A. Material and experimental method
III. The eggs of Monochamus tesserula White of Cerambycidae, were gathered in
3) Monochamus tesserula white
Tables 28, 29, 30 show the mean of head width, standard deviation, coe飾cient of
variation, maximum value, minimum value and growth ratio of the 27 larvae that reached the last instar by breeding. According to this, in the cases of the 9th, the 8th
and the 7th instar larva the standard deviation increases while the coe鯖cient of varia‑
tion decreases according as the instar goes on. This was also the case with the abovementioned Cryptorrhynchus insidiosus Roelofs. The growth is not uniform for all the instars ; it being 1.20 for the 91h instar larvae, 1.24 for the 8th instar larvae
and I.30 for the ヮth instar 一arvae. In other words, the smaller the instar number is,
the greater the growth ratio becomes. As for the mean of each instar, the 9th instar larva shows the highest growth ratio of I.33 between the 2nd and the 3rd instar, and then the ratio becomes lower gradually till it falls to 1.05 in the last instar. The 8th instar larva shows the highest growth ratio between the lst and the 2nd instar, and also between the 2nd and the 3rd instar, and then the ratio falls to 1.05 in the last instar, which is also the cane with the 9th instar larva. The 7th instar larva shows a striking growth ratio of 1.47 between the lst and the 2nd instar, then 1.33, 1.38, and 1.31 between
the 2nd and the 3rd, between the S∫d and the 4th, and between the 4th and the 5th
instar respectively, and then the ratio tapers down until it falls to I.15 in the 7th instar. As stated above, the number of moultings and the head width of the last instar
60 Physiological and Ecological Studies on the Pine Bark Beet一es
Table 28 A Mean Width of head capsules in each instar of the larvae
(Monochamus tesserula white) with eight lnOults
Iustar ﾄﾖV Td:av蕊Lcfe:rat.iiCai:in.tniMin‑Maxi 僮nstar ratio 背& wF & FR
1 蒙ﾒ 0.943±ニ0.009 鑓ｽ mm!%immi 剴 ?｣ｳC｢ sC)?｢粤店ｮﾒ靈鞴 R r
2 域ﾓ " 刧V/Ⅱ 白 2
3 ﾃs3 ﾓ r 刧W/Ⅲ 白
4 8 ﾓ #b 0.1014.58 ∴∴ 鐙蓼 井 2經c蔦2繝c" 2繝 ﾓB B BﾓB紊#R Ⅴ/Ⅳ 白
5 繝S ﾓ 3 刧Y/V r
6 c ﾓ 3r 刧Z/Ⅶ 白貳ﾂ
7 縱CH ﾓ 3 刧[/Ⅶ
8 釘 C8 ﾓ 3 刧¥/Ⅶ[ R
9 釘 C ﾓ SB 刧]
Table 29 B Mean width of head capsules in each instar of the larvae
(Monochamus tesseruta white) with eight moults.
Instar 白 ﾖV ﾓｦ eF B 逃F Vff 坊蹌 ef & F柳 Min.‑Max. i 粕也7F " ﾇ& F薬 iGrowth Irate
1 蒙ﾒ0.962±0.007 mm 冷ﾗ鉅#" 2.37 ｺ(ﾜ｢繝Srﾓmm # R 1.36
2 8 ﾓ 2 0.110 湯紊 1.172‑1.584 b uR 1.36
3 縱s ﾓ b 0.168 湯經 1.488‑2.049 r ub 1.34
4 3 ﾓ #r 0.314 2紊B I.800‑2.849 ur 1,29
5 #H6ｨ ﾓ 3B 0.42 B " 2.424‑3.600 ｢ b 1.18
6 經c( ﾓ 3 0.303 唐經 2.995‑4.024 ｢ u 1.10
7 X ﾓ C 0.267 澱繝 3.288‑4.425 ｢ u｢ I.05
8 釘 ( ﾓ Sb 0.265 澱紊b 3.684‑4.572 ﾒ 1.24
Table 30 C Mean width of head capsules in each instar of the larvae
(Monochamus tesserula White) with six moults
Mean i dSetsrad.?.r:悠oSEaf,i宝器tn i Mュn.‑Ma翼∴ ).na菩.I I Gr.oayeth
1 蒙ﾒ 纉S( ﾓ b 冦m 0.039 4.14 冦m 0.915‑I.052 剿 R 1.47 2 " 2 2 B 412±0 # 0 0 0 0 0 10 Cr #CR 10 ig 鼎b 1 1 2 2 3 3 S2ﾔ 570 b uR 1 1 1 1 1 1 2
3 56±0 2 剴 " 都 "ﾓ" OoO r ub r
4 41±0 3 剴cB ィﾓ" 800 ur
5 85±0 CB #V湯 涛 都 "ﾓ2 425 禎b
6 85±0 Sr 仗譁r 都 鼎#RﾓB 224 ｢ u R
7 82±0 c2 剴cb 都 ふB 314 ｲ u｢
Table 31 Equation calculted from the growth width of llead capsules on the
pine bark beetles Monchamus tesserula White
FH｢ight‑ou,tslarva UfV贍 VﾇG6ﾆ %f siXmoultslarVa
二王言.0088+0.082̲7X 犯 u ｨ ｳ S rｳ ｺ犯 u ｨ ｳ s# rｳ uﾒ
aGnaadinpebSel.tLogY.‑8'870;5xt0.0257Ⅹ 偖ﾆu xｶ9 さ 3 ﾘｹ 遁X ｣ C Xuﾒ
･okunagaILog‑‑‑879y6二‑i‑‑‑0..096‑.=三; 彦 rﾒﾓΕ"ﾓ ﾓG椿辻ﾒﾓ ③ﾕI(h自<Rﾓ scｇBﾕBﾂ
do not increase gradually, but they tend to approximate to the mean of the last instar.
