Of Euercusglauca

The LepidopterologicalSocietyLepidopterological Society of Japan

ectigk Trans. tepid. Soc. Japan 61 (1): 68-78, May 2010

The relationship between the characteristics of euercus glauca Thunb. Ieaves and the number of feeding larvae

Shintaro FuNAKosm

Namazu Naigu-cho 1-25, Mizuho, Gifu, 501-0213 Japan

Abstract In auercus gtauca which grow where the sun often $hines, the characteristics ef the leaves are different from the leaves of those which grow where the sum hardly shines. Leaves that grow in places where the sun often shines all day are firmer and contain more tannin than leaves in places where the sun hardly shines all day. A 1arge number of individuals and species of moth lar- yae were found on the shade leaves during most seasons. The number ef larvae on the sunny leaves

only increased in April, The relationship between leaf characteristics and the number of larvae present is discussed.

Key words euercus glauca, leaf characteristics, stiffness, tarmin amount, Iarva] number.

Introduction

There have been many papers detailing food habit investigations o'f moth 1arvae feeding on plants in the Fagaceae, e.g. euereus agrijiolia Ne6 (Opler, 1974), euere"s cri.vputa Blume (Ybshida, l986), e"ercus acutissima Carruthers, 2uereus variabilis Blume and euercus serrata Thunb, ex. Murray (TEIeramoto, 1996) Fkegus crenata Btume ([[bgashi, 1984) and euere"s dentata Thunb. ex Murray (Kogi, 2001).

euere"s glauca is a universally distributed tree, with its highest density in the second- growth fOrest in the Tbkai region of Japan, growing naturally even in the north and inland in the warm-temperate zone.

The characteristics of the leaves of evergreen eueicus gtauca are likely to be diiierent in growth areas with di{iering conditions. For this reason. the characteristics of et{ereus glauca leayes were investigated, arid the relationship with feeding larvae is discussed.

Materials and methods

Larvae eating euereus gtauca were collected irom 1999 to 2007 by the method of beating twigs on hilly ground in the southern part of Gifu Prefecture, central region of Japan. The investigation procedure was carried out 124 times. About 30 trees were beaten during each investigation, and numbers of all falling 1arvae and fami]ies were recorded. Most of the lar-

vae were collected and taken te the laboratory. Immature larvae of the same species were put in a plastic case (30 mm in diameter, 50 mm in depth), and mature Iarvae were put in a plastic case individually, and were reared on euerc"s glauca leaves. The number of plastic cases using for rearing was 1,116. Emerging individuals were identified and recorded according to appearance and generation. Some larvae died due to parasitism, pathogenesis, and other factors along the way. Ainong those, individuals which reached the pupal stage were identified to species by observing genitalia with a microscope. The numbers of individuals collected and of species were totalled fbr the mean value for the first and second halves of each month.

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69 Characteristics ef euercus glauca ]eaves and the number of feeding larvae zoocesl- g5 seE-eG. i4Et3e:t21

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ee 3o Apr Mey Jun Jul Aug Sep± Oct Nov Dec Jan Feb Mar o

1 Jan Feb Mer Apr May Jun Jul Aug Sept Oct Nov Vec U.,D.e'gsgO.7fqSe,6gO.5

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Apr May Jun Jul Aug Sept Oet Nev Dec Jan Fch NSar

Fig. 1. Annual changes in number of individual larvae. Fig. 2. Annual changes in number of

spccies of 1arvae. Fig. 3. Annual changes in the stiffhess ef the leaf. Fig. 4. Annual changes Ln the

amount ofmoisture. Fig, 5. Annual changes in the amount of tannin.

