Effect of grazing intensity on the habitat of Shijimiaeoides divinus asonis (Matsumura) (Lepidoptera, Lycaenidae)

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TThhee LLeepipdiopdteorpoltoegircaollSoocgieitycal Society ooff JJaapapnan
wttlk 7>"ans,lepidS,oc,mpan 59(3)2:51-259, June2008

Etfect of grazing intensit yon the habitat of Shijimiaeoide sdivinus asonis
(Matsumura)(LepidopteLrycaa,enidae)

Kouhei MuRATA*, Chinobu OKAMoTo, Asana MATsuuRA and Makio lwATA
Schoo ]of Agriculture T,okai Universit Myi,namiaso, Aso, Kumamoto Pref. ,869-1404 Japan
Abstract The populatio onf a lycaenid ,Shijimiaeoide sdivinus asonis (Matsumur aha)s been re-
duced by environmental changes in some habita tisn the Aso area. We conducted route census sur-
veys of this butterfl yin 2006 and 2007. The study area is located on the volcanic glopes of Mt Aso
in the center of Kyushu, Japan. At the study site, the natural herbaeeou gsrassland ,which had been
almos tcempLetely grazed, was subjected to routine grassland burnin gevery spring. The results ob-
tained are summarized as follows :(1 )Pleioblastu schino (Franc het. Savat. M)akino var. viridis
(Makino S). Suzuki was one of the dominan tspecies at the study sites with normal grazin gintensi-
ty. Zo])si ajaponic Sateud. was one of the dominant species with high grazing intensit y.On the
other hand, Miscanth" sEinensis Anderss ,was the dominan tspecies at non-grazing sites. (2 )The
individua ldensity of the host plant ,Sophora j7avesc eAnits ,was significantly diiferen tat each study
site. (3 )The heigh tof the host plan tat the non-grazing sites was highe rthan at ether study sites,
(4 )The number of branches of the host plant at the sites with normal grazing intensi tways 1arger
than at other sites ,(5 )The individua [crown area was bigger at the sites with normal grazing .On
the other hand ,the heigh tand crown area of the host plant at sites with high grazing intensit ywas
smaller than at sites with other grazin gintensitie s(.6 )Adult butterfii eapspear in ear!y May almost
disappea bry mid June .Individu anulrnbers were affected by low tempcratures from Apri1 to May,
and the density of butterfli emsarkedly decreased in 2007 at all study sites. (7 )The number of 1ar-
vae was significantly differe antt each study site when popu]ati odnensit byecame high .(8 )The
nurnber of adults and eggs increased alongside an incrcase in the number of nectar plants at the
grassland where grazing ceased, Based on these results, i tis concluded that customary grazin gin-
tensity is most suitable for the conservation of this butterf} iyn the Aso area.
Key words Pasturage ,grassland ,Shc'iimiaeoi ddievsittu assonis, larg eshijimi blue ,conservation.
Introduction
The lycaenid, Shijimiaeoid edsivinus asonis (Matsumura )is, one of the rarest butterfl iiens
Kyushu, only found on limite dareas of the volcanic slopes of Mt Aso. The larv afeeds on
flower buds of Sophora flavesc eAints .The grasslan dhas been managed as meadows by
farmer sfbr severa] hundred years . This lycaeni dwas designate din 1995 as a National
Endangered Specie sin the Law fbr the Conservatio onf Endangered Specie sof Wild Fauna
and Flora legislat ebyd the Environment Agency of Japan ,Recently ,numbers of this but-
terfl yhave been reduced by environmental changes in some habitat isn the Aso area. Our
previou sstudy showed that habita tchange factor scan be divided into four groups ;human ei
fect ,grasslan dmanagement, volcanic activity and climate (Murat a& Nohara, 1993),
Habita tchange caused decline osf attendant ants, host plan tand nectar plants a,nd increases
in some natural enemies, and these phenomena resulted in the decline of the butterf lpyopu-
lation(sMurat&aNohara,1993;Murata 1998;Murata& Nohara,2001,2003,2005).
et aZ.,
On the other hand, the populatio nof the butter fhlays not been declinin ign areas where rou-
tine grasslan dburnin ghas taken place (Murat aet al,, 1998). Routine grasslan dburning
*Corresponding author: kn][email protected]
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252 KeuheiMu/RA'rAC,hinobuOKAMoTo,AsanaMATsuuRA MakioIwA'rA
and
seems to have a positive infiuenc oen the butterf lpyopulatio n,Tradition aglrasslan dburn-
ing and continuous grazing are importan tfor the sustainable conservation of the butterfly.
Recent studies have reported that how the pattern osf species diversi toyf butterfl icheasnge
along a gradien otf human economic disturbance (Balme &r Erhardt 2,000; Kitahara & Sei,
2001; Inoue, 2003; Nisinaka & Ishi i2,006) .However, it was not clear how the grazing in-
tensity affects the habita atnd the population of this butterfiy.
This paper reports an investigati coonnducted to make c]ear the elfect of grazing intensity
on abundance of the butterf loyn, the densit yof the host plant and on the nectar plant flora
used by this butterf liyn the Aso area,
Location,
study sites and methods
Location
a) and study sites
The study area is locate don the vo]canic slopes of Mt Aso. Three sites (A-C )with dilferent
grazin gintensit iweerse surveyed in the butterf ihyabitat (sFi g1.). All study sites, routine
grasslan dburnin gwas carried out every spring. At al Istudy sites were classified as grass-
land mainly covered with natural herbaceous plants .At site A, grazin gjntensi t(ydayslani-
mal unit) was normal for the Aso area, and at site B, grazin ghad been stopped since 1998 at
site B. At site C, grazin gintensit ywas higher than at site A, consequently constituting the
highes tinensit oyf the three sites ,At each study site grazing intensi treymained unchanged
from 2000 to2007,

