Table Of ContentNAT. HIST. BULL. SIAM Soc. 50(2): 239-243，2 002
，
ECTOPARASITIC MITES (ACARITROMBICULIDAE) ON
，
OPLIONIDS (OPILIONESGAGRELLIDAE) IN NORTHERN
THAILAND
Pakawin Danki.的ipakul1and Saowapa Sonthichai1
ABSTRACT
Five species of opilionids viz，Ga grella alba，G. fumosa，G. sexmaculata，M etagagrella
curvispina，飢 dM.fusca，f rom Doi Inthanon National Park and Doi Suth官:p-PuiNational P訂k，
Chiang Mai Province，n orthern Thailand，ar e reported for the first time in association wi由
toparasiticlarvae of trombiculid mites. Forty-three p ntof opilionid individuals examined
民 巴民活
were carrying mites，m ost of which were attached to the hosts' legs. Different degrees of
p紅asitism泊出eopilionid hosts were observed. The possible reasons for this phenomenon訂e
discussed.
Key words: Opiliones，Ga grella，Me tagagrella，p asiticmites，Tr ombiculidae，百lailand.
釘
INTRODUCTION
Nematodes紅e血emajor p紅asitesof opilionids，bu t several opilionid species have
also been found cryingconspicuous，br ight red mites of the family Thrombidiidae. These
釘
mites are Erythraeus phalangioides，B elaustiurn nernorurn，a nd at least four species of
Leptus (CLOUDSLEY-THOMPSON，1 968; FAIN & D' AMICO，1 997).
So far，n o parasitic Trombiculidae have been found on opilionids. Trombiculid mites
are typically found on vertebrates，w hich they feed on as parasites or use for dispersal
(phoresy). Many住ombiculidmites紅ep釘asiticon rodents，bi rds，a nd bats (AM別ーBAB厄E
EIA L.，19 97; BROWN，1 998; DOOD & KURTA，1 988; GOFF，1 984，1 988; GoFF & WHlTAKER，
1984; GOFF ETA L.，1 984; IWASA ET A ，.L 1990; KOL回 INOVA，1985; MORSY ETA L.，19 99;
SPALD町GEI AL.，1 997; URAKAMI EI AL.，1 999; YANG，1 987; ZHAO，1 984). Some have
been found on m訂supials，reptiles，a nd frogs (GOFF & EASTON，1 989; LESτ'ER，1 983;
OAKWOOD & SPRATT，2 000; SPIELER & LINSENMAIR，1 999). However，to our knowledge，
no trombiculid mite larvae have ever been recorded on opilionids. Here we present the frrst
published descriptions of ectoparasitic trombiculid larvae on opilionids in百lailand.
IDepartrnent of Biology，Fa culty of Science，Ch iang Mai University，Ch iang Mai 50200
Received 3J une 2002; accepted 24 September 2002.
239
240 PAKAWIN DANKl1TIPAKUL AND SAOWAPA SONTHICHAI
MATE悶ALSAND勘血，THODS
The maj'Ority 'Ofr nites and 'Opili'Onids exarnined in this study were c'Ollected 合omD'Oi
InthannN atinal Park (1832' N，9 8・34'E) and from DiS uthep-PuiN atinal Park
'O 'O 0 'O 'O
(18048' N，9 80 55' E)，Ch iang Mai Pr'Ovince，n' Orthem Thailand，be tween June and August
2000，in 血.ec'Ourse 'Off aunistic surveys 'Ofs piders. The 'Opili'Onids were c'Ollected by hand
fr'Om the vegetati'On，pl aced in ap lastic vial，an d ac 'Ott'Onb all with ethyl acetate was added
fra r ninute rs The specimens were then taken tthe Terrestrial Arthrpds Research
'O 'O 'O. 'O 'O'O
labratry，C hiang Mai University，f rs rting and identificatin.