The trees of euere"s gla"ca were divided into three categories according to how much sunlight they received as fbllows (1) sun trees on which the sun often shines all day growing on the outside and the south side of woods, (2) middle trees on which the sun shines fOr several hours each day growing at the edge of or along tracks in the weods and (3) shade trees on `sun which the sun hardly shines at all growing within woods. The expression leayes' refers to leaves of sun trees and similarly with the other categories, mutatis mutandis. The char-

acteristics of 30 leaves collected in each category every month were alse examined. The

stitthess, amount of moisture, and amount of tannin in each leaf was measured. A needle was dropped on the leaf and the sti'eFriess of the leaf was shown as potential energy by cal- culation of the penetrating depth and needle weight. [['wo-gram sections of leaf were ground down and the chlorephyll removed with dichloromethane, After it had been extracted by methanol, it was filtered, The extracted material underwent a chemical reaction using

concentrated hyclrochloric acid and a butanol mixture liquid and changed into a red solu- tion. The amount of tannin was shown by the difference of the red level measured with penetrating light. The moisture content of the leaf was measured by subtracting the dry weight

frem the constant amount of the live weight.

Physical and chemical characteristics of these teaves were measured as part of the science education tujtion of hlgh school students during science club activities,

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Tablel The history of life interpretable with the breeding rcsuk

Number pf' Genus species individuals CaioptiiiaTovolnya]querci oIoiiOiIOAIA:oiiOiIA:oi oioi-I ie Ceraceranthecosma oi ie I" " OieiAe "rchips .fitscocupreanu,y ieAei"oi Archips nigri(/auelanus PtychoXoma techeana HbmonopsisiJlotana oooio Eudemisbrevisetosa oielie

Jb)striahesotus spathanum Ae OAeiie Olethreutesnioderains ieoioiA- (Jet)vhamanoi oieloie

PaFapamrr;ene sp. i-i-i- Zeiraphera,fiiivomixtana ooi

Strophedi'a sp,

Gen. et sp.,

Acanthop,syche niRrat)ia.oa ooi o toie "d2ihasenaaurea lieo"Ioie

tyonetia sp.

}'pselopha parentheseUzas' ie."`oiLeiAe:oie 7hecobathraanas DepFessarjairrqgularis Acria ceramMs loie i- Sop,thropiodesleucpsrola oiooi'

StyCyropiodes lividuta oie i Rhizo,s'thene,s.firlc(forittis Lecithvlaxa thiodora Iie Brachmia.iaponiceita oii oi-Iie" Fbristenia ussurieila ScopeiocMescentraeta Rhodoneura hyphaema iooiooieo o:oi:oie loie oLe Ae Tbeicbepanact'ocea

bfiTerocilix vayrticata oiOA oielo Al,fophila,Ioponenris A:o eL i"oi Maxates protrusa Jbdi,r putata Jbdis urosticta lo oi-oi fibmithea aestivat'ia loi -e Hkmithea tritonaria o oi :i- " ie S(/epuia epiorrhoe oi A i Evirrita viridipumpurescens :Oi i i IA Eupitkecia ciavtfera O Ii iA C:htorociyiis exeisti O IO Ae Lomographa bimacutata 22l62647221 oi lie iieIo Peratostqga deietaria ieooioioo.oiooeoo

Cteora leueephae" oi oi Protoboarmia.faust'inata OLoooiooiooo.o :oieie ie :ie lo Alcis angttldeFa :o"" " Rseucierannisamplipennis lo o o :o oi Ioi I6womecis iundera oi oielo oi o loelo oiOL

Lbvomecis li " lo oo punctinaiis Paradori,sa chloaugeE loi oieoielo"o

i i Efannis htroldu :o oi oi li Phigatiaverecuncinptia :O Oi Oi :A A A PVitemania nitobei