b) Density of S..fZavesce annsd nectar plants
The density ,branch number, individu aclrown area and plant heigh tof S. flaves cweerens
measured in three main quadrats (5 mx5 m) randomly established in each study site.
c) Dominant ratio of nectar plants
The extended summed dominant ratios of nectar plant of this butterfl yand plan theight were
measured in nine subquadrats (1 mx1 m) randomly established in each main quadrat sat all
study sites using the Penfound and Howard method, The dominant ratio of the plant swas
E-SDR2.
calculated using
d) Quantificat iofo nthe adult butterfi yeg,g and larva
The number of adult butterfi iweass recorded by route census surveys for 10 minutes (500
m in distance f)rom 1O: 30 to 13: OO hrs loca ltime under fin eweather conditions during the
adult fiigh steason (fro Ampril to June) (Murat a& Nohara, 2001, 2003, 2005).
Eggs and larya ewere counted on 50 shoots of the host plan tonce a week from May 15 to
June 26 at all study sites in 2006 and 2007.
e) Infiuenc eof the grazing intensity on the adult and egg population
Tiwo quadrat s(20 0mx200 m, site G and site NG) were suryeyed at site C in 2006 and 2007
(Fig 2.) .In 2006, grazin goccurred at both sites ,however, in 2007, grazing did not occur at
sjte NG but was normal at site G. These study sites was adjacent to each other.
The number of adult butterfl iwaess recorded by route census surveys fbr 5 minutes (25 0m
in distance f)rom April to July at site G and site NG in 2006 and 2007, The densit yof eggs
was counted on 25 shoets of the host plan twhich were se]ected at random at both sites in
2007.
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Fig. 2, Two quadrats (si tGe and NG) establighed at
Fig .1 .The study sites undcr dilferc gnrtazing inten-
sities, A. Nonnal grazing intensit yB. Non-
grazin g.C. High grazin gintensity.
Results
1. Influence of grazing intensity on growth of host plant
The landscape sof the study sites were remarkably differe ndtependen ton the pattem of
grazin g(Fi g1,) .The degree of plan tcover was low at site G under high grazin gintensi tiyn
2006 and 2007 (Fi g2.) .Table 1 shows the properti eofs S. flavesc peonpsulatio nT.he indi-
vidual densit yof the host plan twas significantly differe natt each study site (Tukey-
Kramer's test, p<O.05) .The height of the host plan tat site B (non-graz wiasng s)ignificant-
ly highe rthan at sites A (norma lgrazing) and C (hig hgrazing) (Tukey-Kram etres'ts,
p<O.05). The individu aclrown area at sites A and B was bigger than at site C. The braneh
number of host plants at site B was 1arge rtban at sites A and C.
2. Infiuence of grazing intensity on yegetation
[fabl 2e shows the degree of cover of the dominant grass species (E-SDR, )Zb.ysia ]'oponica
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Table1.PropertiesofSophoraflavescenspopulation.

