First survey of ground-dwelling ants (Hymenoptera: Formicidae) on the uninhabited Gaja-jima Island, the Ryukyu archipelago, Japan

2019·0.16 MB·

by  Motoki Katayama

©EntomologicaFennica.18December2013
First survey of ground-dwelling ants (Hymenoptera:
Formicidae) on the uninhabited Gaja-jima Island,
the Ryukyu archipelago, Japan
MotokiKatayama,TadatsuguHosoya&WataruToki
Katayama,M.,Hosoya,T.&Toki,W.2013:Firstsurveyofground-dwellingants
(Hymenoptera:Formicidae)ontheuninhabitedGaja-jimaIsland,theRyukyuar-
chipelago,Japan.—Entomol.Fennica24:216–222.
Theground-dwellingantfaunaontheuninhabitedGaja-jimaIsland,theTokara
Islands,theRyukyuarchipelago,Japanwasinvestigated,whichwasthefirstsur-
veyonantsoftheisland.Twenty-threeantspecieswerefoundduringavisitof
onlyeighthoursindaytime.FourofthemwerenewrecordstotheTokaraIslands.
Ofthefournewrecords,thesouthernlimitofdistributionswasrenewedforthree
species.Threeexoticspecies,Pheidolefervens,Tetramoriumbicarinatum,and
Tapinomamelanocephalumwererecognized,whichseemsrelativelylowgiven
thattenexoticspecieshavebeenaltogetherrecordedfromtheTokaraIslands.
Therelationshipbetweeninvasionbyantsandthescaleofhumanactivityisdis-
cussed.
M. Katayama, Department of Ecology and Environmental Science, Graduate
School of Agriculture, University of the Ryukyus, Nishihara, Okinawa, 903-
0213,Japan;TheUnitedGraduateSchoolofAgriculturalSciences,Kagoshima
University, 1-21-24 Kôrimoto, Kagoshima 890-0065, Japan; present address:
Graduate School of Human and Environmental Studies, Kyoto University,
Yosida-Nihonmatu, Sakyo ku, Kyoto, 6068501, Japan; E-mail: motok.k.ryuk
@gmail.com
T. Hosoya, Division of Biodiversity Sciences, Faculty of Social and Cultural
Studies,KyushuUniversity,744Motooka,Nishi-ku,Fukuoka,819–0395Japan
W. Toki, Center for Ecological Research, Kyoto University, 2-509-3 Hirano,
Otsu,Shiga520-2113,Japan
Received20February2013,accepted1July2013
1.Introduction peciallyinplaceswherediversespecieswouldbe
expectedlikeintropicalandsub-tropicalregions
Specieschecklistsarefundamentalsofmanysci- (Myersetal.2000).
entificstudiesandcontributetobiodiversitycon- The Tokara Islands consists of seven inhab-
servation(Myersetal.2000,Pfeifferetal.2011). ited and five uninhabited islands located in the
However,theyarerecentlyconsideredasminor northernpartofthesubtropicalRyukyuarchipel-
contributionstoscience,partlybecauseofthelow ago (Fig. 1). They have been repeatedly con-
impactfactortheyachieve(Krell2000).Unfortu- nectedanddisconnectedtoEurasiabytheglacial-
nately,speciesinventoryremainsinsufficientes- interglacialcycles,whichmaketheminteresting
ENTOMOL.FENNICAVol.24 (cid:127) Ground-dwellingantsonGaja-jimaIsland 217
Fig.1.MapofthelocationofGaja-jimaIslandinJapan.Left:thelocationoftheTokaraIslands.Right:theloca-
tionofGaja-jimaIslandintheTokaraIslands.
subjectstobiogeographicalstudies(e.g.Kato& ant fauna on Gaja-jima Island. Ants are easily
Yagi 2004, Nakamura et al. 2010). Ahypothe- collected, identified, and an indicator group of
sized biogeographical boundary between Pale- biodiversity(Alonso2000),butnofaunalinvesti-
arctic and Oriental regions called Watase’s line gationsofants,toourknowledge,havebeencon-
has been recognized between Akuseki-jima Is- ductedonthisisland.Asexoticantsofteninvade
landandKodakara-jimaIsland(Fig.1). newareasaccompaniedwithhumanactivities,it
Wegotachancetoinvestigatetheantfauna wouldbeworthtoexamineinfuturestudiesthe
ononeoftheseuninhabitedislands,Gaja-jimaIs- differences in ant fauna between inhabited and
land(29°32’24”N,129°19’12”E)(Fig.1),which uninhabited islands in the Tokara Islands (Hol-
is located in the Palearctic zone, north to the wayetal.2002).