'O 'O 'O 'O 'O
Mites are c'Onsidered t'O be parasitic when their m'Outhparts are fin叫yembedded in血e
cuticle 'Oft he h'Ost. Parasitic rnites were identified t'O farnily using the key 'OfK ETHLEY
(1990) and c'Onfirmed by Dr Sand'OrM ahunka (Hung町).Opili'Onids were identified using
the key prvided by Suzu阻(1985).
'O
RESULTS
Wec llected 205 pilinid individuals，be lnging ttw genera dfive species，
'O 'O 'O 'O 'O 'O 佃
during this study (Table 1). They we Gagrellaalba Suzuki 1985，G . fumosa Suzuki
陀
1985，G . sexmaculata Suzuki 1969，M etagagrella curvispina Suzuki 1985 and M. fusca
Suzuki 1985. A multi-species aggregatinw as bserved at ne lcality，n e ariverbank
'O 'O 'O 'O 紅
in deciduus diptercarp-oak frest abut 1，000 m elevatin nD iI nthann. These were
'O 'O 'O 'O 'O 'O 'O 'O
138 individuals fG . fumosa，18 fG . sexmaculata，4 fM . curvispina，a nd 5 fM . fusca.
'O 'O 'O 'O
The ther specimens were cllected frm different lcalities nD iI nthanna nd Di
'O 'O 'O 'O 'O 'O 'O 'O
Suthep.
All five species were infested with larvae ft rmbiculid mites (Acari，
'O 'O
Trmbidifrmes，T rmbiculidae)，w ith 43 percent fa ll pilinid individuals exarnined
'O 'O 'O 'O 'O 'O
being parasitized (Table 1). The degrees fp itismin each hst varied cnsiderably:
'O 紅白 'O 'O
Metagagrellafusca (100%)，M. curvispina (75%)，G. fumosa (40%)，G. sexmaculata (39%)，
and G. alba (31 %).
The number fr nites per hst specimen ranged frm 1t 10，w ith am ean f1 .5
'O 'O 'O 'O 'O
(::!:: 0.9 SD)，me dian value 1a nd m'Ode 'Of2. Metagagrella fusca was血em'Ost abundantly
p紅asitizedh'Ost，a lways c釘rying3ー10rnites. Several individuals 'OfG . fumosa c紅ried
1-4 rnites，th se fG agrella alba and M. curvispina 1-2 rnites，wh ile all specimens f
'O 'O 'O
G. sexmaculata had nly ne rnite (Table 1).
'O 'O
Table 1. Parasitism 'Oftr 'Ombiculid rnites 'Onf ive species 'Of'O pili'Onids仕omn'Orthem Thailand
Species No. hosts studied No. hosts occupied % parasitism No. mitesJhost
Gagrella alba 16 5 31.3 1-2 (me 1.3)
飢
Gagrella fumosa 162 64 39.5 1-4 (mean 1.6)
Gagrella sexmaculata 18 7 38.8 1-1 (mean 1.0)
。
Metagagrella curvispina 4 3 75.0 1-2 (mean 1.2)
Metagagrella fusca 5 5 100. 3-10 (mean 6.5)
Total 205 84 40.97 1.4-3.8( mean 1.5)
ECTOPARASITIC M汀'ES(ACARI，T ROMBICULIDAE) ON OPLIONIDS 241
Mites were found mainly on the legs of the hosts (Table 2) where they apparently
preferred attach泊gthemselves to the long segments. Mites were most abundant on the
host'sf emora (40%)，pa tellae (39%)，of ten also attached to the tibiae (9%)，an d occasionally
to出emetatarsi (1 %). Seven mites (6%) were present on出edorsal scutum. Nom ites were
found on the ventral part of白ebody such as the stemum and coxae.
Table 2. Numbers of trombiculid mites attached to various ptsof five species of opilionids
釘
= = = =
from northem Thailand. T tarsus，M t metatarsus，T i tibia，P t patella，
= = = = =
Fe femur，T r trochanter，C x coxa，D s dorsal scutum，St stemum.
