SEPTEMBER1990 AN. peneurt STBLTNGSPEcTES 425

DISTRIBUTION OF THE SIBLING SPECIESOF ANOPHELES FARAUTI IN THE , NORTHERN ,

A. W. SWEENEY, R. D. COOPER AND S. P. FRANCES

Armry Malnria ResearchUnit, Ingleburn, NSW 2174,Australin

ABSTRACT. The sibling speciesof Anophnlesfarauti s.l. were collected in larval and adult surveys from 34 localities on Cape York Peninsula and were identified by isoenzymeelectrophoresis. The most common speciesnear the coast was An. farauti I which was often found breeding within 100 m of the sea in either brackish or freshwater habitats. Larvae of the other 2 specieswere not found in brackish water which accordswith previous laboratory observationsof their lower salinity tolerance.Anophelcs farauti 2 appearsto have the widest distribution of the 3 sibling specieson Cape York Peninsula as it was common in both coastal and inland localities, Arnphcles farauti 3 was rarely found near the coast. In one locality at Lockhart River near the east coast of the peninsula larvae of the 3 specieswere found together in a small muddy creek.

INTRODUCTION passing 25,000 km' of land extending from 10"30'5 to 14'S bounded on the west by the Anophelesfarauti Laveran is a major vector and the east by the Coral of malaria in the Southwest Pacific Region and Sea. This is a sparsely populated region which has been incriminated as a vector in malaria was formerly malarious(Black 1972).It is con- outbreaks occurring in northern Australia sidered to be an important area of floral and (Mackerras 1947).Its distribution extends east- faunal interchange between Australia and New ward from the Moluccasthrough the Melanesian Guinea in which elements of the New Guinea islands of New Guinea, the Solomonsand Van- rain forest penetrate southward and the Austra- uatu. In Australia An. farauti s.L has been re- lian savannaextends northward (Taylor 1972). corded in Queenslandnorth of Townsville (lat- Collections of mosquitoesfrom Cape York Pen- itude 19'S), the Northern Territory (Lee and insula include records of An. farautli s.l. from Woodhill 1944) and one record from Western severallocalities (Marks 1980). Australia (Liehneet al. 1976).Cross-mating and Collectingmethods: The surveywas conducted chromosomestudies have shown that this taxon during June 1986, following the north Austra- consists of 3 sibling specieswhich have been lian wet season when mosquitoes are usually designated:An. farauti l, An. farauti 2, and An. most abundant. Collections were greatly facili- farauti 3 (Bryan 1973, Mahon and Miethke tated by the use of a Kiowa helicopter from the 1982). 162 ReconnaissanceSquadron which permitted No reliable morphological characters have visits to inaccessible wilderness areas which been found to distinguish between these sibling could not have been covered by land vehicles. speciesin the field. Consequently,there is little Sorties were made at an altitude of 100-300 m available information on the lawal and adult along the western and eastern coastsas well as biology of the individual speciesand their rela- inland to select suitable localities for adult and tive importance as malaria vectors is not known. larval mosquito collections. The helicopter sur- Similarly, there are few recordsofthe geograph- vey was supplemented by road parties in 4- ical distribution of the member species. Only wheel-drive vehicles. Adult mosquitoes of An. t has been reported in Papua New An. farauti farauti s.l. were caught in carbon dioxide baited Guinea (Charlwoodet al. 1986),though the 3 light traps and in man biting catches from Io- speciesoccur sympatrically at Innisfail, Queens- calities throughout the survey area.Larvae were land, Australia (Mahon and Miethke 1982). collected from breeding sites and were trans- In this paper we report the results of a survey ported to a field laboratory at the town of Weipa. to investigatethe distribution ofthe An. farauti The anopheline larvae were reared to adulthood sibling speciesin the Cape York Peninsula area in trays ofwater from their respectivecollection of northern Queensland.The individual species sites. The salinity of coastal breeding sites was were identified using a starch gel isoenzyme analyzed where possible with a salinity meter electrophoresis method developed by Mahon (Yellow Springs Instruments Co., Inc., model (1984). 33). Adult mosquitoesfrom both kinds of collec- tions were examined with a stereomicroscope. s.J.were stored MATERIALS AND METIIODS Those identified as An. farauti in liquid nitrogen and were subsequently sub- Area couered:The Cape York Peninsula is a jected to starch gel electrophoresisin our labo- triangular tract of far north Queenslandencom- ratory at Ingleburn. The electrophoretic mobil- 426 JounNel oF THE Arr,rpnrcalrMoseurro CoNTRoLAssocrerlorl VoL.6,No.3