Property Study sites
A B C
Stockin gdensit (yanim aunlitlha) 1,123.0 o 1.413,7
Individua ]density (X2 5m2) ± 8.9a 4.7 ± 4.6c ± 11,lb
Branch nurnber (lindividual) 5.5 ± 1.0a 11. 1± 9.6a 5,0 ± O.2a
Individua lcrown aree (1 OO cm2) 33,3 ± 12.9" 27.0 ± 16.ls 16.8 ± 2.7a
Planthei ht(cm) 81,9 13.I' 105,8 172a 70.2 13.2ab
± ± ±
Data were obtained in September.
Differen tlette risn the same ]ine show significant ditierenc eat 5% level sby Turkey-Kramer's
test.
Table 2, Cover degre e(E-SDR, o)fdominant species.
Study
Speciesofdominance sites
A B C
Grazinginsensit(ydaysfanimal 19042.650o.319.725031.6
unit･ha)
Sophoraflavescens
Pteioblastus
chino var. viridis
Miscanthus sinensis 89,O59,4
imperat ac.vlindrica ivan koenigii
Lespedeza striata 27.9
Zoysiaiaponica 52.515.1
Arundinellhairta

Data were obtained in September,
Steud .(E-SDR ,52.5) was most dominant at site C (hig ghrazing) . Miscanthus sinensis
Anderss .(E-SDR ,8,9.0 )was domjnant at site B (non-graz iOnng )th.e other hand, P, chino
(Franc eht .Savat. M)akino var. viridis (Makin oS). Suzuki (E-SDR ,50,,1) and S, flavescens
(E-SDR ,4,2,6) were dominant species at site A (nenma lgrazing ).The higher the grazing
intensi ttyh,e lower the E-SDR, of S, flavesc etennsded to be.
Among nectar sources, Cirsium japonic uDmC, was dominant at sites A and B, and Ii7ola
mandsh"rica W Becker was the most dominant species at site C (Tbb l3e) .The dominant
rations of nectar plants at site A were significantly highe rthan at site C,
3. Influence of grazing intensity on the number of adults
Seasona lfluctuation sof adults, rainfal1, and air temperature were measured in 2006 and
2007 (Fi g3.) .Mean air temperature was similar between 2006 and 2007 except for mid
Apri1 .The tota lamount of rainfa11 was greater in 2006 than 2007. Butterfiie wsere fbund at
all study sites from lat eApri1 to early June, The peak occurred in midd]e of May. The
number of the butterfl ymarkedly decrease dat all sites in 2007. A 1arge rnumber of the but-
terfii ewsas recorded at site A than at sites B and C in 2006 and 2007.
4. Infiuenc eof grazing intensit oyn the number of eggs
The number of eggs was monitored from lat eMay to early June in 2006 and the latte Mray
in 2007, respectively (Fig 4.) .The seasonal change in the number of eggs coincided with
that in the number of adults in both years .Thble 4 shows the densit yof 1arya ein 2006 and
2007. The density of larva ewas significantly differe nbtetween site A and sites B-C on 6
and 13 June in 2006 when populatio wnas high (IUkey-Kram eterst', sp<O.05).
Figure 5 shows seasonal fiuctuatio onfs eggs at site NG (non-grazi anngd) site G (grazing),
The number of eggs at site NG was greater than at site G on 22 and 27 May, 2007 (Fi g5,).
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Table 3. Extended summed dominant ratios of host plant and nectar plants for Shij'imi.aeoi ddeisvinus
in
asonis each p]ant community.
Species S t u d"v sites
A B C
Host plant Sophorafiavescens 56,1 ± 1,7"1,6:O4,74n.8± 9,2ab4.lab336,,86uO±.31a9,6a,O.6bO.8･
NectarplantsCirsiumjaponic"m 7.6 ± 4.9 ± O.4 ±
Viola mandshuria 2.6± 3.0±･ 2.6 ±
Viota gT:v7)oc'era,g O.2 ±
Viola verecunda 1,71±.0 3.0aO,4n 02 ± O.4z･
Viola
siebotdii ±
Seneciointegrijblitts,ftu{riei L4 L6fl
±
Etaeagnus umbellata 1.7 ± 2,9u
Ran"ncLtlusj'aponicus O.4 O.5.
±
Trijbliu mrepens
Total 70.614.63,4･,5.05a7.2 3.8Hb5.44E0b,2 19.7ocO.2b
± ± ±
TotalwithoutSophotu.flavescens ± 9.4 ± 3,6 ±
Data show mean ±standard deviatio nD,ata were obtained in June-July.
Differen tletter sin the same line show $ignificant differen att 5% level sby Turkey-Kramer's test,
The number of adults at site NG was thre etimes as high as at site G in 2007 (Fi g6.).Atat
site NG, the densit yof Senecio nemorensis L,, one o'f the nectar plants w,as greate rthan
G (Fig2.),
site
Discussion
Effec tof grazing intensit oyn butterfl pyopu]ation
Secondarygrasslan dw,hich is oneof themainlandscapeelementtypes,has beenmaln-
e (℃) 2006 lxao20o07 O
e.g･ 30
2010
;･s
(mm) o30020o100
g2:.tu
200100
E .L= '

