DISTRIBUTION, BIOLOGYAND CONSERVATION STATUS OF THE PEPPERMINT STICK INSECT, MEGACRAN1A BATES/1(KIRBY) (PHASMATODEA: PHASMATIDAE), IN QUEENSLAND M. CERMAK ANDJ.W. HASENPUSCH Cermak, M.& Hasenpusch.J.W.2000 1231: Distribution,biologyandconservationstatus ofthepeppermintstick insect,Megacraniabatesii(Kirby)(Phasmatodea: Phasmatidae), in Queensland.MemoirsoftheQueenslandMuseum46(I): 1 1-106.Brisbane.ISSN0079-8835. Megacraniabalesiiwasstudied inthe WetTropicsregion ofnorth Queensland. Its natural history and distribution is reviewed and supplemented by observations in the field and in captivity. Surveysfoundasubstantial,sexually-reproducingpopulationatCapeTribulation inarangeofhabitats.ThreeparthenogenicpopulationssouthofCairnsareconfinedtosmall patches of habitat adjacent to beaches. The reliance of M. balesii on Pandanus was confirmedandtherangeofPandanusspecieseatenwasexpanded. Thespecies is underno immediate threat but fits the IUCN criteria for Vulnerable on the basis that its population occurs over an area of less than 100km" and could be further threatened if any one D subpopulation isextirpated. stickinsects, Phasmatodea. Megacrania. survey, Pandanus, parthenogenesis, conservation. Queensland. Australia. MichaelCermak(email: [email protected]), EnvironmentalProtectionAgency. 10-12McLeodStreet. Cairns4870(presentaddress:RainforestCRCJamesCookUniversity. Cairns Campus. Smithfield 4870): Jack W. Hasenpusch (email: australianinsectfarmia internetnorlh.com.au). AustralianInsectFarm. POBox26. Innisfail4860. Australia: 13July2000. The Peppermint Stick Insect, Megacrania femaleswereeverfoundattheselocalities.Rentz batesii(Kirby), is apoorly known phasmidthat, (1993)drawsattentiontothevulnerablestatusof in Australia, has a restricted and patchy dis- thespeciesinAustraliaandreferstotheEtty Bay tribution in tropical northeast Queensland population as being near 'Mackay' which is a (Franzmann, 1974; Rentz,1996) and the Sir lapseforInnisfail.NoM. batesiimaleshavebeen EdwardPellewIslandsintheGulfofCarpentaria foundsouthoftheDaintreeRiver,sothesouthern (Key, 1991;Rentz, 1996).Thisspeciesisthesole populations were assumed to be parthenogenic representative ofthe subfamily Platycraninae in (Rentz 1996). The same author firstrefers tothe Australia (Key, 1991; Rentz, 1996; Vickery, presenceofmales in somepopulations,notesthe 1983). Its type locality is the Solomon Islands peculiarlocomotionofthespeciesinwhichonly (Kirby, 1896) and this author also refers to the fore and mid legs are used, and records the museum specimens from Malayan and Papuan foodplant as Pandanus tectorius. Brock (1999) Giisllaonldos,,AAmrbuoainndaKeaindDuNleanw,GPuhiilniepap,intehso.uGgohraitmi,s palospoulmaetniotnisonoscctuhrataplaorntgheanofgeewniccoaastnadlbpiasretxsuaolf clearhehadreservationsabouttheconspecificity of some. Modern published records for Mega- NorthQueenslandand illustratestheeggs forthe first time. However he incorrectly describes its crania batesii outside Australia include the locomotion as involving only the fore and hind S19o8lo3m)oanndINsleanwdsG(uCihnieaa-C(hVianHsHueirnwga,a1r9d9e1n;,Vi1c9k9e8ry)., Mleeggs.acAralninieailblyustKreatyion(1i9s9g1i)veanndofcaonloAuurstprhaoltioan- The first Australian specimens of M. batesii graphs have been published by Rentz (1996), were collected at Etty Bay, north Queensland in Hughes (1996) and Brock(1999). 1971 and at Mission Beach in 1973 by Franz- mann (1974). This author also described the This study aims to determine the full extentof peppermint secretion which the species squirts the species' distribution in the wet tropics of from twogland openings ontheprothorax when North Queensland and to determine its disturbed,andillustratedthepositionofthegland conservation status. Observations of living openings. This secretion does not effect human specimens in the field and in captivity between skin (Franzmann, 1974) but irritatesthe eyes on 1991 and 1999 provided additional information contact (J. Seymour, pers. comm. Jan. 1999). onthebehaviourand defencemechanisms ofthe Franzman (1974) also commented that only species. 