Species Ds S。t C。x T。r Fe Pt T。i M。t T。
。。。 。
Gargella alba 1 4 3
。。。。 。。。
Gargella fumosa 5 24 32 7
。。。 。。。
Gagrella sexmaculata 6 2
。。。 。。
Metagagrella curvispina 1 4 3
Metagagrella fusca 。。6 7 4 3 。
Total 7 6 45 44 10
DISCUSSION
Aggr芭gationsof opilionids have been recorded泊somePalpatores including Gagrellidae
(CODD町GTONETA L.，1 990; HOLMBERG ETA L.， 1984). HOLMBERG ETA L.，(1 984) suggested
that gregarious behavior in opilionids occurs in certain places in order to avoid dehydration
and exposure to sunlight. The observed aggregations of G. fumosa toge血erwith other
species (multi-species aggregation) ne釘 ariverbank may explain出isphenomenon，si nce
血ismicrohabitat is constantly moist. As numerous individuals of G. fumosa were found
occu汀ingtogether at the s創neplace (mono-species aggregation)，it is possible that血e
formation of mating groups is another reason for this behavior (see HOLMBERG ETA L.，
1984).
Metagagrella fusca was the most strongly parasitized host species observed，w ith
100% parasitism and with the highest numbers of mites per individual. The physical
factors of the exoskeleton may influence choice of host. All coxae of M. fusca are thickly
coated with aw hite secretion. This secretion，kn own to function in intraspecific recognition
(HOLMBERG，1 986)，m ay contain specific substances白紙 couldstimulate the mites to
attack certain species of opilionids. Another member of the genus，M . curvispina，r anks
second in number of p紅'asites.It is possible白紙Metagagrellaproduces chemical substances
that are attractive to these mites.τ'hec oloration of出eMetagagrella is different合omthat
of other genera. The bodies of the Metagagrella species examined were blackish dorsally
and ventrally，wh ile the species of Gagrella examined were brown or dark yellow in color.
Mites attached to出epatellae of their hosts were mainly found piercing their mouthparts
into the membranous joint between patella and tibia，w here they could feed more easily.
Thel eg femora carried mites mostly in their distal parts，in cluding the membranous joint
242 PAKAWIN DANKITIIPAKUL AND SAOWAPA SONTHICHAI
between the femur and patella. Thel ong femoral segment provides easy access to soft
tissue. Mites were absent on the tarsi，t he long articulated distal segments of the legs，
which bend as the opilionids move. Opilionids carefully clean their distal leg segments by
pulling them through the chelicerae; this habit may explain why there were no mites on
the tarsi and only one mite on the metatars .i
Parasitism of opilionids by mites may be regarded as am odification of an ancestral
behavioral pattem. Some species of mites are rarely found free-living，bu t mostly occur in
association with mammals and other vertebrates where they do not feed directly on the
host，bu t on other mites and insects living on it. It is easy to imagine that some of these
epizoic mites later evolved an easy way to obtain their food by sucking the blood of the
animal on which they lived. By this means，m yfamilies of mites may have become
叩
ectoparasitic on b凶 sand mammals (BELL & WHELAN，1 993; GOFF & W町fA阻 R，1984;
HADI & CARNEY，1 977; PEREIRA-LORENZO，1 993). In the same way，m ites may attack
opilionids for two reasons. First，op ilionids provide ap lace where these mites can obtain
food. Secondly，op ilionids are used as am echanism to stay in moist environments. TODD
(1949) found as trong correlation between humidity and the migration of Phalangiidae.
Later，th ese mites may also have evolved an ew life style and become parasites. However，
they do not remain permanently attached to hosts，bu t feed on them before retuming to the
ground.