ities of lactate dehydrogenase(LDH) and oc- RESULTS tanol dehydrogenase(ODH) of test specimens were comparedwith those of referencecolonies During this survey anopheline mosquitoes of the 3 specieswhich are maintained in our were found in 64 localities, 34 of which con- insectary. Anophelesfarauti 1 adults are homo- tainedAn.farauti s.l. (Fig.1). Of these22were zygousfor a unique allele at the LDH locus and larval sites, 7 were sites of adult collections,and An. farauti 3 individuals are homozygousfor an in the remaining 5 sites both larvae and adults allele at the ODH locus. Simultaneous stainins were collected. The speciescomposition of col- for both enzyme systemspermits unambiguoui lections accordingto their proximity to the coast identification for each of the 3 sibling species are shown in Table 1. All of the adult collections (Mahon 1984). The site numbers indicated in and 17 of the larval collectionswere madewithin the results and discussion correspond to the 5 km of the sea or estuaries,whereas the re- numbers in Table 1 and the numbers (within maining 10 larval collections were made from 7 squares)in Fig. 1. to 68 km from the coast. Most of the coastal

Table 1. Larvae and adults of Anophelcsfarauti sibling speciescollected on Cape York Peninsula. Species Type of Distance Site Location Locality collection from sea 1 10'48'S;142'34'E SaldogooBeach Larvae <100 m -1 2 10'50'3;142"33'E Kilbie Beach Larvae <100m 3 11'18'5;142"07'E Vrilya Point Larvae (br) <100 m / 4 11'28'S;142"05'E Doughboy Creek Larvae <100 m 7 4 11"28'S;I42"05'E Doughboy Creek Adult <100 m 5 11'37'S;142'51'E Captain Billy Landing Larvae (br) <100 m I 6 11'54'5;141"57'E Port Musgrave Adult (t, b) <100 m 7 11'58'3;141"53'E Port Musgrave Adult (t) <100 m o 1n 8 12'48'5;143"21'E fuintel Beach Larvae <100 m 2 9 12'54'S;14t"40'E Boyd Point Larvae <100 m 1

10 13'05'S:141'37'E False Pera Head Larvae <100 m I

11 13'19'S;141'40'E Aurukun Larvae (br) <100 m D 11 13"19'5;141"40'E Aurukun Adult (t) <100 m 108 12 10"5I'S;142"22'E Red Island Point Adult (t) km 7 I 13 11'18'S;142"07'E Vrilya Point Larvae km 2 14 ll'42'S;142"01'E Skardon River Adult (t) km 1 15 12"12'S1'l4l'45'E Adult (t) km o 16 L2"06'S;I41'47'E Pennefather River Adult (t) km 9 L7 12"42'S;I41"55'E Weipa Adult (t) km 31 IO 17 I2"42'S;14L"55'E Weipa Larvae ( 1km ; 18 13"11'5;141'38'E Ina Creek Larvae 1km J o 19 14'10'S;141'36'E Kuchendoopen Larvae 1km 1 20 12"48'S;143'20'E Lockhart River Larvae 3km 20 12"48'S;L43"20'E Lockhart River Adult (t) 3km 1 D 2l L4"22'S;I41"36'E Hersey Creek Larvae 4km 1 22 12'47'S:143"19'E Lockhart River Larvae 5km I I 4 23 13'31'S;141'44'E Adult (t, b) 5km 16 38 23 13"31'5:141'44'E Archer River Larvae 5km 1 1 ! 24 11"37'S;142'48'E Captain Billy Landing Adult (t) 5km 25 12'18'S:141'45'E Pennefather River Larvae 7km I 26 72"44'S:143"17'E Claudie River Larvae 10km 27 12"44'5:143'16'E Claudie River Larvae 13km 51 28 14"06'S;143'26'E Whiphandle Creek Larvae 27 km 11 29 12'10'S;142"18'E Larvae 30 km 22 30 t2"43'S;142'25'E Cox Creek Larvae 35 km 64 31 72"42'S;L42"36'E Batavia Downs Larvae 58 km 66 32 72"40'S;142'40'E Lydia Creek Larvae 64 km 11 7 33 L2'44'S;L42'48'E Lawae 67 km 1 34 12"34'S;142"43'E Wenlock River Larvae 68 km 2 br : Iarvae collected in brackish water; t : adults collected in CO: baited trap; | : adults collected in man biting catch. SEPTEMBER1990 AN, rtneurt Stsr.lttc SpPcrPs