102 MEMOIRS OF THE QUEENSLAND MUSEUM MATERIALS AND METHODS Field surveys were conducted between %. DonovanRange November 1998andFebruary 1999. Preliminary MtSorrow_AAECmamPaegenCk surveys confirmed the presence ofM. batesii at Tribulation CapeTribulation,EttyBayandBingilBay(north ofMission Beach) ( Fig. 1). Subsequent surveys ' ~^^^^CaSpneapKpiemrbeIrsley were conducted to determine the limits to those three populations, and to identify other suitable MOSSMANoC areas containing Pandanus plants along the Wet Tropics coast. Surveys were conducted by searching for ^vBuchanPoint partiallydefoliatedPandanusplantseitherfroma \PalmCove wveahsicrleecoorrdoendfuopoot.nPcrleosseenecxea/maibnsaetnicoenoofftMh.ebpaltaenstsi.i CAIRNSf^l[f)/^-JA 17°00'S Chew marks caused by other insects feeding on Pandanus were recorded for comparison and a collection of Pandanus eating insects was compiled for future reference. Survey sites were chosen by examining char- %%BrBaemascthon acteristicsofknown sitesandchoosinglocations with broadly similar characteristics. In some INNISFAILoLHyBay areasalongthecoastnorthoftheDaintree River, access was difficult. In these situations, surveys were conducted by searchingtransects alongthe iBingilBay CapeTribulationroadandcoastal beaches; ifM. fClumpPoint batesii were found then transects were walked TULLYo :| perpendiculartothebeachand/ortheroad.These LfTtllllli-lo-srlc perpendiculartransectswere ofno setlengthbut ^P PositiveSurveyAreas werMeterminated 100mbeyondthelastoccurrence of batesii.Someareasofthecoastline(e.g.the CARDWELL6y northern aspectofCape Kimberley)weretotally NegativeSurveyAreas inaccessible so were not surveyed. However all other accessible areas containing Pandanus FIG. I. Map of part of the Wet Tropics region of between Donovan Range in the north and Tully Queensland showing distribution of Megacrania Headsinthesouth (Fig. 1)were surveyed. Some bbaltaecski.iA(rKeiarsby)s.urvPeryeesde,ncbeutofwhcioclhonpiersoveisdsnhegoawtnivei,n areas of coast between the Daintree River and areshownstippled. Bramston Beach were deemed unsuitable for Megacrania because ofthe lackofPandanus or The length and width ofeggs collected from of suitable forest type. Proposed survey in the Cape Tribulation, Etty Bay and Bingil Bay Yarrabahregion,southofCairns(whichcontains populations (sample size range 9-13) were suitable habitats) was not possible. Forest types measured using Vernier calipers. Width was Tsruarcveeyye&d Wweerbebc(h1a9r7a5c)tearnidseTdraocneyth(e19c8r7i)te.ria of rceogmrpeasrseeddaigfafienrsetncleesngatmhownhgicphopwulaastitohnesn uussiendgtao Observationsofbehaviourandpredationwere one-way ANOVA. InJuly, whennewlyemerged conducted opportunistically while surveying the nymphswereabundant,wecountedallM. batesii distribution of M. batesii. Feeding and mating feedingon40Pandanusplantsandcalculatedthe trials were conducted in the laboratory by average number of individuals supported by a introducing the insects onto different species of single plant. Pandanus and Freycinetia. RESULTS AND DISCUSSION Body length measurements were obtained from a sample of 10 adult males from Cape DISTRIBUTION AND HABITAT. Megacrania Tribulation and 14 adult females (7 from Cape batesii was found at five locations from Cape Tribulationand 7 from Etty Bay). TribulationtoClumpPoint(Fig. 1,Table 1). The CONSERVATION OF MEGACRAN1A 103 to sea water spray, particularly during windy conditions at high tide, suggesting a high tolerance ofsalt. The natural populations ofMegacrania lie in high rainfall foci where annual rainfall exceeds 3000mm and driest quarter exceeds 160mm (Rainforest CRC, 1998). The presumably intro- ducedcolony in Cairns liesoutsidetheserainfall levels. FOOD PLANTS. During the survey, we observed M. batesii feeding on three species of Pandanus in the wild, P. tectorius Parkinson, P. monticola F.v.Muell. and P. soloms-laubachii F.v.MuelL In captivity, M. batesii fed on two other native species (P. whitei Martelli, and P. gemmifer John) neither of