Watase’sline.Theislandissmall(4.07km2)and
has492.2mheightatmaximum.Peoplehadlived
onthisislandprobablyfrom12thcenturyto1970 2.Materialandmethods
(Kozono1995).Since1970,therehavebeenno
residentsontheisland,butlandinghasbeenmade Gajia-jimaIslandisasmallvolcanicislandsur-
occasionally by people who maintain a light- roundedbyaseacliffmorethan100minheight.
house.Landingontheislandisnowrestrictedby Thefloraofthisislandreachesupto408species
ToshimaVillage. ofplants(Terada1999).Mostpartsoftheisland
Thereexistafewstudiesontheinsectfauna are covered with Pleioblastus linearis Nakai
onGaja-jimaIsland(termites:Ikehara1959,bee- 1925(Poaceae)bamboosespeciallyonthewest
tles:Matsushita1999,Toki&Hosoya2012,but- sidewhereresidentshadlived,whereasrichfo-
terflies:Fukuda2007,mosquitoes:Noda2011). restsexistontheeastside(Terada1999).Apaved
Environmentaldegradationontheislandisacon- roadrunsfromthelandingpointtoalighthouse
cernbecauseofincreasedpopulationsoftwoin- and collections of ground-dwelling ants were
troducedvertebrateherbivores,SikaDeer(Cer- mainlymadealongthisroad(inabout2mwidth
vusnipponmageshimaeKurodaandOkada)and outfromeachsideoftheroad).Theregionaround
domestic goat (Carpa hircus Linnaeus) (Terada the road was divided into three areas based on
1999). three major environments along the road: en-
This article reports on the ground-dwelling trance, former village, and lighthouse. Dry and
218 Katayamaetal. (cid:127) ENTOMOL.FENNICAVol.24
Fig.2.DetailedmapoftheresearchareasonGaja-jimaIsland.Solidlinerepresentsthepaved
roadinvestigated.“Lighthouse”,“Entrance”,and“Formervillage”,separatedbydottedlinesper-
pendiculartothesolidline,showdifferentsubsetsoftheinvestigatedarea.Thedashedline
stretchingsoutheastfromthesouthernmosttipoftheroadrepresentsthedry-upvalleywhichis
includedasapartofthe“Formervillage”area.Thesolidcirclerepresentsthelighthouse.
opengrasslandsspreadintheentranceandlight- queensandmalesifavailablewerecaughtevenif
house areas. The lighthouse area was also sur- awholecolonywasfound.
roundedbyabamboothicket.Incontrast,many All ants collected were identified to species
shrubsandtreescoveredthesamplingsiteinthe andclassifiedintonativeorexoticspeciesbased
formervillagearea,creatingrelativelymoistand on taxonomic literatures by M. K. (Onoyama
darkenvironments.ThetreesweremainlyPinus 1980, Yamane et al. 1999, Onoyama & Yoshi-
thunbergii Parl. 1868 (Pinaceae), Ardisia sie- mura2002,JapaneseAntDatabaseGroup2007,
boldii Miq. 1867 (Myrsinaceae) and Machilus Yoshimura & Onoyama 2007, Yoshimura et al.
thunbergiiSiebold&Zucc.1846(Lauraceae).A 2009, Katayama & Tsuji 2010). Voucher speci-
dry valley in the former village area was also mensaredepositedattheEntomologicalLabora-
searched for the ants (Fig. 2). This valley was toryofUniversityoftheRyukyus.
coveredwithtreeslikeA.sieboldii,M.thunbergii
andCastanopsissieboldii(Makino)Hatus.1971.