Although parasitized opilionids have not yet been collected from localities other than
Doi Inthanon National Park and Doi Suthep-Pui National Park，it is probable that mites
parasitic on opilionids occur commonly elsewhere in百四land.Opilionids in association
with ectoparasitic mites have been reported from different geographical regions by various
authors (CLOUDSLEY-THOMPSON，1 968; FORSTER，1 954; FAIN & D'AMICO，1 997)，b ut all
there records refer to Trombidiidae，no t Trombiculidae.
ACKNOWLEDGMENTS
We 'eespecially grateful to Dr. Peter J. Schwendinger (Musem d'histoire naturelle，
釘
Genとve)，Dr. Stephen Elliott and Mr. J. F. Maxwell (both at Chiang Mai University) for
their critical comments on the manuscrip .tWe eindebted to Dr. Sandor Mahunka (Museum
紅
of Natural History，B udapest) for confirmation of our identifications of mite specimens.
REFERENCES
AMIN-BABJEE，S. M.，C. C. LEE，AN D A. A. MAHMOOD. 1997. Prevalence of ectoparasite infestations in different
age groups of vil1age chickens. Journal Veterinary Malaysia 9(2): 55-59.
BELL，P. J.，A ND P. 1. WHELAN. 1993. As crub typhus vector Leptotrombidium deliense Austra1ia. J. Australian
Entomol. Soc. 32(3): 207-208.
BROWN，W . A. 1998. Walchiella (Acari: Trombiculidae) from rodent hosts from the Philippines. Internat. J.
Acarol. 24(2): 107-112.
CLOUDSLEY-THOMPSON，J. L. 1968. Spiders，S corpions，C entipedes and Mites. Pergamon Press，Ox ford.
CODDlNGTON，J. A.，M. HARNER，AN D E. A. SODERSTROM. 1990. Mass aggregation in tropica1 harvestrnen (Opiliones，
Gagrellidae: Prionostemma spふRevueArachnologique 8: 213-219.
DOOD，S. B.，AN D A. KURTA. 1988. Additional陀cordsof Michigan bat ectoparasites. Great Lakes Entomol. 21 (3):
115-117.
ECTOPARASITIC MITES (ACARI，T ROMBICULIDAE) ONO PLIONIDS 243
FAIN，A .，A ND F. D'AMlCO. 1997. Observation on larval mite (Acari) parasitic on Opilionids from the French
Pyrenees. Internat. J. Acarol. 23: 39-48.
FORSTER，R . R. 1954. TheN ew Zealand Harvestmen (sub-order Laniatores). Canterbury Mus. Bull. 2: 1-329.
GOFF，M . L. 1984. A new species of Gahrliepia (Acari: Trombiculidae) from as Ju官w-hedehog(Insectivora) in
China. J. Med. Entomol. 21(6): 69か691.
GOFF，M. L. 1988. An ew species of chigger (Aωri: Trombiculida付金omav ampire bat (Chiroptera: Desmodontidae)
colle氾tedin Costa Rica. Internat. J. Acarol. 14(1): 5-7.
Go押， M. L.， AND E. R. EASTON. 1989. Two new species and new records of chiggers (Acari: Trombiculidae)
collected from mammals and reptiles in Papua New Guinea. Internat. J. Acarol. 15(4): 235-239.
GOFF，M . L.，A ND J. O. WHITAKER，Jr. 1984. As maIlco llection of chiggers (Ac訂:iTrombiculidae) from mammaIs
collected in Paraguay. J. Med. Entomol. 21(3): 327-335.
GOFF，M . L.， J. O. WHITAKER，JR .，A ND L. 1. BARKLEY. 1984. An ew species of Loomisia (Acari: Trombiculidae)
from aP eruvian bat. J. Med. Entomol. 21(1): 80-81.
HADI，T. R. AND W. P. CA悶 EY.1977. Two new trombiculid mites from mammals of South Vietnam，wi th locaIity
records for six additional species (Acarina: Trombiculidae). J. Med. Entomol. 14(4): 455-460.