which occur in the FIG. 2. Feeding marks on leaves ofPane/amis; A, naturalrangeofthephasmid. Italsoacceptedthe caused by Megacrania batesii; B, caused by the related climbing genus, Freycinetia, and the katydid,Austrosalomonasp. exotic species, Pandanus utilis. AtClump Point, Megacraniawas recorded on Cape Tribulation population is confined to an P. tectorius(the onlyPandanus species present), areabetweenthe Daintree River in the southand whileatBingilBayandEttyBayMegacraniafed EmmagenCreekinthenorth.M. batesiioccurin on both P. tectorius and P. monticola. At Cape PandanusMbeside all types ofshore line in this Tribulation, the phasmids utilised three species, area.No batesiiwerefoundonSnapperIsland P. tectorius, P. monticola and P. soloms- orinsuitablehabitatwiththehostplantalongthe laubachii. coastlinebetweentheDaintreeRiverandCairns. The feeding scars caused by M. batesii are Four separate populations ofM. batesii were readilydistinguished from thoseofthefewother found south oftheDaintree River. The Etty Bay insects that eat Pandanus. Typically, M. batesii populationwaslocatedatthesouthernendofthe bites into the leaf on a slight angle from the beach and on the eastern aspect ofthe adjacent margin towards the mid rib and then proceeds coastal range. Extensive searches north, south longitudinally,backtothemargin(Figs2A,3B). and inland of this area failed to locate any By comparison the feedingscarsoforthopterans Megacrania. The Bingil Bay population, 30km (/h(s/rasa/GW7c>«a,Tettigoniidae) tendto be more to the south ofEtty Bay, occurs over an area of circular (Fig. 2B). The chewing patterns were 3ha extending 1.5km along the beach and 20m used to detect M. batesii, particularly on tall, inlandtotheeasternedgeoftheClumpMountain inaccessible plants. The first and second instar National Park and North Bingil Bay. A further nymphswere foundonyounggrowthofthefood 2.3km south of Bingil Bay, the Clump Point plant, while adults mainly feed on older leaves. population occurs over an even smaller area of about 100m2 A small population ofM. batesii DENSITY. Census of 40 occupied Pandanus wasalso loca.tedinthe Cairns Central Swamp in plants in the field at Etty Bay and Bingil Bay thesuburbofManundawithintheCityofCairns. revealed that a single leaf cluster typically cHaopwteivveesrbtyhisinpsreocbtasbleynthreussuilatsstsfrionmCraeilrenasses(Mo.f 2s.u3p,poSrEted0.119t7o).5 nWyemprhescoorfdeidnstnaorsm1otroe3t(hmaenan3 Trenerry, pers. comm. Jan. 1999). adults per leaf cluster but M. Trenerry (pers. M comm. 1999) reported up to 10 adults and sub- South of Cairns, batesii appears to be adults on one leaf cluster at Etty Bay. Heavy restricted to areaswhere rainforests are adjacent feedingdamagetoayoungplantis shown in Fig. to beaches. AtCapeTribulation, however, itwas 3D. recordedbesiderainforeststreamsorswampsup to 5km inland and at up to 300m altitude on Mt REPRODUCTION AND DEVELOPMENT. Sorrow. The phasmids frequently inhabit The Cape Tribulation population contains both Pandanusgrowingontheseawardedgeofbeach males and females, while the southern pop- vegetation. These plants are regularly subjected ulations appeartoreproduceby parthenogenesis 104 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 3.Megacraniabatesii. A,activeadult 9 on Pandanus leaf(CapeTribulation); B,resting 9 andlastinstar nymph on Pandanus leaf-note position oflegs and feeding marks on leafmargins; note colour pattern of nymph(EttyBay);C,eggs(EttyBay);D,severephasmidfeedingdamagetoajuvenilePandanusplant(Cooper Creek, Daintree). given thatno males were everobserved. Several leaves ofthe host plant. The eggs often rolled males from Cape Tribulation readily mated with downintothespiralcentreofthePandanusplant, females from Etty Bay in the laboratory, but the wherethey wereeventually coveredandsecured resultanteggs did not hatch. by frass from feeding adults. In time, a fungal Megacrania batesiiappears to have an annual growthcementedthefrassintoasolidmassinthe life cycle. In the field at Cape Tribulation eggs axils. Examination of four medium