o40030D20D100 o4003oe2oe100
A L1t A
2N=vHSb'.E'o6Z
o4oe3002oeioo o400300200100
B B
-r
p m
o40030D200100 o4003eo2eo100
c c
/ ×..XX Lr+-x
X...x..-
li'
o rx×--x i' xir2X-X eJ1Aupnr,.-dL-Xx./X-/..MEx T -x-
Apr.-x- May May[Jun."hr
Fig, 3. Seasona lchanges of mean temperature ,tota lamount of rainfall and the adult number of
Shijimiaeoi ddeisL,in aestonsis at three study sites.
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2007
2006

L:'i':II:/lil :i[ A
A
l:[

I'i1

ll:

=-H,
oormo--ooZ
/suy.11:I:.: B txq='ctde/xan･/!: B
L/ac".n/-[4a[o;EO1[b1[[c
..um .." - IH-rrx- -
l,ll1m-///)]mlm-jco･e)-su.orrKpr c
l 1 1 1 1Jun.1

MayFig. Jun. Apr. May

4.Seasonal changes in the number of eggs on cach site.
30025020015010050 2006
gg-odz .x-.
o
300 125020015010050 2007
-- ･-G+NG
×
u ' '
x.
'･x
o a- crmmmff-ct-Dfi-n-ti.t.x 1 ]
Apr. May Jun.

Fig .5.Seasona lchanges in the number of eggs at site C in 2006 and 2007.G: Grazin gin 2006 and
2007; NG: Grazin gin 2006, non-grazing in 2e07.
tained by traditional mowing and grazin gin theAso area. Farmers and cow-breeders have
burned these grassland severy spring for several hundred years ago (Mura t&a Nohara,
1993),
The larva lhost plant ,S, flaves ehnass not been affected of grasslan dburning because the
host plant is perennial . Burning promote germinatio nof some plants ,not includin gS.
flaves e(nMsura taat at., 1998). The number of eggs, larva eand attendant ants decreased
and the population osf some kjnds of natural eneinies increase dwhen burning of grassland
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Table 4. Number of larvae of Shijintiaeoid edsivinus asonis on 10 shoots of
Sophoraflai,escens.

Study
Date of survey A B sites C
200625 May o1.14fi oO.48b oO.66b
6June13 1.31 O,68 O.98
± ± ±
June20 2.14u 1.48 1.34b 1,15 1.54b 1.54
± ± ±
June27 3,76a 5.37 O.28c O,54 1.80b 2.69
± ± ±
June 1,4 [± O.55 o: Oa
200722 May27 OE O.06s O.09 Oa
±
May Oa O.04, ±･ O.09 OnO.02zb
1 June ObO,36a O.08, ±, O.04 ± O.04
7 June12 ± O,41 o.o6a± O,09 O,36a ± O.41
June21 O,48s O.41 O.06J O.09 O,48a O.41
± ± ±
June27 1,10u± O.79 0h 1.10 :±- O.79
June O.20-± O.16 O. o.20a ± O.16
Different lettcr sin the samc linc she", significant difflrre na(t 5% levels by
Turkey-Kramer'stcst.
stopped (Murat &a Nohara, 2003) ,Therefbre g,rasslan dburning may be an importan tfac-
tor in the conservation of this butterf iyM,any rare butterfl ireeqsuire vegetation manage-
ment (grazi mnowgin,g et¢.) for population tso be maintained eifectively (New, 1997).
However, New et al. (1995 r)eported that rare butterfl imeays also exhibit narrow tolerances
for management types for their habitat smo,re so than the flor athey depend on. How does
the grazing intensi tafyfect the population of the butterfly ?The butterf ihyabitat wsere main-
ly cevered with natural herbaceou splants.
The dominant species were Z. J'aponica at site C (hig hgrazing intensit yM),, sinensis at site
B (non-grazi nangd) P, chino var, viridis and S. flaves eatn ssite A (norm aglrazing intensi-
ty) ,respective]y.
Kira (1952 )reported the effect of grazin gintensi tony vegetation in the Aso area, ln his re-
port ,M, sinensis was the dominant species under grazin gintensit yof O.5 animal unitiha, P.
chino var. viridis was dominant under grazin gintensi tofy O,6- 1,O animal unitiha, Z. japon-
ica deminant intensity 1.5
was under grazing over animal unitiha.
In our survey, the degree of cover of P. chino var. viridis and S. .flavesen sat site A (under
1.1 animal unit!ha) was also higher than for other species, At site B (O animal unitiha), the
cover degree of M. sinensis was also highest ,and at site C (1. 4animal unitiha), the cover
degree of Z, japoni cwaas highes t,These results are similar to those of Kira (1952 )H.e did
2009osB.
-G---HG
iso6-.E