Descoreba simplex oiooio

Planociampa antipala

iLfenophra seniiis Afegabiston plttmo.yai'ia IO:Ok .Biston eobust'us

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71 Characteri stics of euercus glauca 1eaves and the number of feeding larvae

ept: ct: ov: ec:an:e : ar ･l : :./ 'i : :/i'l- i i ; ; i 1 1 1 L l l l d l 1 1 1 l l l IO OO IO OO IO OO l l l [ l t l l l l b F l r ] 1 1 E l l l " l t 1 " 1 1 1 1 1 1 1 1 1 1 I N I I I I 1 1 1 T d l i l l l l l - 1 1 1 1 1 1 [ 1 1 1 1 1 1 1 1 Y l I S I I I I - 1 1 1 1 1 l l l l l loo 1 1 1 1 1 1 1 1 1 ] 1 1 1 1 1 1 L l 1 1 1 1 t l ooi li ie l l l I l t l l l l ] r l ] d l l 1 1 1 1 1 1 [ l t d l l I l d l l l 1 1 t t l l 1 1 I I I I l l l i l L ] I S I I I 1 1 1 P l l 1 1 ] 1 1 t l d l P l l 1 1 1 P l l i- ooo lo l l : l l l l : l l olo oo I I I I - L I I I I " i 1 1 1 1 1 i L l l l l l 1 1 1 1 1 J i - 1 1 N l 1 1 1 1 1 i l h l l - 1 l l l l l l ] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 t l l l l l t l l l l l 1 1 1 1 1 1 t l [ 1 1 1 1 1 [ 1 } 1 1 1 1 1 1 d N l b l i l 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 t l l l l l l l l 1 1 1 1 1 d - 1 1 1 d l 1 1 1 1 1 L - I l l a l 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 l i l l l b ol l l l : l 1 1 1 ] t l oi oieoi loieoie A:i i i:L i ilL i i:i i ili i i 1 1 1 1 1 1 l b l l l l 1 1 1 1 1 1 t b l l l l O IOi Oi- l O tOA O O IO O O :O Oi Oi lOi OiL O" l t S l i l l o Io oo lo oo lo oo :o oo lo oo iii li ii Ii Ail OO IO OO :O OO IO OO I S I L I I 1 1 " 1 1 1 l l l l i l 1 1 1 L l l OieOitOielOieOieOi lOi i i li i i :i L i li i i :i i i I E I I I I 1 [ 1 1 1 1 l b ny ny 1 1 1 1 1 1 - 1 lo oo lo oo lo oo lo oo lo l 1 1 b " 1 1 1 1 1 1 1 1 ] 1 1 1 1 1 iiA IA ii li ii lie ie l l l L l l l l l iii Ii ii li ii li AA li -i li ii li i ie 1 1 [ l l l 1 1 I b - L 1 1 1 1 d [ 1 1 1 1 1 1 1 1 1 t l l 1 1 ] 1 1 1 1 1 1 1 1 1 l o lo oo :o oo :o oo lo oo :o o oi 1 1 1 1 1 I b b l l l i 1 1 1 1 1 1 "ie l l l : olo oo :o oo 1 ] 1 1 1 1 [ l IOO IO OO IO OO IO OO [ l r l l l 1 1 [ l t l a l l l l l oi oieie l" i l oo io oo :o oo io oo 1 1 1 " b l iii ii ii ii ii ii iiMiA ik Ai-ii 1 1 [ 1 - b l I I loo :o oo lo oo l t b b l l iii li ii lie ie l : : l 1 : 1 1 1 1 i IL A li ii IA ii li ii :i ii li ii :i ii 1 1 1 1 1 - l t l l l l 1 : " 1 1 1 1 1 1 1 1 1 l l l t l l 1 1 1 1 1 1 [ ] L I L b : I I ] f l E l t l : ] ooi iel l l l l ] 1 1 1 1 1 1 iii li ii li ie iel I : l loo [o ool I ! I

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Table 1 (continued)

Acrodontis kvtshubofi oAeieoo OuraptetJor nivea [oi:oilolooiioo

Ouraptenyyuc obtusica"tla Antheraea .yaniamai ithodinia .fauax fidiivamba sperchivs 17lenteniaoqypete Somena putverea oio"oo Euproetis piperita lo o dallitearzrtaiwana oiOie Iiema nachiensis oioie Oie Lymantria dispar "oie li-lo Lyniantria mathura ie oi lynuantria minomonts i- ie Eiiema.ioponica,icrpenica Lithosia qudea Conitepianigricosta eio Niidoria ranntna 61216ooieoi- oie o"lo" o Lemyra ,flammeeta :oi:L-loiloiIo Lemyrainaequalis ooo Leptyraimparilis Olopollabella Clavipatpsura auTariae Orthosiaparomeea Orthosia.fausta Orthosiagimbata loi Orthosiaodiosa Orthosiagothica,iesoensts