AntcollectionsonGaja-jimaIslandunderthe 3.Results
permission from Toshima Village were carried
outduringan8hoursvisit(from8a.m.to4p.m.) Twenty-three ground-dwelling ant species were
on13.VII.2011.Thesamplingwasrestrictedbe- found on Gaja-jima Island: 2 in the subfamily
causeofonlyaday-timepermissionforaone-day Ponerinae,1inProceratiinae,14inMyrmicinae,
visit. Ant foragers walking on the ground were 1inDolichoderinae,and5inFormicinae(Table
haphazardlycollectedusinganaspirator.Decay- 1).Amongthem,4specieswererecordedinthe
ing woods, grounds under stones, and slopes TokaraIslandsforthefirsttime:Proceratiumitoi
along the road were also searched for ant colo- A. Forel, 1918, Aphaenogaster famelica (F.
nies.Becausethenumberofindividualswecould Smith,1874),AphaenogasterjaponicaA.Forel,
collectwasrestrictedtoabout10individualsfor 1911, and Camponotus yamaokai Terayama et
each species by the permit, only some workers, Satoh,1990.Theother19specieshavebeenre-
ENTOMOL.FENNICAVol.24 (cid:127) Ground-dwellingantsonGaja-jimaIsland 219
Table1.ListofantspeciescollectedonGaja-jimaIslandwithregionsofdistributions(E,exotic;O,Oriental;P,
Palaearctic),sitesofcollection(E,entrance;V,formervillage;L,lighthouse),typesofsampledspecimens(F,for-
ager;C,colony),numbersofspecimenscollected(W,workers;Q,queens;M,males;minorandmajorworkers
wereseparatedforPheidoleasminors+majors).Collectors(Leg.):TH,T.Hosoya;MK,M.Katayama;WT,W.
Toki.V-No.isforthenumberofthevoucherspecimenandstars(*)denotespeciesnewtoTokaraIslands.
Species Region Site Type Numbers Leg. V-No.
W Q M
Ponerinae
HypoponeranipponaF.Santschi,1937 P,O V F 0 1 0 MK 7
PoneratamonTerayama,1996 P,O V C 2 1 0 MK 6
V F 1 0 0 MK 12
Proceratiinae
*ProceratiumitoiA.Forel,1918 P,O V F 1 0 0 MK 18
Myrmicinae
*Aphaenogasterfamelica(F.Smith,1874) P V C 1 1 0 MK 2
*A.japonicaA.Forel,1911 P V F 1 0 0 MK 16
V C 4 0 0 TH 23
V C 3 3 0 MK 31
A.osimensisTeranishi,1940 P,O E F 3 0 0 MK 37
A.tokarainsulanaWatanabeetYamane,1999 P,O V C 6 1 4 MK 8
Carebarayamatonis(Terayama,1996) P,O V C 5 0 0 MK 1
MonomoriumchinenseSantschi,1925 P,O E F 3 0 0 MK 34
PheidolefervensF.Smith,1858 E V C 6+7 6 0 MK 5
V C 2+1 0 0 MK 21
E F 4+1 0 0 MK 33
Ph.pieliSantschi,1925 P,O V C 7+3 0 0 MK 30
PristomyrmexpunctatusF.Smith,1860 P,O V C 5 0 0 MK 25
E F 2 0 0 MK 39
SolenopsisjaponicaWheeler,1928 P,O L F 1 0 0 MK 10
V C 7 0 0 MK 14
V C 16 0 0 MK 29
V C 5 0 0 MK 45
StrumigenyslewisiCameron1886 P,O V C 11 0 0 MK 3
V F 1 0 0 MK 13
V C 18 0 0 MK 28
V F 1 0 0 MK 43
V F 1 0 0 MK 44
Temnothoraxanira(TerayamaetOnoyama,1999) P,O E F 1 0 0 MK 35
TetramoriumbicarinatumNylander,1846 E E F 5 0 0 MK 32
E C 2 3 0 MK 38
VollenhoviabenzaiTerayamaetKinomura,1998 P,O V C 5 3 0 MK 4
V C 7 0 0 MK 11
V F 1 0 0 MK 17
E F 1 0 0 MK 40
Dolichodelinae
TapinomamelanocephalumFabricius,1793 E V F 1 0 0 MK 19
Formicinae
AcropygasauteriA.Forel,1912 P,O V C 9 0 0 MK 15
V C 8 0 0 MK 26
CamponotusdevestivusWheeler,1928 P,O V C 4 1 0 TH 27
*C.yamaokaiTerayamaetSatoh,1990 P L C 18 0 1 WT 22
Nylanderiaamia(H.Forel,1913) P,O E F 4 0 0 MK 42
N.ryukyuensis(Terayama,1999) P,O L C 2 1 0 MK 9
L C 4 1 0 MK 20
V C 4 0 0 MK 24
E F 2 0 0 MK 36
E F 4 0 0 MK 41
220 Katayamaetal. (cid:127) ENTOMOL.FENNICAVol.24
Table2.NumbersofantspeciesrecordedoneachoftheTokaraIslands.InformationisbasedonYamaneetal.