a. Application of growth formula
Concerning the growth of head width, table 31 gives the results obtained by applying
Shigeru lshikubo 〔研究紀要 第14巻〕 61
Table 32 A Theoretical width of head capsules in each instar of the larvae (Monochamus tesserula white) Calculated dy the Dyars′ formula The equations of width are log Yニー0.0088+0.0827Ⅹ (larva with eight mouls) log Yニー0.05107+0.0934Ⅹ (larva with seven mou一ts) and log Yニー0.07217+0.1080Ⅹ (larva with six moults) respectively
･nstar.23日5 劔剴b ー789
iMeasu.‑edvalue剛直94; 剩汕鼬ｾ739十.213 剴"繝Sr 3.368 縱CCB C2 4.248 ica.culatedVa.uem,..185日.434jl.73512.09912.539 劔 .072 縱 cB紊澱 5.439 9惜ie.rencefromobserVed 兩0.2421‑0.1260.004 剴 B 0.320 澱 0.028‑0.353 蔦
i iRateofdifference 蔦#R緜 ﾓ偵s 撞 2 5.15ー 免ﾂ ｣sS 繦D簽 h璽#ゅ 2
;AVeragerateofdiffeでence jinabsolutevatue 繝
MeasuredValuemm 纉c#ｳ 2 縱s 2.33813.024 .562 亦 2纉(ﾜｳB #
CalculatedValuemmIl.102 僮.367 緜途 2.102 亦 緜 S" 3 釘 cB纉c
8 乏 V Vg& ﾖ &W'fVC ﾓ C 蔦 cB 0.074 3c 紊 蔦 3 0.081Lo.866 I
Rateofdifference1‑24.94 i 4.90 釘 s 3 2繝S偵# 剪ﾓ" c ﾓ# 貳ﾂ
AVeragerateofdifference inabsoluteValue 免ﾂ 劔
i MeasuredValuenlm 0.9521 仗 b 經C サ 繝 釘 末
CalculatedValuemm .086 免ﾂ 縱ッ " "纉3c2縱cSB繝3
7 豫Cｧ&V VgF ﾖ '6W%fVI s 3C .0700.251 I .349 # ﾓ 縱C Rateofdifference‑14.081.34‑3.779087 劔 緜" 3.0818坤
?nvearbasg.iuteat:atiedifferencei 唐縱" 劔
the method of least squares to
DyARS formula (1890) log Y‑a+bX
GAINES and CAMPBELL's formula (1935) logY‑a+bX+cX and ToKUNAGA's formula
(1928) log一読二子‑K(I‑T) Tables 32, 33･ 34 shows the calcu‑ated value and the compatibility degree.
According to DyAR's formula, the 7th, the 9th･and the 8th instar have a high degree
of compatibility in the order given, the 7th being the best with 8.72%. According to GAINES and CAMPBELL's Formula, the 8th instar stands hrst with 5.19%, and is followed
by the ヮth and the 9th instar in this order･ According to Tokunaga'si formula, the 8th, the 9th and the ヮth instar come in this order but the compatibility degree is low
in all cases, and especially the 7th instar larva shows 19.07%. When considered in terms of the instar, in the case of the 9th instar larva, DYAR's formula gives 10.88%, GAINES and CAMPBELL 18.22% and ToKUNAGA's formula 18.71%. In the case of the 8th
instar larva, GAINES and CAMPBELL gives 5.19%, which is the highest compatibility
degree of all instar larvae. On the other hand DyAR's and ToKUNAGA's formula give
l1% and show a very low compatibility degree. In the case of the ヮth instar larva, GAINES and CAMPBELL's formula gives 6.52%, DyAR's formula 8.72% and ToKUNAGA's
formula 19.07% which is the lowest compatibility degree. In sum, since the compatibility
degree becomes lower in the order of the 7th, the 8th and the 9th instars, it is concei‑vable that the 8th instar is normal in the number of moulting, and that the number of moulting is due to abnormality in temperature, dryness and nourishment and so on.