Orthesia carnipennis oOA "lena changi blena .formosa Lithophanevenusta Rhynehqgtaea ,;Stseipennis Conisua arttescens Contstra naveae TleloFtaedentata Amphiewamonelitha Amphinyra tripartita

Atnphinyra erebina o"ieo

CbsnTia camptostigma ?Lbicteala eostalis ClethropAora dXstineta oo-oai"oo loiloie lieIo ii Sigtephora ,farreiiutea ,O Oi i- Oruza mlra oi " IVleustretia albicincta lo oIO" OLi- loie oie oiel Catocata hyperconnexa ie t-e Catocala patala Ilavas.iunaGoniecraspid"m

pi),em loi oiloi ie :ieie Slpnetdes picla oiiO :iek"oie:"ie Slv)noides famosa oIoi opnoides hercutes oi:oieieIo- Olulis ayumiae

ramba reseopuspurea ilie 1lrmbacorealis ooioiloi ieli- Sarcopteron .fasciata oioi oiel"oie:ie O O": Lophomilia takao oie oie oi o loie oie oA-: hadennia incongntenv ooo loi i " lltidennia nakzvlanii o o oi :o" o-e oi SimpUcianiphena ooo :Oi i ke Zbnciaffuatha hetva Hlerminia grisealis Hlerminia tar icrinalis

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73 Characteristics of euerctts glauca leaves and the number ｛of feeding 1arvae

聰「、 − 卩【 − − ■ー「− 1111111 ° … 画 − − ー圏 − 卩 − − III − ー − … − − ■ 「闇嚶ー − − ー卩「− − oQ − 圏 − I 圏 − 圏 I ゜ 1 圃 l I − ▲ ▲ ▲ 圏▲ ▲ ▲ 圏 − I ° − … 卩 − I − − ■ − I 圏 0 ▲ ▲ ● ▲ −▲ ● 1 − I − 闇闇 − 1 − − III 隔 − … 0 0 0 −0 0 010 0 0 10 0 0 − ■ − 1 ー O O O ーO O O O O 0 ■ 0 0 0 °Q O O IO O ▲ ▲ ● − … ．闇 −圏ー − ■1 − −ー − ll − − −層 … ． ° 匸− 【馳 … − 鬨 II − 鬨 − − − −圏 … ． ■ −圏圏− − 1 − − − ■ − − − II − − − O O O Q O − − −圏彜圏 − −° ▲ ● ° ． − i − − − − IO − o o −o ▲ ▲ ● o …o ○ O QoO −Q0 ：Ooo ▲ ；▲ ○ o − … − − l 闇 − − … ー − − … − OOOOIOOOOOO− 9 ーー 1 − − … 00 111 ー 1 1 … 卩溷 △ ▲ ▲ 、▲ △ ▲ △ ▲ ▲ ▲ ▲ 圏−▲ A ▲ 1△ ▲ ▲ 闇−▲ ▲ ▲ − ト − − − − − − … −… − − − − − − − 圏 − ° − … −圏 −卩 − −層巳」− −・ ▲ ▲ ▲ −▲ ▲ ▲ ▲ ▲ ▲ …▲ ▲ ▲ −▲ ▲ ▲ 1▲ ▲ ● ・ − … − − ・ー − − … − − − − − − 1 … − −・ −… −ー −・ − − − − − … − − − I ° ー − 鬨− ・ー − − − − ー … − − − ー − − − l − ー − −」 … … − −嘱 △ △ △ − △ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ■ − − ー … − ー・− … − − − … − − −ー … − −ー … … − −ー − − −ー llll … 圏− − −・・ … −ー −・ ▲ ● o ▲ ● o ▲ ● ▲ ● … − − − ・ − − ・− − ーー − ー ▲ ● − … − ▲ 闇 o 0000000… − IOOOOOO − −ー − − − − − − … … ー − OQO 蔔 ▲ O ▲ ○ ▲ ▲ ▲ ▲ ▲ ▲ −▲ ▲ ▲ 1▲ ▲ ▲ −▲ ▲ ▲ − ー … l 圏瀏− … ・− − ． … − ー − 「 − − oo − … − − − … − ー − − − − … − −闇 − O Q b − − − −… − ．− − − ー − − − ー − … − −闇 −闇．− − − − ▲ o O ．O ▲ ▲ ● ▲ ● … … 闇− − −l − − − O 匸− − − −巳 −． … … − −圏 O ▲ O ▲ ● O ．O Q O O O °O O O −o o o lO Oll o ．o − − − − O ▲ ● O ▲ 0 ▲ −0 ▲ O ▲ 0 ▲ …O ▲ 0 ▲ 0 ▲ −O ▲ ● O ▲ 0 ▲ −O ▲ 0 ▲ O ▲ ▲ ▲ ▲ −▲ ▲ ● ▲ ● − − − − ooo Ooo − − 鬨、 − 旨 ▲ ● O O −Q O O ▲ …O ▲ ■ O O …o o o −O Q O 卩o o o ーoo − − 圏 − − ーー − − lo o ーo I … … ー … − −° − −鹽 −ー 0 ▲ ▲ ▲ ▲ ▲ −▲ ▲ ▲ −闇▲ ▲ ▲ 1▲ ▲ ▲ ーl▲ ▲ ▲ −OQO …．OOO ．°OOO ．圏Q l ．コ