(1999),exceptforGaja-jimaIsland.
Numbersofantspecies Islandarea Residents
km2
Total Ground- Exotic(%)
dwelling1
Kuchino-shima 33 29 7(24.1) 13.33 +
Nakano-shima 33 29 7(24.1) 34.47 +
Suwanose-jima 13 12 3(25) 27.66 +
Taira-jima 11 8 3(37.5) 2.08 +
Akuseki-jima 24 18 4(22.2) 7.49 +
Takara-jima 33 28 8(28.6) 7.14 +
Yokoate-jima 15 13 3(23.1) 2.76 –
Gaja-jima 23 22 3(13.6) 4.07 –
Ko-jima 3 3 1(33.3) 0.36 –
Kodakara-jima 4 2 0(0) 1 +
1)Thenotground-dwellinggeneraAmblyopone,Crematogaster,andCamponotusareexcluded.
cordedbeforeonotherislandsoftheTokaraIs- Island. Because the Tokara Islands are not oce-
landswhichcompriseatotalof41ground-dwell- anicislands,thethreespeciescouldhaveexisted
ingantspecies. on Gaja-jima Island before it was isolated geo-
Thenumberofspeciescollectedintheopen graphicallyfromthemainlandofJapan,includ-
entrance area, the forested former village area, ingYaku-shimaIsland.Theseresultssuggestthat
andtheopenlighthousearea(Fig.2)were9,17, Watase’s line might have no clear meaning on
and3respectively.Threeexoticspecies,Pheidole geographicdistributionsofants.
fervensF.Smith,1858,Tetramoriumbicarinatum The three exotic ants recorded from Gaja-
Nylander,1846,andTapinomamelanocephalum jimaIsland arewidely distributed in theTokara
Fabricius,1793,wereobtainedfromtheentrance Islands: P. fervens and T. bicarinatum on Ku-
and/orformervillageareas(Table1). chino-shima, Nakano-shima, Suwanose-jima,
Taira-jima, Akuseki-jima, Takara-jima and
Yokoate-jimaislands,andT.melanocephalumon
4.Discussion Kuchino-shima,Nakano-shima,Suwanose-jima,
Taira-jimaandTakara-jimaislands.Gaja-jimaIs-
Ofthe23ground-dwellingantspeciesfoundon landshowedthelowestpercent(13.6%)ofexotic
Gaja-jima Island, 3 (13%) have been recorded species compared to most other islands (13.6 –
onlyfromthePalearcticregionand20(86.9%), 37.5%),exceptfortwoislandshavingonly few
includingthethreeexoticspecies,havedistribu- ant species (Table 2). Because exotic ants often
tionsonthebothsidesoftheWatase’sline(Table reproduceandmigratewithoutflights(Holwayet
1).Accordingly,allbutthreeantspeciesfoundin al.2002),humanactivitieswouldberequiredto
thisstudyweredistributedregardlessofWatase’s spread their distributions from an island to an-
line.AlthoughWatase’slinehavebeenpostulated other.Minorhumanactivities,suchaslighthouse
astheboundarybetweenPalearcticandOriental repairing,shouldhavesmallcontributionstothe
regions for animal geographical distributions invasionofexotics,becauseitcannotcarrylarge
(Kuroda1939),antsoftenhavewidedistributions stuffs hiding a fraction of a colony. Ants can
intheRyukyuarchipelagos(Yamaneetal.1999). spreadtheirdistributionsoveraseaalsobyraft-
WhileA.famelica,A.japonica,andC.yamaokai ing(Abeetal.2012).However,raftingtoGaja-
had their southern distribution limit on Yaku- jimaIslandfromotherislandsisnotverylikely,
shima Island before this study (Yamane et al. because the Kuroshio Current flows from the
1999),they werealsofoundtobeonGaja-jima westtotheeastoftheTokaraIslands.Someex-
ENTOMOL.FENNICAVol.24 (cid:127) Ground-dwellingantsonGaja-jimaIsland 221
otic ants in the Ryukyu archipelago were re- BulletinofArts&ScienceDivisionRyukyuUniversi-
cordedintheearlyyearsofthe20thcentury.For ty(Mathematics&NaturalSciences)3:43–51.