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Fig. 1. Distribution of Anophelesfarauti sibling speciesin Cape York Peninsula. Numbers within squares refer to collection sites of Table 1. Numbers placed vertically adjacent to right side of squaresindicate sibling speciescollected in that locality. 428 JounNer,oF THEArrarnrcat Mosqumo CoNrnol ASSOCrArron VoL.6,No.3 localities were on the west coastof the peninsula swamps);poolsmade by animals(hooforints and (11 larval and 10 adult collections),with smaller pig wallows); as well as manmade sites (borrow numbers on the east coast (6 larval and 2 adult pits and roadside ditches). Brackish sites of up collections). to 707o salinity of seawater are common near The most common speciescollected on the the coast (Daggy 1945,Belkin 1962).The larval coast was An. farauti 1 (13 larval and 11 adult habitats located in the present survey encom- collections). An. farauti 2 was also common on passedthe typical range of sites found through- the coast (7 larval and 5 adult collections), out the distribution range of this speciescom- whereasAn. farauti 3 wasrelatively rare (1 larval plex. and 2 adult collections). The inland larval sur- Laboratory experiments with colonies and veys yielded approximately equal numbers of field collected individuals of the sibling species An. f arauti 2 and 3 (8 collectionsof eachspecies). showedthat larvae ofAn. farauti t have a higher An. farauti 1 was not collected inland. salinity tolerance than those ofthe other 2 spe- Larvae were found in a variety of ground cies (Sweeney1987). This implies that An. far- water sites, usually close to the edges among auti 2 and,3 may be restricted to freshwater emergentvegetation, algal mats or floating plant habitats and that An. farauti 1 is the species debris. Sevenlarval collections of An. farauti 1,, found in saline sites.The present study provided and 2 collections of An. farauti 2 were made further evidencefor this possibility as the latter within 100m ofthe coast.Five collections ofthe specieswas the only member of the group found former species were made in coastal Iagoons in brackish water (in 3 of 7 collections made formed at the mouth of creeksdammed by beach within 100 m of the sea). In a previous study sand dunes. Three contained fresh water (sites An. farauti 2 was found in a freshwater ground 4, 8 and 12) and the other 2 were brackish with pool within 100 m of the beach at Red Island salinitiesof 50%sea water (site 11) and 80% sea Point near Bamaga, Cape York Peninsula water (site 3). One of the remaining 2 sites of (Sweeney 1980). Larvae of this species were An. farauti 1 within similar proximity to the found in similar proximity to the sea on two coast was a freshwater ground pool (site 2) and occasionsduring the present survey but only in the other was a brackish swamp (site 5). The fresh water (sites I and 9). Arcphcles farauti 3 collections of.An. farauti 2 were made from fresh larvae were not collected closeto the coast. water sites: one in a ground pool (site 9) and the Although An. farauti 1 was common in fresh- other within a swamp (site 1). water larval sites and in adult collectionswithin Larvae of both An. farauti 1 and 2 were also 5 km of the coast, we find it particularly inter- found (both singly and together) in fresh water esting that it was not found further inland. This sitesbetween 1 and 5 km ofthe coast(Table 1). suggeststhat this speciesmay be predominantly Four of these sites were in hooforints and pig coastal.Similarly, it appearsfrom the results of wallows on the edgeof swamps (sites 13, 19, 21 the present survey that An. farauti 2 may be and 23). The 3 sibling specieswere found to- widely distributed in both coastal and inland gether 5 km from the coast in a muddy creek at localities and that An. farauti 3 may prefer in- Lockhart River Settlement (site 22). The most land habitats. Nevertheless,these findings need common inland larval habitats (7/10 sites) were to be interpreted with caution as the present in ground pools within creek beds. Anopheles surveycovered only a small part ofthe geograph- farauti 2 and 3 larvae were collectedtogether in ical areain which An. farauti s.l. occurs.Further 5 of these localities (sites 28, 29, 30,31, 32). work in other regions is required before definite Anophelesfarauti 3 was found in one collection conclusionscan be made about the coastal and in a rockpool on an escarpmentnear the Wen- inland distribution ofthe sibling species. Iock River (site 34). Apart from salinity and distance from the The sites yielding An. farauti s.l. ranged from coast, there was no clear evidencethat the in- 1 to 86 km (average: 26 km) from permanent dividual sibling speciesexhibited differences in human settlements. Seven were within 5 km of their preference for particular larval habitats. human habitations. An. farauti 1 and 2 were often found together in the same sites and so were An. farauti 2 and 3. In one site at Lockhart River Settlement, the 3 ground pool DISCUSSION specieswere found together in a within a freshwater creek (site 22). Larvae of An. farauti s.l. occur in a wide The Great Dividing Rangeextends