O ： larva，△ ： prepupa，▲ ： pupa ，● ：imago

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74 Shintaro Fu･NAKosm

eei .! se g 4ee sog

2otsJ

leo

Fig. 6. Number of larvae each munth totalled frem Tab]e l .

Resuks

Annual changes to the number of individuals and species of larvae

Annual changes of the number of individuals and species of larvae collected in the field are shown in Figs 1 and 2, [Ihe larvae were highest in both individual and species numbers in Apri1. It was not unusual for 100 or more larvae to fall from any of the 30 euercus glauca shrubs, There were large ]arval numbers on both sun trees and middle trees. However, numbers of iarvae on sun trees decreased rapidly and few individuals fe11 from summer to autumn. However, some larvae did fa11 throughout the year on the shade trees, so that it was always possible to obtain sorne individuals, The number of 1arval individuals was highest on shade leaves all year round.

Annual changes to the stiffhess of the leaf

Changes in stiifriess of are shown new the leaves in Fig. 3. The leafof e"ere"s.olauca de- velops frQm the end of March to early May in Tokai district and the whole tree is covered with branches that develop a soft leaf. Afterwards, the new leaf hardens from the end of May to the middle ofJune. The sun leaves stitfened rapidly and were stitfer than the rniddle and shade 1eaves througheut most of the yean

Aanual changes to the amount of moisture

Changes in the amount of moisture in current-year leaves are shown in Fig. 4. The amount of moisture in shade leave's was higher than that in other leaves, although the amount of moisture in ali leayes decreased as the seasons advanced.

Annual change te the amount of tannin

Changes in the tannin content of current-year leaves are shown in Fig. 5. The tannin content of sun leaves increased remarkably until June, after which it decreased. There tended to be no great fiuctuations in the tannin content of middle and shade leaves throughout the year, although it increased slightly from May to June.

Appearance and generation of larvae feeding on euercus glauca

121 species could be identified from the emerging imago or observation of genitalia with a microscope. [lable 1 shows the timing oflife history stages where subsequent rearing made identification possible.

The number of 1arvae each month was totalled from this table and the change of larval

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Characteristics of e"erczas gtauca leaves and the number of feeding larvae 75

species number is shown in Fig. 6. Numbers of Iarvae attached to euercu,y gtauca increased in April and May and decreased in June.