sized were released from November to April and Pandanus leafclusters revealed a mean of27.3 hatched from July to December. Adults then eggs trapped withinthe foliage ofeachplant. peakedfromDecembertoMarch.ByJuly 1999at There was a significant correlation between thesamelocalitytherewereabundantnymphsof egg length and width (R=0.495, p=0.003), so all instars but an almost total absence ofadults. only length data were used in further analysis. However, during subsequent observations at Egas are very large, varying in length from CapeTribulationinJuly2000,Megacraniawere 7.1-8.15mm(mode7.79-7.91mm:39.4%).There abundant in all developmental stages including were no differences in egg length between adults. populations(ANOVA,F=l.2,df=2,p=0.32),and theeggsappearedtohaveidentical sculpturation Eggs are shown in Fig. 3C. Incaptivity, parth- enogenic females from Etty Bay produced and colour. between 60 to 70 eggs in their lifetime. Unlike Mean body length of females at Etty Bay many phasmids, Megacrania do not throw their (111.0mm ± 0.95, n=7) was not significantly eggs with a flick ofthe abdomen at the moment different to that offemales at Cape Tribulation they arereleased. The relatively large eggs were (106.9mm ± 1.22, n=7; T=2.65, 0.02<p<0.05, dropped haphazardly to the ground or on to the df=12), but these were longer than males CONSERVATION OF MEGACRANIA 105 TABLE 1. Geographical locations and classification of forest types (Tracey & Webb 1975) inhabited by Megacrania batesii. Location Foresttype Description Coordinates CapeTribulation la ComplexMesophyllVineForest 16°02,>16°14,30,,S, 14525'>145o28'25"E CapeTribulation 2a MesophyllVineForest 16°02'>16°14*30"S, i4525'>145°28'25"E CapeTribulation 17 CoastalBeachRidgesandSwales 16°02'>16°14'30"S, 145°25,>145°28'25"E CapeTribulation 13a VineForest 16°02- '16°14'30"S, 145°25' 145°28,25"E CapeTribulation 13d VineForest 16°02- i6l,14'3(TS, 145°25*>145°28*25"E EttyBay 2a MesophyllVineForest 16°34"S, I46°05'30"E BingilBay 2b MesophyllVineForest 17°49"45">I7U50,15"S, I46°05,40"=146°06"F: Clump Point 2b MesophyllVineForest I6"51*25"S. 146°07'E CairnsC.Swamp FringingMesophyllVineForestSwamp 161,55'S, 145"45"l (75.3mm ± 0.96, n 10; T=1.96, 0.01<p<0.05, Blattaria, Hemiptera, Flomoptera, Lepidoptera, df=15). Mantodea,Neuroptera.OrthopteraandPhasmida (Gibson, 1995). A total of 56 wasps emerged BEHAVIOUR. Adults andnymphs ofM. balesii from5 M. batesiieggsinJuly 1999( range: 8-15, restwithin the deep groove on the uppersurface sex ratio: 1 male/6 females). ofPandamis leaves, or on the underside. They adopt a distinctive posture with front and mid CONSERVATION. Megacrania batesii in north legs stretched forward and hind legs directed Queenslandhassofarbeenfoundtooccurinfive backwards (Fig. 3B). While feeding, they isolated populations inhumidcoastal habitats on assumed a position along the leaf margin and the eastern aspect of the coastal escarpment whendisturbed,shuttledbackwardstothecentre between Mission Beach in the south and ofthe plant using only their front and mid legs. Emmagen Creekjust north ofCape Tribulation. Thoughboth sexesarewinged,M. batesiidonot Even if Megacrania existed in those few fly. The males, being more gracile and having inaccessible areas between Daintree River and longer wings, are capable ofparachuting to the EmmagenCreekthatweretoodifficulttosurvey, ground when disturbed. Females do not attempt they would still be located well within the Cape to flyatall. Tribulationpopulation boundaries. UnderIUCN Most of the stages of M. batesii are well criteria the species would meet the criteria for camouflaged on the green foliage. However, the Vulnerable: D2 because their range is restricted last nymphal instar is quite conspicuous with to less than 100km" and could be endangered if most individuals being bright blue-green with any ofthepopulations are extirpated. dark segmental margins, yellow, red and black TheCapeTribulationpopulation,inparticular, eyes,andredantennaeandwingbuds(Fig3B). is under no threat because ofthe abundance of suitable habitat