JapaneseAntDatabaseGroup2007:JapaneseAntImage
instance,theinvasiveyellowcrazyant,Anoplo-
Database 2007. — [www database]. URL http://
lepis gracilipes F. Smith 1857, was found on
ant.edb.miyakyo-u.ac.jp/IndexE/.(Citevisitedon18
Amami-OshimaIslandin1930(Wetterer2005). July,2012)
Though the precise information on the date the Katayama,M.&Tsuji,K.2010:Habitatdifferencesand
threeexoticspeciesinvadedisnotavailable,the occurrence of native and exotic ants on Okinawa
Island.—EntomologicalScience13:425–429.
chance that those three species invaded before
Kato,Y.&Yagi,T.2004:Biogeographyofthesubspecies
1970 is relatively high compared to that it hap-
ofParides(Byasa)alcinous(Lepidoptera:Papilioni-
penedafter1970,becausehumanactivitiesbyin- dae)basedonaphylogeneticanalysisofmitochondri-
habitantsonGaja-jimaIslandpracticallyceased alND5sequences.—SystematicEntomology29:1–
by1970.Therefore,itwouldbemostlikelythat 9.
Kozono,K.1995:Toshima-sonshi,EditingCommitteeof
thethreeGajaexoticsinvadedGaja-jimaIsland
Toshima-sonshi,Toshima,Japan.—MedievalPeriod
alreadybeforeleftbyresidents.
inTokara:457–572.
InformationabouttheantfaunaontheTokara Krell,F.2000:Impactfactorsaren’trelevanttotaxonomy.
Islandsisinsufficient,includingthispreliminary —Nature405:507–508.
report on ground-dwelling ants of Gaji-jima Is- Kuroda,N.1939:DistributionofmammalsintheJapanese
empire.—JournalofMammalogy20:37–50.
land. Accordingly, more detailed surveys are
Matsushita,T.1999:Recordofinsect-collectinginuninha-
neededtoclarifydistributionaldifferencesofant
bitedisland“Gaja-jimaIsland,theTokaraIslands”.—
faunaamongislandsintheRyukyuarchipelago. Gekkan-Mushi340:86–97.[InJapanese.]
Myers,N.,Mittermeier,R.A.,Mittermeier,C.G.,daFon-
Acknowledgements.WewishtothankDr.M.Tanahashifor seca,G.A.B.&Kent,J.2000:Biodiversityhotspots
hishelpwiththefieldsurvey,thestaffoftheguest-houseof forconservationpriorities.—Nature403:853–858.
Nagoran-souandthecrewofafishingboatofKaito-maru Nakamura, K., Denda, T., Kokubugata, G., Suwa, R.,
IIfortheirhelpwithconductingthefieldsurvey.Weare Yang,T.Y.A.,Peng,C.&Yokota,M.2010:Phyloge-
gratefultoToshimaVillageforallowingustocollectspeci- ographyofOphiorrhizajaponica(Rubiaceae)incon-
mensandgivinglandingpermissiononGaja-jimaIsland. tinentalislands, the Ryukyu Archipelago, Japan. —
M. K. was partly supported by Mitsui-Bussan Environ- JournalofBiogeography37:1907–1918.
mentalFunds(No.08R-B047)toH.Tatsuta.W.T.was Noda,S.2011:SurveyofmosquitolarvaeonGajaIsland,
supportedbyFujiwaraNaturalHistoryFoundation.Two Toshimavillage,Kagoshimaprefecture.—Occasio-
anonymousreviewersgreatlyimprovedthismanuscript. nalPapersin Kagoshima University Repository 51:
94–96.[InJapanesewithEnglishabstract.]