Relationship between leaf stith)ess and number of Iarval individual and speeies

The relationship between the stiifiiess o'f the current-year leaf and the number of larval indi-

viduals and species is shown in Fig. 7 and Fig. 8. Both the number oflarval individuals and

specjes decreases as the leaf stifTiness increases and there is a stutistical correlation between leaf stiffness and the number ef larval individuals and species (regression analysis. p

Relationship betweell amount of moisture in leaves and number of ]arval individuals and species

The relationship between the amount of moisture in current-year leaves and the number of

larva] individuals and species is shown in Fig. 9 and Fig. 10. Both the number of larval in-

dividuals and species increases as the amount of moisture increases and there is a statistical correlation between the amount of moisture and the number of larval indivicluals and species (regression analysis. p

Relationship betweelt amount of tannin in leaves and number of larval individuals and .specles

The relationship between the arnount of tannin in current-year leaves and the number of lar-

val individuals and species is shown in Fig. 11 and Fig, 12. The number of]arval individu-

als and species decreases as the amount of tannin increases. There is a statistical correlation between the amount of tannin and the number of iarval individuals (regression analysis. pO,05).

Discussion

The characteristics of leaves of 2uere"s gtauca which grow where the sun often shines und where it hard]y shines are different. The number of jndividuals and the number of species oflarvae that eat these leaves are a]so dilferent.

In a previous study it was fOund that herbivore densities were not significantly different between the upper tree canopy and the understory for 2 species of Quercus, but herbivore species richness was significantly greater in the understory than in the canopy for both tree `sun species (Corfr & Marquis, l999). The canopy corresponds to the leaves' in my study `shade in that the sun often shines there and the understory corresponds to my leaves' where the sunlight hardly reaches at al1.

An investigation of rolls made by pyralid and ctenuchid moths on a Panamanian shrub found that leaves which einerged within the shaded bud remained sefter and with ]ower tannin levels than usual, without any decline in nitrogen or water content (Sagers, 1992), Though the pyralid larva was hardly seen in this study, the shade leaf remained softer than the sun leaC and the shade lea'f gained a higher moisture and tannin centent. Oak tannin is important in the protection of foliage from caterpillar damage (Feeny, 1968). Synthesized tannin inhibits the growth of cutworm 1arvae and that inhibitory effk}ct is proportional to the amount of tannin ingested (Nomura & Itioka, 2002),

Leaves of euereus glauca which grew where the sun often shines all day were firmer ttnd contained mere tannin than leaves growing where the sun hardly shines al] day.

A large number of individuals and species of 1aryae were found on shade leuves of e"ereus

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76 Shmtaro FuNAKosHI

toee.'. pt ss

ce E ･ x' eei' t t s gge,f oug.. t nefi "rV' n' " . IS{ ' rlo pme ..., :",s:'SjY"""`" ' :

e t 2 3 4 5 e 1 2 3 4 S LeafstiffnessVlgCroJ LeafstntnessflleeO"

e tco-sv M 4t)"8;vi.

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tooeg 3sVg . n 30e soE. asgng 6egg

40= 15S to 20o 5

O 1 2 3 4 5 S O t 2 3 4 5 6 Amount ef ta"nin Vl eee lux Ameuntef tannin ljtOOO Iux

Fig 7 Relationghip between leafstiffhegs andnumber of1arval mdividuals Fig 8 Rela"ontihip

betwcen leaf stiI]hcss and number of larvai spec]es Fig 9 Re]ationship between dmount of mos-

ture in leaves and number of larval mdrviduals Fig 10 Relationbhip between amount of meibture

in Ieaves and number of larval specieg Rg 1 1 Rela"onship between amount ot tannm in Ieavets

and number of Larval lndividua[s Fig 12 Relazionghip between amount ot tannin m Ieaveg and

number of 1arval tspecies

gla"ca dunng motst tseasons Sun leaves only gaw an mcrease in larvae in April I conclude

that the stiiinegs and crmount ot tannrn contained in the leaf has a relattonship to the number ef larval mdividualg aiid gpecies for evergreens 1ike euercus gtauca