northward variety of aquatic situations which are usually close to the eastern seaboardof the Cape York semi-permanent,partly shadedand with emer- Peninsula and the major river systems flow gent vegetation.These include natural bodiesof westward to the Gulf of Carpentaria. The ground water (creeks, ground pools and swamps and tributaries associatedwith these AN.rnntury SIBLINcSPEcIES rivers provide considerable larval habitats for Royal Australian Army Medical Corps for as- mosquitoesalong the westerncoast. The present sistance with collections. Thanks are also due survey was made when the south easterly winds to C. D. Rogers for technical assistance' We are associatedwith the north Australian dry season grateful to R. J. Mahon, CSIRO' Canberra, for had already commenced.The dry windy condi- critical review of the manuscript. tions which prevailed at this time were not con- ducive to adult mosquito activity on the east CITED coast.It is therefore not surprisingthat a larger REFERENCES number of collections (both larval and adult) Belkin, J. N. 1962. The mosquitoes of the South were made on the western coast even though Pacific (Diptera, Culicidae), vol. 1. Univ. Calif' comparable surveys were made on the eastern Press,Berkeley. coast. Black, R. H. 1972. Malaria in Australia, Australian Early observationson An. s.l. in Aus- Government Publishing Sewice, Canbera. farauti punntu- tralia indicated that it tended to concentrate Bryan, J. H. 19?3. Studies on the Anophzles by proboscis mor- but that it was an lotus complex. 1. Identification near human settlements, phologicalcriteria and by cross-matingexperiments. man opportunistic feeder which readily fed on Trans. R. Soc. Trop. Med. Hyg. 67:$4-69. and other animals with no particular preference Charlwood, J. D,, P. M. Graves and M. P. Alpers. between them (Mackerras 1947). The use of a 1986. The ecology of the Anopheles punctulatus helicopter in the present surveypermitted larval group of mosquitoes from Papua New Guinea: a and adult collections in very isolated areas far review of recent work. Papua New Guinea Med. J. from roads and permanent human dwellings. 29:19-26. Many of these areaswould be visited from time Daggy, R. H. 1945.The biology and seasonalcycle of to time by small numbers of people including Arnphelesfarauti on Espiritu Santo, New Hebrides. Am. 38:1-13. stockmen, prospectors and fisher- Ann. Entonol. Soc. aborigines, and A. R. Woodhill, 1944.The anopheline provide a Lee, D. J. men. Nevertheless, man would not mosquitoesof the Australasian region. University reliable sourceof blood meals for mosquitoesin of Sydney,Dept. of Zoology,Monograph no. 2' the majority of.An. farauti s.l. localities in this Liehne, P. F. S., N. F. Stanley,M. P. Alpers and C. survey. The 3 specieswere found biting man in G. Liehne. 19?6. Ord River arboviruses-the study an adult catch in a very isolated site near a site and mosquitoes.Aust. J. Exp. Biol. Med. Sci. tributary of the Archer River (site 23), but it 54:487-497. would appear that the primary blood sources Mackerras, I. M. 1947.The Australasian anophelines available in such places would be animals such as vectols of malaria. Med. J. Aust. 1:1-8. 1984. The status and means of identi- as cattle, feral pigs, birds and marsupials. Mahon, R. J. the membersof the Anoph.eles Laveran for fying farauti The implications of these observations complexof sibling species.pp. 152-156.In: Malaria. malaria epidemiology are not yet clear as the Proceedingsof a conferenceto honour Robert H. vectorial capacitiesofthe individual speciesare Black. Australian Government Publishing Service, not known. Nevertheless, the finding of all Canberra. members of the group far from human habita- Mahon, R. J. and P. M. Miethke. 1982. Anoph'elcs tions suggeststhat the malaria receptive area of farauti No.3, a hitherto unrecognized biological northern Australia is not restrictedto towns and species of mosquito within the taxon A. farauti settlements.There is the possibility of the dis- Laveran (Diptera: Culicidae). Trans. R. Soc. Trop. easebeing reestablishedif increasedtourism and Med. Hyg. 76:8-12. Marks, E. N. 1980.Mosquitoes (Diptera: Culicidae) of with the introduction mining activities, together Cape York Peninsula, Australia. pp. 59-76. .In: of gametocytecarriers, extend into formerly iso- N. C. Stevens and A. Bailey (eds.), Contemporary Iated areas. CapeYork Peninsula.Royal Societyof Queensland. Sweeney,A. W. 1980. Anophzlzs farauti No. 2 ae a possible vector of malaria in Australia. Trans. R. Soc.Trop. Med. Hyg. 74:830-831. Sweeney,A. W. 1987.Larval salinity tolerancesof the ACKNOWLEDGMENTS sibling speciesof Anophcl.esfarauti. J. Am. Mosq. Control Assoc.3:589-592. This paper is published with the approval of Taylor, R. W. 1972. Biogeographyof insects of New the Director General of Army Health Services. Guinea and Cape York Peninsula, pp.2L3-230. In: We wish to thank the members of 162 Recon- D. Walker (ed.), Bridge and barrier: the natural and naissanceSquadron, Australian Army Aviation cultural history of Torres Strait. Australian Na- Corps and 1 Preventive Medicine Company, tional University, Canberra.