ioe.FozO'
50
'Tr''I1JD..iiPNDihx'bss
D.
,DJ - " '-1-- L
o
Apr. May Jun.
Fig. 6. Seasona lchanges in adult numbers at site C in 2007. G: Grazing; NG: Non-grazing,
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258 Kouhei MuRATA, Chinobu OKAMoTo, Asana MATsuuRA and Makio IwATA
not mention S. flaves ehonwesv:er, our results suggest that there is some optimal grazin gin-
tensit yfor S. Ilavese nsT.he populati oofn this butterf iways highes tat site A (1,1animal
unit/ha) where the degree of cover of the host plant was the highes tbetween the three sites,
These results suggest that maintenance of the optimal grazin gintensi tiys importan tfor con-
servation of this butterily,
Efft}c tof grazing intensity on nectar plants
There are thirtee nspecies of nectar plant sfor this butterf iiyn the Aso area (Mura t&a
Nohara, 2001) .It is importan tte conserve these nectar plant sfOr this butterf lyH.owever,
the effect of grazing intensi tony the quantit yof nectar plant swas not clear. In this survey,
the populatio nof C. 1'aponict twams higher where the degree of cover of the host plant was
lower. The degree of cover of V, mandshurica was high at site B where grazing did not
occur. These results suggest that grazin gintensi tmyay be the importan tfacto rfor the
growth of nectar and host plants
Infiuenc eof grazing intensit oyn the number of adults and eggs
There was no significant differen cien the number of eggs between sjte G and site NG in
2006. In 2007, the adu]t number at site NG was three times greater than at site G (Fig 6,),
The egg number at site NG was also greater than at sjte G (Fig 5,). These results may be
explained by the densit yof S. nemorensis, whose density at site NG was much greate trhan
at site G in 2007. These results suggest that higher grazin gmight suppress the growth of
some kinds of nectar plants.
Effect of grazing intensit oyn the growth of host plant
Distributio nof S, flaves weasn snot uniform in the Aso area (Mura tanad Nohara, 1993) .In
our results, the popu]atio nof S. flaves ewanss higher at sites A and C than site B, There
were significant difference sin the population of S.,flavese ants each survey site, Crown size
of host p]ant swas large rat site A than sites B and C, and the branch number of host plants
was also large rat site A (norm aglrazin gintensit tyh)an at other sites. A bigger crown size
of the host plant may increas ethe availability of buds for Iarvae ,It is suggested that the
host plants were able to grow 1arge rin an open situation proyidin gsuracient sunlight as a
result of burning and optimal grazing intensit yI,n contrast, the heigh tof the host plan twas