Herbivory losses are more posMvely correldted with toughness thcm with phenolics (Lowman & Box, 1983) The relationship between stiiftiess and the number of mdividuals ot feedrng 1arvae was calculated, followed by the relatronship between the amount of tdnnin

and the number of mdividual feeding larvae, and there was a clear correlation, the result being that st]ffriegs was more important although damage by teedmg larvae wag prevented tQ obtam thig research

I conclude that fbr larvae feedmg on e"ereus glauca, changes in numbers weie more due to ststhess than to tannm content

References

Corff, J L and R J Marquis, 1999 Differences between undergtorey dnd canopy in herbivere commumty composi"on and leaf quahty for two oak species m Missoun Ecol Ent 24 46-S8

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77 Characteristics of （euercus glauca leaves and the number 【〕f feeding larvae

Feeny， P．，1968． Effect of oak leaf tannin on larval growth of the winter lnoth Operoplttera brumata ．ノ． lnsect − Phvsiol．14 ： 805 817． ’ K H ．200し Moth feeding on 麗 s dentate Thunb as larvae in Hokkajdo Heter ｝ gi，， Cuerc ，．Japan ‘ c 召r謡 5 」． − 212 ： 232 234 ．（1n Japanese） Lowmun ， M 、 D ． and J． D ． Box ，1983． Variation血 leaf toughness and phenohc content on8 nve species of Australian rain forest trees． Aust ．」． Ecot．8： 17−25． − Nomura ， M ． and T ． Itioka，2002． Effects of synthesized tam 血 on the growth and surviva ユof a gencralist hcr bivorous insect，血 e coInmon cutworm ，5｝，o 加 6r α 伽 r α Fablicius（Lepidoptera： Noc 加 idae）． Appl ． E 彫． − Zool．37：285 289， − Op ［er， P ． A ．，1973． Biology ， ecology ， and host specificity of microlepidoptera agsociated with （］uerc ” ，v clgri − 、folia（Fagaceae ）． University of Catifornia Pub 旋 ations in Entomotogy 75： 1 83． Sagers， C ． L．，1992． Manipulation of hc〕st p］ant q 岨 lity： herbivores keep leaves in the dark， Ft‘nct ． Ecot ．6 ： 741 −743 ． Teramoしo ， N ．，1996 ． Studies on Lepidopterous insect fauna on Fagaceous plants， as the food plants of the wild silk mo ［ Anther α e α ． Spec． BuU ， Shiea a8ric ，， Srn．216pp ．ln Japanese ． h，．vamamai ．（） ’ − Togasi， 1．，1984． Moths feeding on larva ofb θech ， Fagu ．s crenata Blume ．．ノapan Heterocerists 」． L29； 59 62．（In Japanese） Yoshida K 1986 ，，．， Seasonalpopulation trends of macrolepidoptereus larvaeon oak tree in Hokkaido， − Nothem Japan， Jap．」． E 砿 53： 125 133．

摘要

アラカシ葉の性質と蛾類幼虫の個休数（船越進太郎）

1999 年より 2 07 年にかけて．岐阜県南部の丘陵地において叩き網法により，アラカシにつく鱗翅目幼虫を採集した．延べ調査回数は 124 回に及んだ．1 回の調査で約 30 本の樹を叩き，落下した全ての幼虫の個体数と種を記録した．ほとんどの幼虫を持ち帰り，若齢のうちは同種の数匹ずつを誠熟幼虫は 1 ー匹ずつをプラスチックケスに入れてアラカシ葉を与えて飼育した．羽化まで至った個体は，種を確認ぬするとともに，発生消長を記録した．途中で寄生や病気の発生その他の要因で死個体が多かったが，一蛹にまで至った個体の部は，交尾器を取り出して検鏡し種を確認した．幼虫の落下個体数と種数に関しては，各月の前半と後半ごとに平均値を求めて集計した．ー一アラカシの樹木を陽の当たり具合から 3 つのカテゴリに分けた．すなわち，（1）太陽光の口中当た・一のの 2 ののたいの 3 とどる林外や南側樹木，（）口内，数時間光が当る遊歩道沿や林縁樹木，（）光がほん当たらない林内の樹木である．