HOLMBERG，R. G. 1986. Thes cent glands of Opilionids: Ar eview of their function. Proc. 9血Intemat.Congress
of Arachno10gy，P anama，1 983，S mithsonian Ins .tPress.
HOLMBERG，R . G.，N . P. D. ANGERLLI，A ND 1. L. LACASSE. 1984. Overwintering agg陀gationof Leiobunum
paessleri in caves and mines (Arac胎IIda，Opiliones). J. Arachnol. 12: 195-204.
Iwasa，M .，S. KASUYA，N. NODA，A. HIOKI，A. lTO，A ND H. OHTOMO. 1990. Trombiculid mites (Acari; Trombiculi-
dae) and Rickettsia tsutsugamushi isolated from wild rodents in new endemic釘eaof Japan. J. Med
Entomol. 27(4): 501-508.
KETHLEY，J. 1990. Ac釘ina:Prostigmata (Actinedida). Pp.667・778in Dindal，D. L. (edふSoilBiology Guide. John
Wiley & Sons，N ew Yo rk.
KOLEBINOVA，M . G. 1985. Parasitism of rodents of the genus Apodemus Kaup in Bulg紅iaby trombiculid larvae
(Acina，Trombiculidae). Acta Zoologica Bulgarica 27: 21-26.
紅
LESTER，L. 1983. Two new chiggers針。mAustraIian marsupials (Acari: Trombiculidae). Proc. Linnean Soc. New
South Wales 107(4): 493-499.
MORSY，T. A.，S. A. MAZYARD，A ND M. S. YOUNIS，1 999. Feather and nest mites of two common" resident birds
in two eco10gicaI1y di能rentEgyptian govemorates. J. Egyptian Soc. Parasitol. 29 (2): 417-430.
OAKWOOD，M .，A ND D. M. SPRATT. 2000. Parasites of the northem quoll，D asyurus hallucatus (MarsupiaIia:
Dasyuridae) in tropical savanna，N orthem Teπitory. Australian J. Zool. 48(1): 79-90.
PERElRA-LoRENZO，A . 1993. Chiggers (Acぽina:Trombiculidae) p訂'asitisingsmaIlm ammals in GaIicia (NW
Spain). Acarologia 34(4): 323-329.
SPALDING，M . G.，W . J. W阻 NN，S. T. SCHWIKERT，A ND 1. A. SCHMIDT. 1997. Dermatitis in young F10rida sandhill
cranes (Grus cannadensis pratensis) due to infestation by血e.chigger，Bl ankaartia sinnamaryi.よParasitol.
83(4): 768-771.
SPIELER，M .，A ND K. E. LINSENMAIR. 1999.ηle larval mite Endotrombicula pillersi (Ac釘ina:Trombiculidae) as
as pecies-specific par副総ofaW est African savannall frog (Phrynobatrachusfrancisci). Amer. Midl. Nat.
142(1): 152-161.
SUZUKI，S. 1985. As ynopsis of the Opilionids of Thailand (Araciulida) II. Palpatores. Steenstrupia 11 (7): 209-257.
TODD，V. 1949. The habits and ecology of the British harvestmen (Arachnida，Op iliones)，w i血specialreference
to those of the Oxford distric .tJ. Anim. Ecol. 18: 209-216.
URAKAMI，H .，A . TAMURA，I. V. TARASEVICH，T. KADOSAKA，A ND F. N. SHUBIN. 1999. Decreased preva1ence of
Orientia tsutsugamushi in trombiculid mites and wild rodents in the Primorye region，F ar East Russia.
Microbiol. Immunol. 43(10): 975-978.
YANG，B. X. 1987. Investigation of ectoparasitic mites of rodents in Sandu District，Fu jian Provinω.An n. Bull.
Soc. Parasitol.，G uangdong Province 8-9: 37.
ZHAO，S. X. 1984. An ew species of chigger mite parasitic on bats (Acarina: Trombiculidae). Acta Zootaxonomica
Sinica 9(3): 281-283.