low under high grazing intensi t(ysi tCe) because cows directl ydestro ythe host plant.
Furthermore ,at site B (non-grazi ntghe) ,height of the host plant swas talle rand the crown
size smaller because of the high populatio dnensity of tall grasses,
In conclusion, it may be importan tto keep grazin gintensi taryound 190 daysfanimal unit･ha
fOr conservation of butterf lhyabita tthrough the maintenance of grasslan icnl the Aso area.
Acknowledgments
We sincerely thank Dr Keigo Nohara for his critical review of the manuscript and helpfu]
discussion ,We also thank the staff ofAso City for allowing us to survey pasturage.
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　　the　butterf，l∫y’liimiaeoides　divinus　ason ．is（Matsumura ）．　Jap．．ノ．　Ent．（NS ）12 レ33（in　Japanes）e，
New ，　T．　R．1997．　Buttec）t’lConserレation （2皿d　Edn）．248pp．　Oxford　Universit　yPress，　New 　York
New ．　T．　R．，　Pyle，　R．　M ．，　Thomas ，　J．　A，，　Thomas ．　C ，　D，　and 　P．　C，　HammQnd ，1995、　 Butter且y　conservation
　Nis　himnaak】コaag，　cYmon．　tand ．　　MA．．　1I〜sevhi．　，iE2n0t0．64．0　：E5ff7’e−c8ts3　．of　experimental 　mowing 　on 　species 　diversit　yand 　assemblage 　struc −
　　ture　of　butterfli　eisn　coppice 　on　M しMikusa，　northern 　Osaka，　eentra1 　Japan．　Trans．　lepi‘1．　Soc．　J‘lpctn，57：
　 　 202−216．
S　w　enBgieoll，　、　AC，　‘丿Bns，e，lw19、9873．　；7E7f−f8e9c．t　osf　management 　on　butterf　labyundance 　in　tal　lgrass　prairi　eand　pine　barren．s
摘 要
・ ・ ・
オオル リシジ ミの発生 に及ぼす放牧圧の影響（村田浩平 岡本智伸 松浦朝奈 岩田眞木郎）
’
阿蘇地域に生息するオオルリシジミShiJimiaeoid　edsivint　tassonis の個体数は，その生息環境の変化に
より幾つ かの生息地では減少傾向にある．本研究では，本種の発生や食草，蜜源植物相に及ぼす放牧
圧の影響を明らかにするため，生息地の植生を明らかにすると共に，食草や蜜源植物の密度と本種の発
生および密度につ い て慣行的な放牧圧である草原と，高い放牧圧の草原，休牧中の草原につ い て調査を
行っ た．生息地は，毎春，野焼 きが実施されて きた阿蘇地域の半自然草地である．本調査を実施し，得
られた結果は次の 通りである．
（t）本種の 生息地の植生 と放牧の 関係を調査 したところ，阿蘇地域の慣行的な放牧圧である調査地で
は，ネザサPteiobtas“ts　chino 　var ．　viridis が最優占種であっ たが，放牧圧が高い 調査地では．シバ Zoysia
jap・nica が最優占種であっ た．また，休牧rPの 調査地で は，ス ス キMi，s’cantht ｛s　sinensis が最優 占種 とな
り，放牧圧 は，生息地 の植生 に影響を及ぼ してい る こ とが示 された．（2）食草であるクララ sθphora
flavesceのn被s覆度（E−SDR 、）は、高い放牧圧1×：に比べ て阿蘇地域の慣行的な放牧圧で高かっ た．〔3）ク
ララの草丈は，休牧中の調査地において高い傾向が見られた，（4）クララの分枝数は，慣行的な放牧圧で
ある調査地におい て多かっ た，（5）クララの クラウ ン面積は，慣行的な放牧圧である調査地におい て大
きかっ た．一方，高い放牧圧で は，クラ ラの クラ ウン血積 と草丈は小 さくなる傾向が見られた．（6）本
種の成虫は．5 月上旬に出現し，6月中旬に見 られなくなっ た．2007年の本種成虫の個体数は，4月か ら5
月にかけての低温の影響を受け，2006年に比べ て全ての調査地で低 く推移した．（7）幼虫密度が高い
とき，幼虫数は，調査地ご とに違い が認め られ，幼虫の密度に放牧圧が影響を及ぼ してい る可能性が
示唆された．（8）こ れまで野焼 き，放牧を継続的に実施して きた草地で 休牧すると，蜜源植物が増加
し，本種の成虫数 卵数を増加 させるこ とが示唆された，これらの結果から、阿蘇地域におい て本種を保
護するため に最適な放牧圧は，同地域における慣行的な放牧圧であるこ とがわかっ た．
（Accepted　Novernber　17，2007）
Publishe　bdy　the　Lepidopterologi　Scoacliet　yof　Japan，
5−20，Motoyokoyama2，Hachiqli，Tokyo，192−0063Japan

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