and because the core of the PREDATORS. The following predators were population is essentially protected within the observedfeedingonM. batesii:huntsmanspiders Cape Tribulation National Park. The Etty Bay (Sparassidae), jumping spiders (Salticidae), population appears to be relatively secure as it centipedes (Scolopendrida), green tree ants occurswithintheJohnstoneShire'sConservation (Oecopliy/la smaragdina FabriciusJ. praying Area and is also situated within the Wet Tropics mantids (Hierodula majuscula Tindale), World Heritage Area. The Bingil Bay, Clump katydids(Tettigoniidae)andBlackButcherBirds PointandCairns Central Swamppopulationsare (CracticusquoyiLesson). distributed over very small areas and therefore PARASITES. Some eggs from all three sub- are ofsomeconservation concern. populations were parasitised by a species of To fullyevaluatetheconservation statusofthe DNA chalcidoid wasp, Anastatus sp (Eupelmidae: species, assay ofthe existing populations Eupelminae), identified by Dr Chris Burwell of would be very valuable. This would not only the Queensland Museum. These gregarious determinewhetherthefourpopulationscomprise endoparasitoidshavebrachypterous femalesand a homogenous species or more than one macropterous males. Anastatus are primary taxonomicunit,butwouldalsoshedlightontheir parasitoids ofawidevariety ofinsects including geographic relationships. Ifgenetic differences 106 MEMOIRS OF THE QUEENSLAND MUSEUM betweenthe five M. bateslipopulations is small, Entomological Society of Queensland 2(5): then we can assume that the species is more 63-64. mobile than we suspect, and therefore presents HUGHES,L. 1996.Whenaninsectismorelikeaplant. littleconservation concern. However, ifthepop- NatureAustraliaAutumn 1996: 30-38. ulations are genetically distinct, then they may KEY, K.H.L. 1991. Phasmatodea (Stick-insects). Pp. 394-404. In CSIRO. Insects of Australia, 2nd rmeapnraesgeenmtendetclsihnoiunlgdrbeemnaapnptlsieda.ndDcNoAnsearnvaaltyisoins eMdenl.b,ouvronle.).1. (Melbourne University Press: would also shed light on whether the Cairns KIRBY,W.F. 1896.OnsomeneworrarePhasmidaein Central Swamp population is introduced and, if the collection ofthe British Museum. Transact- so, from where. ionsoftheLinneanSocietyofLondon6:471-472. ACKNOWLEDGEMENTS RAINFORESTCRC 1998.Rainfall intheWetTropics Poster. (RainforestCRC: Cairns). We thank the Environmental Protection RENTZ, D.C.F. 1993. Orthopteroid insects in threat- Agency, Queensland Parks and Wildlife Service ened habitats inAustralia. InGaston, K.J., New, for recognising the importance of invertebrate T.R.&Samways,M.J.(eds)Perspectivesininsect fauna inthe Wet Tropics and for supporting this conservation(Intercept: Andover, Hampshire). project. We also thank Mike Trenerry, Leasie 1996. Grasshopper country. The abundant Helderhof, Dr Andrew Dennis, Dr Jamie NoretwhopStoeurtohidWainlseesctPsreosfs:AuSstyrdanleiya)..(University of Seymour,DrStephenGarnett,AndrewSmalland TRACEY, J.G. 1982. The vegetation of the humid Lyle Naylorfortheir contributions andhelp, the tropical region of north Queensland. (CSIRO: Marine Parks personnel for their help to access Melbourne). Snapper Island, and Dr Chris Burwell for TRACEY,J.G. & WEBB, L.J. 1975.Thevegetationof identifyingtheparasitic wasp. the humid tropical region ofnorth Queensland. LITERATURE CITED (15 maps at 1:100 000 scale and key.) (CSIRO: Indooroopilly,Queensland). BROCK, P.D. 1999. The amazing world ofstick and VAN HERWAARDEN, H.C.M. 1998. A guide to the leaf-insects. The Amateur Entomologist 26: genera of stick- and leaf-insects (Insecta: 1-165. M Phasmida) ofNew Guinea and the surrounding CHIA-CHI HSUING 1991. The identity of batesii islands. Science inNewGuinea24(2). species ofTaiwan (Cheleutoptera: Phasmatidae) VICKERY, V.R. 1983. Catalogue ofAustralian stick Oriental Insects25: 171-177. insects(Phasmida, Phasmatodea,Phasmatoptera, FRANZMAN, B.A. 1974. A new subfamily of the or Cheleutoptera). Division of Entomology, PhasmatodeafromAustralia.NewsBulletinofthe CSIRO, Melbourne. Technical PaperNo.20.