rmpae crc{civova Boisduval. Bull ,7bdyo Gafenge iUdeiv .Pt, 19, Sect. 4. 1 :
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TThhee　 LLeepipdiopdteorpoltoegiroaollogical　 SSoooiceityety 　ooff　 JJaapapnan
Larval　Instars　of （勉π6据α mellonella 235
−
　　34 41（in　Japanes　ewith 　English　summary ｝．
Masaki ，　S．，−1966．　 Climatic　adaptation 　and 　geograph 童cal　variation 　of　insect．s ∫海o々幼％醜 βo謝 ，　Tokyo
　　20：243 249（in　Japanes）e．
Masaki，　S．　and 　N ．　Oyama ，1963．　 Photoperiodi　ccontrol 　ef　growth 　and 　wing 　form　in　Nemobius　yeioensis
　　Shiraki（Orthoptera：Gryllida）e．　Kontyf　i31： 16−26．
Metcalfe，　M ．　E．，1932．　 On　a　suggested 　me 亡hod　for　determining　the　number 　of　larval　instar　sin　SitrodrePa
−
　　Panicea　L．　Ann ．　apPL　BioL　19：413 419．
Milum ，　V ．　G．　and 　H ．W ．　Geuther，1935．　 Observations　on 　the　biology　of　the　greater　wax 　moth ，翩 嬬 α
　　mellonella 　L．　f，　econ．　Ent．28：576−578．
N　ag　as（Fawaabri，　cSiu．，）s．195（4加．　 一Oκno　πt願he　l1oc0a：l　1va5r0ia−t1io5n2（i　no　fJ　aelpytaranle　s　dewiimthens　iEonngl　iinsh　亡hsuemm　afrylea　be）e．tle，　PleJ，llotret　ast｝勿 lata
N　i　el1s0e1n，−　1R0．　3A．．　and 　D．　Brister，1977．　 The　greater 　wax 　moth ： adult 　behavior．　 Ann ．　ent ．　Soc．　Am ．70：
　　　　and 　　　　 ，1979．　 The　greater　wax 　moth ；behavior　of　larvae．　 Ibid．72：811−815．
PPaardkdo，c0k．，，　ユF9．　4H9．　，，1A9p1p8l．　icTa亡hieo　nb　oefem亡hoet　hco　novre　rsweax 　　Bmeotrhgma．n　nTe　pvrais　nacgipγilec　．to聊　th．　eS　cta．　rBabuiUd．　2b3e1e；tl3，e8　D．icaela　sPuiPur−
　　at4s ．　Ph）’siol．　Zool．22：　359−372．’
Plantevin，　G．，1975．　 ContributiQ　na　letude 　de　Ia　biologi　ede 磁 〃¢碗 meilone 〃a，　mues ，　croissance 　ct
　　de▽elopPemen 亡．　Anngs　ZooL　Ecol．　anine ．7：365−397．
Sasaki，　M 、，1981．　 Physiology　and 　ecology 　of　honeybees ．動 Sakamoto ，　Y ．　and 　I．　Okada （eds），　Chikusan
　　Konchugafeu．298　pp ．，　Buneid ，　Tokyo （in　Japanes）e．
S　ta　iransd，　G　i．　tRs　．s，pe1c97量8f．i　c　BEa丘cuecltosv　iorfu　sa　．w　ideEnv　irrang．　eEn　tof．　7te：m2p9e7r−aZt9u9re．s 　on 　the　development　of 磁 」♂θ瀚 mellonelia
Utida，　T．，1957．　 Developmental　zero 　temperature 　in　insect．　s fap．　f，吻 ）乙 Ent．　Zool．1：46−53 （in