62 Physiological and Ecological Studies on the Pine Bark Beetles
Table 33 B Theoretical width of head capsules in each instar of theiarvae (Monochamus
tesserula white) calculated by the Gaines and Campbells formula The equations of
width are log Y ‑ 0.0775+0.0257Ⅹ+0.0057Xg (larva with eight moults) log Yニー0.2351
+0･2038X+0･0123Xe (larva with seven. moults) and log Y‑‑0･0969+0･1415X‑0･0051XB
(larva with six moults) respectively
Table 34 C Theoretical width of head capsules each instar of the larvae (Monochamus tesserula white) calcu一ated by the Tokunagas formula The equations of width are log y/8.496‑y ‑ 0.1096(t‑T) (一arva with eight moults) (log y/8.204‑y‑0.1127 (t‑T)
(larva with seven moults) and log y/8.164‑y‑0.0768 (t‑T) (larva with six moults) respectively
I,萱:三･:I.I̲̲:I‑‑‑:.'･.. I,'･'･..I...I::･.:'享:I.I:.諾.:I:･'''
b. Individual variation in growth pattern.
As stated above, on examining DyAR's formula, GAINES and CAMPBELL's formula and ToKUNAGA's formula, it was found out that in the case of the 7th and 8th instars, GAINES and CAMPBELL's formula had a comparatively high degree of compatibility and the other two had not, It may be inferred that there are many variations in growth pattern. Therefore the rate of increase was computed from the mean of each instar and individual measured value, and the changes which are attendant upon the increase
ratio were studied. Table 35 and table 36 show the rate of increase in erch instar.
According to these, the mean of the rate of increase in each instar larvae is 1.20.
Generally speaking the lst, 2nd, 3rd and 4th instar larvae show a considerably high
increaslng rate, and from the 5th instar on down, the rate falls o描 graduaily. Each
instar larva seems to show its own variations.
In the case of the loth instar larva, the缶rst instar is low and then the rate tends to become high until it reaches its peak in the 3rd instar and falls 0倍 gradually
Table 35 The growth rate of width of head Capsules in each instar of the larvae
(Monochamus tesserula white) that moulted nene, eight, seven and six times
respectively
64 PhysiologlCa1分nd EcologlCal Studies on the Pine Bark Beetles
Table 36 The mean growth rate of width of head capsules in each instar of the
lal‑Vae (Monochamus tesserula white) that moulted nine, eighL Seven and six times respectively
Ⅳ/v
1.18 1.20
Ⅶ/Ⅵ i Ⅶ/Ⅶ I K/Ⅷ 〜 X/Ⅸ 1.09 I 1.06
i
1.08 1.07 7 ; 1･ll i l･08 8 1.10 I 1.05 8 1 1.15 i
1.07 ! 1.09
there after. In the case of the 9th instar larva, the increasing rate of the缶rst instar is comparatively high and範uctuates to some extend until the 4th instar and then falls
oHthere after. Inthe case or the 8th instar･ larva, the let instar has the highest rate, and maintains a pretty high rate until the 4th instar as in the case of the 8th instar.
The 7th instar larva is characteri2!ed by its highest increasing rate in the nrst instar, and there after shows the same tendency as the above‑mentioned three kinds of larvae.
After all the 7th instar shows the same pattern ad the 8th, can be looked upon as typical･ Therefore the loth, 9th and 7th instar types are considered as variations of the 7th instar type, Incidentally in terms of the mean of increasing rate for each instar, the loth instar is the lowest with 1.17 and the 9th and 8Lh instars are higher and the 7th instar is the highest with 1.30. From this fact, it may safely be infreed that the head width does not increase in direct proportion to the number of moultings,
but that it takes the approximate value at the缶nal instar.
Results
The writer carried out the individual breeding of Myelophilus piniperda L., Cryp‑
torrhynchus insidiosus Roelofs and Monochamus tesserula white, which are the general
species of the pine bark beetle, and by measurlng the width of the head, Obtained data by which the instar can be determined. In addition the growth rate was applied to various experimental formula and their compatibility degree was studied, and at the same time individual variation in the growth pattern was also examined.(1) In the case of Myelophilus piniperda L. it was conhrmed as a result of
measurement that there are 4 instars in the larva stage. The growth rate is approxi･血ately the same in each instar, and the individual variation is small and progresses
similarly and harmonically on the whole. The growth rate is applicable to GAINES and CAMPBELL's formula the best, with Tokunaga's formula following, and DyAR's formula is somewhat inapplicable.
(2) In the case of Cryptorrhynchus insidious Roelofs, there are the 7th instar larva and the 8th instar larva. The growth rate of the 7th instar larva is a little higher than that of the 8th instar larva. The growth rate ot he head is applicable to
GAINES and CAMPBELL's formula and Tokunaga's formula in the ヮth alld extent in the case of the 8th instar larva, but in the case of the 7th instar larva, a great di托erence
was observed･ The rate of increase of the head width is highest in the lst and instars
both the case of the 7th and 8th instar larvae, and then the rate falls o任as the instar
advances･ But when studied individually,Some variations can be observed which have
an increasing rate quite di仔erent from the mean value.
(3) The number of moulting of Monochamus tesserula white is not constant. Of
the loth, 9th, 8th, and 7th instar larvae, the 8th instar larva is considered to be typical.As for the growth formula, GAINES and CAMPBELL's formula applies to the 8th and the
Ⅳ一29 29 29 29 31