それぞれの場所より毎月 30 枚ずつの葉を収集し葉の性質を調べた．調査内容は，葉の硬さ，水分量，タ

ニエーンン量である．針を葉の上に落下させて貫通する高さと針の重量から位置ネルギを算出した。ー葉の硬さは，位置エネルギで示した．また、2g の葉をすりつぶし，ジクロロメタンでクロロフィルを・ーンニン抽出除去し，濃塩酸ブタノル混合液で発色させた．タ量は，赤く発色した溶液の透過光量で一・示した．そして，乾燥重量は，定量の生葉から乾燥葉の重量を引いて求めた，これらの葉の物理化学一的な性質の測定は，高等学校科学部の生徒に対する理科教育指導の環として行った．

成虫を羽化，もしくは交尾器の検鏡などで種が確認できたのは 121 種に及んだ．幼虫は種数・個体数と

4 で 30 のカシ正00 こっ．こも月最も多く，本あたりアラ灌木より頭以上が落ちるとも珍しくなかたまた．・の季節は，陽樹中間樹の落下数が多く陰樹に勝っていた．しかし，その後，5 月に入って個体数は，急

速に減少し，夏季から秋季にかけては，ほとんど落ちないこともあった．それに対し，陰樹は年間を通し

て幼虫が落下し，ある程度の個体数が常に得られて全く採集できなくなることはなかった．1 年間の総

数は，陰樹の個体数が遙かに勝っていた．

このいカの 3 の 5Jj のい地方におてアラシ葉は，月下旬．より上中句までは新葉が展開し，柔らか葉を付けた枝が樹木の表面を覆う、その後，5 月中・卜旬より6 月中旬までは新葉が硬くなり，6 月下旬以降は，当年葉がさらに硬化して旧葉との区別ができなくなる．1場樹葉は，硬化も急速に起こり年間を通して硬

っい．つつさに勝てた当年葉の全ての葉で，月［．・1が経にれて水分量は減少したが，陰樹葉の含有量は他

に勝っていた．1場樹葉で 6 月にかけて著しくタンニン量が増加したがその後，減少した．年間を通して一陰樹葉，中間樹葉は大きな変動がなく，5 月から6 月にかけてわずかに増加するものの，ほぼ定の量で

一 NII-ElectronicN 工工 Eleotronio Library Service The LepidopterologioalLepidopterological SooietySociety of Japan

78 Shintaro FUN 八 KDSHI

推移した．

幼虫の個体数および種数のいずれもが葉が硬くなるほど減少し，葉の硬さとの問に相関が見られた，また，幼虫個体数および種数のいずれもが葉の水分量が多くなるほど増加し．葉の水分量との間に相関が見られた．さらに，タンニン量が増えるほど幼虫個体数は減少し，相関が認められたが，幼虫種数とタンニン量の間には相関が見られず，タンニンに強く適応した種がいることが示唆された．陽樹葉のタンニン量は 6 月まで急速に増加するがその後減少した．減少する頃から陽樹では堅果が成長し始める．この減少は堅果の発達と関わりが深いと考えられた．しかし，減少しても陰樹や巾問樹よりは，陽樹葉のタンニン含有量は多く．摂食幼虫からの食害を阻害する効果が保たれていた．

陽樹葉のタンニンの多い硬い葉は，幼虫の食害を受けにくいが，タンニン量よりも硬さの方が個体数を減少させる効果があるように思われた．

（Received Augu 呂t 30，2 08 Accepted F6brua τy 26 ，2010 ）

Published by the Lepidopterological Society of Japan ， − − 5 20，Motoyokoy a 2， Hachioji， Tokyo ，192 0063 Japan

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