　　Japalles　ewi 亡h　English　summary ）．
摘 要
・
ハ チ ノス ツヅ リガ （鱗翅目 ：メイガ科）の幼虫齢数と発育 （松本聖子 矢野宏二 ）
一
養蜂害虫で ある 方，生物検定用な どに も広 く利用 され てい るハ チ ノス ツ ヅ リガ の幼虫齢数は，北
米 とフ ラン ス の個体群 につ い て 7 ない し8齢であると報告されてい る．そ こで，日本の個体群につ
い て，その点を検討す るこ とと，飼育温度による形態変化 （幼虫の頭幅）を調査する こ とを目的 と
して本研究を行っ た．餌は山口市内の養蜂家より入手した巣を高温処理 したの ち使用した．飼育は
20℃，25℃，30℃，35℃ の恒温器で 日長 16L：8D とし，それぞれの温度下で 2世代以上経過 してか ら
調査を開始 した．
1，幼虫齢数
頭幅の頻度分布か ら判断す る と，2 ℃ と 25℃ で は 8齢経過 し 30℃ と 35℃ で は 7齢を経過 した．
，
25℃ と 30℃ の間に これ らの違っ た経過齢数を分ける温度が ある こ と，お よび，高温が齢数 を減少
させ て い る こ とが判明 した．0．153mm か らO．408・mm の 頭幅の間で，飼育温度に よ り3齢経過
（20℃ と25℃）と 2齢経過 （30℃ と35eC）の差が認め られた こ と，1齢 とその後 の齢の頻度分布か ら
判断す ると，1齢に お け る飼育温度が齢数の差を決めて い る と思われた．本結果に よ り，既往知見
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を統 的に解釈する ことが可能 となっ た．
2．頭幅の測定範囲
頭幅の頻度分布を経験的に正 規分布 とみなし 各齢頭幅の 測定範囲 と平均値，標準偏差 を統計的に
算出した．1齢の頭幅範囲は温度に よ る差は，ない が 2−4齢で は差が認め られた．7齢経過個体群
，
（30℃ と 35℃）で は，各齢と もこれ らの温度間で有意差がな い が，8齢経過個体群 （20℃ と25℃）で
は 2，4，6齢で温度間で有意差が 認め られた．本種は 18℃ 以下あるい は 40℃ 以上で は発育で きない
ため，18℃ に近い 20℃ では差を生じ，40℃ か ら離れた 30℃ で は差が生 じなか っ た と推察される．
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TThhee　 LLeepipdiopdteorpoltoegiroaollogical　 SSoooiceityety 　ooff　 JJaapapnan
236 Seiko　MATsuMoTo 　and 　K6ji　YANo
3．頭幅に対す る飼育温度の影響
発育適温帯を離れた温度帯で成育する動物や 昆虫で ，体サイズが大型化す る種がある こ とが知られ
てい る．本実験の結果，本種は約 30℃ が適温 と判断されたが，その温度帯を離れて も頭幅に明ら
か な差はで なか っ た．これ は各温度帯で飼育した経過世代数が少ない ためか，あるい は飼育温度が
サ イズに影響しない のか も知れ ない ．
4，発育
発育速度をもとに算出した卵か ら羽化ま．での発育段階の 理論的発育零点は 5． ℃ 有効積算温度 は
11666760．7日日度度前で後あとっなたる．．本羽種化は率羽は化3後0℃24で時最間大以で内あにっ交た尾．・発産育卵デをーすタるのの結で果， と1巣世の代温，の度有か効積ら判算断温し度ては，
本種の発育適温は約 30℃ と判断され る．
5． その他
30℃ と35℃ で は経過齢数が 1齢少な く7齢となっ たが，8齢経過個体群と頭幅を比較する と，7齢
経過個体群の 2齢頭幅は 8齢個体群の 3齢頭幅 とほぼ一致 し，それぞれ以降の齢で も同様に 一致す
る．つ ま り，両個体群の最終齢で はほぼ一致す る．そ こで，8齢経過個体群の 2齢が過剰齢 （extra
insta）rであ り，7齢経過個体群で はそれが欠けてい る と解釈するこ とがで きる．
（Accepted　August　11，1995）
Published　by　the　Lepidopterologic　aSlociety　of　Japan
c〆00gata 　Building，2−17，　Imabashi　3−chome ，　Chuo−ku，，　Osaka，541　Japan
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