Onoyama,K.1980:AnintroductiontotheantfaunaofJa-
pan,withachecklist(Hymenoptera,Formicidae).—
References
Kontyu48:193–212.
Onoyama,K.&Yoshimura,M.2002:Theantsofthege-
Abe,T.,Yamane,S.&Onoyama,K.2012:Antscollected nus Proceratium (Hymenoptera: Formicidae) in Ja-
ontheKrakatauIslands100yearsafterthegreaterup- pan.—EntomologicalScience5:29–49.
tions.—Biogeography14:65–75. Pfeiffer,M.,Mezger,D.,Hosoishi,S.,Yahya,B.E.&Ko-
Alonso,L.E.2000:Antsasindicatorsofdiversity.—In: hout,R.J.2011:TheFormicidaeofBorneo(Insecta:
Agosti,D.,MajerJ.,Alonso,E.&Schultz,T.R.(eds.), Hymenoptera): a preliminary species list. — Asian
Ants:standardmethodsformeasuringandmonitoring Myrmecology4:9–58.
biodiversity:80–88.SmithsonianInstitutionPublica- Terada,J.1999:Shinnyudoubutugamujin-tounosyoku-
tions,WashingtonDC.280pp. seiniataerueikyou.–Gaja-jimanosyokubutsu-soto
Fukuda,H.2007:Autumnalmassflightofthepowdered gensonsyokusei–[Theimpactsofexoticherbivorous
oakblue,Narathurabazalus(Hewitson)(Lepidoptera, vertebratesonthefloraofanuninhabitedisland.–Flo-
Lycaenidae)observedonGaja-JimaIs.,Tokaralsls., raandcurrentvegetationinGaja-jimaIsland].—Mi-
southernJapan.—TransactionsoftheLepidopterolo- nami-Nihon-Bunka33:59–108.[InJapanese.]
gicalSocietyofJapan58:91–96.[InJapanesewith Toki,W.&Hosoya,T.2012:Newhostplantandsouthern-
Englishabstract.] mostrecordsofasymmetriclizardbeetleDoubledaya
Holway,D.A.,Lach,L.,Suarez,A.V.,Tsutsui,N.D.& bucculentaLewis(Coleoptera:Erotylidae:Langurii-
Case,T.J.2002:Thecausesandconsequencesofant nae).—ElytraNewSeries1:253–254.
invasions.—AnnualReviewofEcologyandSyste- Wetterer,J.K.2005:Worldwidedistributionandpotential
matics33:181–233. spreadofthelong-leggedant,Anoplolepisgracilipes
Ikehara,S.1959:ThetermitefaunaoftheRyukyuIslands (Hymenoptera:Formicidae).—Sociobiology45:77–
anditseconomicsignificance(IV)(Tokara-retto).— 97.
222 Katayamaetal. (cid:127) ENTOMOL.FENNICAVol.24
Yamane,S.,Ikudome,S.,Terayama,M.1999:Identifica- 50 years of contributions, American Entomological
tionguidetotheAculeataoftheNanseiIslands,Japan. Institute,Gainesville:664–690.
HokaidoUniversityPress,Japan,830pp. Yoshimura,M.,Hosoishi,S.,Kuboki,Y.,Onoyama,K.&
Yoshimura,M.&Onoyama,K.2007:Anewsiblingspe- Ogata,K.2009:NewsynonymandnewJapanesere-
ciesofthegenusStrumigenys,witharedefinitionof cordoftheantgenusPonera(Hymenoptera:Formici-
S. lewisi Cameron. — Advances in ant systematics dae).—EntomologicalScience12:194–201.
(Hymenoptera:Formicidae):homagetoE.O.Wilson